Amendments To Rules For Ships Parts A To F EIF 1.7.2024

Amendments to the “RINA Rules for the Classification of Ships”
Effective from 1/7/2024
Reasons of the amendments
Part A – Classification and Surveys

Chapter/Section/Paragraph Reason
amended
Ch 1, Sec 2, [4.2.1], [4.2.15], to clarify the requirements for the additional service feature “BC”
[4.2.16] (eliminating confusing references to the additional service feature “BC Ch
XII”) and to allow the owner to request the assignment of the service
notation “bulk carrier ch xii” in lieu of the service notation “general cargo
ship” with service feature “BC Ch XII” (Prop. 252)
Ch 1, Sec 2, [4.5.2] to introduce IACS UR Z10.1 (Rev.25 - Feb 2023) “Hull Surveys of Oil
Ch 4, Sec 3, [6.5.1] Tankers”
Ch 2, Sec 2, [2.2.2] to introduce IACS UR Z10.2 (Rev.37 - Feb 2023) “Hull Surveys of Bulk
Ch 4, Sec 2, [3.2.1], [4.2.5] Carriers”
Ch 2, Sec 2, [2.2.2] to introduce IACS UR Z10.5 (Rev.20 - Feb 2023) “Hull Surveys of double
Ch 4, Sec 9, [1.2.3], [2.7](new), skin bulk carriers”
[3.2.1], [4.2.5], [4.2.8](new),
Tab 15(new)
Ch 2, Sec 2, [2.2.18], [2.2.20] to introduce IACS UR Z10.4 (Rev.18 - Feb 2023) “Hull Surveys of Double
Ch 4, Sec 4, [4.5.1] Hull Oil Tankers”
Ch 3, Sec 2, [1.1.2] to introduce IACS UR PR1A (Rev.9 - Aug 2023) “Procedure for Transfer
of Class”
Ch 4, Sec 5, [1.2.3] to introduce IACS UR Z10.3 (Rev.21 - Aug 2023) “Hull Surveys of
Chemical Tankers”
Part B - Hull and Stability

amended
Ch 1, Sec 3, Tab 1 to introduce IACS UR A1 (Rev.8 - June 2023) “Anchoring Equipment”
Ch 10, Sec 4, [1.1.4](new),
[1.1.5](new),[1.1.6](new),
[1.1.7](new),[1.1.8](new),
[2.1.4](new), [3.3.5]
Ch 7, Sec 5, New to introduce IACS UR S35 (New - Feb 2023) “Buckling Strength
Assessment of Ship Structural Elements”; and
to specify that, until the next revision of IACS UR S11 “Longitudinal
Strength Standard”, the applicable buckling requirements for hull girder
strength prescriptive analysis remain those reflecting UR S11 (Rev.10) in:
 Ch 6 and Ch 7, Sec 1 for plates;
 Ch 7, Sec 2 for ordinary stiffeners; and
 Ch 7, Sec 3 for primary supporting members
while the new requirements in Ch 7, Sec 5, [3] - reflecting section 3 of new
IACS UR S35 - are to be considered for information only, to avoid conflicts
with the requirements in UR S11 (Rev.10) and be in line with para. 1.1.1
of UR S35, which specifies that UR S35 is to be applied only in conjunction
with UR S21 for hatch cover structures (i.e. Rev.6 of UR S21 also in force
from 1 July 2024).
Ch 9, Sec 4, Tab 5 to introduce IACS UR S3 (Rev.2 - June 2023) “Strength of End Bulkheads
of Superstructures and Deckhouses”:
by adapting the UR S3 formula of the minimum thickness of plating to the
symbols used in RINA Rules, where the ship’s scantling length “L” is used
(not the ship’s length “L1” as defined in UR S3); and
by specifying that for ship’s scantling length less than 65m the alternative
less conservative formula of UR S3 can be used.
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Ch 9, Sec 7, Symbols, [1.1.1], to introduce IACS UR S21 (Rev.6 - Jan 2023) “Evaluation of Scantlings of
[1.2](new), [1.2.1](renumbered Hatch Covers and Hatch Coamings and Closing Arrangements of Cargo
1.3.1), [1.4](new), Holds of Ships” (previously applicable only to Bulk Carriers, Ore Carriers
[1.3.1](renumbered 1.5.1), and Combination Carriers and now applicable all types of ships due to a
[1.4.2](renumbered 1.6.2), Tab complete revision to update the requirements and incorporate IACS UR
1 ("paper carriers" in Tab 8 of S21A - applicable to all ships except Bulk Carriers, Ore Carriers and
UR S21 not included as RINA Combination Carriers - that was consequently deleted)*;
has no this service notation), to provide an indication (last sentence of Pt B, Ch 9, Sec 7, [4.2.3]) on the
[2.2.2] and [2.2.3](deleted as it technical considerations to be made to determine, case by case, the
duplicates [1.4]), thickness of the lower plating when the lower plating is not considered as
[2.2.4](deleted as it duplicates a strength member of the hatch cover (left to individual class society’s
[4.6.2]), [2.3.6] to [2.3.9](new*), rules in para. 3.2.2 of UR S21 (Rev.6)); and
[3.1.1](new), to require a proportion check for the flange outstand of the primary
[3.1.1](renumbered 3.2.1), Tab supporting members (last sentence of Pt B, Ch 9, Sec 7, [4.4.1]) - taken
2, [3.2.1](renumbered 3.3.1), from Pt B, Ch 7, Sec 3 - to complement the requirements for primary
Tab 3, [3.3.2](new), supporting members
[3.3.1](renumbered 3.4.1),
[3.4.1](renumbered 3.5.1), * Some requirements previously in Pt E, Ch 4 “Bulk Carriers”; Pt E, Ch 5
[3.4.2](renumbered 3.5.2), “Ore Carriers”; and Pt E, Ch 6 “Combination Carriers” have been moved
[3.4.3](renumbered 3.5.3), to Pt B, Ch 9, Sec 7 (applicable to all ships), as follows:
[4.1.1], Tab 5(new), [4.1.2], - in [2.3.6] to [2.3.9], the requirements previously in:
[4.2.1], [4.2.3], [4.3.1], [4.4.1], o Pt E, Ch 4, Sec 3, [9.6.1]
[4.4.2], [4.5.1], [4.5.2](deleted), o Pt E, Ch 5, Sec 3, [6.6.1]
[4.5.3](renumbered 4.5.2), Fig o Pt E, Ch 6, Sec 3, [9.6.1]
5(new), Tab 5(deleted), [4.6.1], - in [7.1.2] to [7.1.4], the requirements previously in:
Fig 5(deleted), Tab 6(deleted), o Pt E, Ch 4, Sec 3, [9.7.4] to [9.7.6]
Tab 7(deleted), [4.6.2], [4.6.3], o Pt E, Ch 5, Sec 3, [6.7.4] to [6.7.6]
Tab 6(new), Tab 7(new), Fig o Pt E, Ch 6, Sec 3, [9.7.4] to [9.7.6]
6(new), Fig 7(new), Tab
8(deleted), [4.6.4] to [4.6.7]
deleted, Fig 6 to Fig 8(deleted),
[5.2.1], [5.2.2](deleted),
[5.2.3](renumbered 5.2.2), Tab
9(deleted), [5.2.4](renumbered
5.2.3), [6.1.1], [6.2.1], [6.3.2],
Fig 10(renumbered 9),
[7.1.1](deleted text covered in
7.1.5), [7.1.2]*, [7.1.3]*,
[7.1.4](new*),
[7.1.4](renumbered 7.1.5),
[7.1.5](renumbered 7.1.6), Fig
11 and Fig 12(deleted), [7.2.1],
[7.2.2], Tab 10(renumbered 8),
[7.2.3] and other editorial
corrections
Ch 9, Sec 7, [9.1.1] to introduce IACS UR S26 (Rev.5 - May 2023) “Strength and Securing of
Small Hatches on the Exposed Fore Deck”
Ch 10, Sec 1, Symbols, to introduce IACS UR S10 (Rev.7 - Feb 2023, Corr.1 - June 2023 and
[1.1.5](new), [1.3.3], [1.5.3], Corr.2 – May 2024) “Rudders, sole pieces and rudder horns”
Fig 1 (new), [4.2.2], [5.3.2],
[5.4.3], [6.2.4], [6.4.5], Fig 9
(new), [7.3.1], [8.4.2], Figures
renumbered
Ch 10, App 1, [1.2.2], Fig 1,
[1.3.2], Fig 2(deleted), Fig
2(new), Fig 3(new), [1.7.2],
Figures renumbered
Ch 10, Sec 4, [1.2.3], [3.5.5], to eliminate specific requirements for synthetic fibre wires as IACS Rec
[3.5.7](deleted) 10 (Rev.5 - June 2023) “Chain Anchoring, Mooring and Towing
Ch 10, App 4, (new) Equipment” requires (in para. 2.1) that the line design break force (LDBF)
of a line be 100%-105% of the ship design minimum breaking load, for
wires made of all types of materials, without making any difference
between steel wires/natural fibre ropes and synthetic fibre wires
Part C - Machinery, Systems and Fire Protection
amended
Ch 1, Sec 2, [1.1.1] to introduce IACS UR M82 (New - Mar 2023) “Type Testing Procedure of
Ch 1, App 17(new) Explosion Relief Devices for Combustion Air Inlet and Exhaust Gas
Manifolds of I.C. Engines Using Gas as Fuel”
Ch 1, Sec 2, Tab 8 to introduce IACS UR M72 (Rev.3 - Apr 2023) “Certification of Engine
Components”
Ch 1, Sec 10, [8.8.1] and Tab to clarify the source of Figure 3: Overboard discharge arrangement; and
22(deleted) to eliminate “Table 22: Thickness of scupper and discharge pipes led to
the shell, according to their location” as its contents are already covered
by “Figure 3: Overboard discharge arrangement” and “Table 23:
Thickness of scupper and discharge pipes led to the shell” and it included
references to paragraphs deleted in 2017 when Fig.3 was introduced
(Prop 255)
Ch 1, Sec 10, [11.6.1], [11.8.3], to update some requirements for fuel oil treatment systems that are based
[11.9.3], [11.10.1], [11.10.4] on IACS Rec 151, following the publication of Rec 151 (Rev 2 - Nov 2023)
Ch 1, Sec 10, [20.7.2], to introduce IACS UR M81 (Rev.1 - July 2023) “Safety measures against
[20.7.3](new) chemical treatment fluids used for exhaust gas cleaning systems and the
residues which have hazardous properties”
Ch 1, Sec 14, [2.3.3], [3.1.3], to introduce IACS UR M73 (Rev.2 - May 2023) “Turbochargers”
[3.2.2], [3.4.1]
Ch 1, App 1, [10.4.3] to introduce IACS UR M53 (Rev.5 - May 2023) “Calculations for I.C.
Engine Crankshafts”
Ch 2, Sec 3, Tab 4 to Tab 10 to update the tables on maximum rated conductor temperature (Tab. 4),
Ch 3, Sec 2, [2.1.1] current carrying capacity for continuous service of cables (Tab 5 to Tab 9)
and correction factors applicable to the current carrying capacity in Tab 5
to Tab 9 when the actual ambient temperature obviously differs from 45°C
(Tab 10) in line with the latest edition of IEC 60092-352; and
to correct a typo
(Prop 246)
Ch 2, Sec 8, [1.2.3], [1.2.6] to update two references to an IEC standard for switchgear and control
gear assemblies (IEC 60092-302 has been replaced by IEC 60092-302-
2, which has already led to improvements to RINA requirements since 1
January 2021, even if these two references were inadvertently left
unchanged at that time)
Part D – Materials and Welding

amended
Ch 2, Sec 1, Tab 34, [11.4.3], to introduce IACS UR W31 (Rev.3 - Mar 2023) “YP47 Steels and Brittle
[11.5.1], [11.5.2] Crack Arrest Steels”
Ch 2, App 4, [1.1.1](deleted),
[1.2.1], [1.3](deleted), [2.1.1],
[2.2](deleted), [2.3](deleted),
[3] to [7](deleted),
[8.1.1](renumbered 3.1.1),
[8.2](deleted),
[8.3.1](renumbered 3.2.1),
[9](deleted)
Ch 2, App 5, [1.1.3], [1.2.1],
[2.1.4], [3.1.1], Tab 1, [3.2.1],
[3.4.4], [3.5.1], [3.6.1], [4.2.4],
[4.2.5](new), [4.3.2], [6.1.1]
Ch 2, App 6(new)
Ch 4, Sec 1, [5.3.1], [5.4.4] to introduce IACS Rec 10 (Rev.5 - June 2023) “Chain Anchoring, Mooring
and Towing Equipment”; and
to eliminate specific requirements for synthetic fibre wires as Rec 10
(Rev.5) requires (in para. 2.1) that the line design break force (LDBF) of a
line be 100%-105% of the ship design minimum breaking load, for wires
made of all types of materials, without making any difference between
steel wires/natural fibre ropes and synthetic fibre wires
Part E – Service Notations
amended
Ch 4, Sec 3, [9.1.1] and to replace the structural requirements for hatch covers, hatch coamings
deletion of other paragraphs in and closing devices of bulk carriers (in Ch 4, Sec 3, [9]), ore carriers (in
[9] Ch 5, Sec 3, [6]) and combination carriers (in Ch 6, Sec 3, [9]) with a
Ch 5, Sec 3, [6.1.1] and reference to those applicable to all ship types included in Pt B, Ch 9, Sec
deletion of other paragraphs in 7 due to the introduction of IACS UR S21 (Rev.6 - Jan 2023) “Evaluation
[6] of Scantlings of Hatch Covers and Hatch Coamings and Closing
Ch 6, Sec 3, [9.1.1] and Arrangements of Cargo Holds of Ships”
deletion of other paragraphs in
[9]
Ch 11, Sec 3, [1.1.3], [1.1.6] to tighten the criteria for accepting the use of movable obstacles (chains,
railings or similar devices) during navigation to avoid crowding of
passengers on one side of the ship, to be able to board a greater number
of passengers while continuing to remain within the maximum heeling
angle values not to be exceeded; and
to improve the wording of some requirements on crowding of passengers
and correct erroneous cross references
(Prop 259)
Ch 11, Sec 3, [8.3.2], [8.6.1], to better clarify the application of the formula for calculating the minimum
[8.7.1] thickness of balustrade glasses in passenger ships; and
to specify that, in the absence of direct calculations, the glass supporting
structures can only be accepted upon issuance of Type Approval
Certificate (TA) based on testing
(Prop 244)
Ch 13, Sec 2, [12.1.6](new) to introduce IACS UR A1 (Rev.8 - June 2023) “Anchoring Equipment”
Ch 14, Sec 2, [2.7.5](new)
Ch 14, Sec 2, [2.7.1] to align the formula to calculate the equipment number for tugs with
unrestricted navigation with the one in A1.3.1 of IACS UR A1 “Anchoring
Equipment” (Prop 254)
Ch 19, Sec 2, [6.1.1](new) to exempt barges, pontoons and barge-shaped assisted propelled units
of less than 100 m in length from the application of the requirements
related to the bottom impact pressure, when a reduction of the speed is
provided in relation with the sea state to avoid bottom impact pressure for
flat bottom area (Prop 251)
Ch 25, Sec 1, [1.1.1] to correct an error in the name of a service notation
Part F – Additional Class Notations

amended
Ch 3, Sec 1, Tab 3 to correct a typo in Table 3 “Monitored parameter for main propulsion trunk
piston diesel engine” of the requirements for the assignment of the
Unattended machinery Spaces (AUT-UMS) additional class notation
Ch 4, Sec 1, [1.3.2] to update the list of international standards applicable to a centralized
Ch 13, Sec 35, [2.1.1], [3.1.1] navigation control system for the assignment of SYS-NEQ additional class
notation, in line with updated editions of some IEC standards; and
to correct typos in the requirements for the assignment of NH3 FUELLED
READY additional class notation
(Prop 246)
Ch 9, Sec 3, [2.6.2] to correct - due to an editorial oversight - a coefficient to reflect the
Finnish-Swedish Ice Class Rules
Ch 10, Sec 3, [1.1.1], to introduce IACS UR I3 (Rev.2 - Jan 2023) “Machinery Requirements for
[1.2.1](new), Polar Class Ships”, with the following corrections/integrations:
[1.2.1](renumbered 1.2.2),  the formula of the immersion function f in [4.3.9] has been corrected
[1.2.2](renumbered 1.2.3), in line with the one for the ICE CLASS additional class notation in Pt
[1.2.3](renumbered 1.2.4), F, Ch 9, Sec 3, [2.5.2], i)
[1.3.1](deleted),  the definition of E0 (number of ice blocks in contact) has been
[1.3.2](renumbered 1.3.1), introduced in the requirements for frequency domain excitation in
[1.3.3](renumbered 1.3.2), [4.6.3], b)
[1.3.3](new), [1.3.4](new),  a wrong coefficient in the formula for calculation of ρ parameter for
[2.1.1](new), two-slope S-N curve in [5.3.3], b) has been corrected
[2.1.1](renumbered 2.2.1),
[2.2.1](renumbered 2.3.1),
[2.3.1](renumbered 2.4.1),
[3](new), Tab 1(new), Fig
1(new), [3.1.1](renumbered
4.1.1), [3.2.1](renumbered
4.2.1), Tab 1(renumbered Tab
2), [3.3.1](renumbered 4.3.1),
[3.3.2](renumbered 4.3.2),
[4.3.3] to [4.3.9](new), Tab 3
and Tab 4(moved under para
4), Fig 2(new), Tab 5(new),
[3.3.3] to [3.4.5](deleted),
[3.5](title - renumbered 4.4),
[3.5.1] and [3.5.2](deleted),
Tab 2(deleted),
[3.5.3](renumbered 4.4.1),
[4.4.2](new), Fig 3(new), [4.5]
to [4.7](new), Tab 6 to Tab
10(new), Fig 4(new),
[4.1.1](renumbered 5.1.1), [5.2]
to [5.5](new), Fig 5 to Fig
11(new), Tab 11 to Tab
14(new), [4.2.1](renumbered
5.6.1), [4.3] and [4.4](deleted),
[6](new), [5.1.1](renumbered
7.1.1), [5.2.1](renumbered
7.2.1), [6.1.2](renumbered
8.1.2), [7.1.1] to
[7.1.3](renumbered 9.1.1 to
9.1.3), [7.1.7](renumbered
9.1.7), [7.1.9](renumbered
9.1.9), [9.1.1](renumbered
11.1.1), [9.1.2](deleted),
[9.1.3](renumbered 11.1.2),
[12](new), Tab 15 to Tab
17(new), Fig 1(deleted), Fig 12
and Fig 13(new)
Ch 13, Sec 18, [2.1.1] to clarify that ships intended for the carriage of "cargoes which may
undergo dynamic separation" (as defined in ISMBC Code, as amended
by IMO Res. MSC.500(105)) and complying with the stability requirements
in Pt E, Ch 13, Sec 2, [1.1.2], are already in compliance with the stability
criteria for the assignment of IMSBC-A additional class notation as the
stability calculation required in Pt E, Ch 13, Sec 2 takes already into
account the shifting of cargo due to its total or partial liquefaction (Prop
247)
Pt A, Ch 1, Sec 2
SECTION 2 CLASSIFICATION NOTATIONS
1 General brackets does not form part of the classification notation

indicated in the Register of Ships and on the Certificate of
Classification):
1.1 Purpose of the classification notations
C HULL MACH
1.1.1 The classification notations give the scope according
(main class symbol, construction marks)
to which the class of the ship has been based and refer to
the specific rule requirements which are to be complied oil tanker-chemical tanker-ESP-Flash point > 60°C
with for their assignment. In particular, the classification (service notation and additional service features)
notations are assigned according to the type, service and
Unrestricted navigation
navigation of the ship and other criteria which have been
provided by the Interested Party, when applying for (navigation notation)
classification. SYS - NEQ
The Society may change the classification notations at any
(additional class notation).
time, when the information available shows that the
requested or already assigned notations are not suitable for
the intended service, navigation and any other criteria taken 2 Main class symbol
into account for classification.
Note 1: Reference should be made to Sec 1, [1.3] on the limits of 2.1 Main class symbol
classification and its meaning.
2.1.1 The main class symbol expresses the degree of
1.1.2 The classification notations assigned to a ship are
compliance of the ship with the rule requirements as
indicated on the Certificate of Classification, as well as in
regards its construction and maintenance. There is one
the Register of Ships published by the Society.
main class symbol, which is compulsory for every classed
1.1.3 (1/7/2008) ship.
Ships and units, other than those covered in Parts B, C, D, E
2.1.2 (1/1/2009)
and F, are to comply with specific Rules published by the
Society, which also stipulate the relevant classification The main class symbol C is assigned to ships built in
notations. accordance with the requirements of the Rules or other
rules recognised as equivalent, and maintained in a
1.1.4 The classification notations applicable to existing condition considered satisfactory by the Society. The period
ships conform to the Rules of the Society in force at the date of class (or interval between class renewal surveys) assigned
of assignment of class, as indicated in Ch 2, Sec 1. to a ship is maximum 5 years; see Ch 2, Sec 2, [4].
However, the classification notations of existing ships may Except for special cases, class is assigned to a ship only
be updated according to the current Rules, as far as when the hull, propulsion and auxiliary machinery
applicable. installations, and equipment providing essential services
have all been reviewed in relation to the requirements of
1.2 Types of notations assigned the Rules.
Note 1: The symbol C with the 5 year class period is to be
1.2.1 The types of classification notations assigned to a understood as being the highest class granted by the Society.
ship are the following:
Note 2: The symbol C may be followed by the additional
a) main class symbol construction feature light ship in case of ships or other units having
b) construction marks restricted navigation notations and generally having length not
greater than 50 m as well as speed greater than 15 knots, whose
c) service notations with additional service features, as hull scantlings and outfitting comply with the applicable
applicable requirements of Chapters 3 and 6 of the "Rules for the Classification
d) navigation notations of High Speed Craft", issued separately by the Society.
e) operating area notations (optional)

f) additional class notations (optional)
3 Construction marks
The different classification notations and their conditions of
assignment are listed in [2] to [6] below, according to their 3.1 General
types.
3.1.1 The construction mark identifies the procedure
1.2.2 As an example, the classification notations assigned under which the ship and its main equipment or
to a ship may be as follows (the kind of notation shown in arrangements have been surveyed for initial assignment of
RINA Rules 2024 41

Pt A, Ch 1, Sec 2
the class. The procedures under which the ship is assigned 4 Service notations
one of the construction marks are detailed in Ch 2, Sec 1.
4.1 General
3.1.2 One of the construction marks defined below is
assigned separately to the hull of the ship and its 4.1.1 The service notations define the type and/or service
appendages, to the machinery installation, and to some of the ship which have been considered for its
installations for which an additional classification notation classification, according to the request for classification
(see [6] below) is assigned. signed by the Interested Party. At least one service notation
The construction mark is placed before the symbol HULL is to be assigned to every classed ship.
for the hull, before the symbol MACH for the machinery Note 1: The service notations applicable to existing ships conform
installations, and before the additional class notation to the Rules of the Society in force at the date of assignment of
granted, when such a notation is eligible for a construction class. However, the service notations of existing ships may be
mark. updated according to the current Rules, as far as applicable, at the
request of the Interested Party.
When the same construction mark is assigned to both hull
4.1.2 (1/4/2006)
and machinery, the construction mark is assigned globally
to the ship without indication HULL and MACH after the The assignment of any service notation to a new ship is
main class symbol. subject to compliance with general Rule requirements laid
down in Part B, Part C and Part D of the Rules and, for some
If the ship has no machinery installations covered by service notations, the additional requirements laid down in
classification, the symbol MACH is not granted and the Part E and in the Common Structural Rules for bulk carriers
construction mark will be placed before the symbol HULL. and double hull oil tankers.
3.1.3 The construction marks refer to the original 4.1.3 A ship may be assigned several different service
condition of the ship. However, the Society may change the notations. In such case, the specific rule requirements
construction mark where the ship is subjected to repairs, applicable to each service notation are to be complied
conversion or alterations. with. However, if there is any conflict in the application of
the requirements applicable to different service notations,
the Society reserves the right to apply the most appropriate
3.2 List of construction marks requirements or to refuse the assignment of one of the
requested service notations.
3.2.1 The mark  is assigned to the relevant part of the
4.1.4 (1/7/2013)
ship, when it has been surveyed by the Society during its
construction in compliance with the new building A service notation may be completed by one or more
procedure detailed in Ch 2, Sec 1, [2.1]. additional service features, giving further precision
regarding the type of service of the ship, for which specific
3.2.2 (1/7/2011) rule requirements are applied.
The mark  is assigned to the relevant part of the ship, For each service notation, the different service features
when the latter is classed after construction in compliance which may be assigned are indicated in this item [4].
with the procedure detailed in Ch 2, Sec 1, [3.2] and it was However, at the request of the Interested Parties, an
built under the survey of a QSCS Classification Society and additional service feature may be assigned together with
was assigned by this Society a class deemed equivalent to service notations different from those for which the
that described in the Rules. additional service feature is specifically foreseen in this item
[4], upon acceptance of the Society, taking into account the
This mark is assigned to ships: service of the ship for which the assignment of the
a) admitted to class in the course of construction surveyed additional service feature is required.
by another QSCS Classification Society; 4.1.5 (1/7/2009)
b) for which the procedure detailed in Ch 2, Sec 1, [3.2] The different service notations which may be assigned to a
does not apply, as it was disclassed from a QSCS ship are listed in [4.2] to [4.12], according to the category
Classification Society for a period longer than six to which they belong. These service notations are also listed
months, but which was built according to the Rules and in alphabetical order in Tab 1.
under the survey of a QSCS Classification Society. In this As a rule, all notations in [4.2], [4.3], [4.5] and [4.6] are
case, the admission to class survey is to confirm that the only to be assigned to self-propelled units.
ship has not undergone conversions or modifications or
alterations, which were not approved by a QSCS 4.1.6 (1/7/2009)
Classification Society. The list of the service notations which may be assigned in
accordance with separate Rules is indicated in Tab 2.
3.2.3 The mark  is assigned to the relevant part of the In addition, for ships engaged in inland navigation the
ship, where the procedure for the assignment of relevant list of service notations is given in the specific
classification is other than those detailed in [3.2.1] and "Rules for the classification of inland waterway ships and for
[3.2.2], but however deemed acceptable. conformity to Directive 2016/1629/EU".
42 RINA Rules 2024

...OMISSIS...
Pt A, Ch 1, Sec 2
4.1.7 (1/7/2009) 4.2 Cargo ships

The assignment of a service notation does not absolve the 4.2.1 (1/7/2024)
Interested Party from compliance with any international and The service notations related to self-propelled ships
national regulations established by the Administrations. intended for the carriage of cargo are listed in [4.2.2] to
Neither does it waive the requirements in Sec 1, [3.3.1]. [4.2.174] belowand [4.2.16] to [4.2.17].
Table 1 : List of service notations assigned in accordance with the requirements of these Rules (1/1/2022)
Reference Reference chapter

Service notation
for definition in Part E
asphalt tanker [4.5.8] Part E, Chapter 7
asphalt tanker ESP [4.5.9] Part E, Chapter 7
barge [4.9.1] Part E, Chapter 19
bulk carrier ch xii [4.2.16] (1)
bulk carrier ch xii - double side-skin [4.2.17] (1)
bulk carrier ESP [4.3.2] Part E, Chapter 4
bulk carrier ESP CSR [4.3.3] Part E, Chapter 4
cable laying unit [4.8.7] Part E, Chapter 7
chemical recovery ship [4.8.6] Part E, Chapter 28
car carrier [4.2.5] (1)
chemical tanker [4.5.4] Part E, Chapter 8
chemical tanker - assisted propulsion [4.5.14] Part E, Chapter 31
chemical tanker ESP [4.5.4] Part E, Chapter 8
cement carrier [4.2.10] Part E, Chapter 23
combination carrier/OBO ESP [4.3.6] Part E, Chapter 6
combination carrier/OOC ESP [4.3.7] Part E, Chapter 6
compressed natural gas carrier [4.2.11] Part E, Chapter 24
container ship [4.2.6] Part E, Chapter 2
deck cargo ship [4.2.12] (1)
dredger [4.7.2] Part E, Chapter 13
escort tug [4.8.2] Part E, Chapter 14
fire-fighting ship [4.8.4] Part E, Chapter 16
fishing vessel [4.10.1] Part E, Chapter 20
fly ash carrier [4.2.9] (1)
FLS tanker [4.5.6] Part E, Chapter 7
general cargo ship [4.2.2] (1)
general cargo ship - double-side-skin [4.2.13] (1)
hopper dredger [4.7.2] Part E, Chapter 13
hopper unit [4.7.2] Part E, Chapter 13
liquefied gas carrier [4.5.5] Part E, Chapter 9
livestock carrier [4.2.7] Part E, Chapter 3
marine mobile desalination unit [4.5.13] Part E, Chapter 30
offshore support vessel [4.8.5] Part E, Chapter 32
oil carrier - assisted propulsion [4.5.11] Part E, Chapter 25
oil recovery ship [4.8.5] Part E, Chapter 17
(1) No additional requirements are specified in Part E for this service notation.
(2) No additional requirements are specified in Part E for this service notation; however the requirements of Part F, Chapter 8 for the
assignment of the additional class notation REF-CARGO are to be applied.
(3) These ships are considered on a case by case basis by the Society according to their type of service.
RINA Rules 2024 ...OMISSIS... 43

Pt A, Ch 1, Sec 2
4.2.15 (1/7/2024) - XII/13: "Availability of Pumping Systems".

The service notations listed in [4.2.12] to [4.2.134] may be Ships having reduced freeboard are to comply with
completed by the following additional service features, as the requirements in Parts A, B, C and D, as applica-
applicable: ble, and with the requirements in SOLAS, Chapter
• equipped for carriage of containers, where the ship's XIIfor the assignment of the additional service fea-
fixed arrangements comply with the applicable rule ture BC Ch XII.
requirements in Part E, Chapter 2 • BC Ch XII: applicable to ships intended to primarily
• heavycargo [ AREA1, X1 kN/m2 - AREA2, X2 kN/m2 - carry dry cargoes in bulk, which are not constructed
... with the typical midship section arrangements as per
[4.3.2] or [4.3.3] and comply with the requirements in
when the cargo areas intended to support heavy cargoes Parts A, B, C and D, as applicable, and with the
fulfill the appropriate rule requirements. The values Xi requirements in SOLAS, Chapter XII.
indicate the maximum allowable local pressures on the
various AREAs where the cargo is intended to be • H-CNG: applicable to car carriers when ro-ro spaces
stowed. The requirements for the assignment of this comply with the rule requirements in Part E, Chapter 1.
additional service feature are given in Pt B, Ch 5, Sec 6,
4.2.16 (1/7/2024)
[4.1.2]
bulk carrier ch xii , for general cargo ships intended to
• nonhomload, when the ship has been designed in such primarily carry dry cargoes in bulk, which are not
a way that the cargo spaces may be loaded non- constructed with the typical midship section arrangements
homogeneously, including cases where some holds may as per [4.3.2] or [4.3.3] and comply with the requirements
be empty, at a draught up to the scantling draught and in Parts A, B, C and D, as applicable, and with the
fulfill the appropriate rule requirements for general requirements in SOLAS, Chapter XII.
strength, and when the corresponding loading
conditions are listed in the reviewed loading manual. At Owner request this notation can be assigned in lieu of
This notation can be completed with the indication of the notationas equivalent to that assigned for a general
the different maximum loads allowed in each hold and cargo ship, with service feature BC Ch XII (refer to [4.2.15])
which holds may be empty, if appropriate. and may be completed by other additional service features
in [4.2.15], as applicable.
• P when the ship is intended for the exclusive carriage of
goods in package or any other form excluding solid 4.2.17 (1/1/2018)
goods in bulk, bulk carrier ch xii - double side-skin applies to ships in
• BC applicable to: compliance with [4.2.16] and with double side-skin
extending for the entire length of the cargo area, and for the
a) single skin ship having length less than 100 m and entire height of the cargo hold to the upper deck.
no reduced freeboard which is intended to carry dry
cargoes in bulk and comply with the following
requirements of SOLAS Ch XII regulations:
4.3 Bulk, ore and combination carriers
- XII/11: "Loading Instrument" 4.3.1 (1/7/2016)
- XII/12: "Hold, Ballast and Dry Space Water The service notations related to self-propelled ships (see
Ingress Alarms" Note 1) intended for the carriage of dry cargo in bulk are
listed in [4.3.2] to [4.3.7] below.
- XII/13: "Availability of Pumping Systems".
The service notations described in this item are always
Ships having length greater than or equal to 100 m completed by the additional service feature ESP, which
or reduced freeboard are to comply with the means that these ships are submitted to the Enhanced
requirements in Parts A, B, C and D, as applicable, Survey Program as laid down in Ch 4, Sec 2.
and with the requirements in SOLAS, Chapter XIIfor
the assignment of the additional service feature BC Example: ore carrier ESP
Ch XII. Note 1: Self-propelled ships are ships with mechanical means of
propulsion not requiring assistance from another ship during
b) double skin ship having no reduced freeboard
normal operation.
which is intended to carry dry cargoes in bulk and
comply with the following requirements of SOLAS The service notation bulk carrier is completed by the
Ch XII regulations: additional service feature CSR for bulk carriers built in
accordance with:
- II-1/3-2.2: "Protective Coatings of Dedicated
Seawater Ballast Tanks in All Types of Ships and • the "Common Structural Rules for Bulk Carriers” (i.e
Double-Side Skin Spaces of Bulk Carriers" single side skin and double side skin bulk carriers with
unrestricted navigation, having length L of 90 m or
- XII/6.2, 6.3 and 6.4: "Structural and Other greater, contracted for construction on or after 1 April
Requirements for Bulk Carriers" 2006 but before 1 July 2015), or
- XII/11: "Loading Instrument" • the "Common Structural Rules for Bulk Carriers and Oil
- XII/12: "Hold, Ballast and Dry Space Water Tankers" (i.e. single side skin and double side skin bulk
Ingress Alarms" carriers, self-propelled with unrestricted navigation,
RINA Rules 2024 49

...OMISSIS...
Pt A, Ch 1, Sec 2
b) BC-B: for bulk carriers designed to carry dry bulk these ships are submitted to the Enhanced Survey Program
cargoes of cargo density of 1,0 t/m3 and greater with all as laid down in Ch 4, Sec 3 or Ch 4, Sec 4, as applicable.
cargo holds loaded in addition to BC-C conditions. Note 1: Oil tankers that do not comply with MARPOL I/19 may be
subject to international and/or national regulations requiring phase
c) BC-C: for bulk carriers designed to carry dry bulk
out under MARPOL I/20 and/or MARPOL I/21.
cargoes of cargo density less than 1,0 t/m3.
The service notation may be completed by the following
The following additional service features are to be provided additional service features, as applicable:
giving further detailed description of limitations to be • flash point > 60°C, where the ship is intended to carry
observed during operation as a consequence of the design only such type of products, under certain conditions
loading condition applied during the design in the
• double hull, when the ship is constructed in accordance
following cases:
with the definition given in Ch 2, Sec 2, [2.2.18]
• maximum cargo density (in t/m3) for notations BC-A and • double hull (heavy grades), when the ship is
BC-B, if the maximum cargo density is less than 3.0 t/m3 constructed in accordance with the definition given in
• no MP for all notations, when the vessel has not been Ch 2, Sec 2, [2.2.20]
designed for loading and unloading in multiple ports in • double hull (independent tanks), when the ship is
accordance with the conditions specified in Pt E, Ch 4, constructed in accordance with the definition given in
Sec 3, [4.5.4] Ch 2, Sec 2, [2.2.19]
• allowed combination of specified empty holds for • product, where the ship is intended to carry only
notation BC-A. products other than crude oil.
Note 1: The requirements of this item [4.4] are not intended to The additional requirements of Part E, Chapter 7 are
prevent any other loading conditions being included in the loading applicable to these ships.
manual, for which calculations are to be submitted as required; nor 4.5.3 (1/7/2016)
are they intended to replace in any way the required loading
manual/instrument.
The service notation oil tanker ESP is always completed by
the additional service feature CSR for oil tankers built in
Note 2: A bulk carrier in actual operation may be loaded differently accordance with:
from the design loading conditions specified in the loading
manual, provided limitations for longitudinal and local strength as • the "Common Structural Rules for Double Hull Oil
defined in the loading manual and loading instrument on board Tankers" (i.e double hull oil tankers, having length L of
and applicable stability requirements are not exceeded. 150 m or greater, contracted for construction on or after
1 April 2006 but before 1 July 2015), or
4.5 Ships carrying liquid cargo in bulk • the "Common Structural Rules for Bulk Carriers and Oil
Tankers" (i.e. double hull oil tankers, self-propelled with
4.5.1 (1/5/2013) unrestricted navigation, having length L of 150 m or
The service notations related to self-propelled ships (see greater, contracted for construction on or after 1 July
Note 1) intended for the carriage of liquid cargo in bulk are 2015).
listed in [4.5.2] to [4.5.10] below.
Example: oil tanker ESP CSR
Note 1: Self-propelled ships are ships with mechanical means of
propulsion not requiring assistance from another ship during
The additional requirements of Part E, Chapter 7 are
normal operation. applicable to these ships with the limitations indicated
therein.
The service notations related to assisted propulsion units
(see [4.9.4]) intended for the carriage of liquid cargo in bulk 4.5.4 (1/8/2022)
are listed in [4.5.11] and [4.5.12] below. chemical tanker, for self-propelled ships which intended
primarily to carry in bulk chemical products presenting
4.5.2 (1/7/2024)
safety and/or pollution hazards. This notation is to be
oil tanker, for self-propelled ships which are intended assigned to tankers of both single and double hull
primarily to carry in bulk crude oil or other oil products construction, as well as tankers with alternative structural
having any flash point, liquid at atmospheric pressure and arrangements, provided they are deemed equivalent by the
ambient temperature (or thus maintained by heating) in Society.
bulk in cargo tanks forming an integral part of the ship's For chemical tankers with integral cargo tanks, the service
hull, including ship types such as combination carriers notation chemical tanker is always completed by the
(Ore/Oil ships etc.) but excluding ships carrying oil in additional service feature ESP (i.e. chemical tanker ESP),
independent tanks not part of the ship's hull such as asphalt which means that these ships are submitted to the Enhanced
carriers. Survey Program as laid down in Ch 4, Sec 5.
This notation is to be assigned to tankers of both single and The additional requirements of Part E, Chapter 8 are
double hull construction, as well as tankers with alternative applicable to these ships.
structural arrangements, provided they are deemed
The list of products the ship is allowed to carry is attached
equivalent by the Society.
to the Certificate of Classification or the Certificate of
For oil tankers with integral cargo tanks, the service Fitness, where issued by the Society, including, where
notation oil tanker is always completed by the additional necessary, the maximum allowable specific gravity and/or
service feature ESP (i.e. oil tanker ESP), which means that temperature.
52 ...OMISSIS... RINA Rules 2024

Pt A, Ch 2, Sec 2
SECTION 2 MAINTENANCE OF CLASS
1 General principles of surveys The surveys are to be carried out in accordance with the
relevant requirements in order to confirm that the hull,
machinery, equipment and appliances comply with the
1.1 Survey types applicable Rules and will remain in satisfactory condition
based on the understanding and assumptions mentioned in
1.1.1 Classed ships are submitted to surveys for the Ch 1, Sec 1, [3.3].
maintenance of class. These surveys include the class
Where the conditions for the maintenance of main class,
renewal survey, intermediate and annual survey, bottom service notations and additional class notations are not
survey (either survey in dry condition or in-water survey), complied with, the main class and/or the service notation
tailshaft survey, boiler survey, and surveys for the and/or the additional class notations as appropriate will be
maintenance of additional class notations, where suspended and/or withdrawn in accordance with the
applicable. Such surveys are carried out at the intervals and applicable Rules given in Sec 3.
under the conditions laid down in this Section. In addition
Note 1: It is understood that requirements for surveys apply to
to the above periodical surveys, ships are to be submitted to
those items that are required according to the Rules or, even if not
occasional surveys whenever the circumstances so require; required, are fitted on board.
refer to [11].
1.1.3 Unless specified otherwise, any survey other than
1.1.2 The different types of periodical surveys are bottom survey and tailshaft survey may be effected by
summarised in Tab 1. The intervals at which the periodical carrying out partial surveys at different times to be agreed
surveys are carried out are given in the items referred to in upon with the Society, provided that each partial survey is
the second column of Tab 1. The relevant extent and scope adequately extensive. The splitting of a survey into partial
are given in Chapter 3 and Chapter 4 for all ships and for surveys is to be such as not to impair its effectiveness.
service notations, respectively, while surveys related to
additional class notations are given in Chapter 5.
1.2 Change of periodicity, postponement or
Where there are no specific survey requirements for advance of surveys
additional class notations assigned to a ship, equipment
and/or arrangements related to these additional class 1.2.1 The Society reserves the right, after due
notations are to be examined, as applicable, to the consideration, to change the periodicity, postpone or
Surveyor’s satisfaction at each class renewal survey for the advance surveys, taking into account particular
main class. circumstances.
Table 1 : List of periodical surveys (1/1/2016)
Type of survey Reference in this Section Reference to scope of survey

Class renewal - hull [4] Ch 3, Sec 5 and Chapter 4 (1)
Class renewal - machinery [4] Ch 3, Sec 5 and Chapter 4 (1)
Annual - hull [5.1] Ch 3, Sec 3 and Chapter 4 (1)
Annual - machinery [5.1] Ch 3, Sec 3 and Chapter 4 (1)
Intermediate - hull [6.1] Ch 3, Sec 4 and Chapter 4 (1)
Intermediate - machinery [6.1] Ch 3, Sec 4 and Chapter 4 (1)
Bottom - dry condition [7.1] Ch 3, Sec 6
Bottom - in water [7.1] Ch 3, Sec 6
Shaft - Method 1,2,3,4 [8.1] Ch 3, Sec 7
Boiler - complete [9.1] Ch 3, Sec 8
(1) As applicable, according to the service notation assigned to the ship
94 RINA Rules 2024

Pt A, Ch 2, Sec 2
1.2.2 (1/7/2020) 1.4.5 (1/7/2006)

When a survey becomes overdue during a voyage, the As a general rule, all materials, machinery, boilers, auxiliary
following applies: installations, equipment, items etc. (generally referred to as
a) In the case of a class renewal survey, the Society may, "products") which are covered by the class and used or
under exceptional circumstances, grant an extension to fitted on board ships inspected by the Society during
allow for completion of this survey provided there is surveys after construction are to be new and, where
documented agreement to such an extension prior to intended for essential services as defined in Ch 1, Sec 1,
the expiry date of the Certificate of Classification, [1.2.1], tested by the Society.
adequate arrangements have been made for the Second hand materials, machinery, appliances and items
attendance of the Surveyor at the first port of call and may be used subject to the specific agreement of the
the Society is satisfied that there is technical justification Society and the Owner.
for such an extension. Such an extension will be granted
only until arrival at the first port of call after the expiry The requirements for the selection of materials to be used in
date of the Certificate of Classification the construction or repair of the various parts of existing
ships, the characteristics of products to be used for such
b) In the case of annual and intermediate surveys, no parts and the checks required for their acceptance are to be
postponement is granted. Such surveys are to be as stated in Part C and Part D, as applicable, or in other Parts
completed within their prescribed windows; see [2.1.3] of the Rules or as specified on approved plans. In particular,
c) In the case of all other periodical surveys and conditions the testing of products manufactured according to quality
of class, extension of class may be granted until the assurance procedures approved by the Society and the
arrival of the ship at the port of destination. approval of such procedures are governed by the
requirements of Pt D, Ch 1, Sec 1, [3].
1.3 Extension of scope of survey
1.5 Appointment of another Surveyor
1.3.1 The Society and/or its Surveyors may extend the
scope of the provisions in Chapter 3 to Chapter 5, which 1.5.1 In compliance with the provisions of Ch 1, Sec 1,
set forth the technical requirements for surveys, whenever [2.5.1], should a disagreement arise between the Owner
and so far as considered necessary, or modify them in the and the Surveyor during a survey, the Society may, at the
case of special ships or systems. request of the Owner, designate another Surveyor.
1.3.2 The extent of any survey also depends upon the

condition of the ship and its equipment. Should the 2 Definitions and procedures related
Surveyor have any doubt as to the maintenance or to surveys
condition of the ship or its equipment, or be advised of any
deficiency or damage which may affect the class, then
2.1 General
further examination and testing may be conducted as
considered necessary.
2.1.1 Period of class
Period of class means the period starting either from the
1.4 General procedure of survey
date of the initial classification, see Sec 1, [5], or from the
1.4.1 The general procedure of survey consists in: credited date of the last class renewal survey, and expiring
at the limit date assigned for the next class renewal survey.
• an overall examination of the parts of the ship covered
by the rule requirements 2.1.2 Anniversary date
• checking selected items covered by the rule Anniversary date means the day of the month of each year
requirements in the period of class which corresponds to the expiry date
• attending tests and trials where applicable and deemed of the period of class.
necessary by the Surveyor.
2.1.3 Survey time window
1.4.2 The Society's survey requirements cannot be
Survey time window, or more simply window, mean the
considered as a substitute for specification and acceptance
fixed period during which annual and intermediate surveys
of repairs and maintenance, which remain the responsibility
are to be carried out.
of the Owner.
1.4.3 In accordance with the provisions of Ch 1, Sec 1, 2.1.4 Overdue surveys (1/7/2001)
[3.1.5], the Society will, at the request of the Owner, apply Each periodical survey is assigned a limit date specified by
the regulations of Administrations concerning the scope the relevant requirements of the Rules (end of survey
and periodicity of surveys when they differ from those laid interval or end date of window) by which it is to be
down in Part A. completed.
A survey becomes overdue when it has not been completed
1.4.4 During the surveys, the Surveyor does not check that
by its limit date.
the spare parts are kept on board, maintained in working
order and suitably protected and lashed. Examples:
RINA Rules 2024 95

Pt A, Ch 2, Sec 2
• Anniversary date: 15th April "Common Structural Rules for Bulk Carriers" in force at
The 2000 annual survey can be validly carried out from the date of contract for construction;
16th January 2000 to 15th July 2000. If not completed • for oil tankers, having notation "oil tanker ESP CSR",
by 15th July 2000, the annual survey becomes overdue. contracted for construction on or after 1 April 2006 but
• Last bottom survey 20th October 2000 (periodicity 2.5 before 1 July 2015, reference is to be made to the
years, with a maximum interval between successive "Common Structural Rules for Double Hull Oil Tankers"
examinations not exceeding 3 years) in force at the date of contract for construction; and
The next bottom survey is to be carried out before 20th • for bulk carriers, having notation "bulk carrier ESP CSR"
October 2003. If not completed by 20th October 2003, and oil tankers, having notation "oil tanker ESP CSR",
the bottom survey becomes overdue. contracted for construction on or after 1 July 2015,
reference is to be made to the "Common Structural
2.1.5 Conditions of class (1/7/2020) Rules for Bulk Carriers and Oil Tankers" in force at the
A condition of class is a requirement to the effect that date of contract for construction.
specific measures, repairs and/or surveys are to be carried
out within a specific time limit in order to retain 2.2.2 Ballast tanks (1/7/2024)
classification. A condition of class is pending until it is a) Ships with the ESP notation:
cleared. Where it is not cleared by its limit date, the
As far as oil tankers and chemical tankers are
condition of class is overdue.
concerned, a Ballast Tank is a tank which is used
primarily for the carriage of salt water ballast.
2.1.6 Memoranda (1/7/2020)
Those defects and/or deficiencies which do not affect the As far as oil tankers and chemical tankers are
maintenance of class and which may therefore be cleared at concerned, a Combined Cargo/Ballast Tank is a tank
the Owner’s convenience and any other information which is used for the carriage of cargo or ballast water
deemed noteworthy for the Society’s convenience are as a routine part of the vessel's operation and will be
indicated as memoranda. Memoranda are not to be treated as a Ballast Tank. Cargo tanks in which water
regarded as conditions of class. ballast might be carried only in exceptional cases
according to MARPOL I/18.3 are to be treated as cargo
2.1.7 Exceptional circumstances (1/7/2005) tanks.
Exceptional circumstances' means unavailability of dry- As far as bulk carriers are concerned, a Ballast Tank is a
docking facilities; unavailability of repair facilities; tank which is used solelyprimarily for salt water ballast,
unavailability of essential materials, equipment or spare or, where applicable, a space which is used for both
parts; or delays incurred by action taken to avoid severe cargo and ballast will be treated as a Ballast tank when
weather conditions. substantial corrosion has been found in that space.
As far as double skin bulk carriers are concerned, a
2.1.8 Force Majeure (1/7/2005)
Ballast Tank is a tank which is used solelyprimarily for
'Force Majeure' means damage to the ship; unforeseen salt water ballast, or, where applicable, a space which is
inability of the Society to attend the ship due to government used for both cargo and ballast will be treated as a
restrictions on right of access or movement of personnel; Ballast tank when substantial corrosion has been found
unforeseeable delays in port or inability to discharge cargo in that space. A Double Side Tank is to be considered as
due to unusually lengthy periods of severe weather, strikes a separate tank even if it is in connection with either the
or civil strife; acts of war; or other force majeure. topside tank or the hopper side tank.
2.1.9 Remote surveys (1/1/2023) b) Other ships:
Remote Survey is a process of verifying that a ship and its A Ballast Tank is a tank that is being used primarily for
equipment are in compliance with the Rules where the salt water ballast.
verification is undertaken, or partially undertaken, without
attendance on board by a Surveyor. 2.2.3 Spaces (1/1/2008)
Note 1: Remote classification activities not requiring a survey, such Spaces are separate compartments including holds, tanks,
as some administrative tasks, are not to be considered as remote cofferdams and void spaces bounding cargo holds, decks
surveys. and the outer hull.
2.2 Terminology related to hull survey 2.2.4 Overall survey

An overall survey is a survey intended to report on the
2.2.1 Common Structural Rules (1/7/2015) overall condition of the hull structure and determine the
Where in these Rules the term "Common Structural Rules" is extent of additional close-up surveys.
used, the pertinent edition of the Common Structural Rules
is to be applied as follows: 2.2.5 Close-up survey
• for bulk carriers, having notation "bulk carrier ESP CSR", A close-up survey is a survey where the details of structural
contracted for construction on or after 1 April 2006 but components are within the close visual inspection range of
before 1 July 2015, reference is to be made to the the Surveyor, i.e. normally within reach of hand.
96 RINA Rules 2024

Pt A, Ch 2, Sec 2
2.2.6 Transverse section • fair: condition with local breakdown at edges of

A transverse section includes all longitudinal members stiffeners and weld connections and/or light rusting over
contributing to longitudinal hull girder strength, such as 20% or more of areas under consideration, but less than
plating, longitudinals and girders at the deck, side shell, as defined for poor condition
bottom, inner bottom, longitudinal bulkheads, and sloped • poor: condition with general breakdown of coating over
plating in upper and lower side tanks, as well as relevant 20% or more of areas or hard scale at 10% or more of
longitudinals, as applicable for the different ships. For a areas under consideration.
transversely framed ship, a transverse section includes
adjacent frames and their end connections in way of Note 1: For oil tankers ESP, both single and double hull, and
chemical tankers ESP, reference is made to IACS Recommendation
transverse sections.
No.87 "Guidelines for Coating Maintenance & Repairs for Ballast
Tanks and Combined Cargo / Ballast Tanks on Oil Tankers".
2.2.7 Representative tanks or spaces (1/7/2006)
Representative tanks or spaces are those which are 2.2.14 Cargo area (ships carrying liquid cargo in
expected to reflect the condition of other tanks or spaces of bulk)
similar type and service and with similar corrosion The cargo area is that part of the ship which contains cargo
prevention systems. When selecting representative tanks or tanks, slop tanks and cargo/ballast pump rooms,
spaces, account should be taken of the service and repair cofferdams, ballast tanks and void spaces adjacent to cargo
history on board and identifiable critical structural areas tanks and also deck areas throughout the entire length and
and/or suspect areas. breadth of the part of the ship over the above-mentioned
spaces.
2.2.8 Renewal thickness (1/7/2012)
Renewal thickness (tren) is the minimum allowable 2.2.15 Cargo length area (dry cargo ships) (1/7/2006)
thickness, in mm, below which renewal of structural The cargo length area is that part of the ship which includes
members is to be carried out. all cargo holds and adjacent areas including fuel tanks,
cofferdams, ballast tanks and void spaces.
2.2.9 Substantial corrosion (1/7/2012)
Substantial corrosion is an extent of corrosion such that 2.2.16 Cargo area (ships carrying liquefied gases in
assessment of the corrosion pattern indicates a wastage in bulk) (1/7/2008)
excess of 75% of allowable margins, but within acceptable Cargo area is that part of the ship which contains cargo
limits. tanks, cargo/ballast pump rooms, compressor rooms,
cofferdams, ballast tanks and void spaces adjacent to cargo
For ships built under the Common Structural Rules, tanks and also deck areas throughout the entire length and
substantial corrosion is an extent of corrosion such that the breadth of the part of the ship over the above-mentioned
assessment of the corrosion pattern indicates a measured spaces.
thickness between tren + 0,5mm and tren.
2.2.17 Prompt and Thorough Repair (1/7/2020)
2.2.10 Suspect areas
A Prompt and Thorough Repair is a permanent repair
Suspect areas are locations showing substantial corrosion completed at the time of survey to the satisfaction of the
and/or considered by the Surveyor to be prone to rapid Surveyor, therein removing the need for the imposition of
wastage. any associated condition of class.
2.2.11 Critical Structural Area (1/7/2006) 2.2.18 Double hull oil tanker (1/7/2024)
Critical Structural Areas are locations which have been A double hull oil tanker is a ship which is constructed pri-
identified from calculations to require monitoring and/or marily for the carriage of oil (see Note 1) in bulk, which has
which, from the service history of the subject ship or from the cargo tanks forming an integral part of the ship's hull
similar or sister ships (if available), have been identified as and is protected by a double hull which extends for the
sensitive to cracking, buckling or corrosion which would entire length of the cargo area, consisting of double sides
impair the structural integrity of the ship. and double bottom spaces for the carriage of water ballast
or spaces other than tanks that carry oil (see Note 1).
2.2.12 Corrosion Prevention System (1/7/2008)
Note 1: MARPOL Annex I cargoes. The requirements relevant to
A Corrosion Prevention System is normally considered a full these ships given in Ch 4, Sec 4 are also applicable to existing
hard protective coating. double hull tankers not complying with MARPOL Regulation 13F,
but having a U-shaped midship section.
Hard Protective Coating is usually to be epoxy coating or
equivalent. Other coating systems which are neither soft nor 2.2.19 Double hull oil tanker with independent
semi-hard coatings may be considered acceptable as tanks (1/1/2009)
alternatives provided that they are applied and maintained
A double hull oil tanker with independent tanks is a ship
in compliance with the Manufacturer's specifications.
which is constructed for the carriage of oil, as per MARPOL
Annex I cargoes, in bulk, which is fitted with independent
2.2.13 Coating condition (1/7/2006)
cargo tanks located at distances from the outer shell in
Coating condition is defined as follows: accordance with the requirements of MARPOL Annex I
• good: condition with only minor spot rusting Regulation 19, for the entire length of the cargo area.
RINA Rules 2024 97

Pt A, Ch 2, Sec 2
2.2.20 Double hull oil tanker for heavy grade Ore and combination carriers are not covered by the
oils (1/7/2024) Common Structural Rules.
A double hull oil tanker for heavy grade oils is a ship which Note 1: For combination carriers with longitudinal bulkheads, sur
is constructed primarily for the carriage of oil (see Note 1) vey requirements are specified in both Ch 4, Sec 2 and Ch 4, Sec 3
or Ch 4, Sec 4, as applicable.
in bulk, which has the cargo tanks forming an integral part
of the ship's hull dedicated to the carriage of heavy grade 2.2.22 Bulk carrier (1/7/2012)
oils (see Note 2) and is protected by a double hull which A bulk carrier is a ship which is constructed generally with
extends for the entire length of the cargo area, consisting of single deck, double bottom, topside tanks and hopper side
the following: tanks in cargo spaces, and is intended primarily to carry dry
• double bottom spaces for the carriage of water ballast or cargo in bulk. Combination carriers are included (see
spaces other than tanks that carry oil and Note 1). Ore and combination carriers are not covered by
the Common Structural Rules.
• double side spaces for the carriage of water ballast or Note 1: For single skin combination carriers, survey requirements
spaces other than tanks that carry heavy grade oils. are specified in both Ch 4, Sec 2 and Ch 4, Sec 3.
The capacity of each cargo tank is not to exceed 700 m3. 2.2.23 Special consideration (1/7/2006)
Special consideration or specially considered (in
Note 1: MARPOL Annex I cargoes. The requirements relevant to
these ships given in Ch 4, Sec 4 are also applicable to existing
connection with close-up surveys and thickness
double hull tankers not complying with MARPOL Regulation 13F, measurements) means sufficient close-up inspection and
but having a U-shaped midship section. thickness measurements are to be taken to confirm the
actual average condition of the structure under the coating.
Note 2: MARPOL Annex I Regulation 21.2. Heavy grade oil means
any of the following: 2.2.24 Pitting corrosion (1/7/2012)
• crude oils having a density at 15°C higher than 900 kg/m3; Pitting corrosion is defined as scattered corrosion
spots/areas with local material reductions which are greater
• oils, other than crude oils, having either a density at 15°C than the general corrosion in the surrounding area. Pitting
higher than 900 kg/m3 or a kinematic viscosity at 50°C higher intensity is defined in App 2, Fig 12.
than 180 mm2/s; or
• bitumen, tar and their emulsions. 2.2.25 Edge corrosion (1/7/2012)

Edge corrosion is defined as local corrosion at the free
2.2.21 Double skin bulk carrier (1/7/2012) edges of plates, stiffeners, primary support members and
around openings. An example of edge corrosion is shown
A double skin bulk carrier is a ship which is constructed in Fig 1.
generally with single deck, double bottom, topside tanks
and hopper side tanks in cargo spaces, and is intended 2.2.26 Grooving corrosion (1/7/2012)
primarily to carry dry cargo in bulk, including such types as Grooving corrosion is typically local material loss adjacent
ore carriers and combination carriers (see Note 1), in to weld joints along abutting stiffeners and at stiffener or
which all cargo holds are bounded by a double side skin plate butts or seams. An example of groove corrosion is
(regardless of the width of the wing space). shown in Fig 2.
Figure 1 : Edge corrosion (1/7/2012)

Attached plating Attached plating
Inverted angle
Flatbar
hstf or built-up
stiffener
stiffener
0,25hstf
0,25bstf
bstf
98 RINA Rules 2024

...OMISSIS...
Pt A, Ch 3, Sec 2
SECTION 2 SURVEY FOR ASSIGNMENT OF CLASS OF A SHIP

IN SERVICE
1 Surveys required by IACS but less than 20 years of age, the survey has the
scope of a class renewal survey or an intermediate
Procedural Requirement PR1A
survey, whichever is due next;
5) for all ships which are 20 years of age and above,
1.1 Transfer to the Society's class of a ship
the survey has the scope of a class renewal survey
in service classed by another QSCS (this is also applicable to ships having their hull
Classification Society and in full under continuous survey);
compliance with all applicable and 6) in the context of applying items 4) and 5) above, if
relevant IACS Resolutions dry-docking of the ship is not due at the time of
transfer, consideration can be given to carrying out
1.1.1 General (1/7/2020)
an underwater examination in lieu of dry-docking;
Surveys for assignment of class may be credited as
periodical surveys for maintenance of class, provided that 7) in the context of applying items 4) and 5), as
the losing Society is a QSCS Classification Society as applicable, the anchors and anchor chain cables
defined in Ch 2, Sec 1, [1.1.1]. In this case, all conditions of ranging and gauging for vessels over 15 years of age
class due for compliance at that periodical survey are to be is not required to be carried out as part of the class
complied with. entry survey unless the class entry survey is being
credited as a periodical survey for maintenance of
1.1.2 Surveys (1/7/2024) class.
Notwithstanding the records indicating that all surveys are If the class entry survey is to be credited as a
up-to-date, a survey for assignment of class is held by the periodical survey for maintenance of class,
Society, the extent of which is based on the age of the ship consideration may be given by the gaining society to
and the losing Society's class status as follows: the acceptance of the anchors and anchor chain
a) Hull: cables ranging and gauging carried out by the losing
society provided they were carried out within the
1) for ships less than 5 years of age the survey takes the
applicable survey window of the periodical survey
form of an annual survey;
in question;
2) for ships between 5 and 10 years of age the survey
8) in the context of applying items 1) to 6) above, as
includes an Annual Survey and inspection of a
applicable:
representative number of ballast spaces;
• if the class entry survey is to be credited as a
3) for ships of 10 years of age and above but less than
periodical survey for maintenance of class,
20 years of age, the survey includes an Annual
consideration may be given by the Society to the
Survey and inspection of a representative number of
acceptance of thickness measurements taken by
ballast spaces and cargo spaces. For gas carriers, in
the losing society provided they were carried out
lieu of the internal inspection of cargo spaces, the
within the applicable survey window of the
following applies:
periodical survey in question;
• inspection of surrounding ballast tanks and void
• if the class entry survey is not to be credited as a
spaces, including external inspection of
periodical survey for maintenance of class,
independent cargo tanks and associated
consideration may be given by the Society to the
supporting systems as far as possible;
acceptance of thickness measurements taken by
• review of cargo log books and operational the losing society provided they were carried out
records to verify the correct functioning of the within 15 months prior to completion of the
cargo containment system. class entry survey when it is within the scope of
For oil tankers (including product carriers), and a Class Renewal Survey, or within 18 months
chemical carrierstankers of 10 years of age and prior to completion of the class entry survey
above but less than 15 years of age, in lieu of the when it is within the scope of an Intermediate
internal inspection of cargo tanks not fitted with Survey.
internal stiffening and framing, inspections of In both cases, the thickness measurements are to be
surrounding ballast tanks, void spaces and deck reviewed by the Society for compliance with the
structure are to be applied; applicable survey requirements, and confirmatory
4) for ships provided with the Additional Service gaugings are to be taken to the satisfaction of the
Feature "ESP" which are 15 years of age and above Society.
222 RINA Rules 2024

...OMISSIS...
Pt A, Ch 4, Sec 2
SECTION 2 BULK CARRIERS, COMBINATION CARRIERS AND

SELF-UNLOADING BULK CARRIERS OF SINGLE
SIDE SKIN CONSTRUCTION
1 General renewal surveys for purposes of verifying continuing com-

pliance with Ch 6, Sec 2, [7].
1.1 Application 1.1.6 (1/1/2019)
1.1.1 (1/1/2017) When, in any survey, thickness measurements are required :
The requirements of this Section apply to all self-propelled • the procedure detailed in Ch 2, Sec 2, [2.3] is to be
bulk carriers other than double skin bulk carriers as defined applied
in Sec 9. These ships are assigned with one of the following • the thickness measurement firm is to be part of the sur-
service notations: vey planning meeting held prior to commencing the
• bulk carrier ESP survey.
• bulk carrier ESP CSR
1.1.7 (1/7/2006)
• combination carrier/OBO ESP (see Note 1)
Special consideration may be given to the extent of close-
• combination carrier/OOC ESP (see Note 1) up surveys and/or thickness measurements in cargo holds as
• Self-unloading bulk carriers ESP required below for class renewal, intermediate or annual
surveys, when all internal and external surfaces of hatch
Note 1: For single skin combination carriers additional require-
coamings and hatch covers, and all internal surfaces of the
ments are specified in Sec 3.
cargo holds, excluding the flat tank top areas and the hop-
1.1.2 (1/7/2006) per tank sloped plating approximately 300 mm below the
The requirements apply to the surveys of the hull structure side shell frame end brackets, have protective coating in
and piping systems in way of cargo holds, cofferdams, pipe good condition.
tunnels, fuel oil tanks and void spaces within the cargo
The above special consideration may also be given to exist-
length area and all salt water ballast tanks. They are addi-
ing bulk carriers, where Owners elect to coat or re-coat
tional to the requirements applicable to the remainder of
cargo holds, in accordance with the Manufacturers’ recom-
the ship, given in Chapter 3 according to the relevant sur-
mendations. However, prior to re-coating the cargo holds,
veys.
scantlings are to be assessed in the presence of a Surveyor
1.1.3 The requirements contain the minimum extent of of the Society.
examination, thickness measurements and tank testing. 1.1.8 (1/7/2006)
When substantial corrosion, as defined in Ch 2, Sec 2,
For bulk carriers with hybrid cargo hold arrangements, e.g.
[2.2.9], and/or structural defects are found, the survey is to
with some cargo holds of single side skin and others of dou-
be extended and is to include additional close-up surveys
ble side skin, the requirements of Sec 9 are to apply to
when necessary.
cargo holds of double side skin and associated wing spaces.
1.1.4 (1/7/2004)
Ships required to comply with the provisions in Ch 6, App 1 1.2 Documentation on board
are subject to the additional thickness measurement guid-
ance in Ch 6, Sec 2, [1.3] for the vertically corrugated trans- 1.2.1 (1/7/2016)
verse watertight bulkhead between cargo holds Nos. 1 and The Owner is to supply and maintain documentation on
2 for purposes of determining compliance with Ch 6, App 1 board as specified in [1.2.2] and [1.2.3], which is to be
prior to the relevant compliance deadline stipulated in readily available for examination by the Surveyor.
Ch 6, Sec 2, [1.2] and at subsequent intermediate surveys
(for ships over 10 years of age) and renewal surveys for pur- The documentation is to be kept on board for the lifetime of
poses of verifying continuing compliance with Ch 6, App 1. the ship.
1.1.5 (1/7/2004) For bulk carriers subject to SOLAS Chapter II-1 Part A-1
Regulation 3-10, the Owner is to arrange the updating of
Ships required to comply with the provisions in Ch 6, Sec 2,
the Ship Construction File (SCF) throughout the ship's life
[7] are subject to the additional thickness measurement
whenever a modification of the documentation included in
guidance in Ch 6, App 2 for side shell frames and brackets
the SCF has taken place.
for the purposes of determining compliance with Ch 6,
Sec 2, [7] prior to the relevant compliance deadline stipu- Documented procedures for updating the SCF are to be
lated in Ch 6, Sec 2, [7] and at subsequent intermediate and included within the Safety Management System.

Pt A, Ch 4, Sec 2
2.8 Self unloading bulk carrier - cargo han- the total number and type of ballast tanks. If such over-
dling system(s) all survey reveals no visible structural defects, the exam-
ination may be limited to verification that the corrosion
2.8.1 (1/1/2017)
prevention system remains efficient.
Cargo handling systems not covered by the additional class
notation CARGO HANDLING such as, but not limited to: b) Where poor a hard coating is found to be in less than
good condition, corrosion or other defects are found in
• belt conveyors,
water ballast tanks or where a hard protective coating
• spiral conveyors, has not been applied since the time of construction, the
• crew conveyors examination is to be extended to other ballast tanks of
• pneumatic conveyors the same type.
• chain conveyors (buckets , pockets, etc...) c) In ballast tanks other than double bottom tanks, where a
• wire conveyors hard protective coating is found in poor to be in less
than good condition, and it is not renewed, or where a
• cable conveyors (wagons, buckets, pockets, …)
soft or semi-hard coating has been applied, or where a
• chain elevators (buckets, pockets, etc..) hard protective coating has not been applied since the
• cable elevators (buckets, pockets, etc..) time of construction, the tanks in question are to be
• loading and discharging boom(s) examined and thickness measurements carried out as
considered necessary at annual surveys. When such
and combinations of these, have to be annually inspected. breakdown of hard protective coating is found in ballast
The survey is to include: double bottom tanks, or where a soft or semi-hard coat-
• verification that no modification of the cargo handling ing has been applied, or where a hard protective coating
system(s) layout has been made. Particular attention is to has not been applied, the tanks in question may be
be paid to cargo handling arrangements passing in close examined at annual surveys. When considered neces-
proximity to accommodation and/or control stations sary by the Surveyor, or where extensive corrosion
• verification that, when expected and fitted, special exists, thickness measurements are to be carried out.
arrangements to avoid unintentional release of lifted d) In addition to the requirements above, suspect areas
cargo are maintained and unmodified identified at previous surveys are to be examined.
• general examination, as far as applicable, of cargo han-
3.2.2 Cargo holds (1/7/2006)
dling system(s) with particular attention to the connec-
tion of their foundations to the hull structure a) An overall survey of all cargo holds, including close-up
survey of sufficient extent, minimum 25% of frames, is
• an examination of the instruction/installation manual to
to be carried out to establish the condition of:
verify the layout of the complete system(s) and confirm
correspondence to the actual system(s) fitted on board • Shell frames including their upper and lower end
• verification that maintenance of the system(s) has been attachments, adjacent shell plating, and transverse
carried out according to the Manufacturer's instructions bulkheads in the forward cargo hold and one other
and schedules. selected cargo hold;
• a general examination of components of the system in • Areas found suspect at previous surveys.
order to verify their satisfactory condition of mainte- b) Where considered necessary by the Surveyor as a result
nance of the overall and close-up survey as described in a), the
• verification and test of the cargo handling system alarm survey is to be extended to include a close-up survey of
and safety devices all of the shell frames and adjacent shell plating of that
cargo hold as well as a close-up survey of sufficient
• a running test of the system in order verify the satisfac-
extent of all remaining cargo holds.
tory working and operation conditions.
3.2.3 Extent of Thickness Measurements (1/7/2012)
3 Intermediate survey - Hull items a) Thickness measurements are to be carried out to an
extent sufficient to determine both general and local
3.1 General corrosion levels in areas subject to close-up survey as
3.1.1 (1/7/2006) described in [3.2.2] a). The minimum requirements for
thickness measurements at the intermediate survey are
The survey extent is dependent on the age of the ship as
areas found to be suspect areas at previous surveys.
specified in [3.2], [3.3] and [3.4] and shown in Tab 3 and
Tab 4. b) The extent of thickness measurement may be specially
considered, provided the Surveyor is satisfied by the
3.2 Ships between 5 and 10 years of age close-up survey that there is no structural diminution
and the hard protective coatings are found to be in a
3.2.1 Ballast tanks (1/7/2024) good condition.
a) For tanks used for water ballast, an overall survey of rep- c) Where substantial corrosion is found, the extent of
resentative tanks selected by the Surveyor is to be car- thickness measurements is to be increased in accord-
ried out. The selection is to include fore and aft peak ance with the requirements of Tab 7 to Tab 11. These
tanks and a number of other tanks, taking into account extended thickness measurements are to be carried out

Pt A, Ch 4, Sec 2
3.3 Ships between 10 and 15 years of age The survey program is to be in a written format, based on
the information in [4.9]. The survey is not to commence
3.3.1 (1/7/2006)
until the survey program has been agreed. The survey pro-
The requirements of the intermediate survey are to the same
gram at intermediate survey may consist of the survey pro-
extent as the previous class renewal survey as required in
gram at the previous class renewal survey supplemented by
[4]. However, internal examination of fuel oil tanks and
the condition evaluation report of that class renewal survey
pressure testing of all tanks are not required unless deemed
and later relevant survey reports.
necessary by the attending Surveyor.
The survey program is to be worked out taking into account
3.3.2 (1/1/2003)
any amendments to the survey requirements after the last
In application of [3.3.1], the intermediate survey may be class renewal survey carried out.
commenced at the second annual survey and be progressed
during the succeeding year with a view to completion at the 4.1.2 (1/7/2006)
third annual survey in lieu of application of Ch 2, Sec 2, In developing the survey program, the following documen-
[4.2.2]. tation is to be collected and consulted with a view to select-
ing tanks, holds, areas and structural elements to be
3.3.3 (1/1/2003)
examined:
In application of [3.3.1], an underwater survey may be con-
• survey status and basic ship information
sidered in lieu of a bottom survey in dry condition (see
Ch 3, Sec 5, [2]). • the documentation on board, as described in [1.2.2]
and [1.2.3]
3.4 Ships over 15 years of age • main structural plans (scantling drawings), including
information on use of high tensile steels (HTS)
3.4.1 (1/7/2006)
• relevant previous survey and inspection reports from
The requirements of the intermediate survey are to the same both the Society and the Owner
extent as the previous class renewal survey as required in
[4]. However, internal examination of fuel oil tanks and • information on the use of ship holds and tanks, with
pressure testing of all tanks are not required unless deemed regard to the nature of the typical cargoes transported
necessary by the attending Surveyor. and other useful data
• information on the corrosion prevention level on the
3.4.2 (1/1/2003)
new building
In application of [3.4.1], the intermediate survey may be
commenced at the second annual survey and be progressed • information on the relevant maintenance level during
during the succeeding year with a view to completion at the operation.
third annual survey in lieu of application of Ch 2, Sec 2,
4.1.3 The survey program is to comply, at least, with the
[4.2.2].
requirements for close-up surveys, thickness measurements
3.4.3 (1/7/2002) and tank testing given in [4.4], [4.5] and [4.6], respectively.
In application of [3.4.1], a bottom survey in dry condition is In addition, the survey program is to include at least:
to be part of the intermediate survey. The overall and close- • basic ship information and particulars
up surveys and thickness measurements, as applicable, of
• main structural plans (scantling drawings), including
the lower portions of the cargo holds and ballast tanks (see
information on the use of high tensile steels (HTS)
Note 1) are to be carried out in accordance with the appli-
cable requirements for intermediate surveys, if not already • plan of holds and tanks
performed. • list of holds and tanks including information on their
Note 1: Lower portions of the cargo holds and ballast tanks are use, protective coating, if any, and its condition
considered to be the parts below the light ballast waterline. • conditions for survey, with regard to holds, tanks and
spaces which are to be safe for access, i.e. cleaned, gas
4 Class renewal survey freed, ventilated, illuminated
• provisions and methods for access to structures
4.1 Survey program and preparation for sur- • equipment for surveys
vey • nomination of holds, spaces and areas for close-up sur-
4.1.1 (1/1/2008) veys according to Tab 5
The Owner, in cooperation with the Society, is to work out a • nomination of sections and areas for thickness measure-
specific survey program prior to the commencement of any ments according to Tab 6
part of: • nomination of holds, if any, and tanks for tank testing
• the class renewal survey according to [4.6]
• the intermediate survey for bulk carriers over 10 years of • damage experience and repair history related to the ship
age. in question.
Prior to the development of the survey program, the Survey 4.1.4 The survey program is also to include the maximum
Planning Questionnaire is to be completed by the Owner acceptable structural corrosion diminution levels applicable
based on the information set out in [4.10], and forwarded to to the ship. The Society will advise the Owner of this infor-
the Society. mation.

Pt A, Ch 4, Sec 2
Age of ship (in years at time of intermediate survey)

5 < age  10 10 < age  15 age > 15
See (1) , (2) and (3)
The minimum requirements are areas found to be suspect areas at previous survey (see See [3.3] See [3.4]
Ch 2, Sec 2, [2.2.10]).
See (4) and (5)
(1) When such overall survey reveals no visible structural defects, the examination may be limited to verification that the corrosion
prevention system remains efficient.
(2) Where poor coating condition, corrosion or other defects are found in water ballast tanks or where a hard protective coating
has not been applied since the time of construction, the examination is to be extended to other ballast tanks of the same type.
(3) For ballast tanks other than double bottom tanks, where a hard protective coating is found in poor condition and is not
renewed, or where soft coating has been applied or where a hard protective coating has not been applied since the time of con-
struction, the tanks in question are to be internally examined and thickness measurement carried out as considered necessary at
annual surveys.
When such breakdown of hard protective coating is found in ballast double bottom tanks and is not renewed, or where soft
coating has been applied or where a hard protective coating has not been applied, the tanks in question may be internally
examined at annual surveys. When considered necessary by the surveyor or where extensive corrosion exists, thickness meas-
urements are to be carried out.
(4) Where substantial corrosion is found, the extent of thickness measurements is to be increased in accordance with Tab 7 to
Tab 11.
These extended thickness measurements are to be carried out before the survey is credited as completed. Suspect areas identi-
fied at previous surveys are to be examined. Areas of substantial corrosion identified at previous surveys are to be subjected to
thickness measurements.
(5) The extent of thickness measurements may be specially considered provided the Surveyor is satisfied by the close-up surveys
that there is no structural diminution and the hard protective coating is found to be in good condition.
4.2 Scope of survey attending Surveyor's satisfaction to ensure that tightness and
condition remain satisfactory.
4.2.1 (1/7/2007)
In addition to the requirements of annual surveys, the class 4.2.4 The survey extent of ballast tanks converted to void
renewal survey is to include examination, tests and checks spaces will be specially considered by the Society in rela-
of sufficient extent to ensure that the hull and related pip- tion to the requirements for ballast tanks.
ing, as required in [4.2.3], are in a satisfactory condition 4.2.5 (1/7/2024)
and are fit for their intended purpose for the new period of Where provided, the condition of the corrosion prevention
class to be assigned, subject to proper maintenance and system of ballast tanks is to be examined.
operation and to periodical surveys being carried out at the For ballast tanks, excluding double bottom tanks, where a
due dates. hard protective coating is found in poorto be in less than
4.2.2 (1/7/2007) good condition, and it is not renewed, or where a soft or
semi-hard coating has been applied, or where a hard pro-
All cargo holds, ballast tanks, including double bottom
tective coating has not been applied since the time of con-
tanks, pipe tunnels, cofferdams and void spaces bounding
struction, the tanks in question are to be examined at
cargo holds, decks and outer hull are to be examined, and
annual surveys. Thickness measurements are to be carried
this examination is to be supplemented by thickness meas-
out as deemed necessary by the Surveyor.
urement and testing as required in [4.5] and [4.6] respec-
tively, to ensure that the structural integrity remains When such a breakdown of hard protective coating is found
effective. The aim of the examination is to discover substan- in water ballast double bottom tanks and is not renewed,
tial corrosion, significant deformation, fractures, damage or where a soft or semi-hard coating has been applied, or
other structural deterioration that may be present. where a hard protective coating has not been applied since
the time of construction, the tanks in question may be
4.2.3 (1/7/2006) examined at annual surveys. When considered necessary
All piping systems within the above spaces are to be exam- by the Surveyor, or where extensive corrosion exists, thick-
ined and operationally tested to working pressure to the ness measurements are to be carried out.
272 RINA Rules 2024

...OMISSIS...
Pt A, Ch 4, Sec 3
SECTION 3 OIL TANKERS AND COMBINATION CARRIERS
1 General 1.2.2 A survey report file is to be a part of the documenta-

tion on board consisting of:
1.1 Application • reports of structural surveys
• hull condition evaluation report (summarising the
1.1.1 (1/7/2011)
results of class renewal surveys)
The requirements of this Section apply to all self-propelled
• thickness measurement reports.
ships, other than double hull oil tankers, which have been
assigned one of the following service notations: The survey report file is also to be available in the Owner's
• asphalt tanker ESP management office.
• oil tanker ESP 1.2.3 (1/1/2008)
• combination carrier/OBO ESP The following additional supporting documentation is to be
• combination carrier/OOC ESP available on board:
• survey program, as required in [6.1], until such time as
Self-propelled ships which have been assigned the service the class renewal survey or the intermediate survey, as
notation oil tanker, without integral cargo tanks and having applicable, has been completed
independent cargo tanks within the hull, are to be surveyed, • main structural plans of cargo tanks/holds and ballast
as far as applicable, according to the provisions given for tanks
ships having the service notation liquefied gas carrier, as far
• previous repair history
as hull surveys are concerned, as laid down in Sec 6.
• cargo and ballast history
1.1.2 The requirements for hull surveys apply to the sur- • extent of use of inert gas system and tank cleaning pro-
veys of the hull structure and piping systems in way of cargo cedures
tanks, pump rooms, cofferdams, pipe tunnels and void • ship’s personnel reports on:
spaces within the cargo area and all salt water ballast tanks.
- structural deterioration/defects in general
They are additional to the requirements applicable to the
remainder of the ship, given in Chapter 3 according to the - leakage in bulkheads and piping systems
relevant surveys. - condition of coatings or corrosion prevention sys-
tems, if any
1.1.3 The requirements contain the minimum extent of • any other information that may help to identify critical
examination, thickness measurements and tank testing. structural areas and/or suspect areas requiring inspec-
When substantial corrosion, as defined in Ch 2, Sec 2, tion.
be extended and is to include additional close-up surveys 1.2.4 Prior to survey, the Surveyor examines the documen-
when necessary. tation on board and its contents, which are used as a basis
1.1.4 (1/1/2019) for the survey.
When, in any survey, thickness measurements are required :
• the procedure detailed in Ch 2, Sec 2, [2.3] is to be 1.3 Reporting and evaluation of surveys
applied 1.3.1 The data and information on the structural condition
• the thickness measurement firm is to be part of the sur- of the ship collected during survey are evaluated for
vey planning meeting held prior to commencing the acceptability and structural integrity of the ship's cargo
survey. area.
1.1.5 The requirements for machinery surveys apply to 1.3.2 (1/7/2005)
surveys of the machinery and equipment in the cargo area In the case of oil tankers of 130 m in length and upwards
or dedicated to cargo service systems and are additional to (as defined in the International Convention on Load Lines in
those given in Chapter 3 for all ships. force), the ship's longitudinal strength is to be evaluated by
using the thickness of structural members measured,
renewed and reinforced, as appropriate, during the class
1.2 Documentation on board
renewal survey carried out after the ship reached 10 years
1.2.1 The Owner is to supply and maintain documentation of age in accordance with the criteria for longitudinal
on board as specified in [1.2.2] and [1.2.3], which is to be strength of the ship's hull girder for oil tankers specified in
readily available for examination by the Surveyor. The doc- Ch 2, App 4.
umentation is to be kept on board for the lifetime of the The final result of evaluation of the ship's longitudinal
ship. strength required above, after renewal or reinforcement

Pt A, Ch 4, Sec 3
4.4.3 (1/7/2006) • gas distribution lines and shut-off valves, including soot
In application of [4.4.1], an underwater survey may be con- blower interlocking devices, are to be examined as
sidered in lieu of the requirements of [6.2.5]. deemed necessary
• all automatic shutdown devices and alarms are to be
4.5 Ships over 15 years of age examined and tested.
4.5.1 (1/7/2006)
6 Class renewal survey - Hull items
The requirements of the intermediate survey are to be to the
same extent as the previous class renewal survey as
required in [6]. However, pressure testing of cargo and bal-
6.1 Survey program and preparation for hull
last tanks and the provisions for longitudinal strength evalu- survey
ation of the hull girder as given in Ch 2, App 4, [6] are not 6.1.1 (1/1/2008)
required unless deemed necessary by the attending Sur- The Owner, in co-operation with the Society, is to work out
veyor. a specific survey program prior to the commencement of
4.5.2 (1/7/2006) any part of:
In application of [4.5.1], the intermediate survey may be • the class renewal survey
commenced at the second annual survey and be progressed • the intermediate survey for oil tankers over 10 years of
during the succeeding year with a view to completion at the age.
[4.2.1]. Prior to the development of the survey program, the Survey
Planning Questionnaire is to be completed by the Owner
4.5.3 (1/7/2006) based on the information set out in [6.9], and forwarded to
In application of [4.5.1], a bottom survey in dry condition is the Society.
to be part of the intermediate survey. The overall and close- The survey program is to be in a written format, based on
up surveys and thickness measurements, as applicable, of the information in [6.8]. The survey is not to commence
the lower portions of the cargo tanks and ballast tanks (see until the survey program has been agreed. The survey pro-
Note 1) are to be carried out in accordance with the appli- gram at intermediate surveys may consist of the survey pro-
cable requirements for intermediate surveys, if not already gram at the previous class renewal survey supplemented by
performed. the condition evaluation report of that class renewal survey
Note 1: Lower portions of the cargo and ballast tanks are consid- and later relevant survey reports.
ered to be the parts below the light ballast waterline.
any amendments to the survey requirements implemented
5 Intermediate survey - Cargo machin- after the last class renewal survey carried out.
ery items 6.1.2 (1/1/2019)
In developing the survey program, the following documen-
5.1 Cargo area and cargo pump rooms tation is to be collected and consulted with a view to select-
ing tanks, areas and structural elements to be examined:
5.1.1 A general examination of the electrical equipment a) survey status and basic ship information
and cables in dangerous zones such as cargo pump rooms
and areas adjacent to cargo tanks is to be carried out for b) documentation on board, as described in [1.2.2] and
defective and non-certified safe type electrical equipment [1.2.3]
and fixtures, non-approved lighting and fixtures, and c) main structural plans of cargo and ballast tanks (scant-
improperly installed or defective or dead-end wiring. ling drawings), including information regarding use of
high tensile steels (HTS);
5.1.2 The electrical insulation resistance of the electrical
d) Executive Hull Summary (or Condition Evaluation
equipment and circuits terminating in or passing through
Report);
the dangerous zones is to be tested; however, in cases
where a proper record of testing is maintained, considera- e) relevant previous damage and repair history;
tion may be given to accepting recent test readings effected f) relevant previous survey and inspection reports from
by the ship’s personnel. both the recognised organisation and the Owner;
g) cargo and ballast history for the last 3 years, including
5.1.3 The satisfactory condition of the cargo heating sys-
carriage of cargo under heated conditions;
tem is to be verified.
h) details of the inert gas plant and tank cleaning proce-
dures;
5.2 Inert gas system
i) information and other relevant data regarding conver-
5.2.1 For ships over 10 years old at the time of the interme- sion or modification of the ship's cargo and ballast tanks
diate survey due date, the following is to be carried out: since the time of construction;
• main parts such as the scrubber, washing machines, j) description and history of the coating and corrosion
blowers, deck water seal and non-return valve are to be protection system (including previous class notations), if
opened out as considered necessary and examined any;
292 RINA Rules 2024

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Pt A, Ch 4, Sec 3
Table 8 : Requirements for extent of thickness measurements at those areas of substantial corrosion
Class renewal survey of oil tankers and combination carriers within the cargo area
TRANSVERSE BULKHEADS AND SWASH BULKHEADS

Structural member Extent of measurement Pattern of measurement
Deckhead and bottom strakes, and strakes Plating between pair of stiffeners at three 5-point pattern between stiffeners over 1
in way of stringer platforms locations : approximately 1/4, 1/2 and 3/4 metre length
width of tank
All other strakes Plating between pair of stiffeners at mid- Single measurement
dle location
Strakes in corrugated bulkheads Plating for each change of scantling at 5-point pattern over about 1 square metre
centre of panel and at flange of fabricated of plating
connection
Stiffeners Minimum of three typical stiffeners For web, 5-point pattern over span
between bracket connections (2 measure-
ments across web at each bracket connec-
tion and one at centre of span). For flange,
single measurements at each bracket toe
and at centre of span
Brackets Minimum of three at top, middle and bot- 5-point pattern over area of bracket
tom of tank
Deep webs and girders Measurements at toe of bracket and at For web, 5-point pattern over about 1
centre of span square metre. Three measurements across
face flat
Stringer platforms All stringers with measurements at both 5-point pattern over 1 square metre of
ends and middle area plus single measurements near
bracket toes and on face flats
6.4.5 (1/7/2006) surveyor provided the following conditions are complied

For areas in tanks where hard protective coatings are found with:
to be in good condition as defined in Ch 2, Sec 2, [2.2.13], a) a tank testing procedure, specifying fill heights, tanks
the extent of thickness measurements according to Tab 4 being filled and bulkheads being tested, has been sub-
may be specially considered. mitted by the owner and reviewed by the Society prior
to the testing being carried out;
6.4.6 (1/7/2005)
b) the tank testing is carried out prior to overall survey or
Transverse sections are to be chosen where the largest close-up survey;
reductions are suspected to occur or are revealed from deck
plating measurements. c) the tank testing is carried out within the special survey
window and not more than 3 months prior to the date
6.4.7 (1/7/2005) on which the overall or close up survey is completed;
In cases where two or three sections are to be measured, at bd) the tank testing has been satisfactorily carried out and
least one is to include a ballast tank within 0,5L amidships. there is no record of leakage, distortion or substantial
corrosion that would affect the structural integrity of the
In the case of oil tankers of 130 m in length and upwards (as
tank;
defined in the International Convention on Load Lines in
force) and more than 10 years of age, for the evaluation of c) the tank testing has been satisfactorily carried out within
the ship's longitudinal strength as required in [1.3.2], the special survey window not more than 3 months prior to
sampling method of thickness measurements is given in the date of the survey on which the overall or close up
Ch 2, App 4, [6]. survey is completed;
ed) the satisfactory results of the testing are recorded in the
6.5 Tank testing vessel's logbook; and
fe) the internal and external condition of the tanks and
6.5.1 (1/7/2024) associated structure are found satisfactory by the
The minimum requirements for ballast tank testing at surveyor at the time of the overall and close up survey.
renewal survey are given in [6.5.3] and Tab 9.
6.5.2 The Surveyor may extend the tank testing as deemed
The minimum requirements for cargo tank testing at necessary.
renewal survey are given in [6.5.4] and Tab 8. 6.5.3 (1/7/2006)
Cargo tank testing carried out by the vesselship's crew Boundaries of ballast tanks are to be tested with a head of
under the direction of the Master may be accepted by the liquid to the top of air pipes.
RINA Rules 2024 299

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Pt A, Ch 4, Sec 4
SECTION 4 DOUBLE HULL OIL TANKERS
1 General umentation is to be kept on board for the lifetime of the

ship.
1.1 Application For tankers and bulk carriers subject to SOLAS Chapter II-1
Part A-1 Regulation 3-10, the Owner is to arrange the
1.1.1 (1/7/2011) updating of the Ship Construction File (SCF) throughout the
The requirements of this Section apply to all self-propelled ship's life whenever a modification of the documentation
ships which have been assigned one of the following ser- included in the SCF has taken place. Documented proce-
vice notations: dures for updating the SCF are to be included within the
• oil tanker ESP - double hull Safety Management System.
• oil tanker ESP CSR. 1.2.2 (1/1/2003)

A survey report file is to be a part of the documentation on
Self-propelled ships which have been assigned the service board consisting of:
notation oil tanker-double hull, without integral cargo tanks
• reports of structural surveys
and having independent cargo tanks within the hull, are to
be surveyed, as far as applicable, according to the provi- • hull condition evaluation report (summarising the
sions given for ships having the service notation liquefied results of class renewal surveys)
gas carrier, as far as hull surveys are concerned, as laid • thickness measurement reports.
down in Sec 6.
The survey report file is also to be available in the Owner's
1.1.2 (1/1/2003) management office.
The requirements for hull surveys apply to the surveys of the 1.2.3 (1/7/2016)
hull structure and piping systems in way of cargo tanks,
pump rooms, cofferdams, pipe tunnels and void spaces The following additional supporting documentation is to be
within the cargo area and all salt water ballast tanks. They available on board:
are additional to the requirements applicable to the remain- • survey program, as required in [4.1], until such time as
der of the ship, given in Chapter 3 according to the relevant the class renewal survey or the intermediate survey, as
surveys. applicable, has been completed
1.1.3 (1/1/2003) • main structural plans of cargo and ballast tanks (for CSR
ships these plans are to include for each structural ele-
The requirements contain the minimum extent of examina-
ment both the as-built and renewal thickness. Any thick-
tion, thickness measurements and tank testing. When sub-
ness for voluntary addition is also to be clearly indicated
stantial corrosion, as defined in Ch 2, Sec 2, [2.2.9], and/or
on the plans. The Midship Section plan to be supplied
structural defects are found, the survey is to be extended
on board the ship is to include the minimum allowable
and is to include additional close-up surveys when neces-
hull girder sectional properties for the tank transverse
sary.
section in all cargo tanks)
1.1.4 (1/1/2019) • previous repair history
When, in any survey, thickness measurements are required: • cargo and ballast history
• the procedure detailed in Ch 2, Sec 2, [2.3] is to be • extent of use of inert gas system and tank cleaning pro-
applied cedures
• the thickness measurement firm is to be part of the sur- • ship's personnel reports on:
vey planning meeting held prior to commencing the
- structural deterioration/defects in general
survey.
- leakage in bulkheads and piping systems
1.1.5 (1/1/2003)
- condition of coatings or corrosion prevention sys-
For machinery surveys, the requirements given in Sec 3 tems, if any
apply.
• any other information that may help to identify critical
structural areas and/or suspect areas requiring inspec-
1.2 Documentation on board tion.
1.2.1 (1/7/2016) For double hull tankers subject to SOLAS Chapter II-1 Part
The Owner is to supply and maintain documentation on A-1 Regulation 3-10, the Ship Construction File (SCF), lim-
board as specified in [1.2.2] and [1.2.3], which is to be ited to the items to be retained on board, is to be available
readily available for examination by the Surveyor. The doc- on board.
RINA Rules 2024 307

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Pt A, Ch 4, Sec 4
4 Class renewal survey - Hull items l) information regarding the relevant maintenance level
during operation including Port State Control reports of
inspection containing hull related deficiencies, Safety
4.1 Survey program and preparation for hull Management System non-conformities relating to hull
survey maintenance, including the associated corrective
4.1.1 (1/1/2008) action(s); and
The Owner, in co-operation with the Society, is to work out m) any other information that will help identify suspect
a specific survey program prior to the commencement of areas and critical structural areas.
any part of:
4.1.3 (1/1/2019)
• the class renewal survey
The submitted survey program is to take account of and
• the intermediate survey for double hull oil tankers over comply with at least the requirements for close-up surveys,
10 years of age. thickness measurements and tank testing given in Tab 2,
Prior to the development of the survey program, the Survey Tab 3 and [4.5], respectively. In addition, the survey pro-
Planning Questionnaire is to be completed by the Owner gram is to include at least:
based on the information set out in [4.9], and forwarded to a) basic ship information and particulars;
the Society.
b) main structural plans (scantling drawings), including
The survey program is to be in a written format, based on information regarding use of high tensile steels (HTS);
the information in [4.8]. The survey is not to commence
c) plan of tanks
until the survey program has been agreed. The survey pro-
gram at intermediate surveys may consist of the survey pro- d) list of tanks with information on use, corrosion preven-
gram at the previous class renewal survey supplemented by tion and condition of coating;
the condition evaluation report of that class renewal survey e) conditions for survey (e.g. information regarding tank
and later relevant survey reports. cleaning, gas freeing, ventilation, lighting etc);
The survey program is to be worked out taking into account f) provisions and methods for access to structures;
any amendments to the survey requirements implemented
after the last class renewal survey carried out. g) equipment for surveys;
4.1.2 (1/1/2019) h) nomination of tanks and areas for close-up survey (see
[4.3]);
In developing the survey program, the following documen-
tation is to be collected and consulted with a view to select- i) nomination of sections for thickness measurement (see
ing tanks, areas and structural elements to be examined: [4.4]);
a) survey status and basic ship information; j) nomination of tanks for tank testing (see [4.5]);
b) documentation on board, as described in [1.2.2] and k) identification of the thickness measurement firm;
[1.2.3]
l) damage experience related to the ship in question;
c) main structural plans of cargo and ballast tanks (scant-
m) critical structural areas and suspect areas, where rele-
ling drawings), including information regarding use of
vant.
high tensile steels (HTS);
4.1.4 (1/1/2003)
d) Executive Hull Summary (or Conditional Evaluation
Report); The survey program is also to include the maximum accept-
able structural corrosion diminution levels applicable to the
e) relevant previous damage and repair history;
ship. The Society will advise the Owner of this information.
f) relevant previous survey and inspection reports from
4.1.5 (1/1/2003)
both the recognised organisation and the Owner;
In addition, the survey program is to include proposals on
g) cargo and ballast history for the last 3 years, including how to conduct surveys and tests in a safe and practical
carriage of cargo under heated conditions;. way, including the means of providing access to structures
h) details of the inert gas plant and tank cleaning proce- for close-up survey, thickness measurements and tank test-
dures; ing. All other provisions described in Ch 2, Sec 2, [2.3],
i) information and other relevant data regarding conver- Ch 2, Sec 2, [2.5], Ch 2, Sec 2, [2.7], Ch 2, Sec 2, [2.8] and
sion or modification of the ship's cargo and ballast tanks Ch 2, Sec 2, [2.10] regarding procedures for thickness
since the time of construction; measurements, conditions for survey, access to structures,
equipment for survey and survey at sea or at anchorage,
j) description and history of the coating and corrosion respectively, are also to be complied with.
protection system (including previous class notations), if
any; 4.1.6 Survey Planning Meeting (1/1/2019)
k) inspections by the Owner's personnel during the last 3 Proper preparation and close co-operation between the
years with reference to structural deterioration in gen- attending Surveyor(s) and the Owner's representatives on
eral, leakages in tank boundaries and piping, and condi- board prior to and during the survey are an essential part in
tion of the coating and corrosion protection system, if the safe and efficient conduct of the survey. During the sur-
any (guidance for reporting is shown in Tab 15); vey on board safety meetings are to be held regularly.
RINA Rules 2024 311

...OMISSIS...
Pt A, Ch 4, Sec 4
4.4.3 (1/7/2006) date on which the overall or close up survey is

The Surveyor may further extend the thickness measure- completed;
ments as deemed necessary. bd) the tank testing has been satisfactorily carried out and
4.4.4 (1/1/2016) there is no record of leakage, distortion or substantial
For ships not built under the Common Structural Rules, corrosion that would affect the structural integrity of the
when pitting is found on bottom plating and its intensity is tank;
20% or more, thickness measurements are to be extended c) the tank testing has been satisfactorily carried out within
in order to determine the actual plate thickness out of the special survey window not more than 3 months prior to
pits and the depth of the pits. Where the wastage is in the the date of the survey on which the overall or close up
substantial corrosion range or the average depth of pitting is survey is completed;
1/3 or more of the actual plate thickness, the pitted plate is
to be considered as a substantially corroded area. ed) the satisfactory results of the testing are recorded in the
vessel's logbook; surveyor at the time of the overall and
For ships built under the Common Structural Rules, the close up survey.s logbook; and
acceptance criteria for pitting is:
fe) the internal and external condition of the tanks and
• according to Section 12 of the Common Structural Rules associated structure are found satisfactory by the
for Oil Tankers and as specified in Ch 2, App 3, [4.2.2] surveyor at the time of the overall and close up survey.
for ships contracted for construction on or after 1 April
2006 but before 1 July 2015, or 4.5.2 (1/1/2003)
• according to Ch 2, App 3, [4.2.2] for ships contracted The Surveyor may extend the tank testing as deemed neces-
for construction on or after 1 July 2015. sary.
4.4.5 (1/7/2006) 4.5.3 (1/7/2006)

For areas in tanks where hard protective coatings are found Boundaries of ballast tanks are to be tested with a head of
to be in good condition as defined in Ch 2, Sec 2, [2.2.13], liquid to the top of air pipes.
the extent of thickness measurements according to Tab 3 4.5.4 (1/7/2006)
may be specially considered. Boundaries of cargo tanks are to be tested to the highest
4.4.6 (1/7/2005) point that liquid will rise to under service conditions.
Transverse sections are to be chosen where the largest 4.5.5 (1/7/2006)
reductions are suspected to occur or are revealed from deck
The testing of double bottom tanks and other spaces not
plating measurements.
designed for the carriage of liquid may be omitted, provided
4.4.7 (1/7/2005) a satisfactory internal examination is carried out together
In cases where two or three sections are to be measured, at with an examination of the tank top.
least one is to include a ballast tank within 0,5L amidships.
In the case of oil tankers of 130 m in length and upwards (as 4.6 Cargo area and cargo pump rooms
defined in the International Convention on Load Lines in
4.6.1 (1/7/2013)
force) and more than 10 years of age, for the evaluation of
the ship's longitudinal strength as required in [1.3.2], the Cargo piping on deck, including crude oil washing (COW)
sampling method of thickness measurements is given in piping, and cargo and ballast piping within the cargo area
Ch 2, App 4, [6]. are to be examined and operationally tested to working
pressure to the attending Surveyor's satisfaction to ensure
that their tightness and condition remain satisfactory. Where
4.5 Tank testing provided, special attention is to be given to any ballast pip-
4.5.1 (1/7/2024) ing in cargo tanks and any cargo piping in ballast tanks and
The minimum requirements for ballast tank testing at void spaces.
Special Survey are given in [4.5.3] and Tab 9. Surveyors are to be advised on all occasions when this pip-
The minimum requirements for cargo tank testing at Special ing, including valves and fittings, is opened during repair
Survey are given in [4.5.4] and Tab 9. periods and can be examined internally.
Cargo tank testing carried out by the vessel's crew under the The Surveyor may require dismantling and/or thickness
direction of the Master may be accepted by the surveyor measurements of piping. A hydraulic test is to be carried out
provided the following conditions are complied with: in the event of repair or dismantling of cargo, crude oil
a) a tank testing procedure, specifying fill heights, tanks washing, or ballast piping, or where doubts arise.
being filled and bulkheads being tested, has been It is to be confirmed that pipelines are electrically bonded
submitted by the owner and reviewed by the Society to the hull or, alternatively, electrical resistance to the hull is
prior to the testing being carried out; to be verified.
b) the tank testing is carried out prior to overall survey or 4.6.2 (1/1/2003)
close-up survey; All safety valves on cargo piping and of cargo tanks are to
c) the tank testing is carried out within the special survey be dismantled for examination, adjusted and, as applicable,
window and not more than three months prior to the resealed.
318 RINA Rules 2024

...OMISSIS...
Pt A, Ch 4, Sec 5
SECTION 5 CHEMICAL TANKERS
1 General Surveyor. The documentation is to be kept on board for the

lifetime of the ship.
1.1 Application 1.2.2 Survey Report File
1.1.1 (1/7/2011) A survey report file is to be a part of the documentation on
The requirements of this Section apply to all self-propelled board consisting of:
ships which have been assigned the service notation • reports of structural surveys
chemical tanker ESP.
• hull condition evaluation report (summarising the
Self-propelled ships which have been assigned the service results of class renewal surveys)
notation chemical tanker, without integral cargo tanks and
having independent cargo tanks within the hull, are to be
surveyed, as far as applicable, according to the provisions The survey report file is also to be available in the Owner's
given for ships having the service notation liquefied gas management office.
carrier, as far as hull surveys are concerned, as laid down in
Sec 6. 1.2.3 Supporting documents (1/7/2024)
The following additional supporting documentation is to be
1.1.2 The requirements for hull surveys apply to the available on board:
surveys of the hull structure and piping systems in way of
cargo tanks, pump rooms, cofferdams, pipe tunnels and • survey program, as required in [6.1], until such time as
void spaces within the cargo area and all salt water ballast the class renewal survey or the intermediate survey, as
tanks. These requirements, however, do not apply to applicable, has been completed
independent tanks on deck. They are additional to the • main structural plans of cargo and ballast tanks
requirements applicable to the remainder of the ship, given • previous repair history
in Chapter 3 according to the relevant surveys. • cargo and ballast history
1.1.3 The requirements contain the minimum extent of • extent of use of inert gas system and tank cleaning
examination, thickness measurements and tank testing. procedures
When substantial corrosion, as defined in Ch 2, Sec 2, • inspections by ship’s personnel reports onwith reference
[2.2.9], and/or structural defects are found, the survey is to to:
be extended and is to include additional close-up surveys - structural deterioration/defects in general
when necessary.
- leakage in bulkheads and piping systems
1.1.4 (1/1/2019)
- condition of coatings or corrosion prevention
When, in any survey, thickness measurements are required :
systems, if any
• the procedure detailed in Ch 2, Sec 2, [2.3] is to be
- a guidance for reporting is shown in Tab 1
applied
• the thickness measurement firm is to be part of the
survey planning meeting held prior to commencing the • any other information that may help to identify critical
survey. structural areas and/or suspect areas requiring
inspection.
1.1.5 (1/1/2019)
When close-up surveys are required, consideration maybe 1.2.4 Prior to survey, the Surveyor examines the
given by the Surveyor to allow the use of Remote Inspection documentation on board and its contents, which are used
Techniques (RIT), according to the provisions of Ch 2, as a basis for the survey.
Sec 2, [2.3.3] and Ch 2, Sec 2, [2.6].
1.3 Reporting and evaluation of surveys
1.1.6 The requirements for machinery surveys apply to
surveys of the machinery and equipment in the cargo area 1.3.1 The data and information on the structural condition
or dedicated to cargo service systems and are additional to of the ship collected during survey are evaluated for
those given in Chapter 3 for all ships. acceptability and structural integrity of the ship's cargo
area.
1.2 Documentation on board 1.3.2 (1/7/2006)
1.2.1 General (1/1/2010) For ships subject to the requirements of this Section, the
The Owner is to obtain, supply and maintain surveys of hull structure and piping systems are reported in
documentation on board as specified in [1.2.2] and [1.2.3], conformance to the Survey Reporting Principles laid down
which is to be readily available for examination by the in App 1.
326 RINA Rules 2024

...OMISSIS...
Pt A, Ch 4, Sec 9
SECTION 9 DOUBLE SKIN BULK CARRIERS AND SELF-

UNLOADING BULK CARRIERS OF DOUBLE SKIN
CONSTRUCTION
1 General 1.1.6 (1/1/2017)

For self-unloading bulk carrier the additional requirements
for the cargo handling system are given in Sec 2, [2.8] and
1.1 Application
Sec 2, [4.8], respectively for annual survey and class
1.1.1 (1/1/2017) renewal survey.
The requirements of this Section apply to all self-propelled
double skin bulk carriers. These ships are assigned with one 1.2 Documentation on board
of the following service notations: 1.2.1 (1/7/2016)
• bulk carrier ESP - double skin The Owner is to supply and maintain documentation on
• ore carrier ESP board as specified in [1.2.2] and [1.2.3], which is to be
readily available for examination by the Surveyor.
• combination carrier/OBO ESP (see Note 1)
For bulk carriers subject to SOLAS Chapter II-1 Part A-1
• combination carrier/OOC ESP (see Note 1) Regulation 3-10, the Owner is to arrange the updating of
• bulk carrier ESP CSR - double skin. the Ship Construction File (SCF) throughout the ship's life
whenever a modification of the documentation included in
• Self-Unloading Bulk Carrier ESP - double skin. the SCF has taken place.
Note 1: For combination carriers with longitudinal bulkheads, Documented procedures for updating the SCF are to be
additional requirements are specified in Sec 3 or Sec 4, as included within the Safety Management System.
applicable.
1.2.2 (1/1/2005)
1.1.2 (1/1/2005)
A survey report file is to be a part of the documentation on
For bulk carriers with hybrid cargo hold arrangements, e.g. board consisting of:
with some cargo holds of single side skin and others of
• reports of structural surveys
double side skin, the requirements of Sec 2 are to apply to
cargo holds of single side skin. • hull condition evaluation report (summarising the
results of class renewal surveys)
1.1.3 (1/1/2005)
The requirements apply to surveys of the hull structure and
piping systems in way of cargo holds, cofferdams, pipe The survey report file is also to be available in the Owner's
tunnels and void spaces within the cargo area and all salt management office.
water ballast tanks. They are additional to the requirements 1.2.3 (1/7/2024)
applicable to the remainder of the ship, given in Chapter 3
according to the relevant surveys. The following additional supporting documentation is to be
available on board:
1.1.4 (1/1/2005)
a) survey program, as required in [4.1], until such time as
The requirements contain the minimum extent of the class renewal survey or the intermediate survey, as
examination, thickness measurements and tank testing. applicable, has been completed
When substantial corrosion, as defined in Ch 2, Sec 2,
b) main structural plans of cargo holds and ballast tanks,
(for CSR ships these plans are to include for each
be extended and is to include additional close-up surveys
structural element both the as-built and renewal
when necessary.
thickness.
1.1.5 (1/1/2019) Any thickness for voluntary addition is also to be clearly
When, in any survey, thickness measurements are required: indicated on the plans. The midship section plan to be
supplied on board the ship is to include the minimum
• the procedure detailed in Ch 2, Sec 2, [2.3] is to be
allowable hull girder sectional properties for hold
applied
transverse section in all cargo holds).
• the thickness measurement firm is to be part of the
c) previous repair history
survey planning meeting held prior to commencing the
survey. d) cargo and ballast history
374 RINA Rules 2024

Pt A, Ch 4, Sec 9
e) inspection by ship's personnel reports onwith reference 1.3.2 (1/7/2006)

to: For ships subject to the requirements of this Section, the
• structural deterioration/defects in general surveys of hull structure and piping systems are reported in
conformance to the Survey Reporting Principles laid down
• leakage in bulkheads and piping systems
in App 1.
• condition of coatings or corrosion prevention
systems, if any 1.3.3 (1/1/2005)
A hull condition evaluation report (summarising the results
• a guidance for reporting is shown in Tab 15
of class renewal surveys) is issued by the Society to the
f) any other information that may help to identify critical Owner, who is to place it on board the ship for reference at
structural areas and/or suspect areas requiring future surveys. The hull condition evaluation report is
inspection. endorsed by the Society.
For bulk carriers subject to SOLAS Chapter II-1 Part A-1
Regulation 3-10, the Ship Construction File (SCF), limited to 2 Annual survey
the items to be retained onboard, is to be available on
board.
2.1 General
1.2.4 (1/1/2018)
2.1.1 (1/1/2019)
Prior to survey, the Surveyor examines the documentation
The survey is to consist of an examination for the purpose of
on board and its contents, which are used as a basis for the
ensuring, as far as practicable, that the hull, weather decks,
survey.
hatch covers, coamings and piping are maintained in a
For bulk carriers subject to SOLAS Chapter II-1 Part A-1 satisfactory condition and is to take into account the service
Regulation 3-10, on completion of the survey, the surveyor history, condition and extent of the corrosion prevention
is to verify that the update of the Ship Construction File system of ballast tanks and areas identified in the survey
(SCF) has been done whenever a modification of the report file.
documentation included in the SCF has taken place.
For the SCF stored on board ship, the surveyor is to examine 2.2 Hull Structure and Equipment
the information on board ship. 2.2.1 (1/1/2005)
In cases where any major event, including, but not limited Examination of:
to, substantial repair and conversion, or any modification to • the hull plating and its closing appliances as far as can
the ship structures, the surveyor is to also verify that the be seen
updated information is kept on board the ship.
• the watertight penetrations as far as practicable.
If the updating of the SCF onboard is not completed at the
time of survey, the Surveyor records it and requires
2.3 Weather decks, hatch covers and
confirmation at the next periodical survey.
coamings
For the SCF stored on shore archive, the surveyor is to
2.3.1 (1/1/2005)
examine the list of information included on shore archive.
Confirmation is to be obtained that no unapproved changes
In cases where any major event, including, but not limited have been made to the hatch covers, hatch coamings and
to, substantial repair and conversion, or any modification to their securing and sealing devices since the last survey.
the ship structures, the surveyor is to also verify that the
updated information is stored on shore archive by 2.3.2 (1/1/2008)
examining the list of information included on shore archive A thorough survey of cargo hatch covers and coamings is
or kept on board the ship. only possible by examination in the open as well as closed
positions and is to include verification of proper opening
In addition, the surveyor is to confirm that the service
and closing operation. As a result, the hatch cover sets
contract with of the Archive Center is valid.
within the forward 25% of the ship's length and at least one
If the updating of the SCF Supplement ashore is not additional set, such that all sets on the ship are assessed at
completed at the time of survey, the Surveyor records it and least once in every 5-year period, are to be surveyed open,
requires confirmation at the next periodical survey. closed and in operation to the full extent in each direction
For bulk carriers subject to SOLAS Chapter II-1 Part A-1 at each annual survey, including:
Regulation 3-10, on completion of the survey, the surveyor a) stowage and securing in open condition;
is to verify any addition and/or renewal of materials used for b) proper fit and efficiency of sealing in closed condition;
the construction of the hull structure are documented and
within the Ship Construction File list of materials.
c) operational testing of hydraulic and power components,
wires, chains, and link drives.
1.3 Reporting and evaluation of surveys
The closing of the covers is to include the fastening of all
1.3.1 (1/1/2005) peripheral and cross-joint cleats or other securing devices.
The data and information on the structural condition of the Particular attention is to be paid to the condition of the
ship collected during survey are evaluated for acceptability hatch covers in the forward 25% of the ship's length, where
and structural integrity of the ship's cargo area. sea loads are normally greatest.
RINA Rules 2024 375

...OMISSIS...
Pt A, Ch 4, Sec 9
Suspect areas identified at previous surveys are to be 2.6 Additional requirements after
examined. Areas of substantial corrosion identified at determining compliance with SOLAS
previous surveys are to be subjected to thickness
regulations XII/12 (water level
measurements.
detectors) and XII/13 (availability of
For ships built under the Common Structural Rules, the
pumping systems)
annual thickness gauging may be omitted where a
protective coating has been applied in accordance with 2.6.1 (1/1/2007)
the coating manufacturer's requirements and is For ships complying with the requirements of SOLAS XII/12
maintained in good condition. for hold, ballast and dry space water level detectors, the
annual survey is to include an examination and a test, at
c) All piping and penetrations in cargo holds, including
random, of the water ingress detection systems and of their
overboard piping, are to be examined.
alarms.
2.6.2 (1/1/2007)
2.5 Ballast tanks
For ships complying with the requirements of SOLAS XII/13
2.5.1 (1/1/2005) for the availability of pumping systems, the annual survey is
Ballast tanks are to be internally examined when required to include an examination and a test of the means for
as a consequence of the results of the class renewal survey draining and pumping ballast tanks forward of the collision
or intermediate survey. bulkhead and bilges of dry spaces, any part of which
extends forward of the foremost cargo hold, and of their
2.5.2 (1/7/2012)
controls.
When considered necessary by the Surveyor, or where
extensive corrosion exists, thickness measurements are to
be carried out. If the results of these thickness 2.7 Examination of double-side skin void
measurements indicate that substantial corrosion is present, spaces for bulk carriers exceeding 20
the extent of thickness measurements is to be increased in years of age and of 150 m in length and
accordance with Tab 5 to Tab 8. These extended thickness upwards
measurements are to be carried out before the annual 2.7.1 (1/7/2024)
survey is credited as complete.
Examination of double-side skin void spaces, for bulk
2.5.3 (1/7/2012) carriers exceeding 20 years of age and of 150 m in length
Suspect areas identified at previous surveys are to be and upwards, are to be carried out when required as a
examined. Areas of substantial corrosion identified at consequence of the results of the renewal survey (as
previous surveys are to be subjected to thickness required by [4.2.8]) and intermediate survey (as required by
measurements. [3.3.1]). When considered necessary by the Administration,
or when extensive corrosion exists, thickness measurements
should be carried out. If the results of these thickness
annual thickness gauging may be omitted where a
measurements indicate that substantial corrosion is found,
protective coating has been applied in accordance with the
the extent of thickness measurements should be increased
coating manufacturer's requirements and is maintained in
in accordance with Tab 5 to Tab 8. These extended
good condition.
thickness measurements should be carried out before the
2.5.4 (1/7/2011) survey is credited as completed. Suspect areas identified at
Confirmation is to be given that the corrosion prevention previous surveys should be examined. Areas of substantial
system fitted to dedicated ballast water tanks when corrosion identified at previous surveys should have
appropriate is maintained. thickness measurements taken.
For bulk carriers built under the Common Structural Rules,
the annual thickness gauging may be omitted where a
protective coating has been applied in accordance with the
coating manufacturer's requirements and is maintained in
good condition.
2.8 Means of access

2.8.1 (1/7/2011)
Confirmation is to be given, when appropriate and as far as
is practicable when internal spaces are examined, that the
means of access to cargo and other spaces remain in good
condition.
RINA Rules 2024 377

Pt A, Ch 4, Sec 9
3 Intermediate survey 3.2.3 Extent of thickness measurements (1/7/2012)
a) Thickness measurements are to be carried out to an

3.1 General extent sufficient to determine both general and local
corrosion levels in areas subject to close-up survey,
3.1.1 (1/7/2006) where required as per [3.2.2] b), and as provided in
[3.2.1] c).
The survey extent is dependent on the age of the vessel as
specified in [3.2] to [3.4] and shown in Tab 1. b) The extent of thickness measurement may be specially
considered provided the Surveyor is satisfied by the
3.2 Ships between 5 and 10 years of age close-up survey that there is no structural diminution
and the hard protective coatings are found to be in a
good condition.
3.2.1 Ballast tanks (1/7/2024)
c) Where substantial corrosion is found, the extent of
a) For tanks used for water ballast, an overall survey of
thickness measurements is to be increased in
representative tanks selected by the Surveyor is to be
accordance with the requirements of Tab 5 to Tab 8.
carried out. The selection is to include fore and aft peak
These extended thickness measurements are to be
tanks and a number of other tanks, taking into account
carried out before the survey is credited as completed.
the total number and type of ballast tanks. If such
Suspect areas identified at previous surveys are to be
overall survey reveals no visible structural defects, the
examined. Areas of substantial corrosion identified at
examination may be limited to verification that the
previous surveys are to be subjected to thickness
corrosion prevention system remains efficient.
measurements.
b) Where poor coating a hard coating is found to be in less
than good condition, corrosion or other defects are identified substantial corrosion areas may be:
found in water ballast tanks or where a hard protective
coating has not been applied since the time of 1) protected by coating applied in accordance with the
construction, the examination is to be extended to other coating manufacturer's requirements and examined
ballast tanks of the same type. at annual intervals to confirm the coating in way is
still in good condition, or alternatively
c) In ballast tanks other than double bottom tanks, where a
hard protective coating is found in poor to be in less 2) required to be measured at annual intervals.
than good condition, and it is not renewed, or where a
soft or semi-hard coating has been applied, or where a d) Where a hard protective coating is fitted in cargo holds,
hard protective coating has not been applied since the as defined in Sec 2, [1.1.7], and is found in good
time of construction, the tanks in question are to be condition, the extent of close-up surveys and thickness
examined and thickness measurements carried out as measurements may be specially considered.
considered necessary at annual surveys. When such
breakdown of hard protective coating is found in ballast 3.3 Ships between 10 and 15 years of age
double bottom tanks, or where a soft or semi-hard
coating has been applied, or where a hard protective 3.3.1 (1/7/2006)
coating has not been applied, the tanks in question may
be examined at annual surveys. When considered
same extent as the previous class renewal survey as
necessary by the Surveyor, or where extensive corrosion required in [4]. However, internal examination of fuel oil
exists, thickness measurements are to be carried out. tanks and pressure testing of all tanks are not required
d) In addition to the requirements above, suspect areas unless deemed necessary by the attending Surveyor.
identified at previous surveys are to be examined. 3.3.2 (1/1/2005)
3.2.2 Cargo Holds (1/1/2005) In application of [3.3.1], the intermediate survey may be
commenced at the second annual survey and continued
The requirements of the survey are the following. during the following year with a view to completion at the
third annual survey in lieu of the application of Ch 2, Sec 2,
a) Overall survey of all cargo holds
[4.2.1].
b) Where considered necessary by the Surveyor as a result
3.3.3 (1/1/2005)
of the overall survey as described in a), the survey is to
be extended to include a close-up survey of those areas In application of [3.3.1], an underwater survey may be
of structure in the cargo holds selected by the Surveyor. considered in lieu of the requirements of [4.2.6].
378 RINA Rules 2024

Pt A, Ch 4, Sec 9
Table 1 : Minimum requirements of overall and close-up survey and thickness measurements at intermediate
survey of double skin bulk carriers and self-unloading bulk carriers of double skin construction (1/1/2017)
Age of ship (in years) at time of intermediate survey

5 < age 10 10 < age  15 age >15
Overall survey of representative ballast tanks selected by the attending Surveyor (the The requirements of The requirements of
selection is to include fore and aft peak tanks and a number of other ballast tanks, tak- the previous the previous
ing into account the total number and type of ballast tanks) Renewal Survey. Renewal Survey.
See [3.3]. See [3.4].
Overall and close-up survey of suspect areas identified at previous surveys
Overall survey of all cargo holds
Thickness measurements to an extent sufficient to determine both general and local cor-
rosion levels in areas subject to close-up survey and suspect areas identified at previous
surveys
3.4 Ships over 15 years of age Prior to the development of the survey program, the Survey
Planning Questionnaire is to be completed by the Owner
3.4.1 (1/7/2006) based on the information set out in [4.9], and forwarded to
the Society.
same extent as the previous class renewal survey as The survey program is to be in a written format, based on
required in [4]. However, internal examination of fuel oil the information in [4.8]. The survey is not to commence
tanks and pressure testing of all tanks are not required until the survey program has been agreed. The survey
unless deemed necessary by the attending Surveyor. program at intermediate survey may consist of the survey
program at the previous class renewal survey supplemented
3.4.2 (1/1/2005) by the condition evaluation report of that class renewal
In application of [3.4.1], the intermediate survey may be survey and later relevant survey reports.
commenced at the second annual survey and continued
during the following year with a view to completion at the
any amendments to the survey requirements after the last
class renewal survey carried out.
[4.2.1].
4.1.2 (1/7/2006)
3.4.3 (1/7/2006)
In developing the survey program, the following
In application of [3.4.1], a bottom survey in dry condition is documentation is to be collected and consulted with a view
to be part of the intermediate survey. The overall and close- to selecting tanks, holds, areas and structural elements to be
up surveys and thickness measurements, as applicable, of examined:
the lower portions of the cargo holds and ballast tanks (see
Note 1) are to be carried out in accordance with the • survey status and basic ship information
applicable requirements for intermediate surveys, if not
• the documentation on board, as described in [1.2.2]
already performed.
and [1.2.3]
Note 1: Lower portions of the cargo holds and ballast tanks are
• main structural plans (scantling drawings), including
considered to be the parts below the light ballast waterline.
information on use of high tensile steels (HTS)
• relevant previous survey and inspection reports from
4 Class renewal survey both the Society and the Owner
• information on the use of ship holds and tanks, with
4.1 Survey program and preparation for regard to the nature of the typical cargoes transported
survey and other useful data
4.1.1 (1/1/2008) • information on the corrosion prevention level on the

new building,
The Owner, in cooperation with the Society, is to work out a
specific survey program prior to the commencement of any • information on the relevant maintenance level during
part of: operation.
• the class renewal survey 4.1.3 (1/1/2005)

• the intermediate survey for double skin bulk carriers The survey program is to comply, at least, with the
over 10 years of age. requirements for close-up surveys, thickness measurements
RINA Rules 2024 379

Pt A, Ch 4, Sec 9
and tank testing given in [4.4], [4.5] and [4.6], respectively. a) schedule of the ship (i.e. the voyage, docking and
In addition, the survey program is to include at least: undocking manoeuvres, periods alongside, cargo and
• basic ship information and particulars ballast operations etc);
• main structural plans (scantling drawings), including b) provisions and arrangements for thickness
information on the use of high tensile steels (HTS) measurements (i.e. access, cleaning/de-scaling,
illumination, ventilation, personal safety);
• plan of holds and tanks
c) extent of the thickness measurements;
• list of holds and tanks including information on their
use, protective coating, if any, and its condition d) acceptance criteria (refer to the list of minimum
• conditions for survey, with regard to holds, tanks and thicknesses);
spaces which are to be safe for access, i.e. cleaned, gas e) extent of close-up survey and thickness measurement
freed, ventilated, illuminated considering the coating condition and suspect
• provisions and methods for access to structures areas/areas of substantial corrosion;
• equipment for surveys f) execution of thickness measurements;
• selection of holds, spaces and areas for close-up surveys g) taking representative readings in general and where
according to Tab 2 uneven corrosion/pitting is found;
• selection of sections and areas for thickness h) mapping of areas of substantial corrosion;
measurements according toTab 4 i) communication between the attending Surveyor(s), the
• selection of holds, if any, and tanks for tank testing thickness measurement firm operator(s) and the
according to [4.6] Owner's representative(s) concerning findings.
• damage experience and repair history related to the ship
in question. 4.2 Scope of survey
4.2.1 (1/1/2005)
4.1.4 (1/1/2005)
In addition to the requirements of annual surveys, the class
The survey program is also to include the maximum renewal survey is to include examination, tests and checks
acceptable structural corrosion diminution levels applicable of sufficient extent to ensure that the hull and related
to the ship. The Society will advise the Owner of this piping, as required in [4.2.3], are in satisfactory condition
information. for the new period of class of five years to be assigned,
4.1.5 (1/1/2005) subject to proper maintenance and operation and to
In addition, the survey program is to include proposals on periodical surveys being carried out at the due dates.
how to conduct surveys and tests in a safe and practical 4.2.2 (1/7/2006)
way, including the means of providing access to structures All cargo holds, ballast tanks, including double bottom and
for close-up survey, thickness measurements and tank double side tanks, pipe tunnels, cofferdams and void spaces
testing. All other provisions described in Ch 2, Sec 2, [2.3], bounding cargo holds, decks and outer hull are to be
Ch 2, Sec 2, [2.5], Ch 2, Sec 2, [2.7], Ch 2, Sec 2, [2.8] and examined, and this examination is to be supplemented by
Ch 2, Sec 2, [2.10] regarding procedures for thickness thickness measurement and testing as required in [4.5] and
measurements, conditions for survey, access to structures, [4.6], to ensure that the structural integrity remains
equipment for survey and survey at sea or at anchorage, effective. The aim of the examination is to discover
respectively, are also to be complied with. substantial corrosion, significant deformation, fractures,
damage or other structural deterioration, that may be
4.1.6 Survey Planning Meeting (1/1/2019)
present.
The establishment of proper preparation and close co-
4.2.3 (1/1/2005)
operation between the attending Surveyor(s) and the
Owner's representatives on board prior to and during the All piping systems within the above spaces are to be
survey are an essential part in the safe and efficient conduct examined and operationally tested to working pressure to
of the survey. During the survey on board safety meetings the attending Surveyor's satisfaction to ensure that tightness
are to be held regularly. and condition remain satisfactory.
Prior to commencement of any part of the renewal and 4.2.4 (1/1/2005)

intermediate survey, a survey planning meeting is to be held The survey extent of ballast tanks converted to void spaces
between the attending Surveyor(s), the Owner's will be specially considered by the Society in relation to the
representative in attendance, the thickness measurement requirements for ballast tanks.
firm representative, where involved, and the Master of the 4.2.5 (1/7/2024)
ship or an appropriately qualified representative appointed Where provided, the condition of the corrosion prevention
by the Master or Company for the purpose of ascertaining system of ballast tanks is to be examined.
that all the arrangements envisaged in the survey program For ballast tanks, excluding double bottom tanks, where a
are in place, so as to ensure the safe and efficient conduct hard protective coating is found in poor to be in less than
of the survey work to be carried out. Refer also to Ch 2, good condition, and it is not renewed, where a soft or semi-
Sec 2, [2.3.1]. hard coating has been applied, or where a hard protective
The following is an indicative list of items that are to be coating has not been applied since the time of construction,
addressed in the meeting: the tanks in question are to be examined at annual surveys.
380 RINA Rules 2024

...OMISSIS...
Pt A, Ch 4, Sec 9
Table 5 : Requirements for extent of thickness measurements in those areas of substantial corrosion of double
skin bulk carriers and self-unloading bulk carriers of double skin construction, within the cargo length area
(1/1/2017)
BOTTOM, INNER BOTTOM AND HOPPER STRUCTURE

Structural member Extent of measurement Pattern of measurement
Bottom, inner bottom and hopper Minimum of three bays across double bottom Five-point pattern for each panel between
structure plating tank, including aft bay longitudinals and floors
Measurements around and under all suction
bell mouths
Bottom, inner bottom and hopper Minimum of three longitudinals in each bay Three measurements in line across flange and
structure longitudinals where bottom plating measured three measurements on the vertical web
Bottom girders, including watertight At fore and aft watertight floors and in centre Vertical line of single measurements on girder
girders of tanks plating with one measurement between each
panel stiffener, or a minimum of three meas-
urements
Bottom floors, including watertight Three floors in bays where bottom plating Five-point pattern over two square metre area
floors measured, with measurements at both ends
and middle
Hopper structure web frame ring Three floors in bays where bottom plating Five-point pattern over one square metre of
measured plating Single measurements on flange
Hopper structure transverse water- • lower 1/3 of bulkhead • five-point pattern over one square metre
tight bulkhead or swash bulkhead of plating
• upper 2/3 of bulkhead • five-point pattern over two square metres
of plating
• stiffeners (minimum of three) • For web, five-point pattern over span (two
measurements across web at each end
and one at centre of span).
For flange, single measurements at each
end and centre of span
Panel stiffening Where applicable Single measurements
4.2.8 (1/7/2024) 4.3.3 (1/1/2005)

For double-side skin void spaces bounding cargo holds for A check is to be made of the effectiveness of sealing
bulk carriers exceeding 20 years of age and of 150 m in arrangements of all hatch covers by hose testing or
length and upwards, where provided, the condition of the equivalent.
corrosion prevention system of void spaces is to be
4.3.4 (1/7/2016)
examined. Where a hard protective coating is found to be
in poor condition, and it is not renewed, or where a soft or Close-up survey and thickness measurement (see Note 1) of
semi-hard coating has been applied, or where a hard the hatch cover and coaming plating and stiffeners is to be
protective coating has not been applied from the time of carried out as given in Tab 2 or Tab 3, as applicable, and
construction, the void spaces in question are to be Tab 4.
examined at annual intervals. Thickness measurements are Note 1: Subject to cargo hold hatch covers of approved design
to be carried out as deemed necessary by the surveyor. which structurally have no access to the internals, close-up
survey/thickness measurement shall be done of accessible parts of
hatch covers structures.
4.3 Hatch covers and coamings
4.3.1 (1/1/2008) 4.4 Overall and close-up surveys
A thorough inspection of the items listed in [2.3] is to be
carried out, in addition to all hatch covers and coamings. 4.4.1 (1/7/2006)
An overall survey of all cargo holds, tanks and spaces is to
4.3.2 (1/1/2005)
be carried out at each class renewal survey. For fuel oil
A check of the satisfactory operation of all mechanically tanks in the cargo length area, the requirements given in
operated hatch covers is to be made, including: Ch 3, Sec 5, Tab 5 are to be complied with.
• stowage and securing in open condition; 4.4.2 (1/7/2008)
• proper fit and efficiency of sealing in closed condition; The minimum requirements for close-up surveys at each
• operational testing of hydraulic and power components, class renewal survey are given in Tab 2 for double skin bulk
wires, chains and link drives. carriers, excluding ore carriers, and in Tab 3 for ore carriers.
386 RINA Rules 2024

...OMISSIS...
Pt A, Ch 4, Sec 9
Table 15 (1/7/2024)
Ship Name: ........................

OWNERS INSPECTION REPORT - Structural Condition
For Tank No: .................
Grade of steel: Deck: .............. Side : ...................
Bottom: ........... Long. Bhd : ...................
Elements Cracks: Buckles: Corrosion: Coating cond. Pitting Mod./Rep.

Other
Deck:
Bottom:
Side:
Long. bulkhead:
Transv. bulkheads:
Repairs carried out due to (1):
Thickness measurements carried out (dates):
Results in General:
Overdue Surveys:
Outstanding Conditions of class:
Comments:
(1) Repairs are to be surveyed by the Society

Date of Inspection : ....................................................................................................................................
Inspected by : ............................................................................................................................................
Signature : .................................................................................................................................................
398 RINA Rules 2024

Pt B, Ch 1, Sec 3
SECTION 3 DOCUMENTATION TO BE SUBMITTED
1 Documentation to be submitted for 1.1.3 Number of copies

all ships The number of copies to be submitted for each plan or doc-
ument is to be agreed with the Society on a case by case
1.1 Ships built under the Society’s supervi- basis depending on the specific conditions under which
sion plan approval and supervision during construction are
organised. However, it is generally equal to:
1.1.1 Plans and documents to be submitted for
approval • 3 for plans and documents submitted for approval
The plans and documents to be submitted to the Society for • 2 for plans and documents submitted for information.
approval are listed in Tab 1. This list is intended as guidance
for the complete set of information to be submitted, rather
than an actual list of titles. 2 Further documentation to be submit-
The above plans and documents are to be supplemented by ted for ships with certain service
further documentation which depends on the service nota- notations or additional class nota-
tion and, possibly, the additional class notation (see Pt A,
tions
Ch 1, Sec 2) assigned to the ship, as specified in [2].
Structural plans are to show details of connections of the
various parts and, in general, are to specify the materials 2.1 General
used, including their manufacturing processes, welded pro-
cedures and heat treatments. See also Ch 12, Sec 1, [1.6]. 2.1.1 Depending on the service notation and, possibly, the
additional class notation (see Pt A, Ch 1, Sec 2) assigned to
1.1.2 Plans and documents to be submitted for the ship, other plans or documents may be required to be
information (1/7/2011)
submitted to the Society, in addition to those in [1.1]. They
In addition to those in [1.1.1], the following plans and doc- are listed in [2.2] and [2.3] for the service notations and
uments are to be submitted to the Society for information: additional class notations which require this additional doc-
• general arrangement umentation.
• capacity plan, indicating the volume and position of the
centre of gravity of all compartments and tanks However, the additional documentation relevant to a ser-
vice notation or an additional class notation may be
• lines plan
required also for ships to which it is not assigned, when this
• hydrostatic curves is deemed necessary by the Society on the basis, inter alia,
• lightweight distribution of the ship service, the structural arrangements, the type of
• towing and mooring arrangement plan, containing the cargo carried and its containment.
information specified in Ch 10, Sec 4, [3.1]
• list of dangerous goods intended to be carried, if any. 2.2 Service notations
In addition, when direct calculation analyses are carried out
by the Designer according to the rule requirements, they 2.2.1 The plans or documents to be submitted to the Soci-
are to be submitted to the Society. ety are listed in Tab 2.
20 RINA Rules 2024

Pt B, Ch 1, Sec 3
2.3 Additional class notations

2.3.1 The plans or documents to be submitted to the Soci-
ety are listed in Tab 3.
Table 1 : Plans and documents to be submitted for approval for all ships (1/7/2024)
Plan or document Containing also information on

Midship section Class characteristics
Transverse sections Main dimensions
Shell expansion Minimum ballast draught
Decks and profiles Frame spacing
Double bottom Contractual service speed
Pillar arrangements Density of cargoes
Framing plan Design loads on decks and double bottom
Deep tank and ballast tank bulkheads, wash Steel grades
bulkheads Location and height of air vent outlets of various compartments
Corrosion protection
Openings in decks and shell and relevant compensations
Boundaries of flat areas in bottom and sides
Details of structural reinforcements and/or discontinuities
Bilge keel with details of connections to hull structures
Loading manual and loading instruments See Ch 11, Sec 2, [3]
Watertight subdivision bulkheads Openings and their closing appliances, if any
Watertight tunnels
Fore part structure Location and height of air vent outlets of various compartments
Transverse thruster, if any, general arrangement,
tunnel structure, connections of thruster with tun-
nel and hull structures
Aft part structure Location and height of air vent outlets of various compartments
Machinery space structures Type, power and r.p.m. of propulsion machinery
Foundations of propulsion machinery and boilers Mass and centre of gravity of machinery and boilers
Superstructures and deckhouses Extension and mechanical properties of the aluminium alloy used (where appli-
Machinery space casing cable)
Bow doors, stern doors and inner doors, if any, Closing appliances
side doors and other openings in the side shell Electrical diagrams of power control and position indication circuits for bow
doors, stern doors, side doors, inner doors, television system and alarm systems
for ingress of water
Hatch covers, if any Design loads on hatch covers
Sealing and securing arrangements, type and position of locking bolts
Distance of hatch covers from the summer load waterline and from the fore end
Movable decks and ramps, if any
Windows and side scuttles, arrangements and
details
Scuppers and sanitary discharges
Bulwarks and freeing ports Arrangement and dimensions of bulwarks and freeing ports on the freeboard
deck and superstructure deck
(1) Where other steering or propulsion systems are adopted (e.g. steering nozzles or azimuth propulsion systems), the plans show-
ing the relevant arrangement and structural scantlings are to be submitted. For azimuth propulsion systems, see Ch 10, Sec 1,
[11].
(2) Apply to ships of 500 gross tonnage and upwards.
(3) Apply to ships of 80 m or more in length, where the height of the exposed deck in way of the item is less than 0,1L or 22 m
above the summer load waterline, whichever is the lesser.
(4) For documents to be submitted see the requirements in Ch 10, Sec 4, [2.1.4] and Pt E, Ch 13, Sec 2, [12.1.6].
RINA Rules 2024 21

Pt B, Ch 1, Sec 3
Plan or document Containing also information on

Rudder and rudder horn (1) Maximum ahead service speed
Sternframe or sternpost, sterntube
Propeller shaft boss and brackets (1)
Derricks and cargo gear Design loads (forces and moments)
Cargo lift structures Connections to the hull structures
Sea chests, stabiliser recesses, etc.
Hawse pipes
Plan of outer doors and hatchways
Plan of manholes
Plan of access to and escape from spaces
Plan of ventilation Use of spaces
Plan of tank testing Testing procedures for the various compartments
Height of pipes for testing
Plan of watertight doors and scheme of relevant Manoeuvring devices
manoeuvring devices Electrical diagrams of power control and position indication circuits
Freeboard calculations
Stability documentation See Ch 3, Sec 1, [3.1]
Calculations relevant to intact stability
Equipment number calculation or Geometrical elements for calculation
Direct Force Calculation For Anchoring Equipment List of equipment
(4) Construction and breaking load of steel wires
Material, construction, breaking load and relevant elongation of synthetic ropes
Helicopter deck, if any General arrangement
Main structure
Characteristics of helicopters: maximum mass, distance between axles of
wheels or skids, print area of wheels or skids, rotor diameter
Emergency towing arrangement See Ch 10, Sec 4, [4.3]
Windlass Design loads, scantlings and connections to the hull structures
Towing and mooring arrangements (2) Design loads, scantlings and connections to the hull structures
Ventilator pipes within forward quarter length of Scantlings and connections to the hull structures
the ship (3)
(1) Where other steering or propulsion systems are adopted (e.g. steering nozzles or azimuth propulsion systems), the plans show-
ing the relevant arrangement and structural scantlings are to be submitted. For azimuth propulsion systems, see Ch 10, Sec 1,
[11].
(2) Apply to ships of 500 gross tonnage and upwards.
(3) Apply to ships of 80 m or more in length, where the height of the exposed deck in way of the item is less than 0,1L or 22 m
above the summer load waterline, whichever is the lesser.
(4) For documents to be submitted see the requirements in Ch 10, Sec 4, [2.1.4] and Pt E, Ch 13, Sec 2, [12.1.6].

Pt B, Ch 7, Sec 5
SECTION 5 BUCKLING STRENGTH ASSESSMENT OF SHIP

STRUCTURAL ELEMENTS
1 Application And Definitions UP : Unstiffened Panel, as defined in [1.3.3], c)
1.1 Abbreviations 1.2 Application
1.1.1 (1/7/2024) 1.2.1 Relevant requirements concerning Strength of

Ships (1/7/2024)
EPP : Elementary Plate Panel, as defined in [1.3.3], a)
This Section establishes a general buckling assessment
PSM : Primary Supporting Member procedure as illustrated in Fig 1 and is to be applied in
SP : Stiffened Panel, as defined in [1.3.3], c) conjunction with Ch 9, Sec 7 for hatch cover structures.
Figure 1 : Overview of applying this Section in conjunction with Ch 9, Sec 7 (1/7/2024)
1.2.2 Application of this Section (1/7/2024) • [5] for the determination of buckling capacities of
a) Articles of this Section plate panels, stiffeners, primary supporting members
and column structures.
The buckling checks are to be performed according to:
b) Buckling assessment with this Section
• [1] for general definitions regarding buckling
For the buckling assessment of a ship hull girder, a hatch
capacity, allowable buckling utilisation factors and
cover or some structural component, the slenderness
buckling check criteria.
requirements as defined in [2] and the buckling
• [2] for the slenderness requirements of longitudinal requirements as defined in [3] or [4] are to be checked
and transverse stiffeners. as per the requirements of Ch 9, Sec 7.
• [3] for the prescriptive buckling requirements of c) Alternative methods
plates, longitudinal and transverse stiffeners, primary This Section contains the general methods for the
supporting members and other structures subject to determination of buckling capacities of plate panels,
hull girder stresses. stiffeners, primary supporting members, and columns.
• [4] for direct strength analysis (usually by finite For special cases not covered in this Section, such as a
element method) buckling requirements of hatch whole plate structure with stiffeners in two directions
cover structural members including plates, stiffeners (i.e., a stiffened panel with both primary and secondary
and primary supporting members. stiffeners), other more advanced methods, such as finite
RINA Rules 2024 119

Pt B, Ch 7, Sec 5
element analysis methods, can be used when found in 1.3.3 Structural Idealisation (1/7/2024)
compliance with the calculation methods used to
a) Elementary plate panel
develop the formulations in this Section. Acceptability
of such methods is subject to a dedicated assessment of An elementary plate panel (EPP) is the unstiffened part
the Society. of the plating between stiffeners and/or primary
supporting members. The plate panel length, a, and
breadth, b, of the EPP are defined respectively as the
1.3 Terminology and Assumptions longest and shortest plate edges, as shown in Fig 2.
b) Standard types of stiffeners

1.3.1 Buckling (1/7/2024)
Definitions of the cross-sectional dimensions of typical
a) Buckling strength stiffener types are shown in Fig 3, which are flat bars,
bulb flats, angles, L2 and T bars. If applicable, other
Buckling strength or capacity refers to the strength of a types of stiffeners can be idealized to one of the typical
structure under in-plane compressions and/or shear and types in Fig 3 for buckling check. For the U-type
lateral load. Buckling strength with consideration of the stiffener which is usually fitted in some hatch covers, the
buckling behaviour in [1.3.1], b) gives a lower bound definition of its cross-sectional dimensions is shown in
estimate of ultimate capacity, or the maximum load a Fig 4.
structural member can carry without suffering major
Unless otherwise specified, the full span or full length l,
permanent set. in mm, of a stiffener is to be used for buckling check,
For each structural member, its buckling strength is to be which equals to the spacing between primary
supporting members.
taken as corresponding to the most unfavourable or
critical buckling mode. Symbolic dimensions of the cross-sections are as below:
b) Buckling behaviour b1 : Width of the attached plate enclosed by the

U-type stiffener, in mm, as shown in Fig 4.
Buckling strength assessment takes into account both
b2 : Width of the attached plate between
elastic buckling and post-buckling behaviours. Post-
buckling can consider the internal redistribution of adjacent U-type stiffeners, in mm, as shown
in Fig 4.
loads depending on the load situation, slenderness and
type of structure. Such as for the buckling assessment of bf : Width of the flange or face plate of the
plates, generally its positive elastic post-buckling effect stiffener, in mm, as shown in Fig 3 and Fig 4.
can be utilized.
bf-out : Maximum distance, in mm, from mid
As such, for slender structures, the calculated buckling thickness of the web to the flange edge, in
strength is typically higher than the ideal elastic mm, as shown in Fig 3.
buckling stress (minimum eigenvalue). Accepting elastic df : Breadth of the extended part of the flange
buckling of slender plate panels implies that large for L2 profiles, in mm, as shown in Fig 3.
elastic deflections and reduced in-plane stiffness may
occur at higher buckling utilisation levels. ef : Distance from attached plating to centre of
flange, in mm, as shown in Fig 3. For its
detailed definition, refer to [5.1].
1.3.2 Net Scantling Approach (1/7/2024)
hw : Depth of stiffener web, in mm, as shown in
a) General
Fig 3 and Fig 4.
Unless otherwise specified, all the scantling tf : Net flange thickness, in mm.
requirements, including slenderness requirements, in
this Section are based on net scantlings obtained by tp : Net thickness of plate, in mm.
removing full corrosion addition tc from the gross tw : Net web thickness, in mm.
offered thicknesses.
c) Stiffened panel (SP) and Unstiffened panel (UP)
b) Corrosion addition For a panel with relatively strong interactive effect
between the stiffener and its attached plate, each
Corrosion addition tc referred to in this Section is
stiffener with its attached plate as a whole is to be
defined in Ch 9, Sec 7. modelled as a stiffened panel (SP), so as to be able to
consider both of its local and global buckling modes.
c) Stress calculation models
However, for an EPP, if its buckling strength can be
The structural models used for the calculation of stresses checked without considering its interactive effect with
to be applied for buckling assessment, which are usually stiffeners fitted along its edges, it’s to be modelled as an
based on net scantlings, are defined in Ch 9, Sec 7. unstiffened panel (UP).
120 RINA Rules 2024

Pt B, Ch 7, Sec 5
Figure 2 : Elementary plate panel (EPP) definition (1/7/2024)
Figure 3 : Dimensions of typical stiffener cross sections (1/7/2024)
Figure 4 : Dimensions of a U-type stiffener cross section (1/7/2024)
1.3.4 Sign Convention (1/7/2024) 1.4 Assessment Methods and Acceptance

a) Stresses Criteria
In this Section, compressive and shear stresses are to be
taken as positive, tension stresses are to be taken as 1.4.1 Assessment Methods (1/7/2024)
negative. a) Method A and Method B
The buckling assessment is to be carried out according
to one of the following two methods taking into account
different boundary condition types:
• Method A: All the edges of the EPP are forced to
remain straight (but free to move in the in-plane
RINA Rules 2024 121

Pt B, Ch 7, Sec 5
directions) due to the surrounding b) For combined loads, the utilisation factor, act , is to be
structure/neighbouring plates. defined as the ratio of the applied equivalent stress and
• Method B: The edges of the EPP are not forced to the corresponding buckling capacity, as shown in Fig 5,
remain straight due to low in-plane stiffness at the and is to be taken as:
edges and/or no surrounding structure/neighbouring
plates. W act 1
 act = ----------
- = ----
b) SP-A, SP-B, UP-A and UP-B models Wu c
For the buckling assessment of the stiffened panel (SP) where:
and unstiffened panel (UP) structural models defined in
Wact : Equivalent applied stress. The actual applied
[1.3.3], c), with application of either Method A or
stresses are given in [3] and [4] respectively
Method B for the plate buckling assessment, the
for buckling assessment by prescriptive and
following four buckling assessment models are
direct strength analysis.
established:
Wu : Equivalent buckling capacity. For plates and
• SP-A: a stiffened panel with application of Method
A. stiffeners, their respective buckling or
ultimate capacities are given in [5].
• SP-B: a stiffened panel with application of Method
B. c : Stress multiplier factor at failure.
• UP-A: an unstiffened panel with application of For each typical failure mode, the corresponding
Method A. buckling capacity of the panel is calculated by applying
the actual stress combination and then increasing or
• UP-B: an unstiffened panel with application of
decreasing the stresses proportionally until collapse
Method B.
occurs, i.e., when the increased or decreased stresses
1.4.2 Buckling Utilisation Factor (1/7/2024) are on a buckling strength interaction curve or surface.
a) The utilisation factor,  , is defined as the ratio between Fig 5 illustrates the buckling capacity and the buckling
the applied loads and the corresponding buckling utilisation factor of a structural member subject to x
capacity. and y stresses.
Figure 5 : Illustration of buckling capacity and buckling utilisation factor (1/7/2024)
1.4.3 Allowable Buckling Utilisation

Factor (1/7/2024)
 act   all
a) The allowable buckling utilisation factor all is to be
taken according to Ch 9, Sec 7. where:
1.4.4 Buckling Acceptance Criteria (1/7/2024) act : Buckling utilisation factor based on the
a) A structural member is considered to have an applied stress, defined in [1.4.2], b)
acceptable buckling strength if it satisfies the following
criterion:
122 RINA Rules 2024

Pt B, Ch 7, Sec 5
all : Allowable buckling utilisation factor as

defined in [1.4.3], a). Table 1 : Slenderness coefficients (1/7/2024)
Type of Stiffener Cw Cf
2 Slenderness Requirements
Angle and L2 bars 75 12
2.1 Symbols T-bars 75 12
Bulb flats 45 -
2.1.1 (1/7/2024)
Flat bars 22 -
For symbols not defined in this Article, refer to [1.3.3], b).
ReH : Specified minimum yield stress of the structural 2.4 Primary Supporting Members
2
member being considered, in N/mm .
2.4.1 Proportions and Stiffness (1/7/2024)
a) Proportions of web plate and flange
2.2 General
The scantlings of webs and flanges of primary
2.2.1 (1/7/2024) supporting members are to comply with Ch 7, Sec 3.
The stiffener elements except for U-type stiffeners are to 2.4.2 (1/7/2024)
comply with the applicable slenderness and proportion
The flange outstand of the primary supporting members is to
requirements given in [2.3].
be not greater than 15 times the flange thickness.
2.3 Stiffeners
3 Buckling requirements for hull girder
2.3.1 Proportions of Stiffeners (1/7/2024) prescriptive analysis
a) Net thickness of all stiffener types
3.1 Application
The net thickness of stiffeners is to satisfy the following
criteria: 3.1.1 (1/7/2024)
1) Stiffener web plate: The buckling requirements for hull girder strength
prescriptive analysis to be complied with are:
hw R eH • those in Ch 6 and Ch 7, Sec 1 for plates;
t w  ------  ---------
-
C w 235 • those in Ch 7, Sec 2 for ordinary stiffeners; and
2) Flange: • those in Ch 7, Sec 3 for primary supporting members.
The requirements of this Article, reflecting section 3 of new
b f – out R eH IACS UR S35 "Buckling Strength Assessment of Ship
t f  ------------
-  ---------
-
Cf 235 Structural Elements”, are to be considered for information
purposes only.
where:
Cw, Cf : Slenderness coefficients given in Tab 1. 3.2 Symbols
If requirement 2) is not fulfilled, the effective free
flange outstand, in mm, used in strength assessment 3.2.1 (1/7/2024)
including the calculation of actual net section all : Allowable buckling utilisation factor, as defined
modulus, is to be taken as: in [1.4.3], a).
LCP : Load Calculation Point, as defined in [3.3.2], a).
b f – out – max = C f  t f  235
----------
R eH 3.3 General
For built-up profile where the relevant yielding 3.3.1 Introduction (1/7/2024)
strength for the web of built-up profile without the
edge stiffener is acceptable, as an alternative the a) This Article applies to plate panels including plane and
web can be assessed according to the web curved plate panels, stiffeners and corrugation of
requirements of Angle and L2 bars in Tab 1, and the longitudinal corrugated bulkheads subject to hull girder
edge stiffener can be assessed as a flat bar stiffener compression and shear stresses.
according to [2.3.1], a). The requirement to flange in b) The ship longitudinal extent where the buckling check is
[2.3.1], b) is still to apply. performed for structural elements subject to hull girder
stresses is to be in accordance with IACS Unified
b) Net dimensions of angle and T-bars
Requirements concerning global strength of ships.
The total flange breadth bf, in mm, for angle and T-bars
c) Design load sets: The buckling check is to be performed
is to satisfy the following criterion:
for all design load sets corresponding to the design
bf  0,2hw loading conditions defined in IACS Unified
RINA Rules 2024 123

Pt B, Ch 7, Sec 5
Requirements concerning global strength of ships with The load calculation point for the pressure is located
the most unfavourable pressure combinations. at:
For each design load set, for all static and dynamic load • Middle of the full length, , of the considered
cases, the lateral pressure is to be determined at the stiffener.
load calculation point defined in [3.3.2], a), and is to be • The intersection point between the stiffener and
applied together with the hull girder stress combinations its attached plate.
defined in IACS Unified Requirements concerning
4) LCP for pressure of non-horizontal stiffeners
global strength of ships.
The lateral pressure, P is to be calculated as the
3.3.2 Definitions (1/7/2024) maximum between the value obtained at middle of
the full length, , and the value obtained from the
a) Load calculation point
following formulae:
The load calculation points (LCP) for both elementary
P=(pu+pL)/2: when the upper end of the vertical
plate panels (EPP) and stiffeners are defined as follows:
stiffener is below the lowest zero
1) LCP for hull girder stresses of EPP pressure level.
The hull girder stresses for EPP are to be calculated P=(1/).(pL/2): when the upper end of the vertical
at the load calculation points defined in Tab 2.
stiffener is at or above the lowest zero
2) LCP for hull girder stresses of longitudinal stiffeners pressure level, see Fig 7.
The hull girder stresses for longitudinal stiffeners are where:
to be calculated at the following load calculation 1 : Distance, in m, between the lower end
point:
of vertical stiffener and the lowest zero
• at the mid length of the considered stiffener. pressure level.
• at the intersection point between the stiffener pu, pL : Lateral pressures at the upper and lower
and its attached plate. end of the vertical stiffener span ,
3) LCP for pressure of horizontal stiffeners respectively.
Table 2 : Load calculation points (LCP) coordinates for plate buckling assessment (1/7/2024)
Hull girder bending stress

LCP coordinates Hull girder shear stress
Non horizontal plating Horizontal plating
x coordinate Mid-length of the EPP
y coordinate Both upper and lower ends of the EPP Outboard and inboard ends of Mid-point of EPP
(points A1 and A2 in Fig 6) the EPP (points A1 and A2 in (point B in Fig 6)
Fig 6)
z coordinate Corresponding to x and y values
Figure 6 : LCP for plate buckling assessment (1/7/2024)
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Pt B, Ch 7, Sec 5
Figure 7 : Definition of pressure for vertical buckling check is to be performed for an equivalent
stiffeners (1/7/2024) plate panel width, combined with the smaller plate
thickness, t1. The width of this equivalent plate panel,
beq, in mm, is defined by the following formula:
beq = 1+2.(t1/t2)1,5
where:
1 : Width of the part of the plate panel with the
smaller plate thickness, t1, in mm, as
defined in Fig 8.
2 : Width of the part of the plate panel with the
greater plate thickness, t2, in mm, as defined
in Fig 8.
b) Transverse stiffening with varying plate thickness
In transverse stiffening arrangement, when an EPP is
made with different thicknesses, the buckling check of
the plate and stiffeners is to be made for each thickness
considered constant on the EPP, the stresses and
3.3.3 Assumptions for Equivalent Plate pressures being estimated for the EPP at the LCP.
Panels (1/7/2024)
c) Plate panel with different materials
a) Longitudinal stiffening with varying plate thickness When the plate panel is made of different materials, the
In longitudinal stiffening arrangement, when the plate minimum yield strength is to be used for the buckling
thickness varies over the width b, of a plate panel, the assessment.
Figure 8 : Plate thickness change over the width (1/7/2024)
3.4 Buckling Criteria plate : Maximum plate buckling utilisation factor

as defined in [5.3.2] where SP-A model is to
3.4.1 Overall Stiffened Panel (1/7/2024) be used.
a) The buckling strength of overall stiffened panels is to For the determination of plate of the vertically stiffened
satisfy the following criterion:
side shell plating of single side skin bulk carrier between
overall  all hopper and topside tanks, the cases 12 and 16 of Tab 5
where: corresponding to the shorter edge of the plate panel
clamped are to be considered together with a mean y
overall : Maximum overall buckling utilisation factor
stress and y =1.
as defined in [5.3.1].
3.4.2 Plates (1/7/2024) 3.4.3 Stiffeners (1/7/2024)

a) The buckling strength of elementary plate panels is to a) The buckling strength of stiffeners or of side frames of
satisfy the following criterion: single side skin bulk carriers is to satisfy the following
plate  all criterion:
where: stiffener  all
RINA Rules 2024 125

Pt B, Ch 7, Sec 5
where: shear = bhd / c

stiffener : Maximum stiffener buckling utilisation bhd : Shear stress, in N/mm2, in the bulkhead
factor as defined in [5.3.3]. taken as the hull girder shear stress defined
Note 1: This buckling check can only be fulfilled when the overall in IACS Unified Requirements concerning
stiffened panel buckling check, as defined in [3.4.1], is global strength of ships
satisfied. c : Shear critical stress, in N/mm2, as defined in
Note 2: The buckling check of the stiffeners is only applicable to [5.3.2], c).
the stiffeners fitted along the long edge of the buckling panel.
3.4.5 Horizontally Corrugated Longitudinal
3.4.4 Vertically Corrugated Longitudinal Bulkheads (1/7/2024)
Bulkheads (1/7/2024)
a) Each corrugation unit within the extension of half
a) The shear buckling strength of vertically corrugated flange, web and half flange (i.e. single corrugation as
longitudinal bulkheads is to satisfy the following shown in grey in Fig 9) is to satisfy the following
criterion: criterion:
shear  all column  all
where: where:
shear : Maximum shear buckling utilisation factor, column : Overall column buckling utilisation factor,
defined as: as defined in [5.4.1].
Figure 9 : Single corrugation (1/7/2024)
4 Buckling requirements for direct • Web plate in way of openings.

strength analysis of hatch covers
4.3 Stiffened and Unstiffened Panels
4.1 Symbols
4.3.1 General (1/7/2024)
4.1.1 (1/7/2024) a) The plate panel of a hatch cover structure is to be
Reh_P : Yield stress of the plate panel, as defined in modelled as stiffened panel (SP) or unstiffened panel
[4.3.1], c). (UP), with either Method A or Method B as defined in
Reh_S : Yield stress of the stiffener, as defined in [4.3.1], Sec 1, [3.1.1] to be used for the calculation of the plate
buckling capacity, which in combination is also
c).
equivalent to use the buckling assessment models
 : Aspect ratio of the plate panel, as defined in the defined in [1.4.1], b).
Symbol list of [5].
b) Average thickness of plate panel
all : Allowable buckling utilisation factor, as defined
in [1.4.3], a). For FE analysis, where the plate thickness along a plate
panel is not constant, the panel used for the buckling
assessment is to be modelled with a weighted average
4.2 General
thickness taken as:
4.2.1 Introduction (1/7/2024)
n
a) The requirements of this Article apply to the buckling
assessment of hatch cover structural members based on A  t i i
direct strength analysis (usually by finite element t avr = -------------------

1
-
n
method) and subjected to normal stress, shear stress and
lateral pressure. A i
b) All structural elements in the direct strength analysis 1
carried out according to Ch 9, Sec 7 are to be assessed where:

individually. The buckling checks are to be performed
for the following structural elements: Ai : Area of the i-th plate element.
• Stiffened and unstiffened panels ti : Net thickness of the i-th plate element.
126 RINA Rules 2024

Pt B, Ch 7, Sec 5
n : Number of finite elements defining the Figure 11 : (1/7/2024)

buckling plate panel.
c) Yield stress of the plate panel and stiffener

The panel yield stress Reh_P is taken as the minimum
value of the specified yield stresses of the elements
within the plate panel.
The stiffener yield stress Reh_S is taken as the minimum
value of the specified yield stresses of the elements
within the stiffener. 3) The pair of opposite edges with the smallest total
length is identified, i.e. minimum of d1 + d3 and d2
4.3.2 Stiffened Panels (1/7/2024) + d4.
a) For a stiffened panel (SP), each stiffener with attached
plate is to be idealized as a stiffened panel model of the Figure 12 : (1/7/2024)
extent defined in the Ch 9, Sec 7.
b) If the stiffener properties or stiffener spacing varies

within the stiffened panel, the calculations are to be
performed separately for all configurations of the
panels, i.e. for each stiffener and plate between the
stiffeners. Plate thickness, stiffener properties and
stiffener spacing at the considered location are to be
assumed for the whole panel. 4) A line joins the middle points of the chosen opposite
edges (i.e. a mid-point is defined as the point at half
c) The buckling check of the stiffeners of stiffened panels is
the distance from one end). This line defines the
only applicable to the stiffeners fitted along the longer
longitudinal direction for the capacity model. The
side edges of the buckling panel.
length of the line defines the length of the capacity
model, a, measured from one end point.
4.3.3 Unstiffened Panels (1/7/2024)
5) The length of shorter side, b, in mm, is to be taken
a) Irregular plate panel
as:
In way of web frames and brackets, the geometry of the
panel (i.e. plate bounded by web stiffeners/face plate) b = A/a
may not have a rectangular shape. In this case, for FE where:
analysis, an equivalent rectangular panel is to be
defined according to [4.3.3], b) for irregular geometry A : Area of the plate, in mm²
and [4.3.3], c) for triangular geometry and to comply
with buckling assessment. a : Length defined in 4), in mm.
b) Equivalent EPP of an unstiffened panel with irregular

Figure 13 : (1/7/2024)
geometry
Unstiffened panels with irregular geometry are to be
idealised to equivalent panels for plate buckling
assessment according to the following procedure:
1) The four corners closest to a right angle, 90 deg, in

the bounding polygon for the plate are identified.
Figure 10 : (1/7/2024) 6) The stresses from the direct strength analysis are to
be transformed into the local coordinate system of
the equivalent rectangular panel. These stresses are
to be used for the buckling assessment.
c) Modelling of an unstiffened plate panel with triangular

geometry
Unstiffened panels with triangular geometry are to be

2) The distances along the plate bounding polygon idealised to equivalent panels for plate buckling
between the corners are calculated, i.e. the sum of assessment according to the following procedure:
all the straight-line segments between the end
points. 1) Medians are constructed as shown below.
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Pt B, Ch 7, Sec 5
Figure 14 : (1/7/2024) 4.3.5 Lateral Pressure (1/7/2024)

a) The lateral pressure applied to the direct strength
analysis is also to be applied to the buckling assessment.
For FE analysis, where the lateral pressure is not
constant over a buckling panel defined by a number of
finite plate elements, an average lateral pressure,
N/mm2, is calculated using the following formula:
n
2) The longest median is identified. This median the
length of which is 1, in mm, defines the A  P i i
longitudinal direction for the capacity model. Pavr = ---------------------

n
1
Figure 15 : (1/7/2024) A i
where:
Ai : Area of the i-th plate element, in mm2.
Pi : Lateral pressure of the i-th plate element, in
N/mm2.
n : Number of finite elements in the buckling
panel.
3) The width of the model, 2, in mm, is to be taken as: 4.3.6 Buckling Criteria (1/7/2024)
2 = A /1 a) UP-A
where: The compressive buckling strength of UP-A is to satisfy
A : Area of the plate, in mm² the following criterion:
UP-A  all
Figure 16 : (1/7/2024) where:
UP-A : Plate buckling utilisation factor, equal to
plate as defined in [5.3.2] where UP-A
model is to be used.
b) UP-B
The compressive buckling strength of UP-B is to satisfy
the following criterion:
UP-B  all
where:
4) The lengths of shorter side, b, and of the longer side, UP-B : Plate buckling utilisation factor, equal to
a, in mm, of the equivalent rectangular plate panel plate as defined in [5.3.2] where UP-B
are to be taken as: model is to be used.
b = 2 / Ctri c) SP-A
a = 1 / Ctri The compressive buckling strength of SP-A is to satisfy
where: the following criterion:
SP-A  all
Ctri = 0,4.(2 /1)+0,6
where:
5) The stresses from the direct strength analysis are to SP-A : Buckling utilisation factor of the stiffened
be transformed into the local coordinate system of
panel, taken as the maximum of the
the equivalent rectangular panel and are to be used
buckling utilisation factors calculated as
for the buckling assessment of the equivalent
below:
rectangular panel.
• The overall stiffened panel buckling
4.3.4 Reference Stress (1/7/2024) utilisation factor overall as defined in
a) The stress distribution is to be taken from the direct [5.3.1].
strength analysis according to Ch 9, Sec 7 and applied • The plate buckling utilisation factor
to the buckling model. plate as defined in [5.3.2] where SP-A
b) For FE analysis, the reference stresses are to be model is to be used.
calculated using the stress-based reference stresses as • The stiffener buckling utilisation factor
defined in [6] stiffener as defined in [5.3.3] considering
128 RINA Rules 2024

Pt B, Ch 7, Sec 5
separately the properties (thickness, b : Length of the shorter side of the plate panel, in
dimensions), the pressures defined in mm
[4.3.5] and the reference stresses of each beff : Effective width of the attached plating of a
EPP at both sides of the stiffener. stiffener, in mm, as defined in [5.3.3], e)
Note 1: The stiffener buckling strength check can only be fulfilled
beff1 : Effective width of the attached plating of a
when the overall stiffened panel capacity check, as defined in
[5.3.1], is satisfied. stiffener, in mm, without the shear lag effect
taken as:
d) SP-B
• For x > 0
The compressive buckling strength of SP-B is to satisfy
the following criterion: - For prescriptive assessment:
SP-B all beff1 = (Cx1.b1+ Cx2.b2)/2
where: - For FE analysis:
SP-B : Buckling utilisation factor of the stiffened beff1 = Cx.b
panel, taken as the maximum of the • For x 0
buckling utilisation factors calculated as
beff1 = b
below:
• The overall stiffened panel buckling bf : Breadth of the stiffener flange, in mm
utilisation factor overall as defined in b1,b2 : Width of plate panel on each side of the
[5.3.1]. considered stiffener, in mm. For stiffened panels
fitted with U-type stiffeners, b1 and b2 are as
• The plate buckling utilisation factor
plate as defined in [5.3.2] where SP-B defined in Fig 4.
model is to be used. Cx1,Cx2 : Reduction factor defined in Tab 5 calculated for
• The stiffener buckling utilisation factor the EPP1 and EPP2 on each side of the
stiffener as defined in [5.3.3] considering considered stiffener according to case 1
separately the properties (thickness, d : Length of the side parallel to the cylindrical axis
dimensions), the pressures defined in of the cylinder corresponding to the curved
[4.3.5] and the reference stresses of each plate panel as shown in Tab 6, in mm
EPP at both sides of the stiffener. df : Breadth of the extended part of the flange for L2
Note 2: The stiffener buckling strength check can only be fulfilled profiles, in mm, as shown in Fig 3
when the overall stiffened panel capacity check, as defined in ef : Distance from attached plating to centre of
[5.3.1], is satisfied.
flange, in mm, as shown in Fig 3 to be taken as:
e) Web plate in way of openings ef = hw for flat bar profile
The web plate of primary supporting members with
openings is to satisfy the following criterion: ef = hw - 0,5.tf for bulb profile
.
opening all ef = hw + 0,5 tf for angle, L2 and T profiles
where: Flong : Coefficient defined in [5.3.2], d)
opening : Maximum web plate utilisation factor in Ftran : Coefficient defined in [5.3.2], e)
way of openings, calculated with the hw : Depth of stiffener web, in mm, as shown in Fig
definition in [1.4.2], b) and the stress 3
multiplier factor at failure c which can be  : Span, in mm, of stiffener equal to spacing
calculated following the requirements in between primary supporting members or span
[5.3.4]. of side frame equal to the distance between the
hopper tank and top wing tank in way of the
5 Buckling Capacity side shell
R : Radius of curved plate panel, in mm
5.1 Symbols ReH_P : Specified minimum yield stress of the plate in
N/mm2
5.1.1 (1/7/2024)
ReH_S : Specified minimum yield stress of the stiffener
AP : Net sectional area of the stiffener attached
in N/mm2
plating, in mm2, taken as:
S : Partial safety factor, unless otherwise specified
AP=s.tp in Ch 9, Sec 7, to be taken as 1,0
AS : Net sectional area of the stiffener without s : Stiffener spacing, in mm
attached plating, in mm2 tp : Net thickness of plate panel, in mm
a : Length of the longer side of the plate panel, in tw : Net stiffener web thickness, in mm
mm tf : Net flange thickness, in mm
RINA Rules 2024 129

Pt B, Ch 7, Sec 5
x-axis : Local axis of a rectangular buckling panel • [3] for hull girder prescriptive buckling requirements
parallel to its long edge
• [4] for direct strength analysis buckling requirements
y-axis : Local axis of a rectangular buckling panel of hatch covers.
perpendicular to its long edge
c) Buckling capacity
 : Aspect ratio of the plate panel, defined in Tab 5
to be taken as: = a/b The buckling capacity is calculated by applying the
actual stress combination and then increasing or
 : Coefficient taken as: = (1-)/
decreasing the stresses proportionally until the
 : Coefficient taken as: = min(3,) interaction formulae defined in [5.3.1], a), [5.3.2], a)
x : Normal stress applied on the edge along x-axis and [5.3.3], d) are equal to 1,0, respectively.
of the buckling panel, in N/mm2 d) Buckling utilisation factor
y : Normal stress applied on the edge along y-axis The buckling utilisation factor of the structural member
of the buckling panel, in N/mm2 is equal to the highest utilisation factor obtained for the
different buckling modes.
1 : Maximum normal stress along a panel edge, in
N/mm2 e) Lateral pressure
2 : Minimum normal stress along a panel edge, in The lateral pressure is to be applied and considered as
constant for the calculation of buckling capacities as
N/mm2
defined in [5.2.1], c).
E : Elastic buckling reference stress, in N/mm2 to
be taken as: 5.3 Buckling Capacity of Plate Panels
• For the application of the limit state of plane
plate panels according to [5.3.2], a): 5.3.1 Overall Stiffened Panels (1/7/2024)
a) The elastic stiffened panel limit state is based on the
 E
2
t 2 following interaction formula, which sets a precondition
-   ---p
 E = -----------------------------
12   1 –    b  for the buckling check of stiffeners in accordance with
2
[5.3.3], d):
• For the application of the limit state of
c / GEB = 1
curved plate panels according to [5.3.2], f):
with the corresponding buckling utilization factor
defined as:
 E
2 2
t
-   ---p
 E = -----------------------------
12   1 –    d  overall = 1 / c
2
 : Applied shear stress, in N/mm2 where the stress multiplier factors of global elastic
buckling capacity, GEB , are to be calculated based on
c : Buckling strength in shear, in N/mm2, as
the following formulae:
defined in [5.3.2], c)
GEB = GEB,bi+ for 0 and (x > 0 or y > 0)
 : Edge stress ratio to be taken as:  = 2 / 1
 : Stress multiplier factor acting on loads. When GEB = GEB,bi for 0 and (x > 0 or y > 0)
the factor is such that the loads reach the GEB = GEB, for 0 and (x  0 and y  0)
interaction formulae,  = c
where GEB,bi+ , GEB,bi and GEB, are stress multiplier
c : Stress multiplier factor at failure
factors of the global elastic buckling capacity for
GEB : Stress multiplier factor of global elastic buckling different load combinations as defined in [5.3.1], b),
capacity. [5.3.1], c) and [5.3.1], d), respectively. For the
calculation of GEB,bi+ , GEB,bi and GEB,, neither x
5.2 General nor y are to be taken less than 0.
5.2.1 Introduction (1/7/2024) x , y : Applied normal stress to the plate panel, in

N/mm2, to be taken as defined in [5.3.2], g)
a) This Article contains the methods for determination of
the buckling capacities of plate panels, stiffeners,  : Applied shear stress, in N/mm2, to be taken
primary supporting members and columns. as defined in [5.3.2], g).
b) For the application of this Article, the stresses x, y and b) The stress multiplier factor GEB,bi for the stiffened panel
 applied on the structural members are defined in: subjected to biaxial loads is taken as:
 D 11  L B2 + 2   D 12 + D 33   n  L B1  L B2 + n  D 22  L B1 
4 2 2 2 4 4

2
-  ----------------------------------------------------------------------------------------------------------------------------------------------------
 GEB bi = ----------------------- -
L B1  L B2 L B2  N x + n  L B1  N Y
2 2 2 2 2
130 RINA Rules 2024

Pt B, Ch 7, Sec 5
where: c = 0,5.(1+) for 0 

Nx : Load per unit length applied on the edge
c = 0,5 (1-) .
for 
along x-axis of the stiffened panel, in N/mm,
taken as:  : Edge stress ratio for case 2 according to Tab
5.
Nx = x,av (Ap+As) / s
.
x,av : Average stress for both plate and stiffener,
For stiffened panels fitted with U-type
taken as:
stiffeners, stiffener spacing s is taken as:
for x > 0 and y > 0:
s = b1 + b2
where b1 and b2 are as defined in Fig 4. x,av = x - v.c.y .As / (Ap+As)  0
Ny : Load per unit length applied on the edge for x  0 or y  0:
along y axis of the stiffened panel, in N/mm, x,av = x
taken as Ny = c.y.tp
D11, D12, D22, D33 : Bending stiffness coefficients, in
LB1 : Stiffener span, in mm, distance between
Nmm, of the stiffened panel, defined in
primary supporting members, i.e. LB1 = . general as:
Specially, for vertically stiffened side shell of
single side skin bulk carriers, LB1=0,8.
E  I eff  10 
4
LB2 : Total width of stiffened panel between D 11 = -------------------------- -

s 
lateral supports, in mm, taken as 6 times of 
E  tp   
3
the stiffener spacing, i.e. 6s. D 12 = -----------------------------
-
2 
12   1 –   
n : Number of half waves along the direction 
E  tp
3
perpendicular to the stiffener axis. The -
D 22 = -----------------------------
2 
factor GEB,bi is to be minimized with 12   1 –   
respect to the wave parameters n, i.e. to be 3 
E⋅ t
D 33 = -------------------p-------- 
taken as the smallest value larger than zero. 12   1 +   
c : Factor taking into account the normal stress
distribution in the attached plating acting For stiffened panels fitted with U-type
perpendicular to the stiffener’s axis: stiffeners, D12 and D22 are defined as:
E  tp
3 2
t 3
-  Min  1 0  ---w- 
-  1 2 + 4 8  Min  1 0 --------------------------------
b 1
D 22 = -----------------------------
12   1 –  
2  h w   b 1 + b 2    tp  
D12 = v.D22
hw is the breadth of U-type stiffener web as
defined in Fig 4.
Ieff : Moment of inertia, in cm4, of
the stiffener including the
effective width of the attached
plating, same as I defined in
[5.3.3], d).
c) The stress multiplier factor GEB, for the stiffened panel

subjected to pure shear load is taken as:
for D11.D22  (D12+D33)2
D 11  D 22  D 12 + D 33 
3 2
-  8 125 + 5 64  ------------------------------
D 12 + D 33 
4 2
 GEB  = --------------------------- - – 0 6  ------------------------------
-
L B1
 ------
2
D 11  D 22 D 11  D 22
-  N xy
 2
for D11.D22  (D12+D33)2
2  D 11   D 12 + D 33  D 11  D 22 D 11  D 22
2 2
 GEB  = -----------------------------------------------------
-  8 3 + 1 525  ------------------------------
-2 – 0 493  ------------------------------
-4
 D 12 + D 33   D 12 + D 33 
2
L B1
 -------  N xy
 2
RINA Rules 2024 131

Pt B, Ch 7, Sec 5
where:
Nxy = .tp
d) The stress multiplier factor GEB,bi+ for the stiffened
panel subjected to combined loads is taken as:
 GEB 
2
1 1 1
-  – -------------- + --------------
 GEB bi +  = ------------ + 4  ------------
-
2  GEB bi  GEB bi
2
 GEB 
2
where GEB,bi and GEB, are as defined in [5.3.1], b) and

[5.3.1], c), respectively.
5.3.2 Plates (1/7/2024)

a) Plate limit state
The plate limit state is based on the following
interaction formulae:
e e
-----0 -----0
 -----------------------
c1   x  S  c1   x  S 2   c1   y  S 2   c1   y  S e0   c1    S e0
e0
- – B   -----------------------
-  ------------------------ + ------------------------ + ------------------------ = 1
  cx    cx    cy    cy   c 
2 2
------------- -------------
0 25 0 25
 -----------------------
c2   x  S  c2    S p
p
- +  -----------------------
- = 1 for  x  0
  cx   c 
2 2
------------- -------------
0 25 0 25
 -----------------------
c3   y  S  c3    S p
p
- +  -----------------------
- = 1 for  y  0
  cy   c 
 c4    S
------------------------ = 1
c
with: B : Coefficient given in Tab 3

c =Min (c1,c2,c3,c4) e0 : Coefficient given in Tab 3
and the corresponding buckling utilization factor p : Plate slenderness parameter taken as:
defined as:
plate = 1 / c
b R eH_P
where:  p = ---  -----------
-
tp E
x , y : Applied normal stress to the plate panel, in
N/mm2, to be taken as defined in [5.3.2], g) b) Reference degree of slenderness
 : Applied shear stress to the plate panel, in The reference degree of slenderness is to be taken as:
N/mm2  = (ReH_P / KE)1/2
cx : Ultimate buckling stress, in N/mm2, in
where:
direction parallel to the longer edge of the
buckling panel as defined in [5.3.2], c) K : Buckling factor, as defined in Tab 5 and Tab
cy : Ultimate buckling stress, in N/mm2, in 6.
direction parallel to the shorter edge of the c) Ultimate buckling stresses
buckling panel as defined in [5.3.2], c) The ultimate buckling stresses of plate panels, in
c : Ultimate buckling shear stress, in N/mm2, as N/mm2, are to be taken as:
defined in [5.3.2], c)
cx=Cx.ReH_P
c1,c2,c3,c4 : Stress multiplier factors at failure for
each of the above different limit states. c2 cy=Cy.ReH_P
and c3 are only to be considered when x  The ultimate buckling stress of plate panels subject to
0 and y 0 respectively shear, in N/mm2, is to be taken as:
132 RINA Rules 2024

Pt B, Ch 7, Sec 5
c = C.(ReH_P / 30,5) e) Correction factor Ftran

where: The correction factor Ftran is to be taken as:
Cx, Cy, C: Reduction factors, as defined in Tab 5 • For transversely framed EPP of single side skin bulk
• For the 1st Equation of [5.3.2], a), when x 0 or y carrier, between the hopper and top wing tank:
0, the reduction factors are to be taken as: - Ftran = 1,25 when the two adjacent frames are
Cx = Cy = C supported by one tripping bracket fitted in way
of the adjacent plate panels
• For other cases:
- Ftran = 1,33 when the two adjacent frames are
- For SP-A and UP-A, Cy is calculated according
supported by two tripping brackets each fitted in
to Tab 5 by using:
way of the adjacent plate panels
c1 = (1-1/) 0
- Ftran = 1,15 elsewhere.
- For SP-B and UP-B, Cy is calculated according to
• For the attached plate of a U-type stiffener fitted on a
Tab 5 by using:
hatch cover:
c1 = 1
Ftran = Max(3-0,08.(Ftran0 - 6)2 , 1,0) 
- For vertically stiffened single side skin of bulk
carrier, Cy is calculated according to Tab 5 by where:
using:
6  b2
2
c1 = (1-1/) 0 b
F tran0 = Min  -----2 + ----------------------------------------
t 3
  ---w-  6 for EPP b 2
 b1   hw   b1 + b2   tp  
- For corrugation of corrugated bulkheads, Cy is
calculated according to Tab 5 by using:
c1 = (1-1/) 0 b 6  b1
2
t 3
F tran0 = Min  -----1 + ----------------------------------------   ---w-  6 for EPP b 1
The boundary conditions for plates are to be considered  b2   hw   b2 + b1   tp  
as simply supported, see cases 1, 2 and 15 of Tab 5. If with b1, b2 and hw as defined in Fig 4.
the boundary conditions differ significantly from simple
support, a more appropriate boundary condition can be Coefficient F defined in Case 2 of Tab 5 is to be
applied according to the different cases of Tab 5 subject replaced by the following formula:
to the agreement of the Society.
d) Correction factor Flong Ky
F = 1 –  --------------------------
- – 1   2p  c 1  0
 0 91  F tran 
The correction factor Flong depending on the edge
stiffener types on the longer side of the buckling panel is • For other cases: Ftran = 1.
defined in Tab 4. An average value of Flong is to be used
f) Curved plate panels
for plate panels having different edge stiffeners. For
stiffener types other than those mentioned in Tab 4, the This requirement for curved plate limit state is
value of c is to be agreed by the Society. In such a case, applicable when R/tp  2500. Otherwise, the
value of c higher than those mentioned in Tab 4 can be requirement for plate limit state given in [5.3.2], a) is
used, provided it is verified by buckling strength check applicable.
of panel using non-linear FE analysis and deemed The curved plate limit state is based on the following
appropriate by the Society. interaction formula:
 c   ax  S  1 25
 c   ax  S    c   tg  S    c   tg  S  1 25   c    3  S
2
 ------------------------
- – 0 5   ------------------------
-  ------------------------ + ------------------------ + ------------------------------- = 1
 C ax  R eH_P  C ax  R eH_P  C tg  R eH_P  C tg  R eH_P  C   R eH_P 
with the corresponding buckling utilization factor Cax,Ctg,C : Buckling reduction factor of the curved
defined as: plate panel, as defined in Tab 6.
curved_plate = 1 / c The stress multiplier factor, c , of the curved plate panel
need not be taken less than the stress multiplier factor,
where:
c , for the expanded plane panel according to [5.3.2],
ax : Applied axial stress to the cylinder a).
corresponding to the curved plate panel, in
g) Applied normal and shear stresses to plate panels
N/mm2. In case of tensile axial stresses, ax
The normal stress, x and y, in N/mm2, to be applied
=0
for the overall stiffened panel capacity and the plate
tg : Applied tangential stress to the cylinder panel capacity calculations as given in [5.3.1], a) and
corresponding to the curved plate panel, in [5.3.2], a) respectively, are to be taken as follows:
N/mm2. In case of tensile tangential stresses, • For FE analysis, the reference stresses as defined in
tg = 0 [4.3.4]
RINA Rules 2024 133

Pt B, Ch 7, Sec 5
• For prescriptive assessment of the overall stiffened to [3], at load calculation points of the
panel capacity and the plate panel capacity, the considered elementary plate panel, as defined in
axial or transverse compressive stresses calculated [3.3.2], a), 1)
according to [3], at load calculation points of the • For prescriptive assessment of the overall
considered stiffener or the considered elementary stiffened panel capacity, the shear stresses
plate panel, as defined in item 1) and item 2) of calculated according to [3], at the following load
[3.3.2], a) respectively. However, in case of calculation point:
transverse stiffening arrangement, the transverse
- At the middle of the full span, , of the
compressive stress used for the assessment of the
considered stiffener
overall stiffened panel capacity is to be taken as the
compressive stress calculated at load calculation - At the intersection point between the
points of the stiffener attached plating, as defined in stiffener and its attached plating.
[3.3.2], a), 1) • For grillage beam analysis,  = 0 in the plate
• For grillage analysis where the stresses are obtained attached to the PSM web.
based on beam theory, the stresses taken as:
Figure 17 : Transverse stiffened bilge
plating (1/7/2024)
 xb +    yb
 x = ----------------------------
-
1–
2
 yb +    xb
 y = ----------------------------
-
1–
2
where:
xb, yb : Stress, in N/mm2, from grillage beam
analysis respectively along x or y axis of
the plate attached to the PSM web.
The shear stress , in N/mm2, to be applied for the
overall stiffened panel capacity and the plate panel
capacity calculations as given in [5.3.1], a) and
[5.3.2], a) respectively, are to be taken as follows:
• For FE analysis, the reference shear stresses as
defined in Sec 4, [2.4]
• For prescriptive assessment of the plate panel
capacity, the shear stresses calculated according
Table 3 : Definition of coefficients B and
e0 (1/7/2024)
Applied stress B e0
x 0 and y 0 0,7-0,3 p/ . 2
2 p0,25
.
x 0 or y 0 1,0 2,0
134 RINA Rules 2024

Pt B, Ch 7, Sec 5
Table 4 : Correction factor Flong (1/7/2024)
Structural element types Flong c

Unstiffened Panel 1,0 N/A
Stiffener not fixed at both ends 1,0 N/A
Flat bar (1) Flong = c+1 for tw / tp >1 0,10
Stiffener fixed at Bulb profile Flong = c.(tw / tp)3 for tw / tp 1 0,30
Stiffened both ends
Panel Angle and L2 profiles 0,40
T profile 0,30
Girder of high rigidity 1,4 N/A
(e.g. bottom transverse)
U-type profile fitted on • Plate on which the U-type profile is fitted, including 0,2
hatch cover (2) EPP b1 and EPP b2
- Flong = 1 for b2 < b1
- Flong = (1,55-0,55.b1/ b2).[1+c.(tw / tp)3]
• Other plates of the U-type profile:
Flong = 1
(1) tw is the net web thickness, in mm, without the correction defined in [5.3.3], b).
(2) b1, b2 and tw are defined in Fig 4.
Table 5 : Buckling factor and reduction factor for plane plate panels (1/7/2024)
Stress Aspect
Case Buckling factor K Reduction factor C
ratio  ratio 
1 1>>0 kx = Flong.8,4 / ( + 1,1) When x  0, Cx = 1
When x  0,
0 >  > -1 kx = Flong.[7,63 - (6,26 - 10)]
Cx = 1 for c
Cx = c [(1/ 2) for 
c
  -1 kx = Flong.[5,975·(1 - 2] where:
c = (1,25 - 0,12 1,25
0 8 8
 C = ---  1 + 1 – -------------
c
2 c 
Edge boundary conditions:
Note 1: Cases listed are general cases. Each stress component (x, y) is to be understood in local coordinates.
RINA Rules 2024 135

Pt B, Ch 7, Sec 5
Stress Aspect
ratio  ratio 
2 when y 0, Cy = 1
1>>0 1 2 when y 0
F tran  2   1 + -----2-
 
K y = -----------------------------------------------------------------------------------
 1 –   2 4
1 +  + ------------------   -------- - + 6 9  f 1 1 R + F  H – R -
2
100   2  C y = c  --- – ----------------------------------

 
2 
α≤6 f1= (1-ψ).(α-1) where:

c = (1,25 - 0,12 1,25
α >6 . .
f1 = 0,6 (1-6  + 14/) but not 
grater than14,5-0,35/2
Ky =

2 2 R =   1 – --- for    C
200  F tran   1 +    c
-------------------------------------------------------------------------------------------------------------
 1 – f 3    100 + 2 4   + 6 9  f 1 + 23  f 2 
2
1-4.a/3 
<0
> f1 = 0,6.(1/+14.) but not grater than
6.(1-) 14,5-0,35/2
f2 = f3 = 0
R = 0 22 for    C
3.(1-) f1 = 1/ -1
 f2 = f3 = 0
6.(1-) 0 88
 C = ---  1 + 1 – -------------
c
2 c 
1,5.(1- f1 = 1/ -(2-)4-9.(-1).(2/3-)
)   f2 = f3 = 0
<
F = 1 –  ------------- – 1   2 p  c 1  0
k
3.(1-)  0 91 
1-   For  > 1,5
< p2 = 2 - 0,5 for 1 > p2 > 3
f1 = 2.(1/ -16.(1-)4).(1/-1)
1,5.(1- c1 as defined in [5.3.2], c)
f2 = 3.-2
)
f3 = 0
For   1,5
f1 = 2.(1,5/(1-) -1).(1/-1)
2
f2 = .(1-16.f42).(1-) H =  – -----------------------------------------  R
c   T + T2 – 4 
f3 = 0
f4 = (1,5-Min(1,5, ))2
0,75.(1- f1 = 0
)   f2 = 1+2,31.(-1)-48.(4/3-).f42
< 14 1
f3 = 3.f4.(-1)-(f4/1,81-(-1)/1,31) T =  + ---------- + ---
1- 15 3
f4 = (1,5-Min(1,5, ))2
 < 1-
4.a/3 5 972  F tran  
2
K y = ----------------------------------------
-
1 – f3
where:
f3 = f5.(f5/1,81+(1+3)/5,24)
f5 = (9/16).(1+Max(-1, ))2
RINA
NoteRules 2024 listed
1: Cases are general cases. Each stress component (x, y) is to be understood in local coordinates. 137
Pt B, Ch 7, Sec 5
Stress Aspect
ratio  ratio 
3 For UP-A:
4  0 425 + -----2-
1
1>>0  
K x = -------------------------------------- C x = 1 for   0 75
3 + 1
0 75
C x = ------------- for   0 75
0 >  > -1 
For UP-B:
K x = 4  0 425 + -----2-  1 +   – 5   1 – 3 42 
1
 
C x = 1 for   0 7
1 -
4 C x = ------------------------ for   0 7
 + 0 51
2
1 >  > -1
1 3–
K x =  0 425 + -----2- -------------
  2
> K  = 1 28
1,64
-
1
K  = -----2- + 0 56 + 0 13  
2
  
138 RINA Rules 2024

Pt B, Ch 7, Sec 5
Stress Aspect
ratio  ratio 
6 For UP-A:
4  0 425 +   2
1>>0 K y = ------------------------------------
-
 3 + 1    2
C y = 1 for   0 75
0 >  > -1 1 0 75
K y = 4  0 425 +  2   1 +   -----2- C y = ------------- for   0 75
 
1
– 5   1 – 3 42  -----2- For UP-B:

7 C y = 1 for   0 7
1 >  > -1
1 -
C y = ------------------------ for   0 7
 + 0 51
2
2 3– 
K y =  0 425 +   -------------2
2
-
0 56 0 13
K y = 1 + ------------
- + ------------
-
2 4
C x = 1 for   0 83
K x = 6 97
Cx =
1 0 22
1 13   --- – ------------
- for   0 83
  
2
RINA Rules 2024 139

Pt B, Ch 7, Sec 5
Stress Aspect
ratio  ratio 
10
- C y = 1 for   0 83
2 07- ------------
0 67-
K y = 4 + ------------ +
 
2 4
Cy =
1 0 22
1 13   --- – ------------
- for   0 83
  
2
11 > 4
Kx = 4 C x = 1 for   0 83
-
 
Cx =
4– 4
K x = 4 + 2 74   ------------- 1 0 22
 3  1 13   --- – ------------
- for   0 83
  
2
12 For  
Cy = Cy2
For  > 
- Ky = Ky determined as per case 2
C y =  1 06 + --------------  C y2
1
 10  
where:
Cy2 : Cy determined as per
case 2
140 RINA Rules 2024

Pt B, Ch 7, Sec 5
Stress Aspect
ratio  ratio 
13
- > 4 K x = 6 97 C x = 1 for   0 83
 
Cx =
1 0 22
4–
4 1 13   --- – ------------
- for   0 83
K x = 6 97 + 3 1   -------------   
2
 3 
14
C y = 1 for   0 83
1 4
 4 – ---
6 97 3 1  
K y = ------------ -  -------------
- + --------
   3 
2 2
Cy =
1 0 22
1 13   --- – ------------
- for   0 83
  
2
RINA Rules 2024 141

Pt B, Ch 7, Sec 5
Stress Aspect
ratio  ratio 
15
3   5 34 + -----2-
4
K =
-  
16
C  = 1 for   0 84
4 7 15
K = 3  5 34 + Max  -----2- ------------
-
   2 5 
0 84 for   0 84
C  = -------------

17 K = Kcase15.
Kcase15 : K according to case 15
 : Opening reduction factor taken as
-  = (1-da/a).(1-db/b)
with:
da/a  0,7 and db/b  0,7
142 RINA Rules 2024

Pt B, Ch 7, Sec 5
Stress Aspect
ratio  ratio 
18
3   0 6 + -----2-
4
K =
 a
-
C  = 1 for   0 84
19
-
0 84 for   0 84
C  = -------------

K = 8
RINA Rules 2024 143

Pt B, Ch 7, Sec 5
Table 6 : Buckling factor and reduction factor for curved plate panels with R/tp  2500 (1/7/2024)
Case Aspect ratio Buckling factor K Reduction factor C

1 For general application:
d R 2 d
2 Cax = 1 for 0,25
---  0 5  --- K = 1 + ---  ------------
R tp 3 R  tp Cax = 1,233-0,933. for
0,25<1
Cax = 0,3.3 for 1<1,5
Cax = 0,2.2 for 1,5
2 2
d d t d
d R
---  0 5  --- K = 0 267  ------------  3 – ---  ---p  0 4  ------------ For curved single fields, e.g. bilge
R tp R  tp R R R  t p strake, which are bounded by
plane panels as shown in Fig 17:
Cax = 0,65/2 1,0
2 For general application:

d R d  R  tp 
0 175
Ctg = 1 for 0,4
---  1 63  --- K = ---------------- + 3  --------------------------
0 35
-
R tp R  tp d Ctg = 1,274-0,686. for 0,4<
1,2
Ctg = 0,65/2 for 1,2
For curved single fields, e.g. bilge
2 2 2 strake, which are bounded by
K = 0 3  -----2 + 2 25   -----------
d R d R
---  1 63  --- plane panels as shown in Fig 17:
R tp R  d  t p
Ctg = 0,8/2 1,0
3 As in load case 2
d R
---  ---
R tp
0 6  d Rt R  tp
K = ----------------- + ---------------p- – 0 3  -----------
-
R  tp d 2
d
d R
---  ---
R tp 2 2 2
K = 0 3  -----2 + 0 291   -----------
d R
R  d  t p
144 RINA Rules 2024

Pt B, Ch 7, Sec 5
Case Aspect ratio Buckling factor K Reduction factor C

4 C = 1 for 0,4
d R
---  8 7  --- C = 1,274-0,686. for 0,4<
R tp
0 67  d -
3
1,2
K = 3  28 3 + ----------------------
1 5 1 5
R  tp C= 0,65/2 for 1,2
d R
---  8 7  ---
R tp
0 28  d
2
K = 3  ------------------------
R  R  tp
5.3.3 Stiffeners (1/7/2024)  : Coefficient equal to:

a) Buckling modes
 2
The following buckling modes are to be checked:  120 – h w  
 = 1 1 + ------------------------------ for h w  120
3000
• Stiffener induced failure (SI)
• Associated plate induced failure (PI).  = 1,0 for h’w > 120
b) Web thickness of flat bar d) Ultimate buckling capacity
For accounting the decrease of the stiffness due to local When a+b+w>0 while initially setting =1, the
lateral deformation, the effective web thickness of flat ultimate buckling capacity for stiffeners is to be checked
bar stiffener, in mm, is to be used in [5.3.1] and [5.3.3], according to the following interaction formula:
d) for the calculation of the net sectional area, As, the
net section modulus, Z, and the moment of inertia, I, of
c  a + b +  w
the stiffener and is taken as: ----------------------------------------  S = 1
R eH
2
2
h 2 b eff1  with the corresponding buckling utilization factor
t w_red = t w   1 – -------------   -----w-   1 – ---------
-
 3  s  s  defined as:
stiffener = 1 / c
c) Idealisation of bulb profile
where:
Bulb profiles are to be considered as equivalent angle a : Effective axial stress, in N/mm2, at mid span
profiles. The net dimensions of the equivalent built-up
of the stiffener, acting on the stiffener with
section are to be obtained, in mm, from the following
its attached plating.
formulae.
 s  tp + As
 hw  a =  x  ------------------------------
-
h w = h w – --------
-+2 b eff1  t p + A s
9 2
x : Nominal axial stress, in N/mm2, acting on

the stiffener with its attached plating.
b f =    t w + --------
- – 2
 hw
 6 7  • For FE analysis, x is the FE corrected
stress as defined in [5.3.3], f) in the
tf = h’w/9,2 - 2 attached plating in the direction of the
stiffener axis
tw = t’w
• For prescriptive assessment, x is the
where: axial stress calculated according to
h’w, t’w : Net height and thickness of a bulb section, [3.4.2], a) at load calculation point of
in mm, as shown in Fig 18 the stiffener, as defined in [3.3.2], a)
RINA Rules 2024 145

Pt B, Ch 7, Sec 5
• For grillage beam analysis, x is the • For prescriptive assessment, P is the

stress acting along the x-axis of the pressure calculated at load calculation
attached buckling panel. point of the stiffener, as defined in
[3.3.2], a).
ReH : Specified minimum yield stress of the
Ci : Pressure coefficient:
material, in N/mm2
• Ci = CSI for stiffener induced failure (SI)
• ReH = ReH_S for stiffener induced failure
(SI). • Ci = CPI for plate induced failure (PI).
• ReH = ReH_P for plate induced failure CPI : Plate induced failure pressure coefficient:
(PI). • CPI = 1 if the lateral pressure is applied
b : Bending stress in the stiffener, in N/mm2: on the side opposite to the stiffener
• CPI = -1 if the lateral pressure is applied
b = (M0+M1+M2)/1000.Z
on the same side as the stiffener.
Z : Net section modulus of stiffener, in cm3,
CSI : Stiffener induced failure pressure
including effective width of plating
according to [5.3.3], e), to be taken as: coefficient:
• The section modulus calculated at the • CSI = -1 if the lateral pressure is applied
top of stiffener flange for stiffener on the side opposite to the stiffener
induced failure (SI) • CSI = 1 if the lateral pressure is applied
• The section modulus calculated at the on the same side as the stiffener.
attached plating for plate induced failure M0 : Bending moment, in Nmm, due to the
(PI). lateral deformation w of stiffener:
M2 : Bending moment, in Nmm, due to
eccentricity of sniped stiffeners, to be taken 
as: M 0 = F E  C sl  ------------------  w 0 with precondition  GEB –   0
 GEB – 
• M2=0 for continuous stiffeners
GEB : Stress multiplier factor of global elastic
• M2=Csnip.wna..x.(Ap+As) for stiffeners
buckling capacity as defined in [5.3.1].
sniped at one or both ends.
FE : Ideal elastic buckling force of the stiffener,
Csnip : Coefficient to account for the end effect of
in N:
the stiffener sniped at one or both ends, to
be taken as: FE = (/)2.E.I.104
• Csnip = -1,2 for stiffener induced failure I : Moment of inertia, in cm4, of the stiffener
(SI) including effective width of attached plating
according to [5.3.3], e). I is to comply with
• Csnip = 1,2 for plate induced failure (PI).
the following requirement:
M1 : Bending moment, in Nmm, due to the
I > s.tp3 / 12.104
lateral load P:
tp : Net thickness of plate, in mm, to be taken
for continuous stiffener:
as:
• For prescriptive requirements: the mean
P sl
2
M 1 = C i  --------------------3- thickness of the two attached plating
24  10 panels
for sniped stiffener: • For FE analysis: the thickness of the
considered EPP on one side of the
stiffener.
P sl
2
M 1 = C i  --------------------
- Csl : Deformation reduction factor to account for
8  10
3
global slenderness, to be taken as:

for stiffener sniped at one end and • Csl = 1-(1/12)G4 for G 
continuous at the other end
• Csl = 3/G4 for G 
P sl
2 G : The reference degree of global slenderness
M 1 = C i  -------------------------3-
14 2  10 of the stiffened panel, to be taken as:
P : Lateral load, in kN/m2.  ReH

G = ----------
• For FE analysis, P is the average pressure  GEB
as defined in [4.3.5] in the attached
plating with
146 RINA Rules 2024

Pt B, Ch 7, Sec 5
IT : Net St. Venant’s moment of inertia of the

Min  R eH_P R eH_S  stiffener, in cm4, as defined in Tab 7
 ReH = --------------------------------------------------------------------------
-
 x av +  y –  x av   y + 3  
2 2 2
I : Net sectorial moment of inertia of the
x,av : Average stress for both plate and stiffener as stiffener, in cm6, about point C as shown in
defined in [5.3.1], b) Fig 3, as defined in Tab 7
y : Applied transverse stress to the plate panel tor : Stiffener span, distance equal to spacing
as defined in [5.3.1], a) between primary supporting members, i.e.
 : Applied shear stress to the plate panel as tor =  .When the stiffener is supported by
defined in [5.3.1], a) tripping brackets, tor should be taken as the
w0 : Assumed imperfection, in mm, to be taken maximum spacing between the adjacent
primary supporting members and fitted
as:
tripping brackets
w0= /1000
mtor : Number of half waves, taken as a positive
w : Stress due to torsional deformation, in integer so as to give smallest reference stress
N/mm2, to be taken as: for torsional buckling
• For stiffener induced failure (SI)  : Degree of fixation, in mm2, to be taken as:
- For a > 0 • for bulb, angle, L2 and T profiles:
  3  b 2  h w
 =  ----------
- + -------------
-
m tor   2    t3 tw 
 w = E  y w  e f   0   -----------------
1 3
  ---------------------- – 1 p
  tor     a 
------------
 1 –  ET  • for flat bars:
with precondition ET - a> 0 3

tp 
 =  ------
-
- For a  0  3b
w = 0
Aw : Net web area, in mm2
• For plate induced failure (PI) Af : Net flange area, in mm2
w = 0
e) Effective width of attached plating
yw : Distance, in mm, from centroid of stiffener The effective width of attached plating of stiffeners, beff,
cross section to the free edge of stiffener in mm, is to be taken as:
flange, to be taken as:
• For x > 0
• yw = tw / 2 for flat bar
- For FE analysis
• for angle and bulb profiles:
beff = Min(Cx.b, s.s)
hw  tw + tf  bf
2 2 - For prescriptive assessment
y w = b f – ----------------------------------
-
2  As
C x1  b 1 + C x2  b 2
• for L2 profile: b eff = Min  ------------------------------------------
- , s  s
 2 
hw  tw + tf   bf – 2  bf  df 
2 2
• For x  0
y w = b f – out + 0 5  t w – ------------------------------------------------------------------
-
2  As
beff = s.s
• yw = bf / 2 for T profile.
where:
0 : Coefficient taken as:
s : Effective width coefficient to be taken as:
 tor 1 12  eff
-  10 –4
 0 = --------------------  s = -----------------------------  1 0 -1
for ------
m tor  h w 1 75 s
1 + ------------------ 1 6
-
ET : Reference stress for torsional buckling, in 
 ------
eff
-
 s 
N/mm2, to be taken as:
 eff  eff
m tor    tor  2  s = 0 407  ------
- -1
for ------
 ET = ---   -----------------  I  10 + -------------------------  I T +  -----------------
E 1 –4
   10
2
s s
I p   tor   2  1 + v  m tor  
Ip : Net polar moment of inertia of the stiffener, eff : Effective length of the stiffener, in mm, taken
as:
in cm4, about point C as shown in Fig 3, as
defined in Tab 7 eff =  / 30,5 for stiffener fixed at both ends
RINA Rules 2024 147

Pt B, Ch 7, Sec 5
eff = 0,75. for stiffener simply supported x is to be corrected according to the following
at one end and fixed at the other formulae:
eff =  for stiffener simply supported at • If x < v.y
both ends. xcor = 0
f) FE corrected stresses for stiffener capacity
• If x > v.y
When the reference stresses x and y obtained by FE
analysis according to Sec 4, [2.4] are both compressive, xcor = x - v.y
Table 7 : Moments of inertia (1/7/2024)
Flat bars (1) Bulb, angle, L2 and T profiles
hw  tw A w   e f – 0 5  t f 
3 2
Ip ----------------  ---------------------------------------------
- + A f  e f  10 –4
3  10
4  3 
IT
hw  tw   e f – 0 5  t f   t w  bf  tf 
3 3 3
tw  tw t
----------------  1 – 0 63  -----
- - + ----------------
-  1 – 0 63  --------------------------
----------------------------------------  1 – 0 63  ----f 
3  10  h w 3  10  e f – 0 5  t f 3  10 4  b f
4 4
I For bulb, angle and L2 profiles (2):
Af + Aw ef  Af  bf + Aw  tw  Af   bf – 2  df  + Aw  tw 
3 3 2 2 2 2
- + --------6  -------------------------------------- – ------------------------------------------------------------------- – A f  d f   b f – d f 
-------------------
36  10 10  3 4   Af + Aw  
6
hw  tw
3 3
-------------------
-
36  10
6 For T profile:
bf  tf  ef
3 2
----------------------
12  10
6
(1) tw is the net web thickness, in mm

tw_red as defined in [5.3.3], b) is not to be used in this table.
(2) df is to be taken as 0 for bulb and angle profiles.
Figure 18 : Idealisation of bulb stiffener (1/7/2024)
148 RINA Rules 2024

Pt B, Ch 7, Sec 5
5.3.4 Primary Supporting Members (1/7/2024) • Opening modelled in primary supporting members:
a) Web plate in way of openings av : Weighted average shear stress, in
The web plate of primary supporting members with N/mm2, in the area of web plate being
openings is to be assessed for buckling based on the considered, i.e. P1, P2, or P3 as shown
combined axial compressive and shear stresses. in Tab 8.
The web plate adjacent to the opening on both sides is • Opening not modelled in primary supporting
to be considered as individual unstiffened plate panels members:
as shown in Tab 8.
av : Weighted average shear stress, in
The interaction formulae of [5.3.2], a) are to be used 2
with: N/mm , given in Tab 8.
x = av b) Reduction factors of web plate in way of openings
y = 0 The reduction factors, Cx or Cy in combination with, C
of the plate panel(s) of the web adjacent to the opening
 = av
is to be taken as shown in Tab 8.
where:
c) The equivalent plate panel of web plate of primary
av : Weighted average compressive stress, in supporting members crossed by perpendicular stiffeners
N/mm2, in the area of web plate being is to be idealised as shown in Fig 19.
considered, i.e. P1, P2, or P3 as shown in The correction of panel breadth is applicable also for
Tab 8. other slot configurations provided that the web or collar
For the application of Tab 8, the weighted average shear plate is attached to at least one side of the passing
stress is to be taken as: stiffener.
Figure 19 : Web plate idealization (1/7/2024)
RINA Rules 2024 149

Pt B, Ch 7, Sec 5
Table 8 : Reduction factors (1/7/2024)
C
Configuration (1) Cx, Cy
Opening
Opening modelled in PSM
not modelled in PSM
(a) Without edge reinforcements: (2) Separate reduction Separate reduction factors When case 17 of Tab 5 is
factors are to be are to be applied to areas applicable:
applied to areas P1 P1 and P2 using case 18 or A common reduction factor
and P2 using case 3 case 19 in Tab 5. is to be applied to areas P1
or case 6 in Tab 5, and P2 using case 17 in Tab
with edge stress 5 with:
ratio: av = av (web)
= 1,0
When case 17 of Tab 5 is
not applicable:
Separate reduction factors
are to be applied to areas
P1 and P2 using case 18 or
case 19 in Tab 5 with:
av = av (web).h/ (h-h0)
(b) With edge reinforcements: Separate reduction Separate reduction Separate reduction factors
factors are to be factors are to be applied for are to be applied to areas
applied for areas P1 areas P1 and P2 using case P1 and P2 using case 15 in
and P2 using Cx for 15 in Tab 5. Tab 5 with:
case 1 or Cy for av = av (web).h/ (h-h0)
case 2 in Tab 5 with
stress ratio:
 = 1,0
(c) Example of hole in web: Panels P1 and P2 are to be evaluated in accordance with (a). Panel P3 is to be
evaluated in accordance with (b).
Where:
h : Height, in m, of the web of the primary supporting member in way of the opening
h0 : Height in m, of the opening measured in the depth of the web
av(web) : Weighted average shear stress, in N/mm2, over the web height h of the primary supporting member.
(1) Web panels to be considered for buckling in way of openings are shown shaded and numbered P1, P2, etc.
(2) For a PSM web panel with opening and without edge reinforcements as shown in configuration (a), the applicable buckling
assessment method depends on its specific boundary conditions. If one of the long edges along the face plate or along the
attached plating is not subject to "inline support", i.e. the edge is free to pull in, Method B should be applied. In other cases,
typically such as when the short plate edge is attached to the plate flanges, Method A is applicable.
150 RINA Rules 2024

Pt B, Ch 7, Sec 5
5.3.5 Stiffened Panels with U-type E : Elastic column compressive buckling stress,
Stiffeners (1/7/2024) in N/mm2, according to [5.4.1], b).
a) Local plate buckling ReH_S : Specified minimum yield stress of the
For stiffened panels with U-type stiffeners, local plate considered member, in N/mm2. For built-up
buckling is to be checked for each of the plate panels members, the lowest specified minimum
EPP b1, b2, bf and hw (see Fig 4) separately as follows: yield stress is to be used.
• The attached plate panels EPP b1 and b2 are to be b) Elastic column buckling stress
assessed using SP-A model, where in the calculation
The elastic compressive column buckling stress, E in
of buckling factors Kx as defined in Case 1 of Tab 5,
the correction factor Flong for U-type stiffeners as N/mm2 of members subject to axial compression is to
defined in Tab 4 is to be used; and in the calculation be taken as:
of Ky as defined in Case 2 of Tab 5, the Ftran for U-
type stiffeners as defined in [5.3.2], e) is to be used. I
-  10 –4
 E =   E  f end  ----------------
2
A   pill
2
• The face plate and web plate panels bf and hw are to
be assessed using UP-B model with Flong =1 and where:
Ftran =1. I : Net moment of inertia about the weakest
b) Overall stiffened panel buckling and stiffener buckling axis of the cross section, in cm4
For a stiffened panel with U-type stiffeners, the overall A : Net cross-sectional area of the member, in
buckling capacity and ultimate capacity of the stiffeners cm2
are to be checked with warping stress w = 0, and with
pill : Unsupported length of the member, in m
bending moment of inertia including effective width of
attached plating being calculated based on the fend : End constraint factor, corresponding to
following assumptions: simply supported ends is to be applied
• The two web panels of a U-type stiffener are to be except for fixed end support to be used in
taken as perpendicular to the attached plate with way of stool with width exceeding 2 times
thickness equal to tw and height equal to the the depth of the corrugation, taken as:
distance between the attached plate and the face • fend = 1,0 where both ends are simply
plate of the stiffener supported
• Effective width of the attached plating, beff , taken as • fend = 2,0 where one end is simply
the sum of the beff calculated for the EPP b1 and b2 supported and the other end is fixed
respectively according to SP-A model • fend = 4,0 where both ends are fixed.
• Effective width of the attached plating of a stiffener
without shear lag effect, beff1 , taken as the sum of
6 Stress based reference stresses
the beff1 calculated for the EPP b1 and b2
respectively.
6.1 Symbols
5.4 Buckling Capacity of column structures 6.1.1 (1/7/2024)
5.4.1 Column Buckling of Corrugations (1/7/2024) a : Length, in mm, of the longer side of the plate
panel as defined in [5]
a) Buckling utilisation factor
b : Length, in mm, of the shorter side of the plate
The column buckling utilisation factor, , for axially panel as defined in [5]
compressed corrugations is to be taken as:
Ai : Area, in mm2, of the i-th plate element of the
column = av / cr
buckling panel
where: n : Number of plate elements in the buckling panel
av : Average axial compressive stress in the xi : Actual stress, in N/mm2, at the centroid of the i-
member, in N/mm2. th plate element in x direction, applied along
cr : Minimum critical buckling stress, in N/mm2, the shorter edge of the buckling panel
taken as: yi : Actual stress, in N/mm2, at the centroid of the i-
• cr = E for E ReH_S th plate element in y direction, applied along
the longer edge of the buckling panel
• for E ReH_S :
 : Edge stress ratio as defined in [5]
yi : Actual membrane shear stress, in N/mm2, at the
R eH_S
 cr =  1 – ------------
-  R eH_S centroid of the i-th plate element of the
 4   E
buckling panel.
RINA Rules 2024 151

Pt B, Ch 7, Sec 5
6.2 Stress Based Method 

 n
 
=2 A  x    xi –  Cx i + Dx i + E   = 0
2 2
6.2.1 Introduction (1/7/2024)  C i i

a) This Section provides a method to determine stress 
i=1
n
distribution along edges of the considered buckling  
 =2  A  x   –  Cx i + Dx i + E   = 0
2
panel by second-order polynomial curve, by linear  D i i xi
distribution using least square method and by weighted  i=1

 n
average approach. This method is called Stress based  
= 2  A   –  Cx i + Dx i + E   = 0
2
 E i xi
Method. The reference stress is the stress components at 
centre of plate element transferred into the local system  i=1
of the considered buckling panel.

b
b) Definition: A regular panel is a plate panel of
2
1 b b
rectangular shape. An irregular panel is plate panel 
 x1 = ---   x  x  dx = -----  C + ---  D + E
b 3 2
0
which is not regular, as detailed in [4.3.3], a).
6.2.2 Stress Application (1/7/2024) a

2
 x  x  dx =  a – a  b + -----  C +  a – ---  D + E
1 b b
 x2 = ---  
2
a) Regular panel b  3  2
a–b
The reference stresses are to be taken as defined in
if -D/2C < b/2 or -D/2C > a-b/2 , x3 is to be
[6.3.1] for a regular panel when the following
conditions are satisfied: ignored. Otherwise, x3 is taken as:
• At least, one plate element centre is located in each
third part of the long edge a of a regular panel and xmax
2 2
1 b D
• This element centre is located at a distance in the  x3 = --- 
b   x  x  dx = ------  C – ----------- + E
12 4C
panel local x direction not less than /4 to at least xmin
one of the element centres in the adjacent third part

of the panel. where:
Otherwise, the reference stresses are to be taken as xmin = -b/2 - D/2C
defined in [6.3.2] for an irregular panel. xmax = b/2 - D/2C
b) Irregular panel and curved panel The longitudinal stress is to be taken as:
The reference stresses of an irregular panel or of a x = Max(x1, x2, x3)
curved panel are to be taken as defined in [6.3.2]. The edge stress ratio is to be taken as:
x = 1
6.3 Reference Stresses
• For overall stiffened panel buckling and stiffener
6.3.1 Regular Panel (1/7/2024) buckling assessments, the longitudinal stress x
applied on the shorter edge of the attached plate is
a) Longitudinal stress
to be taken as:
The longitudinal stress x applied on the shorter edge of
the buckling panel is to be calculated as follows: n
• For plate buckling assessment, the distribution of A   i xi

x(x) is assumed as second order polynomial curve  x = ------------------------
i=1 -
n
as:
A i
x = Cx2 + Dx + E i=1
The best fitting curve x(x) is to be obtained by The edge stress ratio x for the stress x is equal to
minimising the square error  considering the area 1,0.
of each element as a weighting factor.
b) Transverse stress
The transverse stress y applied along the longer edges
n
of the buckling panel is to be calculated by
 A  
2
 = –  Cx i + Dx i + E  
2
i xi extrapolation of the transverse stresses of all elements
i=1
up to the shorter edges of the considered buckling
The unknown coefficients C, D and E must yield panel.
zero first derivatives,  with respect to C, D and E, The distribution of y(x) is assumed as straight line.
respectively. Therefore: y(x) =A+Bx
The best fitting curve y(x) is to be obtained by the least
The unknown coefficients C, D and E can be square method minimising the square error 
obtained by solving the 3 above equations. considering area of each element as a weighting factor.
152 RINA Rules 2024

Pt B, Ch 7, Sec 5
n n n n n
       
 =  A i    yi –  A + Bx i  
   
2
 A i   A i  x i   yi –  A i  x i   A i   yi
       
i=1
B = -----------------------------------------------------------------------------------------------------------------------------------
i=1 i=1
n n
i=1
n
i=1
2
-
   2  
The unknown coefficients C and D must yield zero first
partial derivatives,  with respect to C and D, 
  

 A i   A i  x i  –  A i  x i
 
 
i=1 i=1 i=1
respectively.
The transverse stress is to be taken as:
y = max(A, A+Ba)
n
 The edge stress ratio is to be taken as:
A
= 2  A   i yi –  A + Bx i   = 0
i=1
min  A A + B  a 
 = --------------------------------------------- for  y  0
max  A A + B  a 
n

B
= 2  A  x  i i yi –  A + Bx i   = 0 y = 1 for y 
i=1
c) Shear stress
The unknown coefficients A and B are obtained by The shear stress  is to be calculated using a weighted
solving the 2 above equations and are given as follow: average approach, and is to be taken as:
n n n n n
   2    

  

 A i   yi   A i  x i  –  A i  x i   A i  x i   yi
 
  
  A   i i
A = ---------------------------------------------------------------------------------------------------------------------------------------------
i=1
n
i=1
n
i=1
n
i=1
2  = ----------------------
i=1
n
   2  

  

 A i   A i  x i  –  A i  x i
 
  A i
i=1 i=1 i=1 i=1
Figure 20 : Buckling panel (1/7/2024)
6.3.2 Irregular Panel and Curved Panel (1/7/2024) n
a) Reference stresses A   i yi
The longitudinal, transverse and shear stresses are to be  y = ------------------------

i=1 -
n
calculated using a weighted average approach. They are
to be taken as: A i
i=1
n n
 A i   xi A   i i
 x = ------------------------
i=1
n
-  = ----------------------
i=1
n
A i A i
i=1 i=1
x = 1
y = 1
The edge stress ratios are to be taken as
RINA Rules 2024 153

Pt B, Ch 9, Sec 4
SECTION 4 SUPERSTRUCTURES AND DECKHOUSES
Symbols
x, y, z : X, Y and Z co-ordinates, in m, of the calculation The second tier is that located immediately above the low-
point with respect to the reference co-ordinate est tier, and so on.
system defined in Ch 1, Sec 2, [4]
s : Spacing, in m, of ordinary stiffeners 1.4 Connections of superstructures and
k : Material factor, defined in: deckhouses with the hull structure
• Ch 4, Sec 1, [2.3], for steel
1.4.1 Superstructure and deckhouse frames are to be fitted
• Ch 4, Sec 1, [4.4], for aluminium alloys as far as practicable as extensions of those underlying and
tc : Corrosion addition, in mm, defined in Ch 4, are to be effectively connected to both the latter and the
Sec 2, Tab 2. deck beams above.
Ends of superstructures and deckhouses are to be efficiently
1 General supported by bulkheads, diaphragms, webs or pillars.
Where hatchways are fitted close to the ends of superstruc-
1.1 Application tures, additional strengthening may be required.
1.1.1 The requirements of this Section apply for the scant- 1.4.2 Connection to the deck of corners of superstructures
ling of plating and associated structures of front, side and aft and deckhouses is considered by the Society on a case by
bulkheads and decks of superstructures and deckhouses, case basis. Where necessary, doublers or reinforced weld-
which may or may not contribute to the longitudinal ing may be required.
strength.
1.4.3 As a rule, the frames of sides of superstructures and
1.1.2 The requirements of this Section comply with the deckhouses are to have the same spacing as the beams of
applicable regulations of the 1966 International Convention the supporting deck.
on Load Lines, with regard to the strength of enclosed Web frames are to be arranged to support the sides and
superstructures. ends of superstructures and deckhouses.
1.2 Net scantlings 1.4.4 The side plating at ends of superstructures is to be

tapered into the bulwark or sheerstrake of the strength deck.
1.2.1 As specified in Ch 4, Sec 2, [1], all scantlings
Where a raised deck is fitted, this arrangement is to extend
referred to in this Section are net, i.e. they do not include
over at least 3 frame spacings.
any margin for corrosion.
The gross scantlings are obtained as specified in Ch 4,
Sec 2. 1.5 Structural arrangement of superstruc-
tures and deckhouses
1.3 Definitions 1.5.1 Strengthening in way of superstructures and
deckhouses
1.3.1 Superstructures and deckhouses contributing
to the longitudinal strength Web frames, transverse partial bulkheads or other equiva-
lent strengthening are to be fitted inside deckhouses of at
Superstructures and deckhouses contributing to the longitu-
least 0,5B in breadth extending more than 0,15L in length
dinal strength are defined in Ch 6, Sec 1, [2.2].
within 0,4L amidships. These transverse strengthening rein-
1.3.2 Tiers of superstructures and deckhouses forcements are to be spaced approximately 9 m apart and
are to be arranged, where practicable, in line with the trans-
The lowest tier is normally that which is directly situated verse bulkheads below.
above the freeboard deck.
Web frames are also to be arranged in way of large open-
Where the freeboard exceeds one standard superstructure
ings, boats davits and other areas subjected to point loads.
height, defined in Ch 1, Sec 2, Tab 2 for “all other super-
structures”, the lowest tier may be considered as an upper Web frames, pillars, partial bulkheads and similar strength-
tier when calculating the scantlings of superstructures and ening are to be arranged, in conjunction with deck trans-
deckhouses. verses, at ends of superstructures and deckhouses.

Pt B, Ch 9, Sec 4
Table 1 : Lateral pressure for superstructures and Table 3 : Lateral pressure for superstructures and
deckhouses - Coefficient a deckhouses - Coefficient f (1/7/2020)
Type of Rule Length L of ship, in m f

Location a a maximum
bulkhead
L < 150 L 2
------ e –L  300 – 1 –  ----------
L
Unpro- Lowest tier L 4,5  150
2 + ---------- 10
tected 120
front 150  L < 300
Second tier L 3,5 L- –L  300
-----
1 + ---------- e
120 10
Third tier L 2,5 L  300 11,03

0 ,5 + ----------
150
Fourth tier 2,25
0 ,9  0 ,5 + ----------
L Table 4 : Lateral minimum pressure
 150
for superstructures and deckhouses (1/7/2020)
Fifth tier 2,0
0 ,8  0 ,5 + ----------
L
and above  150 Type of bulkhead Location pmin, in kN/m2
Protected Lowest,
L
2,5 Unprotected front Lowest tier 30  25,0 + 0,10L  50
front second and 0 ,5 + ----------
150 Second and 15  12,5 + 0,05L  25
third tiers
third tiers
Fourth tier 2,25
0 ,9  0 ,5 + ----------
L
 150 Fourth and Linear interpolation
fifth tiers
Fifth tier 2,0
0 ,8  0 ,5 + ----------
L
and above  150 Sixth tier and 12,5
above
Side Lowest, 2,5
L
0 ,5 + ---------- Protected front, Lowest, 15  12,5 + 0,05L 25
second and
150 side and aft end second and
third tiers
third tiers
Fourth tier 2,25
0 ,9  0 ,5 + ----------
L
 150 Fourth and Linear interpolation
fifth tiers
Fifth tier 2,0
0 ,8  0 ,5 + ----------
L
 Sixth tier and 2,5
and above 150
above
Aft end All tiers,
L x x
0 ,7 + ------------- – 0 ,8 --- 1 – 0 ,8 ---
when: x/L
1000 L L 3 Plating
 0,5
All tiers,
L x x 3.1 Front, side and aft bulkheads
when: x/L 0 ,5 + ------------- – 0 ,4 --- 0 ,8 – 0 ,4 ---
1000 L L
> 0,5 3.1.1 Plating contributing to the longitudinal
strength
Table 2 : Lateral pressure for superstructures and The net thickness of side plate panels contributing to the
deckhouses - Coefficient b longitudinal strength is to be determined in accordance
with the applicable requirements of Ch 7, Sec 1 or Ch 8,
Location of bulkhead (1) b
Sec 3, as applicable, considering the lateral pressure
x 2 defined in [2.1.2].
x  --- – 0 ,45
1 +  ---------------------
---  0 ,45 L
L  C B + 0 ,2 3.1.2 Plating not contributing to the longitudinal
  strength
2 The net thickness of plating of front, side and aft bulkheads
x
x  --- – 0 ,45 not contributing to the longitudinal strength is to be not less
---  0 ,45  L
1 + 1 ,5 ---------------------
L  C B + 0 ,2 than the value obtained, in mm, from the following formula:
 
t = 0 ,95s kp – t c
(1) For deckhouse sides, the deckhouse is to be subdivided
into parts of approximately equal length, not exceeding without being less than the values indicated in Tab 5, where
0,15L each, and x is to be taken as the co-ordinate of p is the lateral pressure, in kN/m2, defined in [2.2].
the centre of each part considered. For plating which forms tank boundaries, the net thickness
Note 1: is to be determined in accordance with [3.1.1], considering
CB : Block coefficient, with 0,6  CB  0,8 the hull girder stress equal to 0.
RINA Rules 2024 47

Pt B, Ch 9, Sec 4
3.2 Decks  : Coefficient depending on the stiffener end con-

nections, and taken equal to:
3.2.1 The net thickness of plate panels of decks which may • 1 for lower tier stiffeners
or may not contribute to the longitudinal strength is to be
• value defined in Tab 6 for stiffeners of upper
determined in accordance with the applicable requirements
tiers
of Ch 7, Sec 1 or Ch 8, Sec 3, as applicable.
,  : Parameters defined in Ch 4, Sec 2, Tab 1.
Table 5 : Superstructures and deckhouses The section modulus of side ordinary stiffeners need not be
Minimum thicknesses (1/7/2024) greater than that of the side ordinary stiffeners of the tier sit-
uated directly below taking account of spacing and span.
Location Minimum thickness, in mm For ordinary stiffeners of plating forming tank boundaries,
Lowest tier 1/2 the net scantlings are to be determined in accordance with
(5 + 0,01 L) k - tC
[4.1.1], considering the hull girder stress equal to 0.
Second tier and above (4 + 0,01 L) k1/2 - tC
Table 6 : Stiffeners of superstructures and
Note 1:
deckhouses - Coefficient  for end connections
L is to be taken not less than 100m and not greater than
300m.
Note 2: Upper end Bracketed Sniped
Coefficient 
For aluminum superstructures, it is possible to evaluate the welded to deck upper end upper end
minimum thickness on a case-by-case basis taking into
Lower end
account the type and tier level of the superstructure, the 1,00 0,85 1,15
welded to deck
position of the superstructure (front, lateral, aft), the spacing
of the ordinary stiffeners, the navigation and service nota- Bracketed
0,85 0,85 1,00
tions of the ship. lower end
Note 3:
Sniped lower
For ships with actual scantling length L less than 65m, in end
1,15 1,00 1,15
lieu of using the formulas in the table with L = 100m as
per Note 1, the net minimum thickness of the plating can
4.1.3 Minimum section modulus of stiffeners
be taken as follows:
(1/7/2020)
• 5 k1/2 - tC mm for the lowest unprotected front
• 4 k1/2 - tC mm for all other cases. The minimum net section modulus, in cm3, of stiffeners
used for deckhouse and superstructure is to in any case not
be less than:
3.2.2 For decks sheathed with wood, the net thickness
2
obtained from [3.2.1] may be reduced by 10 percent. w min = 2 ,4ks
4 Ordinary stiffeners 4.2 Decks

4.2.1 The net scantlings of ordinary stiffeners of decks
4.1 Front, side and aft bulkheads which may or may not contribute to the longitudinal
strength are to be determined in accordance with the appli-
4.1.1 Ordinary stiffeners of plating contributing to cable requirements of Ch 7, Sec 2.
the longitudinal strength
The net scantlings of ordinary stiffeners of plating contribut- 5 Primary supporting members
ing to the longitudinal strength are to be determined in
accordance with the applicable requirements of Ch 7, Sec 2
or Ch 8, Sec 4, as applicable. 5.1 Front, side and aft bulkheads
4.1.2 Ordinary stiffeners of plating not contributing 5.1.1 Primary supporting members of plating
to the longitudinal strength contributing to the longitudinal strength
The net scantlings of side primary supporting members of
The net section modulus w of ordinary stiffeners of plating
plating contributing to the longitudinal strength are to be
not contributing to the longitudinal strength is to be not less
determined in accordance with the applicable requirements
than the value obtained, in cm3, from the following formula:
of Ch 7, Sec 3 or Ch 8, Sec 5, as applicable.
w = 0 ,35ks p  1 – t c  – t c
2
5.1.2 Primary supporting members of plating not
where: contributing to the longitudinal strength
The net scantlings of side primary supporting members of
 : Span of the ordinary stiffener, in m, equal to the
plating not contributing to the longitudinal strength are to
‘tweendeck height and to be taken not less than
be determined in accordance with the applicable require-
2m
ments of Ch 7, Sec 3 or Ch 8, Sec 5, as applicable, using
p : Lateral pressure, in kN/m2, defined in [2.2] the lateral pressure defined in [2.2].

Pt B, Ch 9, Sec 7
SECTION 7 HATCH COVERS, HATCH COAMINGS AND

CLOSING DEVICES
Symbols
Tfb : the least moulded depth, in m, as defined in innovative designs the approval is subject to the Society’s
ICLL (see also [1.2])according to Regulation 3 consideration on a case by case basis.
of the International Load Line Convention 1966,
as amended. This Section does not apply to portable covers secured
weathertight by tarpaulins and battening devices, or
hn : standard superstructure height, in m:
pontoon covers, as defined in ICLL Regulation 15.
• hn = 1,05 + 0,01 LLL
Hatch covers and hatch coamings of fishing vessels are to
• hn = 1,8  hn  2,3
comply with the requirements in Pt E, Ch 20, Sec 3.
ASh : Net shear sectional area, in cm2, of the ordinary
stiffener or primary supporting member, to be The requirements in this Section are in addition to the
calculated as specified in Ch 4, Sec 3, [3.4], for requirements of the ICLL.
ordinary stiffeners, and Ch 4, Sec 3, [4.3], for The requirements in [9] apply to steel covers of small
primary supporting members hatches fitted on the exposed fore deck over the forward
tC : Corrosion additions, in mm, defined in [1.46] 0,25L.
k : Material factor, defined in Ch 4, Sec 1, [2.3]
aV : Vertical acceleration according to [3.34.1] 1.2 Definitions
g : Gravity acceleration, in m/s2:
1.2.1 ICLL (1/7/2024)
g = 9,81 m/s2.
Where ICLL is referred to in the text, this is to be taken as
the International Convention on Load Lines, 1966 as
1 General amended by the 1988 protocol, as amended in 2003.
1.1 Application 1.2.2 Hatch cover types (1/7/2024)

1.1.1 (1/7/2024) • Single skin cover
The requirements in this Section in [1] to [8] apply to all A hatch cover made of steel or equivalent material that
ships except CSR bulk carriers, and are for all cargo hatch is designed to comply with ICLL Regulation 16. The
covers and coamings on exposed decksto steel hatch covers cover has continuous top and side plating, but is open
in positions 1 and 2 on weather decks, defined in Ch 1, underneath with the stiffening structure exposed. The
Sec 2, [3.16] for all ship types, except ships for which one cover is weathertight and fitted with gaskets and
of the following service notation is assigned:. clamping devices unless such fittings are specifically
excluded.
As specified in this Section, parts of the requirements are for
some specific ship types as categorized below: • Double skin cover
• Type-1 ships, including all ships except bulk carriers, A hatch cover as above but with continuous bottom
self-unloading bulk carriers, ore carriers and plating such that all the stiffening structure and internals
combination carriers, as defined in Pt A, Ch 1, Sec 2, are protected from the environment.
[4]bulk carrier • Pontoon type cover
• Type-2 ships, including all bulk carriers, self-unloading A special type of portable cover, secured weathertight
bulk carriers, ore carriers and combination carriers, as by tarpaulins and battening devices. Such covers are to
defined in Pt A, Ch 1, Sec 2, [4]self-unloading bulk car- be designed in accordance with ICLL Regulation 15 and
rier
are not covered by this Section.
• ore carrier
Note 1: Modern hatch cover designs of lift-away-covers (also called
• combination carrier
lift-on/lift-off, or just simply LoLo covers) are in many cases called
for which the specific requirements of Part E apply. pontoon covers. This definition does not fit to the definition above.
Modern lift-away hatch cover designs should belong to one of the
The strength requirements are applicable to hatch covers two categories-single skin covers or double skin cover.
and hatch coamings of stiffened plate construction and its
closing arrangements. 1.2.3 Positions (1/7/2024)
This Section is applicable to hatch covers and coamings The hatchways are classified according to their position as
made of steel. In case of alternative materials and defined in Ch 1, Sec 2, [3.16].
RINA Rules 2024 61

Pt B, Ch 9, Sec 7
1.32 Materials Stiffeners of hatch coamings are to be continuous over the

breadth and length of hatch coamings, as far as practical.
1.32.1 Steel (1/7/2024)
Hatch covers and coamings are to be made of material in 1.53 Net scantlings approach
accordance with the definitions of Pt B, Ch 4, Sec 1.
Material class I is to be applied for top plate, bottom plate 1.53.1 (1/7/2024)
and primary supporting members. As specified in Ch 4, Sec 2, [1], unless otherwise specified
The formulae for scantlings given in the requirements in [4] allthe scantlings referred to in this Section are net, i.e. they
are applicable to steel. do not include any margin for corrosion.
Materials used for the construction of steel hatch covers are The net thicknesses are the member thicknesses necessary
to comply with the applicable requirements of Part D, to obtain the minimum net scantlings required by [4] and
Chapter 2. [6].
Strength calculations using grillage analysis or FEM are to
1.32.2 Other materials (1/7/2012) be performed with net scantlings.
The use of materials other than steel is considered by the
Society on a case by case basis, by checking that criteria The gross scantlings are obtained as specified in Ch 4,
adopted for scantlings are such as to ensure strength and Sec 2.
stiffness equivalent to those of steel hatch covers.
1.64 Corrosion additions
1.4 General requirements
1.64.1 Corrosion additions for hatch
1.4.1 (1/7/2024) covers (1/7/2012)
Primary supporting members and stiffeners of hatch covers The corrosion addition to be considered for the plating and
are to be continuous over the breadth and length of hatch internal members of hatch covers is the value specified in
covers, as far as practical. When this is impractical, sniped Tab 1 for the total thickness of the member under
end connections are not to be used and appropriate consideration.
arrangements are to be adopted to provide sufficient load
carrying capacity. 1.64.2 Corrosion additions for hatch
Generally, the spacing of primary supporting members coamings (1/7/2024)
parallel to the direction of stiffeners is not to exceed 1/3 of The corrosion addition to be considered for the hatch
the span of primary supporting members. If sufficient coaming structures and coaming stays is the value specified
strength based on FE analysis can be verified, this in Tab 1 for the total thickness of the member
requirement may be waived. under considerationequal to 1,5 mm.
62 RINA Rules 2024

Pt B, Ch 9, Sec 7
Table 1 : Corrosion additions tc for hatch covers and hatch coamings (1/7/2024)
Application Structure tsc [mm]
Weather deck cargo hatches of container ships, car hatch cover 1,0
carriers and passenger ships
hatch coamings 1,0
Weather deck cargo hatches of Type-2 ships Hatch covers in general 2

Top and bottom plating of double skin hatch covers 2
Internal structure of double skin hatch covers 1,5
Hatch coamings and coaming stays 1,5
Hatch covers in general 2
Weather exposed plating and bottom plating of double 1,5
skin hatch covers
Weather deck cargo hatches of all other ship types Internal structure of double skin hatch covers and closed 1,0
covered by this Section box girders
Hatch coamings not part of the longitudinal hull structure 1,5
Hatch coamings part of the longitudinal hull structure 1,5
Coaming stays and stiffeners 1,5
2 Arrangements The ordinary stiffeners and primary supporting members of

the hatch covers are to be continuous over the breadth and
length of the hatch covers, as far as practical. When this is
2.1 Height of hatch coamings impractical, sniped end connections are not to be used and
2.1.1 (1/7/2012) appropriate arrangements are to be adopted to ensure
The height above the deck of hatch coamings closed by sufficient load carrying capacity.
portable covers is to be not less than: 2.2.3 (1/7/2012)
• 600 mm in position 1 The spacing of primary supporting members parallel to the
• 450 mm in position 2. direction of ordinary stiffeners is to be not greater than 1/3
of the span of primary supporting members. When strength
2.1.2 (1/7/2012) calculation is carried out by FE analysis using plane strain
The height of hatch coamings in positions 1 and 2 closed by or shell elements, this requirement can be waived.
steel covers provided with gaskets and securing devices 2.2.4 (1/7/2012)
may be reduced with respect to the above values or the The breadth of the primary supporting member flange is to
coamings may be omitted entirely. be not less than 40% of its depth for laterally unsupported
In such cases the scantlings of the covers, their gasketing, spans greater than 3,0 m. Tripping brackets attached to the
their securing arrangements and the drainage of recesses in flange may be considered as a lateral support for primary
the deck are considered by the Society on a case by case supporting members.
basis. 2.2.25 (1/7/2012)
2.1.3 (1/7/2012) The covers used in 'tweendecks are to be fitted with an
Regardless of the type of closing arrangement adopted, the appropriate system ensuring an efficient stowing when the
coamings may have reduced height or be omitted in way of ship is sailing with open 'tweendecks.
openings in closed superstructures or decks below the 2.2.36 (1/7/2012)
freeboard deck. The ends of hatch covers are normally to be protected by
efficiently secured galvanised steel strips.
2.2 Hatch covers 2.2.47 (1/7/2012)
2.2.1 (1/7/2012) Efficient retaining arrangements are to be provided to
Hatch covers on exposed decks are to be weathertight. prevent translation of the hatch cover under the action of
the longitudinal and transverse forces exerted by the stacks
Hatch covers in closed superstructures need not be
of containers on the cover. These retaining arrangements
weathertight.
are to be located in way of the hatch coaming side brackets.
However, hatch covers fitted in way of ballast tanks, fuel oil Solid fittings are to be welded on the hatch cover where the
tanks or other tanks are to be watertight. corners of the containers are resting. These parts are
2.2.2 (1/7/2012) intended to transmit the loads of the container stacks onto
RINA Rules 2024 63

Pt B, Ch 9, Sec 7
the hatch cover on which they are resting and also to Where the height of the coaming exceeds 900 mm,
prevent horizontal translation of the stacks by means of additional strengthening may be required.
special intermediate parts arranged between the supports of However, reductions may be granted for transverse
the corners and the container corners. coamings in protected areas.
Longitudinal stiffeners are to stiffen the hatch cover plate in 2.3.8 (1/7/2024)
way of these supports and connect at least the nearest three
When two hatches are close to each other, underdeck
transverse stiffeners.
stiffeners are to be fitted to connect the longitudinal
2.2.58 (1/7/2012) coamings with a view to maintaining the continuity of their
The width of each bearing surface for hatch covers is to be strength.
at least 65 mm. Similar stiffening is to be provided over 2 frame spacings at
ends of hatches exceeding 9 frame spacings in length.
2.3 Hatch coamings In some cases, the Society may require the continuity of
coamings to be maintained above the deck.
2.3.1 (1/7/2012)
2.3.9 (1/7/2024)
Coamings, stiffeners and brackets are to be capable of
withstanding the local forces in way of the clamping Where watertight metallic hatch covers are fitted, other
devices and handling facilities necessary for securing and arrangements of equivalent strength may be adopted.
moving the hatch covers as well as those due to cargo
stowed on the latter. 2.4 Small hatchways
2.3.2 (1/7/2012) 2.4.1 (1/7/2012)
Special attention is to be paid to the strength of the fore The height of small hatchway coamings is to be not less
transverse coaming of the forward hatch and to the than 600 mm if located in position 1, and 450 mm if
scantlings of the closing devices of the hatch cover on this located in position 2.
coaming. Where the closing appliances are in the form of hinged steel
2.3.3 (1/7/2012) covers secured weathertight by gaskets and swing bolts, the
height of the coamings may be reduced or the coamings
Longitudinal coamings are to be extended at least to the
may be omitted altogether.
lower edge of deck beams.
2.4.2 (1/7/2012)
Where they are not part of continuous deck girders,
Small hatch covers are to have strength equivalent to that
longitudinal coamings are to extend for at least two frame
required for main hatchways and are to be of steel,
spaces beyond the end of the openings.
weathertight and generally hinged.
Where longitudinal coamings are part of deck girders, their
Securing arrangements and stiffening of hatch cover edges
scantlings are to be as required in Ch 7, Sec 3.
are to be such that weathertightness can be maintained in
2.3.4 (1/7/2012) any sea condition.
Transverse coamings are to extend below the deck at least At least one securing device is to be fitted at each side.
to the lower edge of longitudinals. Circular hole hinges are considered equivalent to securing
devices.
Transverse coamings not in line with ordinary deck beams
below are to extend below the deck at least three 2.4.3 (1/7/2012)
longitudinal frame spaces beyond the side coamings. Hold accesses located on the weather deck are to be
2.3.5 (1/7/2012) provided with watertight metallic hatch covers, unless they
are protected by a closed superstructure. The same applies
Secondary stiffeners of hatch coamings are to be continuous to accesses located on the forecastle deck and leading
over the breadth and length of hatch coamings. directly to a dry cargo hold through a trunk.
2.3.6 (1/7/2024) 2.4.4 (1/7/2012)
Coamings are to be stiffened on their upper edges with a Accesses to cofferdams and ballast tanks are to be
stiffener suitably shaped to fit the hatch cover closing manholes fitted with watertight covers fixed with bolts
appliances. which are sufficiently closely spaced.
Moreover, when covers are fitted with tarpaulins, an angle 2.4.5 (1/7/2012)
or a bulb section is to be fitted all around coamings of more Hatchways of special design are considered by the Society
than 3 m in length or 600 mm in height; this stiffener is to on a case by case basis.
be fitted at approximately 250 mm below the upper edge.
The width of the horizontal flange of the angle is not to be
less than 180 mm. 3 Hatch cover and coaming load
2.3.7 (1/7/2024)
model
Where hatch covers are fitted with tarpaulins, coamings are
to be strengthened by brackets or stays with a spacing not 3.1 General
greater than 3 m. 3.1.1 (1/7/2024)
64 RINA Rules 2024

Pt B, Ch 9, Sec 7
The structural assessment of hatch covers and hatch Where an increased freeboard is assigned, the design load
coamings is to be carried out using the design loads, for hatch covers according to Tab 2 on the actual freeboard
defined in this Article. deck may be as required for a superstructure deck, provided
the summer freeboard is such that the resulting draught will
3.21 Vertical weather design load not be greater than that corresponding to the minimum
freeboard calculated from an assumed freeboard deck
3.21.1 Pressure (1/7/2024)
situated at a distance at least equal to the standard
The pressure pPHC, in kN/m2, on the hatch cover panels is
superstructure height hN below the actual freeboard deck,
given in Tab 2. The vertical weather design load needs not
see Fig 2.
to be combined with cargo loads according to [3.34] and
[3.45]. For hatch covers of cargo holds designed for carriage of
In Fig 1 the positions 1 and 2 are illustrated for an example ballast or liquid cargo, the internal lateral pressures are also
ship. to be considered according to Ch 5, Sec 6.
RINA Rules 2024 65

Pt B, Ch 9, Sec 7
Table 2 : Design load pPHC of weather deck hatches (1/7/2024)
Pressure pPhHC , in kN/m2

Position
x / LLL  0,75 0,75 < x / LLL  1,0
for 24 m  LLL 100 m
on freeboard deck
9 81 x
-------------   4 28  L LL + 28   ------- – 1 71  L LL + 95
76 L LL
9 81
-------------   1 5  L LL + 116  upon exposed superstructure decks located at least one
76
superstructure standard height above the freeboard deck
9 81
-------------   1 5  L LL + 116 
76
for LLL 100 m
on freeboard deck for type B ships according to the IMO

1 International Convention on Load Lines (ICLL)
x
9 81   0 0296  L 1 + 3 04   ------- – 0 0222  L 1 + 1 22
L LL
on freeboard deck for ships with less freeboard than type B

9 81  3 5 according to ICLL
x
9 81   0 1452  L 1 – 8 52   ------- – 0 1089  L 1 + 9 89
L LL
L1 = LLL but not more than 340 m
upon exposed superstructure decks located at least one

superstructure standard height above the freeboard deck
9 81  3 5
for 24 m  LLL 100 m
9 81
-------------   1 1  L LL + 87 6 
76
2 for LLL 100 m
9 81  2 6
upon exposed superstructure decks located at least one superstructure standard height above the low-
est position 2 deck
9 81  2 1
66 RINA Rules 2024

Pt B, Ch 9, Sec 7
Figure 1 : Positions 1 and 2 (1/7/2016)
Figure 2 : Positions 1 and 2 for an increased freeboard (1/7/2016)
3.32 Horizontal weather design load = 10,75 - [( L - 350 ) / 150]1,5 for 350  L < 500 m
3.32.1 1General horizontal weather Ddesign

load (1/7/2024) cL = L-
-----
The horizontal weather design load PA, in kN/m2, for 90
determining the scantlings of outer edge girders (skirt plates) for L < 90 m
of weather deck hatch covers and of hatch coamings is: cL = 1 for L > 90 m
PA = a · c · (b · cL · f - z) a = 20 + L1/12 , for unprotected front coamings and hatch
f = L / 25 + 4,1 for L < 90 m cover skirt plates
= 10,75 - [(300 - L) / 100]1,5 for 90  L < 300 m a = 10 + L1/12 , for unprotected front coamings and hatch
= 10,75 for 300  L < 350 m cover skirt plates, where the distance from the actual free-
RINA Rules 2024 67

Pt B, Ch 9, Sec 7
board deck to the summer load line exceeds the minimum Table 3 : Minimum design load pPA-min (1/7/2024)
non-corrected tabular freeboard according to the IMO
International Load Lines (ICLL) by at least one standard pPA-min in kN/m2 for
superstructure height hN. L
unprotected fronts elsewhere
a = 5 + L1/15 , for side and protected front coamings and
hatch cover skirt plates  50 30 15
a = 7 + L1/100 - 8 · x’ / L , for aft ends of coamings and aft > 50

hatch cover skirt plates abaft amidships 25 + L / 10 12,5 + L / 20
< 250
a = 5 + L1/100 - 4 · x’ / L , for aft ends of coamings and aft
hatch cover skirt plates forward of amidships > 250 50 25
L1 : L, need not be taken greater than 300 m
Note 1: The horizontal weather design load need not be included
 2
in the direct strength calculation of the hatch cover, unless it is uti-
x
 ---- – 0 45 lized for the design of substructures of horizontal support accord-
 x
- for ----  0 45
L
b = 1 0 + ---------------------- ing to [7.2.3].
 C B + 0 2  L
 
3.3.2 Horizontal weather design load applicable to
coamings of Type-2 ships (1/7/2024)
x
 ---- – 0 45
2
The pressure PCoam in kN/m2, on the No. 1 forward
x
b = 1 0 + 1 5   ----------------------- for ----  0 45
L transverse hatch coaming is given by:
 C B + 0 2  L
  PCoam = 220, when a forecastle is fitted in accordance with
the relevant requirements in Pt E, Ch 4, Sec 3, [10.1] for
0,6  CB  0,8, when determining scantlings of aft ends of
ships with service notation bulk carrier ESP, in Pt E, Ch 5,
coamings and aft hatch cover skirt plates forward of
Sec 3, [7.1] for ships with service notation ore carrier ESP
amidships, CB need not be taken less than 0,8.
and in Pt E, Ch 6, Sec 3, [7] for ships with service notation
x’ : distance in m between the transverse coaming combination carrier ESP
or hatch cover skirt plate considered and aft end
of the length L. When determining side PCoam= 290 in the other cases
coamings or side hatch cover skirt plates, the
The pressure PCoam in kN/m2, on the other coamings is
side is to be subdivided into parts of
given by:
approximately equal length, not exceeding 0,15
L each, and x' is to be taken as the distance PCoam = 220
between aft end of the length L and the centre Note 1: The horizontal weather design loads PA and PCoam need
of each part considered not be included in the direct strength calculation of the hatch
z : vertical distance in m from the summer load cover, unless it is utilized for the design of substructures of
line to the midpoint of stiffener span, or to the horizontal support according to [7.2.3].
middle of the plate field
c : 0,3 + 0,7 · (b’/B’) 3.43 Cargo loads
b’ : breadth of coaming in m at the position
3.43.1 Distributed loads (1/7/2024)
considered
The load on hatch covers due to distributed cargo loads pPL,
B’ : actual maximum breadth of ship in m on the
in kN/m2, resulting from heave and pitch (i.e. ship is upright
exposed weather deck at the position
condition) is to be determined according to the following
considered
formula:
b'/B' is not to be taken less than 0,25.
pPL = pPCargo ( 1 + av)
The design load pPA is not to be taken less than the mini-
mum values PA-min given in Tab 3. pPCargo : uniform cargo load, in kN/m2
av : vertical acceleration addition as follows
av = F · m
v
F = 0 11  ------0-
L
x x
m = m 0 – 5  m 0 – 1   --- for 0  ---  0 2
L L
x
m = 1 0 for 0 2  ---  0 7
L
68 RINA Rules 2024

Pt B, Ch 9, Sec 7
hm : designed height of centre of gravity of stack

m0 + 1 x x above hatch cover top in m, may be calculated
m = 1 + ----------------  --- – 0 7 for 0 7  ---  1 0
0 3 L L as weighted mean value of the stack, where the
centre of gravity of each tier is assumed to be
m0 = 1,5 + F located at the centre of each container, to be
taken as follows::
v 0 = maximum speed at number load line draught,

v 0 is not to be taken less than L in knots hm =  z  W   M
i i
v 0 = maximum speed at summer load line draught, zi : distance from hatch cover top to the centre of i-
v 0 is not to be taken less than L in knots th container in m.
Wi : weight of /i-th container in t
3.43.2 Point loads (1/7/2016) b : distance between midpoints of foot points, in m
The load P, in kN, due to a concentrated forces PS, in kN, AZ , B Z : support forces in z-direction at the forward and
except for container load, resulting from heave and pitch aft stack corners
(i.e. in upright condition) is to be determined as follows:
BY : support force in y-direction at the forward and
P = PS (1 + av) aft stack corners.
PS = single force in kN When strength of the hatch cover structure is assessed by
grillage analysis according to 3,5, hm and zi need to be
3.54 Container loads taken above the hatch cover supports. Forces By does not
need to be considered in this case.
3.54.1 General (1/7/2024) Values of AZ and BZ applied for the assessment of hatch
The loads defined in [3.45.2] andto [3.45.34] are to be cover strength are to be shown in the drawings of the hatch
applied where containers are stowed on the hatch cover. covers.
Note 1: It is recommended that container loads as calculated
3.54.2 Corner loads for ship in upright
above are considered as limit for foot point loads of container
condition (1/7/2024)
stacks in the calculations of cargo securing (container lashing).
The load in kN, applied at each corner of a container stack,
and resulting from heave and pitch (i.e. ship in upright Figure 3 : Forces due to container loads (1/7/2016)
condition) is to be determined as follows:
M
P = 9 81 -----  1 + a v 
4
where:
av = acceleration addition according to [23.34.1]
M = maximum designed mass of container stack in t.
3.54.3 Corner loads for ship in heel

condition (1/7/2024)
The following loads, in kN, applied at each corner of a con-
tainer stack and resulting fromdue to heave, pitch, and the
ship's rolling motion (i.e. ship in heel condition) are to be
considereddetermined as follows, (see also Fig 3).
h
A Z = 9 81 -----   1 + a v    0 45 – 0 42 -----m-
M
2  b
h
B Z = 9 81 -----   1 + a v    0 45 + 0 42 -----m-
M
2  b
3.54.4 Load cases with partial loading (1/7/2016)
By = 2,4 · M
The load defined in cases [3.35.2] and [3.45.3] are also to
av : acceleration addition according to [3.34.1] be considered for partial non homogeneous loading which
M maximum designed mass of container stack, in t may occur in practice, e.g. where specified container stack
to be taken as follows: places are empty. For each hatch cover, the heel directions,
as shown in Tab 34, are to be considered
The load case partial loading of container hatch covers can
M = W i
be evaluated using a simplified approach, where the hatch
RINA Rules 2024 69

Pt B, Ch 9, Sec 7
cover is loaded without the outermost stacks, see that are chions are left empty is to be assessed in order to consider
located completely on the hatch cover. If there are addi- the maximum loads in the vertical hatch cover supports.
tional stacks that are supported partially by the hatch cover It may be necessary to also consider partial load cases
and partially by container stanchions then the loads from where more or different container stack places are left
these stacks are also to be neglected, refer to Tab 34. In empty. Partial load case should in general be considered.
addition, the case where only the stack places supported
partially by the hatch cover and partially by container stan-
70 RINA Rules 2024

Pt B, Ch 9, Sec 7
Table 4 : Partial loading of container hatch covers (1/7/2016)
Heel direction ---------------------------------- ----------------------------------

Hatch covers supported
by the longitudinal
hatch coaming with all
container stacks located
completely on the hatch
cover
Hatch covers supported

by the longitudinal
hatch coaming with the
outermost container
stack supported par-
tially by the hatch cover
and partially by con-
tainer stanchions
Hatch covers not sup-

ported by the longitudi-
nal hatch coaming
(center hatch covers)
3.54.5 Mixed stowage of 20’ and 40’ containers on hatch cover are not to be higher than resulting from the
hatch cover (1/7/2016) design stack weight for 40' containers, and the foot point
In the case of mixed stowage (20'+40' container combined forces at the middle of the cover are not to be higher than
stack), the foot point forces at the fore and aft end of the resulting from the design stack weight for 20' containers.
RINA Rules 2024 71

Pt B, Ch 9, Sec 7
3.65 Loads due to elastic deformations of the

ship's hull v =  + 3
2 2
3.65.1 (1/7/2016)
Hatch covers, which in addition to the loads according to  : normal stress, in N/mm2
[3.12] to [3.45] are loaded in the ship's transverse direction  : shear stress, in N/mm2.
by forces due to elastic deformations of the ship's hull, are For FEM calculations, the equivalent stress may be taken as
to be designed such that the sum of stresses does not follows:
exceed the permissible values given in [4.1.1].
v =  –  x   y +  y2 + 3 2
2
4 Hatch cover strength criteria
4.1 Permissible stresses and deflections  vm =  x –  x   y +  y2 + 3 xy

2 2
4.1.1 Yield strengthStresses (1/7/2024) x : normal stress, in N/mm2, in x-direction

All hatch cover structural members are to comply with the y : normal stress, in N/mm2, in y-direction
following formulae: xy : shear stress, in N/mm2, in the x-y plane.
axial : axial stress in rod or beam elements, in N/mm2.
σvm ≤ σa for shell elements in general.
Indices x and y are coordinates of a two-dimensional
σaxial ≤ σa for rod or beam elements in general. Cartesian system in the plane of the considered structural
where: element.
In case of finite element(FEM) calculations using shell (or
σa : Allowable stress as defined in Tab 5.
plante) strain elements, the stresses are to be read from the
ReH : Specified minimum yield stress, in N/mm2, of the centre of the individual element. It is to be observed that, in
material. particular, at flanges of unsymmetrical girders, the
evaluation of stress from element centre may lead to non-
σvm : Von Mises stress, in N/mm2, to be taken as follows: conservative results. Thus, a sufficiently fine mesh is to be
The equivalent stress σv, in N/mm2, in steel hatch cover applied in these cases or, the stress at the element edges
shallis not to exceed the allowable stress. Where shell
structures related to the net thickness shall not exceed 0,8
elements are used, the stresses are to be evaluated at the
F, where F is the minimum yield stress, in N/mm2, of the mid plane of the element.
material. For design loads according to [3.2] to [3.5], the
equivalent stress v related to the net thickness shall not For steels with a minimum yield stress of more than 355
exceed 0,9 F when the stresses are assessed by means of N/mm2, the value of ReH to be applied throughout this
FEM. requirement is to be taken as the minimum yield stress of
the steel used but not exceeding the lower of 0,7 Rm and
For steels with a minimum yield stress of more than 355
N/mm2, the value of F to be applied throughout this 450 N/mm2.
requirement is to be considered on a case by case basis but Stress concentrations are usually to be assessed by means of
is not to be more than the minimum yield stress of the refined local mesh finite element models and using the
material and grillage analysis, the equivalent stress may be specific criteria in Ch 7, Sec 3, [4.3.4]. Other approaches
taken as follows: will be evaluated on a case by case basis.
Table 5 : Allowable stresses (1/7/2024)
Members of Subject to a in N/mm2
Hatch cover structure External pressure, as defined in [3.2] 0,80 ReH

Other loads, as defined in [3.3] to [3.6] 0,90 ReH for static+dynamic load case
0,72 ReH for static load case
4.1.2 Deflection (1/7/2024) 4.2 Local net plate thickness

The vertical deflection of primary supporting members due
to the vertical weather design load according to [3.12] is to 4.2.1 General (1/7/2024)
be not more than 0,0056 lg , where lg is the greatest span of
primary supporting members. The local net plate thickness t, in mm, of the hatch cover
top plating is not to be less than:
Note 1: Where hatch covers are arranged for carrying containers
and mixed stowage is allowed, i.e., a 40'-container stowed on top
of two 20'-containers, particular attention should be paid to the
p
deflections of hatch covers. Further the possible contact of t = F p  15 8  s -----------------------
deflected hatch covers within hold cargo has to be observed. 0 95   F
72 RINA Rules 2024

Pt B, Ch 9, Sec 7
stations, turbines, etc. Cargoes that can be considered as uniformly

distributed over the hatch cover, e.g., timber, pipes or steel coils
P
t = F p  15 8  s -------------------------- need not to be considered as project cargo.
0 95  R eH
When the lower plating is not considered as a strength
and to be not less than 1% of the spacing of the stiffener or member of the hatch cover, the thickness of the lower
6 mm if that be greater. plating is to be determined on a case by case basis also
Fp : factor for combined membrane and bending taking into account the actual technological feasibility of
response welding effectively plates that are too much thin.
= 1,5 in general
= 1,9 · a , for (a) > 0,8 for the attached 4.3 Net scantling of secondary stiffeners
plate flange of primary supporting members
4.3.1 General (1/7/2024)
s : stiffener spacing, in m The net section modulus Z, in cm3, and net shear area Ashr,
pP : pressure pPHC and pPL, in kN/m2, as defined
in cm32, of uniformly loaded hatch cover stiffeners con-
in [3]
straint at both ends is to be not less than:
 : maximum normal stress, in N/mm2, of hatch
cover top plating, determined according to Fig 4
2
defined in Tab 50,8 · σF , in N/mm2 104psl
a : as Z = -------------------- in cm2, for design load according to [3.1]
F
For flange plates under compression sufficient buckling
strength according to [4.6] is to be demonstrated.
2
Psl
Z = -----------  10 in cm3
3
Figure 4 : Determination of normal stress of the hatch f bc  a

cover plating (1/7/2016)
σ = max [ σx ; σy ] 93psl
2
Z = ----------------
- in cm2, for design loads according to [3.3.1]
F
10 8psl
A S = --------------------
- in cm2, for design load according to [3.1]
F
σx
σy σy x
8 7Psl
A Shr = ------------------ in cm2
a
ꞏ
9 6psl
A S = -----------------
- in cm2, for design loads according to [3.3.1]
F
where:
Ll : secondary stiffener span, in m, to be taken as
y the spacing, in m, of primary supporting
members or the distance between a primary
4.2.2 Local net plate thickness of hatch covers for supporting member and the edge support, as
wheel loading (1/7/2012) applicable. When brackets are fitted at both
In general, the local net plate thickness of hatch covers for ends of all stiffener spans, the secondary
wheel loading is obtained by applying the load and strength stiffener span may be reduced by an amount
criteria of Ch 7, Sec 1, [4]. equal to 2/3 of the minimum brackets arm
length, but not greater than 10% of the
4.2.3 Lower plating of double skin hatch covers and unsupported span, for each bracket.
box girders (1/7/2024) s : secondary stiffener spacing, in m
The thickness to fulfill the strength requirements is to be pP : pressure pPHC and pPL, in kN/m2, as defined in
obtained from the calculation according to [4.5] under [3].
consideration of permissible stresses according to [4.1.1].
fbc : boundary coefficient of stiffener, taken equal to:
When the lower plating is taken into account as a strength
fbc = 8, in the case of stiffener simply supported
member of the hatch cover, the net thickness, in mm, of
lower plating is to be taken not less than 5 mm. When at both ends or simply supported at one end
project cargo is intended to be carried on a hatch cover, the and clamped at the other end
net thickness must not be less than: fbc = 12, in the case of stiffener clamped at both
t : 6,5 · s, in mm ends.
s : stiffener spacing, in m. a : allowable stress as defined in Tab 5
Note 1: Project cargo means especially large or bulky cargo lashed For secondary stiffeners of lower plating of double skin
to the hatch cover. Examples are parts of cranes or wind power hatch covers, requirements mentioned above are not
RINA Rules 2024 73

Pt B, Ch 9, Sec 7
applied due to the absence ofif there are no lateral loads. 4.4.2 Edge girders (Skirt plates) (1/7/2024)
For double skin hatch covers of holds designed for ballast or Scantlings of edge girders are obtained from the
liquid cargo, the stiffeners on lower plating are to be calculations according to [4.5] under consideration of
strengthened according to the load and strength criteria of permissible stresses according to [4.1.1].
Ch 7, Sec 2.
The net thickness, in mm, of the outer edge girders exposed
The net thickness, in mm, of the stiffener (except u- to wash of sea shallis not to be less than the largest of the
beams/trapeze stiffeners) web is to be taken not less than 4 following values:
mm.
The net section modulus of the secondary stiffeners is to be
pA
determined based on an attached plate width assumed t = 15 8  s  ----------------------
-
0 95   F
equal to the stiffener spacing.
For flat bar secondary stiffeners and buckling stiffeners, the
ratio h/tw is to be not greater than 15 · k0.5, where: PA
t = 15 8  s  -------------------------
-
0 95  R eH
h : height of the stiffener
tw : net thickness of the stiffener t = 8,5 · s , in mm
k : 235 / F. tmin = 5 mm
Stiffeners parallel to primary supporting members and where:
arranged within the effective breadth according to [4.5.2] pPA : horizontal pressure as defined in [3.23.1]
isare to be continuous at crossing primary supporting mem-
s : stiffener spacing, in m.
ber and may be regarded for calculating the cross sectional
properties of primary supporting members. It is to be veri- For the required moment of inertia of edge girders, refer to
fied that the combined stress of those stiffeners induced by [7.1.4].
the bending of primary supporting members and lateral The stiffness of edge girders is to be sufficient to maintain
pressures does not exceed the permissible stresses accord- adequate sealing pressure between securing devices. The
ing to [4.1.1]. The requirements of this paragraphArticle are moment of inertia, in cm4, of edge girders is not to be less
not applied to stiffeners of lower plating of double skin than:
hatch covers if the lower plating is not considered as
I : 6 · q · S4SD
strength member.
q : packing line pressure, in N/mm, minimum 5
For hatch cover stiffeners under compression sufficient
N/mm
safety against lateral and torsional buckling according to
[4.6.63] and [4.6.7], respectively, is to be verified. SSD : spacing, in m, of securing devices.
For hatch covers subject to wheel loading or point loads
stiffener scantlings are to be determined under 4.5 Strength calculations
consideration of the permissible stresses according to
4.5.1 General (1/7/2024)
[4.1.1] or, equivalently for wheel loading, by applying the
load and strength criteria of Ch 7, Sec 2, [3.5]. The stresses in hatch covers are to be determined by FE
analysis.
4.4 Net scantling of primary supporting The stress calculation model in this Article is to be used for
members both yielding and buckling strength assessments in
accordance with [4.1] and [4.6], respectively.
4.4.1 Primary supporting members (1/7/2024) The net scantlings as defined in [1.5] are to be used.
Scantlings of primary supporting members are obtained Strength calculation for hatch covers may be carried out by
from calculations according to [4.5] under consideration of either grillage analysis or FEM. Double skin hatch covers or
permissible stresses according to [4.1.1]. hatch covers with box girders are to be assessed using FEM,
For all components of primary supporting members suffi- refer to [4.5.3].
cient safety against buckling mustis to be verified according
to [4.6]. For biaxial compressed flange plates this is to be 4.5.2 Effective cross-sectional properties for
verified within the effective widths according to [4.6.5]. calculation by grillage analysis (1/7/2016)
The net thickness, in mm, of webs of primary supporting Cross-sectional properties are to be determined considering
members shallis not to be less than: the effective breadth. Cross sectional areas of secondary
stiffeners parallel to the primary supporting member under
t = 6,5 · s , in mm consideration within the effective breadth can be included,
tmin = 5 mm see Fig 6.
where: The effective breadth of plating em of primary supporting
s : stiffener spacing, in m. members is to be determined according to Tab 5,
The flange outstand of the primary supporting members is to considering the type of loading. Special calculations may
be not greater than 15 times the flange thickness. be required for determining the effective breadth of one-
sided or non-symmetrical flanges.
The effective cross sectional area of plates is not to be less
than the cross sectional area of the face plate.
74 RINA Rules 2024

Pt B, Ch 9, Sec 7
For flange plates under compression with secondary elements or beam elements. Buckling stiffeners may be
stiffeners perpendicular to the web of the primary disregarded for the stress calculation.
supporting member, the effective width is to be determined Hatch covers fitted with U-type stiffeners as shown in Fig 5
according to [4.6.5]. are to be assessed by means of FE analysis.The geometry of
4.5.23 General requirements for the U-type stiffeners is to be accurately modelled using
FEM calculations (1/7/2024) shell/plate elements. Nodal points are to be properly placed
For strength calculationsassessments of hatch covers by on the intersections between the webs of a U-type stiffener
means of finite elementsFE analysis, the hatch cover and the hatch cover plate, and between the webs and
geometry is to be modeledidealized as realistically as flange of the U-type stiffener.
possible. Element size is tobe appropriate to account for Wherever applicable the following boundary conditions are
effective breadth. In no case the element width is to be to be applied to the FE model:
greaterlarger than the stiffener spacing. In way of force
• Boundary nodes in way of a bearing pad on the hatch
transfer points and cutouts the mesh is to be refined where
coamings are to be fixed against displacement in the
applicable. The ratio of element length to width is not to
direction perpendicular to the pad.
exceed 43.
The element size along the height of webs of primary • Lifting stoppers are to be fixed against displacements in
supporting member is not to exceed one-third of the web the direction determined by the stoppers.
height. Stiffeners, which supporting plates againstsubject to • For a folding type hatch cover, the FE nodes connected
lateral pressure loads, haveare to be included in the FE through a hinge are to have the same translational
model idealization. Stiffeners may be modelled by using displacement in the direction perpendicular to the hatch
beam elements, or shell/plate elements, plane stress cover top plating.
Figure 5 : Example of hatch cover fitted with U-type stiffeners (1/7/2024)
Table 5 : Effective breadth em of plating of primary supporting members (1/7/2012)
l/e 0 1 2 3 4 5 6 7 >8
em1/e 0 0,36 0,64 0,82 0.91 0,96 0,98 1,00 1,00
em2/e 0 0,20 0,37 0,52 0,65 0,75 0,84 0,89 0,90
em1 : is to be applied where primary supporting members are loaded by uniformly distributed loads or else by not less than
6 equally spaced single loads
em2 : is to be applied where primary supporting members are loaded by 3 or less single loads
Intermediate values may be obtained by direct interpolation.
l : length of zero-points of bending moment curve:
l = l0 for simply supported primary supporting members
l = 0,6 · l0 for primary supporting members with both ends constraint,
where l0 is the unsupported length of the primary supporting member
e : width of plating supported, measured from centre to centre of the adjacent unsupported fields
4.6 Buckling strength of hatch cover compliance with the requirements in Ch 7, Sec 5 for the
structures conditions specified in [4.6.2] and [4.6.3].
The net scantlings as defined in [1.5] are to be used for
4.6.1 General (1/7/2024) buckling check.
Buckling strength of all hatch cover structures is to be
For hatch cover structures sufficient buckling strength is to
checked. Buckling assessments are to be performed in
be demonstrated according to the requirements of this
paragraph.
RINA Rules 2024 75

Pt B, Ch 9, Sec 7
The buckling strength assessment of coaming parts is to be x* , y* : stresses containing the Poisson-effect.
considered on a case by case basis.
Where compressive stress fulfils the condition y* < 0,3x*,
a : length of the longer side of a single plate field in then y = 0 and x = x*.
mm (x-direction)
Where compressive stress fulfils the condition x* < 0,3y*,
b : breadth of the shorter side of a single plate field then x = 0 and y = y*.
in mm (y-direction)
F1 : correction factor for boundary condition at the
 : aspect ratio of single plate field longitudinal stiffeners according to Tab 6.
=a/b
n : number of single plate field breadths within the Table 6 : Correction factor F1 (1/7/2012)
partial or total plate field
Stiffeners sniped at both ends 1,00
t : net plate thickness, in mm
Guidance values (1) where both 1,05 for flat bars
x : membrane stress, in N/mm2, in x-direction ends are effectively connected to
1,10 for bulb sections
adjacent structures
y : membrane stress, in N/mm2, in y-direction 1,20 for angle and tee-
sections
 : shear stress, in N/mm², in the x-y plane
1,30 for u-type sections
E : modulus of elasticity, in N/mm2, of the material (2) and girders of high
rigidity
= 2,06 · 105 N/mm2, for steel
An average value of F1 is to be used for plate panels having
F : minimum yield stress, in N/mm², of the material different edge stiffeners
Compressive and shear stresses are to be taken positive, (1) Exact values may be determined by direct calculations
tension stresses are to be taken negative. (2) Higher value may be taken if it is verified by a buckling
strength check of the partial plate field using non-linear
FEA, to be accepted by the Society on a case-by-case
Figure 5 : General arrangement of panel (1/7/2012) basis, but not greater than 2,0
long. stiffener single field
partial field
e : reference stress, in N/mm2, taken equal to
= 0,9 · E (t / b)2
 : edge stress ratio taken equal to
n .b = 2 / 1 where:
am
bm b 1 : maximum compressive stress
a 2 : minimum compressive stress or
tension stress
y
S : safety factor (based on net scantling approach),
x transverse stiffener taken equal to:
longitudinal : stiffener in the direction of the length a = 1,25 for hatch covers when subjected to the
transverse : stiffener in the direction of the breath b
vertical weather design load according to [3.1]
= 1,10 for hatch covers when subjected to loads

If stresses in the x- and y-direction already contain the
according to [3.2] to [3.5]
Poisson-effect (calculated using FEM), the following
modified stress values may be used. Both stresses x* and  : reference degree of slenderness, taken equal to:
y* are to be compressive stresses, in order to apply the
stress reduction according to the following formulae:
F
= ------------
-
x = ( x* - 0,3 · y* ) / 0,91 K  e
y = ( y* - 0,3 · x* ) / 0,91 K : buckling factor according toTab 7.
76 RINA Rules 2024

Pt B, Ch 9, Sec 7
Table 7 : Buckling and reduction factors for plane elementary plate panels (1/7/2012)
Buckling- Edge stress Asp. ratio

Buckling factor K Reduction factor k
Load Case ratio   = a/b
1 1>>0 k = 8,4 / ( + 1,1) kx = 1 for c

0 >  > -1 k = 7,63 - (6,26 - 10) kx = c [(1/ 2 ) for c
c = (1,25 - 0,12 1,25
σx σx > 1
t b 0 88
 C = ---  1 + 1 – -------------
c
  -1 k = (1 - 2 · 5,975
2 c 
ψ. σx α . b ψ.σx
Explanations for boundary conditions - - - - - plate edge free

plate edge simply supported
RINA Rules 2024 77

Pt B, Ch 9, Sec 7

2
1>>0 > 1 1 2 2 1 1 R + F  H – R 
2
K = F 1  1 + -----2-  ------------------------- K y = c  --- – ----------------------------------
-
     + 1 1   
2 
σy ψ. σy
c = (1,25 - 0,12 1,25
t b 1    1,5 1 2 2 1  1 +   
σy K = F 1  1 + -----2-  ---------------------------- – -----2-  13 9 – 10 
ψ. σy   1 1 
α.b 0 >  > -1


1 2 2 1  1 +    R =   1 – --- for    C
 > 1,5 K = F 1  1 + -----2-  ---------------------------- – -----2-   5 87 +  c
  1 1 
8 6
- – 10 
+ 1 87  + --------
2

2
1
3(1- /4 1– 2
K = F 1  -------------  5 975 R = 0 22 for    C
  
0 88
 C = ---  1 + 1 – -------------
c
2 c 
  -1
>
F = 1 –  ------------- – 1   2 p  c 1  0
k
3(1- /4  0 91 
 2 p =  2 – 0 5 for 1   2 p  3
1– 2
K = F 1  -------------  3 9675 +
  
1– 4
+ 0 5375   ------------- + 1 87
   F
c 1 =  1 – ----1-   0

2
H =  – -----------------------------------------  R
c   T + T2 – 4
14 1
T =  + ---------- + ---
15 3

78 RINA Rules 2024

Pt B, Ch 9, Sec 7

4  0 425 + -----2-
1
1>>0  
σx σx K = --------------------------------------
3 + 1
t b a>0
ψ. σx α . b ψ. σx
0 >  > -1
K = 4  0 425 + -----2-  1 +   – 5   1 – 3 42 

1 K  = 1 for   0 7
 
1
- for   0 7
K  = ------------------------
 + 0 51
2
ψ. σx ψ. σx 1 >  > -1 >0
t b
1 3–
σx K =  0 425 + -----2- -------------
α . b σx   2
5
K = K  3
τ
τ t τ b -
> 1 4
K  = 5 34 + -----2- K  = 1 for   0 84

τ
α .b 0 84
0    K  = ------------- for   0 84

5 34
K  = 4 + ------------
-
2

4.6.2 Slenderness requirementsProof of top and

lower hatch cover plating (1/7/2024)  x  S e1   x  S e2  x   y  S 2    S  3
e3
- + ---------------- – B  ------------------------
 --------------- - + -------------------------  1 0
 kx  F   ky  F    2F   k  F 
The slenderness requirements are to be in accordance with
those specified in Ch 7, Sec 5, [2]. The slenderness The first two terms and the last term of the above condition
requirements need not be applied to the lower boundary of shall not exceed 1,0.
double skin hatch covers unless the cargo hold is designed The reduction factors Kx, Ky and Kt are given in Tab 7.
for carriage of ballast or liquid cargo.
Where x 0 (tension stress), Kx = 1,0.
The breadth of the primary supporting member flange is to Where y 0 (tension stress), Ky = 1,0.
be not less than 40% of their depth for laterally unsupported
spans greater than 3,0 m. Tripping brackets attached to the The exponents e1, e2 and e3 as well as the factor B are to be
flange may be considered as a lateral support for primary taken as given by Tab 8.
supporting members.
4.6.3 Buckling requirementsWebs and flanges of
Proof is to be provided that the following condition is primary supporting members (1/7/2024)
complied with for the single plate field a · b: a) Application
RINA Rules 2024 79

Pt B, Ch 9, Sec 7
These requirements apply to the buckling assessment of 7. For a web panel with opening, the procedure for
hatch cover structures subjected to compressive and opening should be used for its buckling assessment.
shear stresses and lateral pressures. The buckling For a hatch cover fitted with U-type stiffeners, the
assessment is to be performed for the following additional buckling assessment requirements specific
structural elements: for panels with U-type stiffeners in Ch 7, Sec 5, [5.3.5]
• Stiffened and unstiffened panels, including curved are also to be followed.
panels and panels stiffened with U-type stiffeners. c) Applied lateral pressure and stresses
• Web panels of primary supporting members in way
The buckling assessment of hatch covers is based on the
of openings.
lateral pressure as defined in [3.2], [3.3] and [3.4], and
The buckling strength assessment of coaming parts is to stresses obtained from FE analysis, refer to [4.5].
be done according to Ch 7, Sec 1, for plates, Ch 7, Sec 2
for ordinary stiffeners and Ch 7, Sec 3 for primary d) Safety factors
supporting members. For all hatch cover structural members, safety factor
For rule application, the panel types and assessment S=1,0 is to be applied to both of the plating and stiffener
methods, the applied lateral pressure and stresses, safety buckling capacity formulas as defined in Ch 7, Sec 5,
factors and buckling check criteria are defined in [5.3.2] and Ch 7, Sec 5, [5.3.3], respectively.
[4.6.3], b), c), d) and e), respectively. The procedure and e) Buckling acceptance criteria
detailed requirements for buckling assessment are given A structural member is considered to have an
in Ch 7, Sec 5, [4] and [5], including idealization of acceptable buckling strength if it satisfies the following
irregular plate panels, definition of reference stresses criterion:
and buckling criteria.
act  all
Unless otherwise specified, the symbols used in [4.6.3]
are defined in Ch 7, Sec 5. where:
b) Panel types and assessment methods act : Buckling utilisation factor based on the
The plate panel of a hatch cover structure is to be applied stress, as defined in Ch 7, Sec 5,
modelled as stiffened panel (SP) or unstiffened panel [1.4.1] and Ch 7, Sec 5, [4], and calculated
(UP) as defined in Ch 7, Sec 5, [1]. Assessment Method per Ch 7, Sec 5, [5].
A (-A) and Method B (-B) as defined in Ch 7, Sec 5, [1] all : Allowable buckling utilisation factor, taken
are to be used in accordance with Tab 6, Fig 6 and Fig as given in Tab 7.
Table 6 : Structural members and assessment methods (1/7/2024)
Structural elements Assessment method (1), (2) Normal panel definition

Hatch cover top/bottom plating structures, see Fig 6
Hatch cover top/bottom plating SP-A Length: between transverse girders
Width: between longitudinal girders
Irregularly stiffened panels UP-B Plate between local stiffeners/PSM
Hatch cover web panels of primary supporting members, see Fig 7
Web of transverse/longitudinal UP-B Plate between local stiffeners/face plate/PSM
girder (single skin type)
Web of transverse/longitudinal SP-B (3) Length: between PSM
girder (double skin type) Width: full web depth
Web panel with opening Procedure for opening Plate between local stiffeners/face plate/PSM
Irregularly stiffened panels UP-B Plate between local stiffeners/face plate/PSM
(1) SP and UP stand for stiffened and unstiffened panel respectively.
(2) A and B stand for Method A and Method B respectively.
(3) In case that the buckling carlings/brackets are irregularly arranged in the web of transverse/longitudinal girder, UP-B method
may be used.
Table 7 : Allowable buckling utilisation factors (1/7/2024)
Structural component Subject to all, Allowable buckling utilisation factor
80 RINA Rules 2024

Pt B, Ch 9, Sec 7
Plates and stiffeners External pressure, as defined 0,80

Web of PSM in [3.2]
Other loads, as defined in [3.3] 0,90 for static+dynamic load case
to [3.6] 0,72 for static load case
Figure 6 : Hatch cover top/bottom plating structures (1/7/2024)
Figure 7 : Hatch cover webs of primary supporting members (1/7/2024)
For non-stiffened webs and flanges of primary supporting

Exponents e1 - e3 and factor B Plate panel
members sufficient buckling strength as for the hatch cover
top and lower plating is to be demonstrated according to e1 1 +kx4
[4.6.2].
e2 1 +ky4
Table 8 : Coefficients e1, e2 and e3 and e3 1 + kx · ky· k2
factor B (1/7/2012)
RINA Rules 2024 81

Pt B, Ch 9, Sec 7
Exponents e1 - e3 and factor B Plate panel Single-side welding is not permitted to use for secondary
stiffeners except for u-stiffeners.
B
x and y positive (kx · ky)5 4.6.5 Effective width of top and lower hatch cover
(compression stress) plating (1/7/2012)
For demonstration of buckling strength according to [4.6.6]
B and [4.6.7] the effective width of plating may be
x and y negative 1 determined by the following formulae:
(tension stress) bm = kx · b for longitudinal stiffeners
am = ky · a for transverse stiffeners
4.6.4 Longitudinal and transverse secondary
see also Fig 5.
stiffeners (1/7/2016)
It is to be demonstrated that the continuous longitudinal The effective width of plating is not to be taken greater than
and transverse stiffeners of partial and total plate fields the value obtained from [4.5.2].
comply with the conditions set out in [4.6.6] and [4.6.7]. The effective width e'm of stiffened flange plates of primary
For u-type stiffeners, the proof of torsional buckling strength supporting members may be determined as follows (see
according to [4.6.7] can be omitted. Fig 6):
Figure 6 : Stiffening parallel to web of primary supporting member (1/7/2012)

e
em
em’
σx,em (y)
σx,em’(y)
bm bm
b b b b
b < em
e'm = n · bm
n = integer number of stiffener spacings b inside the effective breadth em according to [4.5.2]
n = int (em / b)
82 RINA Rules 2024

Pt B, Ch 9, Sec 7
Figure 7 : Stiffening perpendicular to web of primary supporting member (1/7/2012)

e e
em
em’
σx1
σx(y)
σx2
am
a > em
e’m = n · am < em
n = 2,7 · em/a  1
e = width of plating supported according to [4.5.2]
For b > em or a < em, respectively, b and a have to be exchanged.
am and bm for flange plates are in general to be determined for  = 1.
Scantlings of plates and stiffeners are in general to be considering the effective breadth or effective
determined according to the maximum stresses x(y) at width, as appropriate
webs of primary supporting member and stiffeners, y : distance of considered location from primary
respectively. For stiffeners with spacing b under supporting member 1
compression arranged parallel to primary supporting Shear stress distribution in the flange plates may be
members no value less than 0,25 F shall be inserted for assumed linearly.
xy=b).
4.6.6 Lateral buckling of secondary
The stress distribution between two primary supporting stiffeners (1/7/2012)
members can be obtained by the following formula:
a + b
------------------ S  1
F
a : uniformly distributed compressive stress, in
N/mm2, in the direction of the stiffener axis
 y y  a : x for longitudinal stiffeners
 x  y  =  x1   1 – --- 3 + d 1 – 4  c 2 – 2 ---  1 + c 1 – 2c 2  
 e e  a : y for transverse stiffeners
b : bending stress, in N/mm2, in the stiffener
M0 + M1
= --------------------
-
Z st  10
3
c1 : x2 / x1 for 0 c1  1
c2 : (1,5 / e) · (e’’m1 + e’’m2) - 0,5 M0 : bending moment, in Nmm, due to the
e’’m1 : proportionate effective breadth em1 or deformation w of stiffener, taken equal to:
proportionate effective width e'm1 of primary
supporting member 1 within the distance e, as pz  w
- with  c f – p z   0
M 0 = F Ki --------------
appropriate cf – pz
e’’m2 : proportionate effective breadth em2 or M1 : bending moment, in Nmm, due to the lateral
proportionate effective width e'm2 of primary
load p equal to:
supporting member 2 within the distance e, as
appropriate
p  b  a2
x1, x2 : normal stresses in flange plates of adjacent M 1 = --------------------3- for longitudinal stiffeners
primary supporting member 1 and 2 with 24  10
spacing e, based on cross-sectional properties
RINA Rules 2024 83

Pt B, Ch 9, Sec 7
p  a  n  b 
2 = 0,5 / (1 -  ) for  < 0
M 1 = ---------------------------------
- for transverse stiffeners
c s  8  10
3 Ax , Ay : net sectional area, in mm2, of the longitudinal
or transverse stiffener, respectively, without
n is to be taken equal to 1 for ordinary transverse stiffeners.
attached plating
p : lateral load, in kN/m2
FKi : ideal buckling force, in N, of the stiffener
m m
 1 =  – t  F  E  ------21- + ------22-  0
a b 
2
F Kix = ----2-  E  I x  10 4 for longitudinal stiffeners
a for longitudinal stiffeners:
a / b > 2,0 : m1 = 1,47 m2 = 0,49
2 a / b < 2,0 : m1 = 1,96 m2 = 0,37
F Kiy = ------------------2-  E  I y  10 4 for transverse stiffeners
n  b  for transverse stiffeners:
Ix, Iy : net moments of inertia, in cm4, of the a / (n · b) > 0,5 : m1 = 0,37 m2 = 1,96 / n2
longitudinal or transverse stiffener including a / (n · b) < 0,5 : m1 = 0,49 m2 = 1,47 / n2
effective width of attached plating according to
[4.6.5]. Ix and Iy are to comply with the w = w0 + w1
following criteria: w0 = assumed imperfection, in mm
w0x  min ( a/250, b/250, 10) for longitudinal stiffeners
b  t3
I x  -------------------4- w0y  min ( a/250, nb/250, 10) for transverse stiffeners.
12  10
For stiffeners sniped at both ends wo is to be taken not less
than the distance from the midpoint of plating to the neutral
a  t3
I y  -------------------4- axis of the profile including effective width of plating.
12  10
w1 = Deformation of stiffener, in mm, at midpoint of
pz : nominal lateral load, in N/mm2, of the stiffener
stiffener span due to lateral load p.
due to x , y and 
In case of uniformly distributed load the following values
for w1 may be used:
p  b  a4
w 1 = --------------------------------------
- for longitudinal stiffeners
384  10  E  I x
7
b 2
= ---  xl   ----------- + 2  c y   y + 2 1 for longitudinal stiffener
t
x
b  a 
5  a  p   n  b 4
w 1 = -------------------------------------------------- for transverse stiffeners
384  10  E  I y  c s
7 2
cf : elastic support provided by the stiffener, in

N/mm2
- For longitudinal stiffeners:
a 2 Ay  2
p zy = --- 2  c x   xl +  y  -----------  1 + --------
t
- + 2 1 c fx = F Kix  ----2-   1 + c px 
a  n  b  a  t a
for transverse stiffeners
1
c px = ---------------------------------------------------------------------
-
12  10  I x
4

0 91  --------------------------- - – 1 
 t3  b 
1 + ------------------------------------------------------------
c xa
Ax 
 xl =  x  1 + --------
-
 b  t a 2b 2
c xa = ------- + ------- for a  2b
2b a
cx , cy : factor taking into account the stresses

perpendicular to the stiffener's axis and
distributed variable along the stiffener's length a 2 2
c xa = 1 +  ------- for  a  2b 
= 0,5 · (1 +  ) for 0   1  2b
84 RINA Rules 2024

Pt B, Ch 9, Sec 7
- For transverse stiffeners:

F
T = --------
-
 KiT
2
c fy = c s  F Kiy  ------------------2   1 + c py 
n  b
E   I   10 2
2
 KiT = ---  --------------------------
-  + 0 385  I T , in N/mm 2
IP  a2 
1
c py = ---------------------------------------------------------------------
-
 10  I y
4
12
0 91   --------------------------- - –1  For IP , IT , I see Fig 8 and Tab 9.
 t3  a 
1 + ------------------------------------------------------------
c ya
Figure 8 : Dimensions of stiffener (1/7/2012)
n  b 2a 2
c ya = ----------- + ----------- for n  b  2a bf
2a n  b bf bf
tw tw tw t w tf
nb 2 2
c ya = 1 +  ----------- for n  b  2a
 2a  hw ef b1 b1 b2
cs : factor accounting for the boundary conditions C C C C ta

of the transverse stiffener
= 1,0 for simply supported stiffeners ef = hw + t / 2

f
= 2,0 for partially constraint stiffeners
Zst : net section modulus of stiffener (longitudinal or IP : net polar moment of inertia of the stiffener, in
transverse), in cm3, including effective width of cm4, related to the point C
plating according to [4.6.5].
IT : net St. Venant's moment of inertia of the
If no lateral load p is acting the bending stress b is to be stiffener, in cm4
calculated at the midpoint of the stiffener span for that fibre
I : net sectorial moment of inertia of the stiffener,
which results in the largest stress value. If a lateral load p is
in cm6, related to the point C
acting, the stress calculation is to be carried out for both
fibres of the stiffener's cross sectional area (if necessary for  : degree of fixation taken equal to:
the biaxial stress field at the plating side).
4.6.7 Torsional buckling of secondary a4

 = 1 + 10 –3 ---------------------------------------------
b 4h w 
---   I   ---3 + ---------
stiffeners (1/7/2012) 3 4
-
4  t 3t 3 w
a) Longitudinal secondary stiffeners
hw : web height, in mm
The longitudinal ordinary stiffeners are to comply with
the following criteria: tw : net web thickness, in mm
bf : flange breadth, in mm
x  S
-  1 0
k T = -------------- tf : net flange thickness, in mm
kT  F
Aw : net web area equal to: Aw = hw · tw
kT : coefficient taken as follows:
Af : net flange equal to: Af = bf · tf
kT = 1,0 for T  0,2
ef : hw + ( tf / 2 ) , in mm
1 b) Transverse secondary stiffeners

k T = ----------------------------------- for  T  0 2
 +  2 – T
2
For transverse secondary stiffeners loaded by compres-

sive stresses and which are not supported by longitudi-
 = 0 5  1 + 0 21   T – 0 2  +  T 
2
nal stiffeners, sufficient torsional buckling strength is to
be demonstrated analogously in accordance with a)
T : reference degree of slenderness taken equal to: above.
RINA Rules 2024 85

Pt B, Ch 9, Sec 7
5 Details of hatch covers elements. Where fitted, compression flat bars or angles
are to be well rounded where in contact with the gasket
and are to be made of a corrosion-resistant material.
5.1 Container foundations on hatch covers
5.1.1 (1/7/2012) c) The gasket material is to be of a quality suitable for al
The substructures of container foundations are to be environmental conditions likely to be experienced by
designed for cargo and container loads according to [23], the ship, and is to be compatible with the cargoes
applying the permissible stresses according to [4.1.1]. carried. The material and form of gasket selected is to be
considered in conjunction with the type of cover, the
5.2 Weather tightness securing arrangement and the expected relative
movement between cover and ship structure. The gasket
5.2.1 General (1/7/2024) is to be effectively secured to the cover.
Further to the following requirements IACS Rec. 14 is to be
applied to hatch covers.The weight of covers and any cargo 5.2.23 Packing material (General) (1/7/2024)
stowed thereon, together with inertial forces generated by
The packing material is to be suitable for all expected
ship motions, are to be transmitted to the ship structure
service conditions of the ship and is to be compatible with
through suitable contact, such as continuous steel to steel
the cargoes to be transported. The packing material is to be
contact of the cover skirt plate with the ship's structure or
selected with regard to dimensions and elasticity in such a
by means of defined bearing pads.
way that expected deformations can be carried. Forces are
5.2.2 Weathertight hatch covers (1/7/2012) to be carried by the steel structure only.
a) The arrangement of weathertight hatch covers is to be The packings are to be compressed so as to give the neces-
such that weathertightness can be maintained in al sea sary tightness effect for all expected operating conditions.
conditions. Special consideration shallis to be given to the packing
b) Weathertight sealings are to be obtained by a arrangement in ships with large relative movements
continuous gasket of relatively soft elastic material between hatch covers and coamings or between hatch
compressed to achieve the necessary weathertightness. cover sections. The specification or grade of the packing
Similar sealing is to be arranged between cross-joint material is to be indicated on the drawings.
Table 9 : Moments of inertia (1/7/2012)
Section IP IT I
Flat bar
h wt
3
hw  t w 
3
h wt w
3 3
-----------------w4- tw 
3  10 -----------------4- 1 – 0 63 -----
- -------------------
-
3  10  h w 36  10 6
Sections with for bulb and angle sections:

bulb or flange hw  t w 
3
tw 
-----------------4- 1 – 0 63 -----
-
3  10  h w A f  e f  b f  A f + 2 6A w
2 2
--------------------------
- ----------------------------
12  10 6  A f + A w 
Aw  hw
2
 ------------------- +
- + A f  e f 2 10 –4
 3  for tee-sections:
bf  t f 
3
t
---------------- 1 – 0 63 ----f  b f  tf  e f
3 2
3  10 4  b f ------------------------
-
12  10 6
86 RINA Rules 2024

Pt B, Ch 9, Sec 7
5.2.34 Dispensation of weather tight gaskets

(1/7/2024) PA
t = 14 2  s -------------------------
- , in mm
For hatch covers of cargo holds solely for the transport of 0 95  R eH
containers, upon request by the owners and subject to
compliance with the following conditions the fitting of
L1
weather tight gaskets according to [5.2.32] may be t min = 6 + ---------
- , in mm
100
dispensed with:
2) For Type-2 ships:
• the hatchway coamings shallare to be not less than 600
mm in height;
• the exposed deck on which the hatch covers are located P Coam
t = 16  s -------------------------
- , in mm
is situated above a depth H(x). H(x) is to be shown to 0 95  R eH
comply with the following criteria:
H (x) > Tfb + fb + h , in m
t min = 9 5 mm
Tfb : draught, in m, corresponding to the assigned
summer load line where:
fb : minimum required freeboard, in m, determined PA : pressure, in kN/m2, as defined in [3.3.1]
in accordance with the IMO International PCoam : pressure, in kN/m2, as defined in [3.3.2]
Convention on Load Lines (ICLL), Reg. 28 as s : stiffener spacing, in m
modified by further regulations as applicable L1 : L, need not be taken greater than 300 m.
h = 4,6 m for ( x / LLL )  0,75 In addition, for both Type-1 and Type-2 ships, Llongitudinal
h = 6,9 m for ( x / LLL ) > 0,75 strength aspects are to be observed.
• Labyrinths, gutter bars or equivalents are to be fitted
proximate to the edges of each panel in way of the 6.2 Net scantling of secondary stiffeners of
coamings. The clear profile of these openings is to be coamings
kept as small as possible. 6.2.1 (1/7/2024)
• Where a hatch is covered by several hatch cover panels The stiffeners must be continuous at the coaming stays. For
the clear opening of the gap in between the panels stiffeners with both ends constraint the elastic net section
shallis to be not wider than 50 mm. modulus Z, in cm3, and net shear area AShr, in cm2,
• The labyrinths and gaps between hatch cover panels are calculated on the basis of net thickness, are to be not less
to be considered as unprotected openings with respect than:
to the requirements of intact and damage stability 1) For Type-1 ships:
calculations.
• DueWith regard is to be given to drainage of cargo
holds and the necessary fire-fighting system reference is 83
Z = ------  s  l  p A
2
made to the relevant sections of Pt C. F
• Bilge alarms should be provided in each hold fitted with

non-weathertight covers. PA  s  l
2
-  10 3
Z = --------------------
• Furthermore, Chapter 3 of IMO MSC/Circ. 1087 is to be f bc  R eH
referred to concerning the stowage and segregation of
containers containing dangerous goods.
10  s  l  p
5.2.45 Drainage arrangements (1/7/2012) A s = -----------------------------A-
F
Cross-joints of multi-panel covers are to be provided with
efficient drainage arrangements.
PA  s  l
A shr = ------------------  10
R eH
6 Hatch coaming strength and local
detailscriteria where:
fbc : 12 in general
6.1 Local net plate thickness of coamings 8 for the end spans of stiffeners sniped at the
coaming corners
6.1.1 (1/7/2024)
The net thickness of weather deck hatch coamings shallis l : secondary stiffener span, in m, to be taken as
not to be less than the larger of the following values: the spacing of coaming stays
s : stiffener spacing, in m.
Note that Ffor sniped stiffeners of coaming at hatch corners
section modulus and shear area at the fixed support haves
pA to be increased by 35%. The gross thickness of the coaming
t = 14 2  s ----------------------
- , in mm
0 95   F plate at the sniped stiffener end shallis not to be less than
RINA Rules 2024 87

Pt B, Ch 9, Sec 7
p A  s   l – 0 5s 
t = 19 6 -----------------------------------------
- , in mm
F
526
Z = ----------  e  h s  p A
2
, in cm3
F
P A  s   l – 0 5s 
t gr = 19 6 -----------------------------------------
- , in mm
1000  R eH

2 e  hS  pA
t w = -----  ----------------------
- + tS , in mm
F hw
P Coam  s  l
2
Z = 1 21  ---------------------------
-  10 3
f bc  c p  R eH
2  P  Sc  Hc
t w = ------------------------------- , in mm
where: h  R eH
fbc : 16 in general where:
12 for the end spans of stiffeners sniped at the Hc : stay height, in m
coaming corners esc : spacing of coaming stays spacing, in m
l : span, in m, of stiffeners hS : height of coaming stays depth, in m, at the
s : spacing, in m of stiffeners connection with the deck
PA : pressure in kN/m2 as defined in [3.3.1] hwP : pressure on coaming, in kN/m2, taken as PA
defined in [3.3.1] in general and as PCoam
PCoam : pressure in kN/m2 as defined in [3.3.2]
defined in [3.3.2] for Type-2 shipsweb height of
Cp : ratio of the plastic section modulus to the elastic coaming stay at its lower end in m.
section modulus of the stiffeners with an tS : corrosion addition, in m, according to [9].
attached plate breadth, in mm, equal to 40 t,
For other designs of coaming stays, such as those shown in
where t is the plate net thickness = 1,16 in the
Fig 98, examples 3 and 4, the stresses are to be determined
absence of more precise evaluation
through a grillage analysis or FEM. The calculated stresses
In addition, for both Type-1 and Type-2 ships, Hhorizontal are to comply with the permissible stresses according to
stiffeners on hatch coamings, which are part of the [4.1.1].
longitudinal hull structure, are to be designed taking into
Coaming stays are to be supported by appropriate substruc-
account the hull girder induced stresses.
tures. For calculating the section modulus of coaming stays,
their Fface plates area is to be taken into account only when
6.3 Coaming stays it is welded with full penetration welds to the deck plating
and adequate underdeck structure is fitted to support the
6.3.1 General (1/7/2012) stresses transmitted by itmay only be included in the calcu-
Coaming stays are to be designed for the loads transmitted lation if an appropriate substructure is provided and weld-
through them and permissible stresses according to [4.1.1]. ing provides an adequate joint. Webs are to be connected
to the deck by fillet welds on both sides with a throat thick-
6.3.2 Coaming stay section modulus and web ness of a=0,44tw. The size of welding for toes of webs at the
thickness (1/7/2024) lower end of coaming stays should be according to Ch 12,
At the connection with deck, the net section modulus Z, in Sec 1 and Ch 12, Sec 2, [2.7].
cm3, and the gross thickness tw, in mm, of the coaming stays Webs are to be connected to the deck by fillet welds on
designed as beams with flange (examples 1 and 2 are both sides with a throat thickness of 0,44tw.
shown in Fig 98) are to be taken not less than: For Type-2 ships, toes of stay webs are to be connected to
the deck plating with full or partial penetration double
bevel welds extending over a distance not less than 15% of
the stay width. For other ship types the size of welding for
P  Sc  H c
2
-  10 3
Z = ------------------------- , in cm3 toes of webs at the lower end of coaming stays should be
1 9  R eH according to Ch 12, Sec 1 and Ch 12, Sec 2, [2.7].
88 RINA Rules 2024

Pt B, Ch 9, Sec 7
Figure 89 : Examples of coaming stays (1/7/2016) Structures under deck are to be checked against the load
transmitted by the stays.
Unless otherwise stated, weld connections and materials
are to be dimensioned and selected in accordance with
Ch 12, Sec 1.
6.4.3 Stays (1/7/2012)

On ships carrying cargo on deck, such as timber, coal or
coke, the stays are to be spaced not more than 1,5 m apart.
6.4.4 Extend of coaming plates (1/7/2012)

Coaming plates are to extend to the lower edge of the deck
beams or hatch side girders are to be fitted that extend to
Example 2
the lower edge of the deck beams. Extended coaming plates
Example 1
and hatch side girders are to be flanged or fitted with face
bars or half-round bars. Fig 109 gives an example.
Figure 10 : Example for the extend of coaming plates
Example 3 Example 4
6.3.3 Coaming stays under friction load (1/7/2016)

For coaming stays, which transfer friction forces at hatch
cover supports, fatigue strength is to be considered on a
case-by-case basis, refer also to [7.2.2].
6.4 Further requirements for hatch

coamings
Figure 9 : Example for a hatch side girder (1/7/2024)
6.4.1 Longitudinal strength (1/7/2012)
Hatch coamings which are part of the longitudinal hull
structure are to be designed taking into account the hull
girder induced stresses.
For structural members welded to coamings and for cutouts
in the top of coamings sufficient fatigue strength is to be
verified.
Longitudinal hatch coamings with a length exceeding 0,1·L
m are to be provided with tapered brackets or equivalent
transitions and a corresponding substructure at both ends.
At the end of the brackets they are to be connected to the
deck by full penetration welds of minimum 300 mm in
length.
6.4.2 Local details (1/7/2012)

For design of local details not contemplated by the present
Article [6], analyses are to be carried out on a case-by-case
basis for the purpose of transferring the loads on the hatch 6.4.5 Drainage arrangement at the coaming
covers to the hatch coamings and, through them, to the (1/7/2012)
deck structures below. Hatch coamings and supporting If drain channels are provided inside the line of gasket by
structures are to be adequately stiffened to accommodate means of a gutter bar or vertical extension of the hatch side
the loading from hatch covers, in longitudinal, transverse and end coaming, drain openings are to be provided at
and vertical directions. appropriate positions of the drain channels.
RINA Rules 2024 89

Pt B, Ch 9, Sec 7
Drain openings in hatch coamings are to be arranged with giving support to battens and wedges and with edges
sufficient distance to areas of stress concentration (e.g. rounded so as to minimise damage to the wedges.
hatch corners, transitions to crane posts). b) Cleats are to be spaced not more than 600 mm from
Drain openings are to be arranged at the ends of drain centre to centre and are to be not more than 150 mm
channels and are to be provided with non-return valves to from the hatch corners.
prevent ingress of water from outside. It is unacceptable to c) The thickness of cleats is to be not less than 9,5 mm for
connect fire hoses to the drain openings for this purpose. angle cleats and 11 mm for forged cleats.
If a continuous outer steel contact between cover and ship d) Where rod cleats are fitted, resilient washers or cushions
structure is arranged, drainage from the space between the are to be incorporated.
steel contact and the gasket is also to be provided for.
e) Where hydraulic cleating is adopted, a positive means is
to be provided to ensure that it remains mechanically
7 Weathertightness, Closing locked in the closed position in the event of failure of
arrangements and securing devices the hydraulic system.
Where rod cleats are fitted, resilient washers or cushions
7.1 Securing devices and Tarpaulins are to be incorporated.
7.1.3 Hydraulic cleatsTarpaulins (1/7/2024)

7.1.1 General (1/7/2024)
Where weathertightness of hatch covers is ensured by
Securing devices between cover and coaming and at cross-
means of tarpaulins, at least two layers of tarpaulins are to
joints are to be installed to provide weathertightness.
be fitted.
Sufficient packing line pressure is to be maintained.
Tarpaulins are to be free from jute and waterproof and are
Securing devices are to be appropriate to bridge to have adequate characteristics of strength and resistance
displacements between cover and coaming due to hull to atmospheric agents and high and low temperatures.
deformations.
The mass per unit surface of tarpaulins made of vegetable
Securing devices are to be of reliable construction and fibres, before the waterproofing treatment, is to be not less
effectively attached to the hatchway coamings, decks or than:
covers. Individual securing devices on each cover are to
• 0,65 kg/m2 for waterproofing by tarring
have approximately the same stiffness characteristics.
• 0,60 kg/m2 for waterproofing by chemical dressing
Sufficient number of securing devices is to be provided at
each side of the hatch cover considering the requirements • 0,55 kg/m2 for waterproofing by dressing with black oil.
of [4.4.2]. This applies also to hatch covers consisting of In addition to tarpaulins made of vegetable fibres, those of
several parts. synthetic fabrics or plastic laminates may be accepted by
Specifications of the materials are to be shown in the draw- the Society provided their qualities, as regards strength,
ings of the hatch covers. waterproofing and resistance to high and low temperatures,
are equivalent to those of tarpaulins made of vegetable
The cover edge stiffness is to be sufficient to maintain ade-
fibres.
quate sealing pressure between securing devices.
Where hydraulic cleating is adopted, a positive means is to
The gross moment of inertia of edge elements is not to be
be provided so that it remains mechanically locked in the
less than:
closed position in the event of failure of the hydraulic sys-
I = 6 pa4 [cm4] tem.
where
7.1.4 Wedges, battens and locking bars (1/7/2024)
p : packing line pressure, with p > 5 [N/mm] a) Wedges
a : maximum of the distances, ai, between two Wedges are to be of tough wood, generally not more
consecutive securing devices, measured along than 200 mm in length and 50 mm in width.
the hatch cover periphery (see Fig 11), not to be
They are generally to be tapered not more than 1 in 6
taken as less than 2.5 ac, [m] ac : max (a1.1, a1.2)
and their thickness is to be not less than 13 mm.
[m]
b) Battens and locking bars
When calculating the actual gross moment of inertia of the
edge element, the effective breadth of the attached plating For all hatchways in exposed positions, battens or trans-
of the hatch cover, in m, is to be taken equal to the lesser of verse bars in steel or other equivalent means are to be
the following values: provided in order to efficiently secure the portable cov-
ers after the tarpaulins are battened down.
• 0,165 a
Portable covers of more than 1,5 m in length are to be
• half the distance between the edge element and the secured by at least two such securing appliances.
adjacent primary member.
7.1.54 Cross-sectional area of the securing devices
7.1.2 Rod cCleats (1/7/2024) (1/7/2024)
a) The arrangements for securing the tarpaulins to hatch The gross cross-sectional area in cm2 of the securing
coamings are to incorporate cleats of a suitable pattern devices is not to be less than:
90 RINA Rules 2024

Pt B, Ch 9, Sec 7
A = 0,28 · q · SsSD · kl where
Correspondingly, the stiffness of edge girders is to be FReH is the minimum yield strength of the material, in
sufficient to maintain adequate sealing pressure between N/mm2, but is not to be taken greater than 0,7 · Rm, where
securing devices. The moment of inertia, in cm4, of edge Rm is the tensile strength of the material, in N/mm2.
girders is not to be less than:
e = 0,75 for FReH > 235 N/mm2
I=6.q.SSD4
= 1,00 for FReH  235 N/mm2
where
Rods or bolts are to have a gross diameter not less than 19
q : packing line pressure, in N/mm, minimum 5 mm for hatchways exceeding 5 m2 in area.
N/mm
Securing devices of special design in which significant
sSSD : spacing between securing devices, in m, not to bending or shear stresses occur may be designed as anti-lift-
be taken less than 2 m ing devices according to [7.1.5]. As load Tthe packing line
pressure q is to be specified, and as load, q multiplied by
kl = ( 235 / ReHF )e the spacing between securing devices SsSD is to be applied.
Figure 11 : Distance between securing devices, measured along hatch cover periphery (1/7/2012)
a1= a 1.1+ a1.2 a1.2 a2 a3
a1.1
a = max ( a , a i+ 1 )
i
a = ( a , a i+ 1 ) / 2
i
7.1.65 Anti lifting devices (1/7/2024) compression-only boundary elements for the vertical hatch
cover supports. If securing devices are omitted, transverse
The securing devices of hatch covers, on which cargo is to
cover guides are to be effective up to a height hE above the
be lashed, are to be designed for the lifting forces resulting
hatch cover supports, where hE is to be not less than:
from loads according to [3.45], refer Fig130. Unsymmetri-
cal loadings, which may occur in practice, are to be consid- hE = 1,75(2se + d2)0.5 - 0,75d [mm]
ered. Under these loadings the equivalent stress in the
securing devices is not to exceed: hE,min = height of the cover edge plate +150 [mm]
σvm = 150 / kl1, in N/mm2. where (see Fig 12):

Note 1: The partial load cases given in Tab 4 may not cover all e : largest distance from the inner edges of the
unsymmetrical loadings, critical for hatch cover lifting transverse cover guides to the ends of the cover
edge plate [mm]
Chapter 5.6 of IACS Rec. 14 is to be referred to for the
omission of anti-lifting devices. s : total clearance within the transverse cover
guide, with 10  s 40 [mm]
Anti-lifting devices may be omitted provided that it is
proven by means of grilage and/or finite element analyses d : distance between upper edge of transverse
that an equilibrium condition is achieved using stopper and hatch cover supports [mm]
RINA Rules 2024 91

Pt B, Ch 9, Sec 7
Figure 12 : Height of transverse cover guides (1/7/2012)
h
E
d e
s
Figure 103 : Lifting forces at a hatch cover (1/7/2012)
A B A B A B A B A B
Z Z Z Z Z Z Z Z Z Z
Lifting Force
7.2 Hatch cover supports, stoppers and pPn = permissible nominal surface pressure, see Tab 108
supporting structures For metallic supporting surfaces not subjected to relative
displacements the nominal surface pressure applies:
7.2.1 Horizontal mass forces (1/7/2024)
For the design of hatch cover supports the securing devices pPn max = 3 · pPn, in N/mm2.
against shifting the horizontal mass forces Fh = m · a are to Note 1: When the maker of vertical hatch cover support material
be calculated with the following accelerations: can provide proof that the material is sufficient for the increased
ax = 0,2 · g in longitudinal direction surface pressure, not only statically but under dynamic conditions
including relative motion for adequate number of cycles,
ay = 0,5 · g in transverse direction permissible nominal surface pressure may be relaxed at the
m : Sum of mass of cargo lashed on the hatch cover discretion of the sSociety. However, realistic long term distribution
and mass of hatch cover of spectra for vertical loads and relative horizontal motion should
be assumed and agreed with the sSociety.
The accelerations in longitudinal direction and in transverse
direction do not need to be considered as acting Drawings of the supports must be submitted. In the
simultaneously. drawings of supports the permitted maximum pressure
given by the material manufacturer must be specified.
7.2.2 Hatch cover supports (1/7/2024)
For the transmission of the support forces resulting from the Table 810 : Permissible nominal surface pressure pPn
load cases specified in [3] and of the horizontal mass forces (1/7/2024)
specified in [7.2.1], supports are to be provided which are
to be designed such that the nominal surface pressures in pPn [N/mm2] when loaded by
general do not exceed the following values:
Support material Vertical Horizontal force
pPn max = d · Ppn, in N/mm2
force (on stoppers)
d = 3,75 - 0,015L
Hull structural steel 25 40
dmax = 3,0
Hardened steel 35 50
dmin = 1,0 in general
= 2,0 for partial loading conditions, see [3.5.1] Lower friction materials 50 -
92 RINA Rules 2024

Pt B, Ch 9, Sec 7
Where large relative displacements of the supporting With the exclusion of No.1 hatch cover, hatch covers are to
surfaces are to be expected, the use of material having low be effectively secured, by means of stoppers, against the
wear and frictional properties is recommended. longitudinal forces acting on the forward end arising from a
The substructures of the supports must be of such a design, pressure of 175 kN/m2.
that a uniform pressure distribution is achieved. No. 1 hatch cover is to be effectively secured, by means of
Irrespective of the arrangement of stoppers, the supports stoppers, against the longitudinal forces acting on the
must be able to transmit the following force Ph in the longi- forward end arising from a pressure of 230 kN/m2.
tudinal and transverse direction:
This pressure may be reduced to 175 kN/m2 when a
forecastle is fitted in accordance with the relevant
P requirements in Pt E, Ch 4, Sec 3, [10.1] for ships with
P h =   ------V-
d service notation bulk carrier ESP, in Pt E, Ch 5, Sec 3, [7.1]
for ships with service notation ore carrier ESP and in Pt E,
Pv : vertical supporting force
Ch 6, Sec 3, [7] for ships with service notation combination
 : frictional coefficientvertical supporting force carrier ESP.
= 0,5 in general The equivalent stress:
For non-metallic, low-friction support materials on steel, the a) in stoppers and their supporting structures, and
friction coefficient may be reduced but not to be less than
b) calculated in the throat of the stopper welds is not to
0,35 and to the satisfaction of the Society.
exceed the allowable value of 0,8ReH.
Supports as well as the adjacent structures and substruc-
tures are to be designed such that the permissible stresses
according to [4.1.1] are not exceeded. 8 Drainage
For substructures and adjacent structures of supports sub-
jected to horizontal forces Ph, fatigue strength is to be con- 8.1 Arrangement
sidered according to the satisfaction of the Society. 8.1.1 (1/7/2012)
Drainage is to be arranged inside the line of gaskets by
7.2.3 Hatch cover stoppers (1/7/2012) means of a gutter bar or vertical extension of the hatch side
Hatch covers shallare to be sufficiently secured against and end coaming.
horizontal shifting. Stoppers are to be provided for hatch
8.1.2 (1/7/2012)
covers on which cargo is carried.
Drain openings are to be arranged at the ends of drain
The greater of the loads resulting from [3.23] and [7.2.1] is channels and are to be provided with efficient means for
to be applied for the dimensioning of the stoppers and their preventing ingress of water from outside, such as non-return
substructures. valves or equivalent.
The permissible stress in stoppers and their substructures, in 8.1.3 (1/7/2012)
the cover, and of the coamings is to be determined in Cross-joints of multipanel hatch covers are to be arranged
accordance with [4.1.1]. In addition, the requirements in with drainage of water from the space above the gasket and
[7.2.2] are to be complied with. a drainage channel below the gasket.
Specifically for Type-2 ships, the following additional 8.1.4 (1/7/2012)
requirements are to be complied with:
If a continuous outer steel contact is arranged between the
Hatch covers are to be effectively secured, by means of cover and the ship’s structure, drainage from the space
stoppers, against the transverse forces arising from a between the steel contact and the gasket is also to be
pressure of 175 kN/m2. provided.
RINA Rules 2024 93

Pt B, Ch 9, Sec 7
9 Small hatches fitted on the exposed Table 911 : Structural scantlings of small
rectangular steel hatch covers (1/7/2012)
fore deck
Hatch Cover plate Primary
Ordinary
9.1 Application nominal size thickness supporting
stiffeners
(mm x mm) (mm) members
9.1.1 General (1/7/2024)
Flat Bar (mm x mm); number
The requirements in [9] apply to steel covers of small
hatches fitted on the exposed fore deck over the forward 630 x 630 8 - -
0,25L, for ships of equal to or greater than 80 m in length,
630 x 830 8 100 x 8 ; 1 -
where the height of the exposed deck in way of the hatch is
less than 0,1L or 22 m above the summer load waterline, 830 x 630 8 100 x 8 ; 1 -
whichever is the lesser.
830 x 830 8 100 x 10 ; 1 -
Small hatches are hatches designed for access to spaces
below the deck and are capable of being closed 1030 x 1030 8 120 x 12 ; 1 80 x 8 ; 2
weathertight or watertight, as applicable. Their opening is 1330 x 1330 8 150 x 12 ; 2 100 x 10 ; 2
generally equal to or less than 2,5 m2.
This Article does not apply to small hatches on container 9.3 Weathertightness
ship giving access to a cargo hold which comply with UI
9.3.1 (1/7/2012)
LL64 except the requirement of [9.2] and [9.4]. Such hatch
covers are considered non-weathertight regardless of The hatch cover is to be fitted with a gasket of elastic
whether it is actually weathertight or not. However, for material. This is to be designed to allow a metal-to-metal
scantlings of small hatches, the strength requirements in contact at a designed compression and to prevent over
[9.2] could be applied instead of clause 6 of UI LL64. compression of the gasket by green sea forces that may
cause the securing devices to be loosened or dislodged. The
9.1.2 Small hatches designed for emergency metal-to-metal contacts are to be arranged close to each
escape (1/7/2012) securing device in accordance with Fig 141, and to be of
Small hatches designed for emergency escape are not sufficient capacity to withstand the bearing force.
required to comply with the requirements in [9.4.1] a) and
b), in [9.4.3] and in [9.5]. 9.4 Primary securing devices
Securing devices of hatches designed for emergency escape 9.4.1 (1/7/2012)
are to be of a quick-acting type (e.g. one action wheel Small hatches located on the exposed fore deck are to be
handles are provided as central locking devices for fitted with primary securing devices such that their hatch
latching/unlatching of hatch cover) operable from both covers can be secured in place and weathertight by means
sides of the hatch cover. of a mechanism employing any one of the following
methods:
9.2 Strength a) Butterfly nuts tightening onto forks (clamps),
9.2.1 (1/7/2012) b) Quick acting cleats, or
For small rectangular steel hatch covers, the plate thickness,
c) Central locking device.
stiffener arrangement and scantlings are to be not less than
those obtained, in mm, from Tab 119 and Fig 141. Dogs (twist tightening handles) with wedges are deemed
unacceptable by the Society.
Ordinary stiffeners, where fitted, are to be aligned with the
metal-to-metal contact points, required in [9.3.1] (see also 9.4.2 (1/7/2012)
Fig 141). Primary supporting members are to be continu- The primary securing method is to be designed and
ous. All stiffeners are to be welded to the inner edge stiff- manufactured such that the designed compression pressure
ener (see also Fig 152). is achieved by one person without the need for any tools.
9.2.2 (1/7/2012) 9.4.3 (1/7/2012)
The upper edge of the hatchway coamings is to be suitably For a primary securing method using butterfly nuts, the forks
reinforced by a horizontal section, normally not more than (clamps) are to be of robust design. They are to be designed
170 to 190 mm from the upper edge of the coamings. to minimise the risk of butterfly nuts being dislodged while
in use, by means of curving the forks upward, a raised
9.2.3 (1/7/2012)
surface on the free end, or a similar method. The plate
For small hatch covers of circular or similar shape, the cover thickness of unstiffened steel forks is to be not less than 16
plate thickness and reinforcement are to comply with the mm. An example of arrangement is shown in Fig 152.
requirements in [4].
9.4.4 (1/7/2012)
9.2.4 (1/1/2004) For small hatch covers located on the exposed deck forward
For small hatch covers constructed of materials other than of the foremost cargo hatch, the hinges are to be fitted such
steel, the required scantlings are to provide equivalent that the predominant direction of green sea will cause the
strength. cover to close, which means that the hinges are normally to
be located on the fore edge.

Pt B, Ch 10, Sec 1
SECTION 1 RUDDERS
Symbols
VAV : maximum ahead service speed, in knots, with 1.1.3 Steering nozzles
the ship on summer load waterline; if VAV is less The requirements for steering nozzles are given in [10].
than 10 knots, the maximum service speed is to
be taken not less than the value obtained from 1.1.4 Special rudder types
the following formula: Rudders others than those in [1.1.1], [1.1.2] and [1.1.3] will
be considered by the Society on a case-by- case basis.
V AV + 20
V MIN = ---------------------
- 1.1.5 (1/7/2024)
3
This Section applies to rudders made of steel for ships with
VAD : maximum astern speed, as defined in SOLAS
L24m.
Regulation II-1/3.15, in knots, to be taken not
less than 0,5 VAV
1.2 Gross scantlings
A : total area of the rudder blade, in m2, bounded
by the blade external contour, including the 1.2.1 With reference to Ch 4, Sec 2, [1], all scantlings and
mainpiece and the part forward of the dimensions referred to in this Section are gross, i.e. they
centreline of the rudder pintles, if any include the margins for corrosion.
k1 : material factor, defined in [1.4.4]
k : material factor, for the rudder trunk, defined in 1.3 Arrangements
Ch 4, Sec 1, [2.3] (see also [1.4.6]
1.3.1 Effective means are to be provided for supporting the
CR : rudder force, in N, acting on the rudder blade, weight of the rudder without excessive bearing pressure,
defined in [2.1.1] and [2.2.1] e.g. by means of a rudder carrier attached to the upper part
MTR : rudder torque, in N.m, acting on the rudder of the rudder stock. The hull structure in way of the rudder
blade, defined in [2.1.2] and [2.2.2] carrier is to be suitably strengthened.
MB : bending moment, in N.m, in the rudder stock, 1.3.2 Suitable arrangements are to be provided to prevent
defined in [4.1]. the rudder from lifting.
In addition, structural rudder stops of suitable strength are
1 General to be provided, except where the steering gear is provided
with its own rudder stopping devices, as detailed in Pt C,
1.1 Application Ch 1, Sec 11.
1.3.3 (1/7/2024)
1.1.1 Ordinary profile rudders (1/7/2016) In rudder trunks which are open to the sea, a seal or stuffing
The requirements of this Section apply to ordinary profile box is to be fitted above the deepest load waterline, to
rudders made of steel, without any special arrangement for prevent water from entering the steering gear compartment
increasing the rudder force, whose maximum orientation at and the lubricant from being washed away from the rudder
maximum ship speed is limited to 35 on each side. carrier. If the top of the rudder trunk is below the deepest
waterline at scantling draught (without trim), two separate
In general, an orientation greater than 35 is accepted for
manoeuvres or navigation at very low speed. watertight seals / stuffing boxes are to be provided.
1.1.2 High lift profiles (1/7/2016) 1.4 Materials

The requirements of this Section also apply to rudders made 1.4.1 (1/7/2016)
of steel fitted with flaps to increase rudder efficiency. For Rudders made of materials others than steel will be
these rudder types, an orientation at maximum speed less considered by the Society on a case-by-case basis.
than 35 may be accepted. In these cases, the rudder forces
are to be calculated by the Designer for the most severe 1.4.2 Rudder stocks, pintles, coupling bolts, keys and cast
combinations between orientation angle and ship speed. parts of rudders are to be made of rolled steel, steel forgings
These calculations are to be considered by the Society on a or steel castings according to the applicable requirements in
case-by-case basis. Part D, Chapter 2.
The rudder scantlings are to be designed so as to be able to 1.4.3 (1/1/2021)
sustain possible failures of the orientation control system, The material used for rudder stocks, pintles, keys and bolts
or, alternatively, redundancy of the system itself may be is to have a specified minimum yield stress not less than
required. 200 N/mm2.
RINA Rules 2024 105

Pt B, Ch 10, Sec 1
1.4.4 (1/1/2021) avoided in or at the end of the radii. Edges of side plate and
The requirements relevant to the determination of scantlings weld adjacent to radii are to be ground smooth.
contained in this Section apply to steels having a specified 1.5.3 (1/7/2024)
minimum yield stress equal to 235 N/mm2. Welds in the rudder side plating subjected to significant
Where the material used for rudder stocks, pintles, coupling stresses from rudder bending and welds between plates and
bolts, keys and cast parts of rudders has a specified heavy pieces (solid parts in forged or cast steel or very thick
minimum yield stress different from 235 N/mm2, the plating) are to be made as full penetration welds. In way of
scantlings calculated with the formulae contained in the highly stressed areas e.g. cut-out of semi-spade rudder and
requirements of this Section are to be modified, as upper part of spade rudder, cast or welding on ribs is to be
indicated, depending on the material factor k1, to be arranged. Two sided full penetration welding is normally to
obtained from the following formula: be arranged. Where back welding is impossible welding is
n
to be performed against ceramic backing bars or equivalent.
k 1 =  ----------
235 Steel backing bars may be used and are to be fitted with
 R eH 
continuously welded on one side to the heavy piece
where: bevelled edge, see Fig 1. The bevel angle is to be at least
15° for one sided welding.
ReH : specified minimum yield stress, in N/mm2, of
the steel used, and not exceeding the lower of
Figure 1 : Use of steel backing bar in way of full
0,7 Rm and 450 N/mm2 penetration welding of rudder side plating (1/7/2024)
Rm : minimum ultimate tensile strength, in N/mm2,
of the steel used
n : coefficient to be taken equal to:
• n = 0,75 for ReH > 235 N/mm2
• n = 1,00 for ReH  235 N/mm2.
1.4.5 (1/1/2021)
Significant reductions in rudder stock diameter due to the
application of steels with specified minimum yield stresses
greater than 235 N/mm2 may be accepted by the Society
subject to the results of a check calculation of the rudder
stock deformations.
Large rudder stock deformations are to be avoided in order
to avoid excessive edge pressures in way of bearings.
1.4.6 Welded parts of rudders are to be made of approved

rolled hull materials. For these members, the material factor
k defined in Ch 4, Sec 1, [2.3] is to be used. 1.5.4 (1/7/2016)
Requirements for welding and design details when the
1.5 Welding and design details rudder stock is connected to the rudder by horizontal flange
1.5.1 (1/7/2016) coupling are described in [5.1.1].
Slot-welding is to be limited as far as possible. Slot welding 1.5.5 (1/7/2016)
is not to be used in areas with large in-plane stresses Requirements for welded connections of blade plating to
transversely to the slots or in way of cut-out areas of semi- vertical and horizontal webs are given in [7.3.8].
spade rudders.
1.5.6 (1/7/2016)
When slot welding is applied, the length of slots is to be Requirements for welding and design details of rudder
minimum 75 mm with breadth of 2 t, where t is the rudder horns are described in [8.2.6].
plate thickness, in mm. The distance between ends of slots
is not to be more than 125 mm. The slots are to be fillet 1.5.7 (1/7/2016)
welded around the edges and filled with a suitable Requirements for welding and design details of rudder
compound, e.g. epoxy putty. Slots are not to be filled with trunks are described in [8.4.2].
weld.
Continuous slot welds are to be used in lieu of slot welds. 2 Force and torque acting on the
When continuous slot welding is applied, the root gap is to rudder
be between 6-10 mm. The bevel angle is to be at least 15°.
1.5.2 (1/1/2021) 2.1 Rudder blade without cut-outs
In way of the rudder horn recess of semi-spade rudders the
radii in the rudder plating except in way of solid part in cast 2.1.1 Rudder blade description
steel are not to be less than 5 times the plate thickness, but A rudder blade without cut-outs may have trapezoidal or
in no case less than 100 mm. Welding in side plate is to be rectangular contour.
106 RINA Rules 2024

...OMISSIS...
Pt B, Ch 10, Sec 1
The total torque MTR acting on the rudder stock, for both be determined according to [4.1.2] through a direct
ahead and astern conditions, is to be obtained, in N.m, calculation
from the following formula:
• for 2 bearing rudders with solepiece and 2 bearing
MTR = MTR1 + MTR2 semi-spade rudders with rudder horn, MB is to be
For the ahead condition only, MTR is to be taken not less calculated according to:
than the value obtained, in N.m, from the following
formula: - [4.1.2] through a direct calculation, or
A1 b1 + A2 b2 - [4.1.3] through a simplified method

M TR ,MIN = 0 ,1C R -----------------------------
-
A
• for 3 bearing semi-spade rudders with rudder horn and
for the rudder types shown in Fig 45, MB may be taken
3 Loads acting on the rudder structure equal to zero.
3.1 General 4.1.2 Bending moment calculated through a direct

calculation (1/7/2016)
3.1.1 Loads
For spade rudders, spade rudders with trunk, 2 bearing
The force and torque acting on the rudder, defined in [2],
rudders with solepiece, 2 bearing semi-spade rudders with
induce in the rudder structure the following loads:
rudder horn and semi-spade rudders with 2-conjugate
• bending moment and torque in the rudder stock elastic support, where a direct calculation according to the
• support forces static schemes and the load conditions specified in App 1 is
• bending moment, shear force and torque in the rudder carried out, the bending moment in the rudder stock is to be
body obtained as specified in App 1.
• bending moment, shear force and torque in rudder
horns and solepieces. 4.1.3 Bending moment calculated through a
simplified method (1/7/2002)
3.1.2 Direct load calculations (1/7/2016)
For 2 bearing rudders with solepiece and 2 bearing semi-
The bending moment in the rudder stock, the support spade rudders with rudder horn, where a direct calculation
forces, and the bending moment and shear force in the according to the static schemes and the load conditions
rudder body and the loads in the rudder horn are to be
specified in App 1 is not carried out, the bending moment
determined through direct calculations to be performed in
MB in the rudder stock is to be obtained, in N.m, from the
accordance to the static schemes and the load conditions
specified in App 1. following formula:
For rudders with solepiece or rudder horns these structures HC

are to be included in the calculation model in order to M B = 0 ,866 ----------R-
A
account for the elastic support of the rudder body.
where H is defined, in m3, in Tab 3.
The other loads (i.e. the torque in the rudder stock and in
the rudder body and the loads in the solepieces) are to be
calculated as indicated in the relevant requirements of this 4.2 Scantlings
Section.
3.1.3 Simplified methods for load calculation 4.2.1 Rudder stock subjected to torque only
(1/7/2016)
For rudder stocks subjected to torque only (3 bearing semi-
For ordinary rudder types, the bending moment in the spade rudders with rudder horn in Fig 23 and the rudder
rudder stock, the support forces, and the bending moment types shown in Fig 45), it is to be checked that the torsional
and shear force in the rudder body may be determined
shear stress , in N/mm2, induced by the torque MTR is in
through approximate methods specified in the relevant
compliance with the following formula:
requirements of this Section.
  ALL
4 Rudder stock scantlings
where:
4.1 Bending moment ALL : allowable torsional shear stress, in N/mm2:
4.1.1 General (1/7/2016) ALL = 68/k1

The bending moment MB in the rudder stock is to be
For this purpose, the rudder stock diameter is to be not less
obtained as follows:
than the value obtained, in mm, from the following formula:
• for spade rudders, spade rudders with trunk and semi-
spade rudders with 2-conjugate elastic support MB is to dT = 4,2 (MTR k1)1/3
RINA Rules 2024 109

Pt B, Ch 10, Sec 1
Figure 5 : Rudder types
4.2.2 Rudder stock subjected to combined torque B : bending stress to be obtained, in N/mm2, from
and bending (1/7/2024) the following formula:
For rudder stocks subjected to combined torque and 10 ,2M B
bending, it is to be checked that the equivalent stress E  B = 10 3 -------------------
3
-
d TF
induced by the bending moment MB and the torque MTR is
T : torsional stress to be obtained, in N/mm2, from
in compliance with the following formula:
the following formula:
E  E,ALL
5 ,1M TR
where:  T = 10 3 ------------------
-
d TF
3
E : equivalent stress to be obtained, in N/mm2, E,ALL : allowable equivalent stress, in N/mm2, equal to:
E,ALL = 118/k1 N/mm2
E =  B2 + 3 T2
110 RINA Rules 2024

Pt B, Ch 10, Sec 1
Table 3 : Factor H (1/7/2002) For this purpose, the rudder stock diameter is to be not less
than the value obtained, in mm, from the following formula:
Rudder type H, in m3
4 M B  2 1 / 6
d TF = 4 2  M TR k 1  1  3  1 + ---  ---------
 3  M TR 
2 bearing
rudders In general, the diameter of a rudder stock subjected to
with torque and bending may be gradually tapered above the
upper stock bearing so as to reach the value of dT in way of
solepiece
the quadrant or tiller.
For a spade rudder with trunk extending inside the rudder,
Aa 1 uH 1
the rudder stock scantlings are to be checked against the
two cases defined in App 1.
5 Rudder stock couplings
5.1 Horizontal flange couplings

2 bearing
semi-spade 5.1.1 General (1/7/2016)
rudders In general, the coupling flange and the rudder stock are to
be forged from a solid piece. A shoulder radius as large as
with
practicable is to be provided for between the rudder stock
rudder horn
and the coupling flange. This radius is to be not less than
0,13 d1 or 45 mm, whichever is the greater, where d1 is the
0,83 B (1) greater of the rudder stock diameters dT and dTF, in mm, to
be calculated in compliance with the requirements in
[4.2.1] and [4.2.2], respectively.
Where the rudder stock diameter does not exceed 350 mm,
the coupling flange may be welded onto the stock provided
that its thickness is increased by 10%, and that the weld
extends through the full thickness of the coupling flange
(1) B is the greater of the absolute values obtained from the and that the assembly obtained is subjected to heat
following formulae: treatment. This heat treatment is not required if the diameter
• B = A1uH1 + A2 (vH1 + wH2) of the rudder stock is less than 75 mm.
• B = A1a2H1 - A2 (a3H1 + 0,5H2) Where the coupling flange is welded, the grade of the steel
where a1, a2, a3, u, v, w are defined in Tab 4. used is to be of weldable quality, particularly with a carbon
content not greater than 0,25% and the welding conditions
(preparation before welding, choice of electrodes, pre and
Table 4 : Coefficients for calculating the bending
post heating, inspection after welding) are to be defined to
moment in the rudder stock
the satisfaction of the Society. The welded joint between the
rudder stock and the flange is to be made in accordance
Coefficient Value
with Fig 56. The throat weld at the top of the flange is to be
a1 2,55 - 1,75c concave shaped to give a fillet shoulder radius as large as
practicable. This radius is to be not less than 45 mm (see
a2 1,75c2 - 3,9c + 2,35 Fig 56).
a3 2,65c2 - 5,9c + 3,25
u 1,1c2 - 2,05c + 1,175
v 1,15c2 -1,85c + 1,025
w -3,05c4 +8,14c3 - 8,15c2 +3,81c -0,735
Note 1:
H1
c = -------------------
-
H1 + HC
H 1, H C : as defined in Tab 3, as applicable.
RINA Rules 2024 111

Pt B, Ch 10, Sec 1
Figure 6 : Welded joints between rudder stock and k 1F

coupling flange (1/7/2016) t P = d B ------
-
k 1B
where:
dB : bolt diameter, in mm, calculated in accordance
with [5.1.2], where the number of bolts nB is to
be taken not greater than 8
k1F : material factor k1 for the steel used for the
flange
k1B : material factor k1 for the steel used for the bolts
In any case, the thickness tP is to be not less than 0,9 dB.
5.1.4 Locking device

A suitable locking device is to be provided to prevent the
accidental loosening of nuts.
5.2 Couplings between rudder stocks and

tillers
5.2.1 Application (1/7/2002)

The requirements in Pt C, Ch 1, Sec 11 apply.
5.2.2 General
The entrance edge of the tiller bore and that of the rudder
stock cone are to be rounded or bevelled.
The right fit of the tapered bearing is to be checked before
final fit up, to ascertain that the actual bearing is evenly
distributed and at least equal to 80% of the theoretical
5.1.2 Bolts bearing area; push-up length is measured from the relative
Horizontal flange couplings are to be connected by fitted positioning of the two parts corresponding to this case.
bolts having a diameter not less than the value obtained, in The required push-up length is to be checked after releasing
mm, from the following formula: of hydraulic pressures applied in the hydraulic nut and in
d 13 k 1B the assembly
d B = 0 ,62 -------------------
-
n B e M k 1S
5.2.3 Keyless couplings through special devices
where: The use of special devices for frictional connections, such
d1 : rudder stock diameter, in mm, defined in as expansible rings, may be accepted by the Society on a
[5.1.1] case-by-case basis provided that the following conditions
k1S : material factor k1 for the steel used for the are complied with:
rudder stock • evidence that the device is efficient (theoretical
k1B : material factor k1 for the steel used for the bolts calculations and results of experimental tests, references
of behaviour during service, etc.) are to be submitted to
eM : mean distance, in mm, from the bolt axes to the
the Society
longitudinal axis through the coupling centre
(i.e. the centre of the bolt system) • the torque transmissible by friction is to be not less than
2 MTR
nB : total number of bolts, which is to be not less
than 6 • design conditions and strength criteria are to comply
with [5.2.1]
Non-fitted bolts may be used provided that, in way of the
mating plane of the coupling flanges, a key is fitted having a • instructions provided by the manufacturer are to be
section of (0,25dT x 0,10dT) mm2 and keyways in both the complied with, notably concerning the pre-stressing of
coupling flanges, and provided that at least two of the the tightening screws.
coupling bolts are fitted bolts.
The distance from the bolt axes to the external edge of the 5.3 Cone couplings between rudder stocks
coupling flange is to be not less than 1,2 dB. and rudder blades with key
5.1.3 Coupling flange 5.3.1 General (1/7/2016)

The thickness of the coupling flange is to be not less than For cone couplings without hydraulic arrangements for
the value obtained, in mm, from the following formula: assembling and disassembling the coupling, a key is to be
112 RINA Rules 2024

Pt B, Ch 10, Sec 1
fitted having keyways in both the tapered part and the taper on diameter in compliance with the following
rudder gudgeon. formula:
The key is to be machined and located on the fore or aft 1 dU – d0 1

------  -----------------  ---
part of the rudder. The key is to be inserted at half-thickness 12 tS 8
into stock and into the solid part of the rudder. where:
dU, tS, d0 : geometrical parameters of the coupling, in mm,
5.3.2 Tapering and coupling length (1/7/2024) defined in Fig 67.
Cone couplings without hydraulic arrangements for The cone shapes are to fit exactly. The coupling length tS , in
mounting and dismounting the coupling should have a mm, is to be, in general, not less than 1,5dU.
Figure 7 : Geometry of cone coupling with key (1/1/2021)
5.3.3 Dimensions of key (1/1/2021) The effective surface area, in cm2, of the key (without
2
The shear area of the key, in cm , is not to be less than: rounded edges) between key and rudder stock or cone
coupling is not to be less than:
17 55Q
a S = -----------------------F 5Q F
d k R eH1 a k = ---------------
-
d k R eH2
where: where:
QF : design yield moment of rudder stock, from the ReH2 : specified minimum yield stress of the key, stock
following formula: or coupling material, in N/m2, whichever is the
less.
3
dT 5.3.4 Slugging nut (1/7/2016)
Q F = 0 02664 ------
-
k1 The cone coupling is to be secured by a slugging nut, whose
Where the actual diameter dTa is greater than the calculated dimensions are to be in accordance with the following
formulae:
dT, the diameter dTa is to be used. However dTa applied to
the above formula need not be taken greater than 1.145dT: dG 0,65 du
dT : rudder stock diameter, in mm, defined in [4.2.1] tN 0,60 dG
dk : mean diameter of the conical part of the rudder dN 1,2 d0 and, in any case, dN 1,5 dG
stock, in mm, at the key where:
ReH1 : specified minimum yield stress of the key dG, tN, dN, d1, d0:geometrical parameters of the coupling,
material, in N/mm2 defined in Fig 67.
RINA Rules 2024 113

Pt B, Ch 10, Sec 1
The above minimum dimensions of the locking nut are only Figure 8 : Geometry of cone coupling without key
given for guidance, the determination of adequate (1/1/2021)
scantlings being left to the Designer.
The nut is to be secured, e.g. by a securing plate as shown

in Fig 67.
5.3.5 Push-up (1/7/2016)
It is to be proved that 50% of the design yield moment is

solely transmitted by friction in the cone couplings. This
can be done by calculating the required push-up pressure
and push-up length according to [5.4.3] and [5.4.4] for a
torsional moment Q'F = 0,5QF.
5.3.6 Rudder torque transmitted entirely by the

key (1/7/2016)
Notwithstanding the requirements in [5.3.3] and [5.3.5],

where a key is fitted to the coupling between stock and
rudder and it is considered that the entire rudder torque is
transmitted by the key at the couplings, the scantlings of the
5.4.2 Tapering and washer (1/7/2018)
key as well as the push-up force and push-up length are to
Cone couplings with hydraulic arrangements for mounting
be evaluated on a case by case basis. The general criteria
and dismounting the coupling should have a taper on
for the scantlings of the key are given by the following
diameter in compliance with the following formula:
formulae.
d – d0 1
1- -----------------
-----  U  ------
The shear area of the key, in cm2, is not to be less than: 20 tS 12
where:
dU, tS, d0,: geometrical parameters of the coupling, defined
35 1Q
a S = --------------------F in [5.3.2]
d k R eH1
A washer is to be fitted between the nut and the rudder
gudgeon, having a thickness not less than 0,09 dG and an
The effective surface area, in cm2, of the key (without
outer diameter not less than 0,13 d0 or 1,6 dG, whichever is
rounded edges) between key and rudder stock or cone
coupling is not to be less than: the greater.
5.4.3 Push-up pressure (1/7/2024)

10Q The push-up pressure in N/mm2, is not to be less than the
a k = ---------------F- greater of the two following values:
d k R eH2
2Q F
p req1 = ---------------------
3
5.4 Cone couplings between rudder stocks d m t i  0
2
10
and rudder blades with special
arrangements for mounting and
dismounting the couplings 6M B 3
p req2 = ----------
- 10
2
ti dm
5.4.1 General (1/7/2016)
For cone couplings with hydraulic arrangements for 6M C 3

p req2 = ----------
2
- 10
assembling and disassembling the coupling, the key may be ti dm
omitted.
where:
Where the stock diameter exceeds 200 mm, the press fit is QF : design yield moment of rudder stock, as defined
recommended to be effected by a hydraulic pressure in [5.3.3]
connection. In such cases the nut is to be effectively dm : mean cone diameter, in mm (see Fig 67)
secured against the rudder stock or the pintle (see Fig 78).
ti : coupling length, in mm, defined in [5.3.2]
For the safe transmission of the torsional moment by the 0 : frictional coefficient, equal to 0,15
coupling between rudder stock and rudder body the push- MBc : bending moment, in N m, in rudder stock at the
up pressure and the push-up length are to be determined top of the cone coupling (e.g. in case of spade
according to [5.4.3] and [5.4.4] respectively. rudders)
114 RINA Rules 2024

Pt B, Ch 10, Sec 1
For spade rudder with trunk extending inside the rudder, the procedure a partial push-up effect caused by the rudder weight is
coupling shall be checked against the two cases defined in given, this may be taken into account when fixing the required
App 1. push-up length, subjected to approval by the Society.
It has to be provided by the designer that the push-up 5.4.5 Instructions (1/7/2016)
pressure does not exceed the permissible surface pressure All necessary instructions for hydraulic assembly and
in the cone. The permissible surface pressure, in N/mm2, is disassembly of the nut, including indication of the values of
to be determined by the following formula: all relevant parameters, are to be available on board.
0 95R eH  1 –  
2
p perm = ------------------------------------------ – pb N  mm
2 5.5 Vertical flange couplings
3+
4
5.5.1 Vertical flange couplings are to be connected by

where: fitted bolts having a diameter not less than the value
obtained, in mm, from the following formula:
3 5M b 0 ,81d k 1B
p b = ----------------
- 10 3 d B = -----------------1 ------
-
d m t i2 k 1S
nB
where:
3 5M C
p b = -----------------
- 10 3 d1 : rudder stock diameter, in mm, defined in
d m t i2
[5.1.1]
ReH : specified minimum yield stress of the gudgeon, k1S, k1B : material factors, defined in [5.1.2]
in N/mm2 nB : total number of bolts, which is to be not less
 : coefficient equal to: than 8.
5.5.2 (1/7/2016)
 = dm  da The first moment of area of the sectional area of bolts about
da : outer diameter of the gudgeon, in mm, see the vertical axis through the centre of the coupling is to be
Fig 67 (The least diameter is to be considered). not less than the value obtained, in cm3, from the following
formula:
The outer diameter of the gudgeon in mm shall not be less
than 1.25 d0, with d0 defined in Fig 67. M S = 0 ,43d 13 10 –3
where:
5.4.4 Push-up length (1/1/2021)
d1 : rudder stock diameter, in mm, defined in
The push-up length , in mm, is to comply with the
following formula: [5.1.1].
1  2 5.5.3 The thickness of the coupling flange, in mm, is to be
where: not less than dB , defined in [5.5.1].
5.5.4 The distance, in mm, from the bolt axes to the

p req d m 0 8R tm
 1 = ------------------------------------------
- + -----------------
- external edge of the coupling flange is to be not less than
 1 – 
2
 d – d dU – d0 1,2 dB , where dB is defined in [5.5.1].
E --------------- -----------------
U 0 -----------------
 2  tS tS
5.5.5 A suitable locking device is to be provided to
prevent the accidental loosening of nuts.
p perm d m 0 8R tm
 2 = ------------------------------------------
- + -----------------
-
d U – d 0  1 –  2 d U – d0
E ----------------- --------------- ----------------- 5.6 Couplings by continuous rudder stock
tS  2  tS
welded to the rudder blade
Rtm : mean roughness, in mm, to be taken equal to
0,01 5.6.1 When the rudder stock extends through the upper
dU, d0, tS : geometrical parameters defined in [5.3.2] plate of the rudder blade and is welded to it, the thickness
pperm : The permissible surface pressure defined in of this plate in the vicinity of the rudder stock is to be not
[5.4.3], in N/mm2 less than 0,20 d1, where d1 is defined in [5.1.1].
Note 1: in case of hydraulic pressure connections the required 5.6.2 The welding of the upper plate of the rudder blade
push-up force Pe for the cone, in N, may be determined by the
with the rudder stock is to be made with a full penetration
following formula:
weld and is to be subjected to non-destructive inspection
through dye penetrant or magnetic particle test and
dU – d0
p e = p req d m t i  ----------------- + 0 02 ultrasonic testing.
 2t S 
The throat weld at the top of the rudder upper plate is to be
The value of 0,02 is a reference for the friction coefficient using oil concave shaped to give a fillet shoulder radius as large as
pressure. It varies and depends on the mechanical treatment and practicable. This radius is to be not less than 0,20 d1, where
roughness of the details to be fixed. Where due to the fitting d1 is defined in [5.1.1].
RINA Rules 2024 115

Pt B, Ch 10, Sec 1
5.7 Skeg connected with rudder trunk 6.2 Rudder stock bearing
5.7.1 In case of a rudder trunk connected with the bottom 6.2.1 (1/7/2016)
of a skeg, the throat weld is to be concave shaped to give a The mean bearing pressure acting on the rudder stock
fillet shoulder radius as large as practicable. This radius is bearing is to be in compliance with the following formula:
considered by the Society on a case by case basis.
pF  pF,ALL
6 Rudder stock and pintle bearings where:
pF : mean bearing pressure acting on the rudder
6.1 Forces on rudder stock and pintle stock bearings, in N/mm2, equal to:
bearings
F A1
p F = ------------
-
6.1.1 Where a direct calculation according to the static dm hm
schemes and the load conditions specified in App 1 is
FA1 : force acting on the rudder stock bearing, in N,
carried out, the support forces are to be obtained as
calculated as specified in [6.1.1]
specified in App 1.
Where such a direct calculation is not carried out, the dm : actual inner diameter, in mm, of the rudder
support forces FA1 and FA2 acting on the rudder stock stock bearings
bearing and on the pintle bearing, respectively, are to be hm : bearing length, in mm. For the purpose of this
obtained, in N, from the following formulae: calculation it is to be taken not greater than:
A G1 h
F A1 =  --------
- + 0 ,87 ------0  C R • 1,2dm, for spade rudders
 A H 0
• dm, for rudder of other types
A G2
F A2 = --------
-C
A R where dm is defined in [6.2.1]
where: pF,ALL : allowable bearing pressure, in N/mm2, defined
AG1 ,AG2 : portions of the rudder blade area A, in m2, in Tab 6.
supported by the rudder stock bearing and by Values greater than those given in Tab 6 may be
the pintle bearing respectively, to be not less accepted by the Society in accordance with the
than the value obtained from Tab 5 Manufacturer's specifications if they are verified
h0 : coefficient defined in Tab 5 by tests, but in no case more than 10 N/mm2.
H0 : distance, in m, between the points at mid-
height of the upper and lower rudder stock 6.2.2 An adequate lubrication of the bearing surface is to
bearings. be ensured.
116 RINA Rules 2024

...OMISSIS...
Pt B, Ch 10, Sec 1
Rudder type AG1, in m2 AG2, in m2 h0 , in m
3 bearing semi-spade rudders

• lower pintle:
with rudder horn
A1 q1 + A2 q2
-----------------------------
-
p
• upper pintle, the greater

0 0
q1
of:
A1 q 1 + A2 q2
G1 A 1 + A 2 – -----------------------------
-
p
p
q2
A1
A1 q1 + A2 q2
G2
0 ,5 -----------------------------
-
A2 p
Hinged rudders and

Simplex type rudders
A
0 ---- 0
n
A A A
  2 + h 2 + h 1 A 2 +  1  A
(1)  = ---------------------------------------------------------------1
A
Note 1:
G, G1, G2 : centres of gravity of area A, A1 and A2 respectively,
n : number of pintles.
6.2.3 (1/7/2016) pF  pF,ALL

The manufacturing tolerance t0 on the diameter of metallic
where:
supports is to be not less than the value obtained, in mm,
from the following formula: pF : mean bearing pressure acting on the gudgeons,
in N/mm2, equal to:
dm
t 0 = ------------
-+1
1000 F A2
p F = ----------
-
dA hL
In the case of non-metallic supports, the tolerances are to
be carefully evaluated on the basis of the thermal and FA2 : force acting on the pintle, in N, calculated as
distortion properties of the materials employed. specified in [6.1.1]
The tolerance on support diameter is to be not less than 1,5
dA : actual diameter, in mm, of the rudder pintles
mm, unless a smaller tolerance is supported by the
manufacturer's recommendation and there is documented hL : bearing length, in mm (see [6.3.3])
evidence of satisfactory service history with a reduced
pF,ALL : allowable bearing pressure, in N/mm2, defined
clearance.
in Tab 6. Values greater than those given in
6.2.4 (1/7/2024) Tab 6 may be accepted by the Society in
Liners and bushes are to be fitted in way of bearings. For accordance with the Manufacturer's
rudder stocks and pintles having diameter less than 200 specifications if they are verified by tests, but in
mm, liners in way of bushes may be provided optionally. no case more than 10 N/mm2.
The minimum thickness of liners and bushes is to be equal
to: 6.3.2 An adequate lubrication of the bearing surface is to
• tmin = 8 mm for metallic materials and synthetic material be ensured.
• tmin = 22 mm for lignum material.
6.3.3 The bearing length, in mm, is to be not less than dA,
6.3 Pintle bearings where dA is defined in [6.4.1]. For the purpose of the
calculation in [6.3.1], the bearing length is to be taken not
6.3.1 (1/7/2016)
greater than 1,2 dA.
The mean bearing pressure acting on the gudgeons is to be
in compliance with the following formula:
118 RINA Rules 2024

Pt B, Ch 10, Sec 1
Table 6 : Allowable bearing pressure (1/1/2021) where:

FA2 : force, in N, acting on the pintle, calculated as
Bearing material pF,ALL , in N/mm2 specified in [6.1.1].
Lignum vitae 2,5 6.4.2 Provision is to be made for a suitable locking device
White metal, oil lubricated 4,5 to prevent the accidental loosening of pintles.
Synthetic material with hardness 5,5 6.4.3 (1/7/2016)

greater than 60 Shore D (1) The pintles are to have a conical coupling with a taper on
diameter in accordance with [5.3.2] for keyed and other
Steel, bronze and hot-pressed bronze- 7,0
graphite materials (2)
manually assembled pintles locking by slugging nut and in
accordance with [5.4.2] for pintles mounted with oil
(1) Indentation hardness test at 23°C and with 50% mois- injection and hydraulic nut.
ture to be performed according to a recognised stand-
ard. Type of synthetic bearing materials is to be The conical coupling is to be secured by a nut, whose
approved by the Society. dimension are to be in accordance with [5.3.4].
(2) Stainless and wear-resistant steel in combination with 6.4.4 (1/7/2016)
stock liner approved by the Society.
The length of the pintle housing in the gudgeon is to be not
less than the pintle diameter dA, where dA is defined in
6.3.4 (1/1/2013) [6.4.1]. dA is to be measured on the outside of liners.
The manufacturing tolerance t0 on the diameter of metallic
The thickness of pintle housing in the gudgeon, in mm, is to
supports is to be not less than the value obtained, in mm,
be not less than 0,25 dA.
6.4.5 (1/7/2024)
dA
t 0 = ------------
-+1 The required push-up pressure for pintle in case of dry
1000
fitting, in N/mm², is to be determined by preq1 as given
In the case of non-metallic supports, the tolerances are to below.
be carefully evaluated on the basis of the thermal and
distortion properties of the materials employed. The required push-up pressure for pintle in case of oil
injection fitting, in N/mm², is to be determined by the
The tolerance on support diameter is to be not less than 1,5 maximum pressure of preq1 and preq2 as given
mm, unless a smaller tolerance is supported by the
belowfollowing formula:
manufacturer's recommendation and there is documented
evidence of satisfactory service history with a reduced F A2 d A
clearance. p req = 0 4 ----------------
-
d 2 Am h L
6.3.5 (1/7/2016)
FA dA
The thickness of any liner or bush, in mm, is to be taken p req1 = 0 4 ----------------
-
d 2 Am h L
equal to the lesser of the following values:
Metallic materials and synthetic material: 6  M bp
p req2 = ----------------
2
-
d Am h L
• t = 0 01 F A2
where:
• t = 8mm FA2 : force, in N, acting on the pintle (e.g FA2 as
defined in Fig 4 for semi-spade rudder),
Lignum material:
calculated as specified in [6.1.1]
• t = 0 01 F A2 dA : actual diameter, in mm, of the rudder pintles,
see Fig 9
• t = 22mm
dAm : mean cone diameter, in mm
where: hL : bearing length, in mm, as defined in [6.3.3].
FA2 : force, in N, acting on the pintle, calculated as Mbp : bending moment in the pintle cone coupling to
specified in [6.1.1]. be determined by:
Mbp = FA. ta
6.4 Pintles
ta : length between middle of pintle-bearing and
6.4.1 (1/7/2016)
top of contact surface between cone coupling
Rudder pintles are to have a diameter not less than the and pintle in m, see Fig 9.
value obtained, in mm, from the following formula:
The required push up length 1 is to be calculated similarly
d A = 0 35 F A2 k 1 as in [5.4.4], using the required push-up pressure as defined
above, and properties for the pintle.
RINA Rules 2024 119

Pt B, Ch 10, Sec 1
Figure 9 : pintle cone coupling indicating ta 7.2 Strength checks

(1/7/2024)
7.2.1 Bending stresses
For the generic horizontal section of the rudder blade it is to
be checked that the bending stress , in N/mm2, induced by
the loads defined in [3.1], is in compliance with the
following formula:
  ALL
where:
ALL : allowable bending stress, in N/mm2, specified
in Tab 7.
Table 7 : Allowable stresses for rudder blade

scantlings (1/7/2019)
Allowable Allowable Allowable

Type of rudder bending shear stress equivalent
blade stress ALL ALL stressE,ALL
in N/mm2 in N/mm2 in N/mm2
In general except
in way of rudder 110/k 50/k 120/k
7 Rudder blade scantlings recess sections
In way of the
7.1 General recess for the rud-
der horn pintle on 75 50 100
7.1.1 Application semi-spade rud-
ders
The requirements in [7.1] to [7.6] apply to streamlined
rudders and, when applicable, to rudder blades of single Note 1:The stresses in way of the recess for the rudder horn
plate rudders. pintle on semi-spade rudders apply equally to high tensile
and ordinary steel
7.1.2 Rudder blade structure
7.2.2 Shear stresses
The structure of the rudder blade is to be such that stresses
For the generic horizontal section of the rudder blade it is to
are correctly transmitted to the rudder stock and pintles. To
this end, horizontal and vertical web plates are to be be checked that the shear stress , in N/mm2, induced by
provided. the loads defined in [3.1], is in compliance with the
following formula:
Horizontal and vertical webs acting as main bending
  ALL
girders of the rudder blade are to be suitably reinforced.
where:
7.1.3 Access openings ALL : allowable shear stress, in N/mm2, specified in
Streamlined rudders, including those filled with pitch, cork Tab 7.
or foam, are to be fitted with plug-holes and the necessary
7.2.3 Combined bending and shear
devices to allow their mounting and dismounting. stresses (1/1/2001)
Access openings to the pintles are to be provided. If For the generic horizontal section of the rudder blade it is to
necessary, the rudder blade plating is to be strengthened in be checked that the equivalent stress E is in compliance
way of these openings. with the following formula:
The corners of openings intended for the passage of the E  E,ALL
rudder horn heel and for the dismantling of pintle or stock where:
nuts are to be rounded off with a radius as large as
E : equivalent stress induced by the loads defined
practicable.
in [3.1], to be obtained, in N/mm2, from the
Where the access to the rudder stock nut is closed with a following formula:
welded plate, a full penetration weld is to be provided.
E =  2 + 3 2
7.1.4 Connection of the rudder blade to the trailing Where unusual rudder blade geometries make it
edge for rudder blade area greater than 6 m2 practically impossible to adopt ample corner
Where the rudder blade area is greater than 6 m2, the radiuses or generous tapering between the
connection of the rudder blade plating to the trailing edge is various structural elements, the equivalent stress
to be made by means of a forged or cast steel fashion piece, E is to be obtained by means of direct
a flat or a round bar. calculations aiming at assessing the rudder
120 RINA Rules 2024

Pt B, Ch 10, Sec 1
blade areas where the maximum stresses, 7.3.2 Thickness of the top and bottom plates of the
induced by the loads defined in [3.1], occur rudder blade
 : bending stress, in N/mm2 The thickness of the top and bottom plates of the rudder
 : shear stress, in N/mm2 blade is to be not less than the thickness tF defined in
[7.3.1], without being less than 1,2 times the thickness
E,ALL : allowable equivalent stress, in N/mm2, specified
obtained from [7.3.1] for the attached side plating.
in Tab 7.
Where the rudder is connected to the rudder stock with a
7.3 Rudder blade plating coupling flange, the thickness of the top plate which is
welded in extension of the rudder flange is to be not less
7.3.1 Plate thickness (1/7/2024) than 1,1 times the thickness calculated above.
The thickness of each rudder blade plate panel is to be not
7.3.3 Web spacing
less than the value obtained, in mm, from the following
formula: The spacing between horizontal web plates is to be not
greater than 1,20 m.
C R 10 –4
t f =  5 ,5s T + ----------------
- k + 2 5 Vertical webs are to have spacing not greater than twice
 A  that of horizontal webs.
where: 7.3.4 Web thickness
 : coefficient equal to: Web thickness is to be at least 70% of that required for
s 2 rudder plating and in no case is it to be less than 8 mm,
 = 1 ,1 – 0 ,5  -----
 b L except for the upper and lower horizontal webs, for which
the requirements in [7.3.2] apply.
to be taken not greater than 1,0 if bL/s > 2,5
When the design of the rudder does not incorporate a
s : length, in m, of the shorter side of the plate mainpiece, this is to be replaced by two vertical webs
panel. closely spaced, having thickness not less than that obtained
bL : length, in m, of the longer side of the plate from Tab 8. In rudders having area less than 6 m2, one
panel vertical web only may be accepted provided its thickness is
T : summerscantling load line draught, in m. at least twice that of normal webs.
RINA Rules 2024

...OMISSIS... 121
Pt B, Ch 10, Sec 1
equivalent strength) and are to be 100% inspected by Figure 12 : Single plate rudder
means of non-destructive tests.
Where the full penetration welds of the rudder blade are

accessible only from outside of the rudder, a backing flat
bar is to be provided to support the weld root.
The external fillet welds between the rudder blade plating

and the rudder flange are to be of concave shape and their
throat thickness is to be at least equal to 0,5 times the S
rudder blade thickness.
Moreover, the rudder flange is to be checked before

welding by non-destructive inspection for lamination and CH
inclusion detection in order to reduce the risk of lamellar
tearing.
7.5.4 Thickness of side plating and vertical web

plates welded to the rudder flange
The thickness of the vertical web plates directly welded to
the rudder flange as well as the plating thickness of the
rudder blade upper strake in the area of the connection with
the rudder flange is to be not less than the values obtained,
in mm, from Tab 8.
8 Rudder horn and solepiece scantlings
7.6 Single plate rudders 8.1 General
7.6.1 Mainpiece diameter 8.1.1 The weight of the rudder is normally supported by a
The mainpiece diameter is to be obtained from the formulae carrier bearing inside the rudder trunk.
in [4.2]. In the case of unbalanced rudders having more than one
pintle, the weight of the rudder may be supported by a
In any case, the mainpiece diameter is to be not less than suitable disc fitted in the solepiece gudgeon.
the stock diameter.
Robust and effective structural rudder stops are to be fitted,
For spade rudders the lower third may taper down to 0,75 except where adequate positive stopping arrangements are
times the stock diameter. provided in the steering gear, in compliance with the
applicable requirements of Pt C, Ch 1, Sec 11.
7.6.2 Blade thickness (1/7/2016)
The blade thickness is to be not less than the value 8.2 Rudder horn
obtained, in mm, from the following formula:
8.2.1 General
t B = 1 ,5sV AV k + 2 5 When the connection between the rudder horn and the hull
structure is designed as a curved transition into the hull
where: plating, special consideration is to be paid to the
s : spacing of stiffening arms, in m, to be taken not effectiveness of the rudder horn plate in bending and to the
greater than 1 m (see Fig 102). stresses in the transverse web plates.
8.2.2 Loads (1/7/2016)

7.6.3 Arms
The following loads acting on the generic section of the
The thickness of the arms is to be not less than the blade rudder horn are to be considered:
thickness.
• bending moment
The section modulus of the generic section is to be not less • shear force
than the value obtained, in cm3, from the following formula:
• torque
Z A = 0 ,5sC V
2
H
2
AV k
The requirements in App 1, [1.6] ore App 1, [1.8] apply for
where: calculating the above loads in the case of 2 bearing semi-
spade rudders and semi-spade rudders with 2-conjugate
CH : horizontal distance, in m, from the aft edge of elastic support respectively.
the rudder to the centreline of the rudder stock
In the case of 3 bearing semi-spade rudders, these loads are
(see Fig 102)
to be calculated on the basis of the support forces at the
s : defined in [7.6.2]. lower and upper pintles, obtained according to [6.1].
RINA Rules 2024 125

Pt B, Ch 10, Sec 1
Figure 14 : Solepiece geometry WY = 0,5 WZ

where:
WZ : section modulus, in cm3, around the vertical
a axis Z (see Fig 124).
8.4 Rudder trunk

b
8.4.1 General (1/1/2021)
The requirements of this Article apply to trunk
configurations which are extended below stern frame and
arranged in such a way that the trunk is stressed by forces
due to rudder action.
x 8.4.2 Materials, welding and connection to the hull
(1/7/2024)
The steel grade used for the rudder trunk is to be of
x : distance, in m, defined in Fig 124. weldable quality, with a carbon content not exceeding
0,23% on ladle analysis and a carbon equivalent CER not
8.3.2 Strength checks exceeding 0,41.
For the generic section of the solepiece within the length Plating materials for rudder trunks are in general not to be
50, defined in Fig 124, it is to be checked that of lower grade than corresponding to class II as defined in
E  E,ALL Ch 4, Sec 1.
B  B,ALL For rudder trunks extending below shell or skeg, Tthe fillet
shoulder radius r, in mm, is to be as large as practicable (see
  ALL Fig 135) and to comply with the following formulae:
where: r = 0,1 d1 /k
E : equivalent stress to be obtained, in N/mm2, without being less than:
r = 60 mm when B > 40 /k N/mm2
E =  B2 + 3 2
r = 30 mm when B < 40 /k N/mm2
B : bending stress to be obtained, in N/mm2, from
where:
d1 : rudder stock diameter, in mm, as defined in
M
 B = -------S- [5.1.1]
WZ
B : bending stress in the rudder trunk, in N/mm2.
 : shear stress to be obtained, in N/mm2, from the
The radius may be obtained by grinding. If disk grinding is
following formula:
carried out, score marks are to be avoided in the direction
F A2 of the weld.
 = -------
AS
The radius is to be checked with a template for accuracy.
MS : bending moment at the section considered, in Four profiles at least are to be checked. A report is to be
N.m, defined in [8.3.1] submitted to the Surveyor.
FA2 : force, in N, defined in [8.3.1] Rudder trunks comprising of materials other than steel are
WZ : section modulus, in cm3, around the vertical to be specially considered by the Society.
axis Z (see Fig 124)
AS : shear sectional area in Y direction, in mm2 Figure 15 : Fillet shoulder radius (1/7/2016)
E,ALL : allowable equivalent stress, in N/mm2, equal to:

E,ALL = 115/k1 N/mm2
B,ALL : allowable bending stress, in N/mm2, equal to:
B,ALL = 80/k1 N/mm2
ALL : allowable shear stress, in N/mm2, equal to:
ALL = 48/k1 N/mm2.
8.3.3 Minimum section modulus around the

horizontal axis
The section modulus around the horizontal axis Y (see
Fig 124) is to be not less than the value obtained, in cm3,

Pt B, Ch 10, Sec 4
SECTION 4 EQUIPMENT
Symbols
EN : Equipment Number defined in [2.1], a) inland navigation vessels
ALL : allowable stress, in N/mm2, used for the b) military vessels
yielding check in [4.9.7], [4.10.7], [4.11.2] and
c) government ships operated for non-commercial
[4.11.3], to be taken as the lesser of:
purposes
• ALL = 0,67 ReH
d) high speed and light crafts
• ALL = 0,40 Rm
e) yachts.
ReH : minimum yield stress, in N/mm2, of the
material, defined in Ch 4, Sec 1, [2] 1.1.7 (1/7/2024)
Rm : tensile strength, in N/mm2, of the material, The anchoring equipment required in this Section applies to
vessels with unrestricted service. The requirements given in
defined in Ch 4, Sec 1, [2].
[3.2.4], Pt D, Ch 4, Sec 1, [1], [3.3.1], Pt A, Ch 3, Sez 5,
[2.2.6], and [3.9] apply to vessels with restricted service
1 General area.
1.1.8 (1/7/2024)
1.1 General
Unrestricted service means a vessel engaged on
1.1.1 The requirements in [2] to [4] apply to temporary international voyages, and not bounded by any limitations
mooring of a ship within or near harbour, or in a sheltered on operating environment reflected in vessel class notation.
area, when the ship is awaiting a berth, the tide, etc.
Therefore, the equipment complying with the requirements 1.2 Definitions
in [2] to [4] is not intended for holding a ship off fully
exposed coasts in rough weather or for stopping a ship 1.2.1 Nominal capacity condition (1/1/2022)
which is moving or drifting. Nominal capacity condition is the theoretical condition
where the maximum possible deck cargoes are included in
1.1.2 The equipment complying with the requirements in the ship arrangement in their respective positions. For
[2] to [4] is intended for holding a ship in good holding container ships the nominal capacity condition represents
ground, where the conditions are such as to avoid dragging the theoretical condition where the maximum possible
of the anchor. In poor holding ground the holding power of number of containers is included in the ship arrangement in
the anchors is to be significantly reduced. their respective positions.
1.1.3 It is assumed that under normal circumstances a ship 1.2.2 Ship Design Minimum Breaking Load
will use one anchor only. (MBLSD) (1/1/2022)
1.1.4 (1/7/2024) Ship Design Minimum Breaking Load is the minimum
The Equipment Number (EN) formulae for anchoring breaking load of new, dry mooring lines or tow line for
equipment as given in [2.1.2] and Pt E, Ch 14, Sec 2, [2.7.1] which shipboard fittings and supporting hull structures are
are based on an assumed maximum current speed of 2,5 designed in order to meet mooring restraint requirements or
m/s, maximum wind speed of 25 m/s and a minimum scope the towing requirements of other towing service.
of chain cable of 6, the scope being the ratio between
length of chain paid out and water depth. For ships with an 1.2.3 Line Design Break Force (LDBF) (1/7/2024)
equipment length, as defined in [2.1.2], greater than 135 m, Line Design Break Force is the minimum force that at which
alternatively the required anchoring equipment can be a new, dry, spliced, mooring line will break at. This is for all
considered applicable to a maximum current speed of 1,54 synthetic cordage materials.
m/s, a maximum wind speed of 11 m/s and waves with This value is declared by the manufacturer on each line's
maximum significant height of 2 m. mooring line certificate and is stated on a manufacturer's
1.1.5 (1/7/2024) line data sheet. LDBF of a line is to be 100% - 105% of the
In addition to planned anchoring for normal operations, ship design minimum breaking load defined in [1.2.2].
anchoring equipment is also important for ship safety in The LDBF for nylon (polyamide) mooring lines is to be spec-
emergency situations such as loss of manoeuvrability, ified as break tested wet, because nylon lines change
unscheduled repairs and other unexpected situations. strength characteristics once exposed to water and gener-
1.1.6 (1/7/2024) ally do not fully dry to their original construction state.
The anchoring equipment required in this Section applies to
self-propelled vessels over 100GT, except for:
RINA Rules 2024 137

Pt B, Ch 10, Sec 4
local discontinuity in the upper deck, and the

2 Equipment number effective height hF.
2.1 Equipment number AFS is taken equal to zero if the funnel breadth
2.1.1 General (1/7/2014) is less than or equal to B/4 at all elevations
along the funnel height.
All ships are to be provided with equipment in anchors and
chain cables (or ropes according to [3.3.5]), to be obtained hF : effective height of the funnel, in m, measured
from Tab 1, based on their Equipment Number EN. from the upper deck at centreline, or notional
deck line where there is local discontinuity in
In general, stockless anchors are to be adopted.
the upper deck, and the top of the funnel.
For ships with EN greater than 16000, the determination of
The top of the funnel may be taken at the level
the equipment will be considered by the Society on a case
where the funnel breadth reaches B/4.
by case basis.
Sshield : is the section of front projected area AFS, in m²,
For ships having the navigation notation coastal area or
sheltered area, the equipment in anchors and chain cables which is shielded by all deck houses having
may be reduced. The reduction consists of entering Tab 1 breadth greater than B/4. If there are more than
one line higher for ships having the navigation notation one shielded section, the individual shielded
coastal area and two lines higher for ships having the sections i.e Sshield1, Sshield 2 etc as shown in Fig 2
navigation notation sheltered area, based on their to be added together. To determine Sshield, the
Equipment Number EN. deckhouse breadth is assumed B for all deck
houses having breadth greater than B/4 as
For ships of special design or ships engaged in special
shown for Sshield1, Sshield 2 in.
services or on special voyages, the Society may consider
equipment other than that in Tab 1. A : side projected area, in m2, of the hull,
superstructures, houses and funnels above the
2.1.2 Equipment Number for ships with summer load waterline which are within the
perpendicular superstructure front bulkhead length LE and also have a breadth greater than
(1/1/2022) B/4 (see Note 1).
The Equipment Number EN is to be obtained from the
following formula: The side projected area of the funnel is
considered in A when AFS is greater than zero.
EN = ∆2/3 + 2(h B + Sfun) + 0,1 A
In this case, the side projected area of the
where: funnel should be calculated between the upper
 : moulded displacement of the ship, in t, to the deck, or notional deck line where there is local
summer load waterline, discontinuity in the upper deck, and the
h : effective height, in m, from the summer load effective height hF,
waterline to the top of the uppermost house, to
be obtained in accordance with the following LE : equipment length, in m, equal to L without
formula: being taken neither less than 96% nor greater
than 97% of the extreme length on the summer
h = a + hn
load waterline (measured from the forward end
When calculating h, sheer and trim are to be of the waterline).
ignored (i.e. h is the sum of freeboard amidships
Fixed screens or bulwarks 1,5 m or more in height are to be
plus the height (at centreline) of each tier of
regarded as parts of houses when determining h and A. In
houses having a breadth greater than B/4),
particular, the hatched area shown in Fig 7 is to be
a : vertical distance at side hull, in m, from the included.
summer load waterline amidships to the upper
deck, The height of hatch coamings and that of any deck cargo,
hn : height, in m, at the centreline of tier “n” of such as containers, may be disregarded when determining h
superstructures or deckhouses having a breadth and A.
greater than B/4. Where a house having a When several funnels are fitted on the ship, the above
breadth greater than B/4 is above a house with a parameters are taken as follows:
breadth of B/4 or less, the upper house is to be
hF : effective height of the funnel, in m, measured
included and the lower ignored.
from the upper deck, or notional deck line
For the lowest tier h1 is to be measured at where there is local discontinuity in the upper
centreline from the upper deck or from a deck, and the top of the highest funnel. The top
notional deck line where there is local of the highest funnel may be taken at the level
discontinuity in the upper deck, (see Fig 1 for an where the sum of each funnel breadth reaches
example), B/4.
Sfun : effective front projected area of the funnel, in AFS : sum of the front projected area of each funnel,
m², defined as: in m², calculated between the upper deck, or
Sfun = AFS - Sshield notional deck line where there is local
discontinuity in the upper deck, and the
AFS : front projected area of the funnel, in m², effective height hF.
calculated between the upper deck at
centreline, or notional deck line where there is

Pt B, Ch 10, Sec 4
Equipment number EN Stockless anchors Stud link chain cables for anchors
A < EN  B Mass per anchor, Diameter, in mm
N Total length, in m
A B in kg Q1 Q2 Q3
5800 6100 2 17800 742,5 132,0 117,0 102,0
6100 6500 2 18800 742,5 120,0 107,0
6500 6900 2 20000 770,0 124,0 111,0
6900 7400 2 21500 770,0 127,0 114,0
7400 7900 2 23000 770,0 132,0 117,0
7900 8400 2 24500 770,0 137,0 122,0
8400 8900 2 26000 770,0 142,0 127,0
8900 9400 2 27500 770,0 147,0 132,0
9400 10000 2 29000 770,0 152,0 132,0
10000 10700 2 31000 770,0 137,0
10700 11500 2 33000 770,0 142,0
11500 12400 2 35500 770,0 147,0
12400 13400 2 38500 770,0 152,0
13400 14600 2 42000 770,0 157,0
14600 16000 2 46000 770,0 162,0
2.1.3 Equipment Number for ships with inclined normal towing of the ship. For emergency towing
superstructure front bulkhead (1/1/2022) arrangements, the requirements in [4] are to be applied.
For ships with navigation notation other than unrestricted Normal towing means towing operations necessary for
navigation and having superstructures with the front manoeuvring in ports and sheltered waters associated with
bulkhead with an angle of inclination aft, the Equipment the normal operations of the ship.
Number EN is to be obtained from the following formula:
For ships, not subject to Regulation 3-4 of Chapter II-1 of
EN = 2/3 + 2 (a B + bN hN sin N+Sfun) + 0,1 A SOLAS Convention, but intended to be fitted with
where: equipment for towing by another ship or a tug, the
requirements designated as 'other towing' are to be applied
a, hN, A and Sfun:as defined in [2.1.2],
to design and construction of those shipboard fittings and
N : angle of inclination aft of each front bulkhead, supporting hull structures.
shown in Fig 8,
Requirements of [3.1] is not applicable to design and
bN : greatest breadth, in m, of each tier n of
construction of shipboard fittings and supporting hull
superstructures or deckhouses having a breadth
structures used for special towing services defined as:
greater than B/4.
Fixed screens or bulwarks 1,5 m or more in height are to be • Escort towing: Towing service, in particular for laden oil
regarded as parts of houses when determining h and A. In tankers or LNG carriers, required in specific estuaries.
particular, the hatched area shown in Fig 8 is to be Its main purpose is to control the ship in case of failures
included. of the propulsion or steering system. It should be
referred to local escort requirements and guidance
2.1.4 (1/7/2024)
given by, e.g., the Oil Companies International Marine
For ships of length less than 90m, alternative methodology Forum (OCIMF); for the requirements of shipboard
using direct force calculation for anchoring equipment fittings and supporting hull structures of ships with
described in App 4 may be used. service notation escort tug , see Pt E, Ch 14, [2] and [4].
• Canal transit towing: Towing service for ships transiting
3 Equipment canals, e.g. the Panama Canal. It should be referred to
local canal transit requirements.
3.1 Shipboard fittings and supporting hull
• Emergency towing for tankers: Towing services to assist
structures tankers in case of emergency. For emergency towing
3.1.1 Application (1/7/2018) arrangements of ships which are to comply with
Regulation 3-4 of Chapter II-1 of SOLAS Convention,
Ships are to be provided with arrangements, equipment and
the requirements in [4] are to be applied.
fittings of sufficient safe working load to enable the safe
conduct of all towing and mooring operations associated The supporting hull structures are constituted by that part of
with the normal operations of the ship. the ship's structure on/in which the shipboard fitting is
The requirements of [3.1] apply to ships of 500 gross placed and which is directly submitted to the forces exerted
tonnage and upwards; in particular they apply to bollards, on the shipboard fitting. The supporting hull structures of
bitts, fairleads, stand rollers, chocks used for normal capstans, winches, etc used for normal or other towing and
mooring of the ship and similar components used for mooring operations are also covered by [3.1].
RINA Rules 2024

...OMISSIS... 141
Pt B, Ch 10, Sec 4
The characteristics of the steel used and the method of b) The anchor weight is to be increased by 25 % compared
manufacture of chain cables are to be approved by the to anchor associated with chain cable according to Tab
Society for each manufacturer. The material from which 1.
chain cables are manufactured and the completed chain c) Unless incompatible with the anchor operation, to be
cables themselves are to be tested in accordance with the evaluated on a case-by-case basis, a short length of
applicable requirements of Pt D, Ch 4, Sec 1. chain cable is to be fitted between the wire rope and the
Chain cables made of grade Q1 may not be used with high anchor, having a length equal to 12,5m or the distance
holding power and super high holding power anchors. from the anchor in the stowed position to the winch,
whichever is the lesser.
3.3.2 Scantlings of stud link chain cables
d) All surfaces being in contact with the wire need to be
The mass and geometry of stud link chain cables, including rounded with a radius of not less than 10 times the wire
the links, are to be in compliance with the requirements in rope diameter (including stem)
Pt D, Ch 4, Sec 1.
e) Steel wire is to be selected to fit for purpose based on
The diameter of stud link chain cables is to be not less than the manufacturer recommendation and is to be
the value in Tab 1. provided with guidance for maintenance and
inspection.
3.3.3 Studless link chain cables
For ships with EN less than 90, studless short link chain 3.4 Attachment pieces
cables may be accepted by the Society as an alternative to
stud link chain cables, provided that the equivalence in 3.4.1 General
strength is based on proof load, defined in Pt D, Ch 4, Where the lengths of chain cable are joined to each other
Sec 1, [3], and that the steel grade of the studless chain is by means of shackles of the ordinary Dee type, the anchor
equivalent to the steel grade of the stud chains it replaces, may be attached directly to the end link of the first length of
as defined in [3.3.1]. chain cable by a Dee type end shackle.
3.3.4 Chain cable arrangement (1/7/2018) A detachable open link in two parts riveted together may be
Chain cables are to be made by lengths of 27,5 m each, used in lieu of the ordinary Dee type end shackle; in such
joined together by Dee or lugless shackles. case the open end link with increased diameter, defined in
[3.4.2], is to be omitted.
The total length of chain cable, required in Tab 1, is to be
Where the various lengths of chain cable are joined by
divided in approximately equal parts between the two
means of lugless shackles and therefore no special end and
anchors ready for use.
increased diameter links are provided, the anchor may be
Where different arrangements are provided, they are attached to the first length of chain cable by a special pear-
considered by the Society on a case-by-case basis. shaped lugless end shackle or by fitting an attachment
piece.
3.3.5 Wire ropes (1/7/2024)
As an alternative to the stud link or short link chain cables 3.4.2 Scantlings
mentioned, wire ropes may be used in the following cases: The diameters of the attachment pieces, in mm, are to be
• wire ropes for both the anchors, for ship length less than not less than the values indicated in Tab 2.
40 m, Attachment pieces may incorporate the following items
• on ships with less than 90 m in length and which will between the increased diameter stud link and the open end
need an anchor for emergency purposes, i.e., not link:
intended to use their anchor in normal temporary • swivel, having diameter = 1,2 d
anchoring operation • increased stud link, having diameter = 1,1 d
• on ships with the anchoring equipment used for
Where different compositions are provided, they will be
positioning with a minimum of 4 points anchoring, e.g.,
considered by the Society on a case-by-case basis.
for cable or pipe laying
• wire ropes for both the anchors, for ships with restricted Table 2 : Diameters of attachment pieces
navigation notations and/or having special anchoring
design and operational characteristics, to be considered
Attachment piece Diameter, in mm
on a case-by-case basis taking into account the
operational and safety aspects; in any case, the weight End shackle 1,4 d
of the anchors is to be 1,25 times the value required
Open end link 1,2 d
according to Tab 1.
Increased stud link 1,1 d
The use of wire rope is subject to the following conditions:
Common stud link d
a) The wire ropes above are to have a total length equal to
1,5 times the corresponding required length of stud link Lugless shackle d
chain cables, obtained from Tab 1, and a minimum
Note 1:
breaking load equal to that given for the corresponding
stud link chain cable (see [3.3.2]). d : diameter, in mm, of the common link.
148 RINA Rules 2024

Pt B, Ch 10, Sec 4
3.4.3 Material 3.5.4 Mooring lines for ships with EN > 2000
Attachment pieces, joining shackles and end shackles are to (1/7/2018)
be of such material and design as to provide strength The minimum strength and number of mooring lines for
equivalent to that of the attached chain cable, and are to be ships with an Equipment Number EN > 2000 are given in
tested in accordance with the applicable requirements of App 2.
Pt D, Ch 4, Sec 1.
3.5.5 Materials (1/7/2024)
3.4.4 Spare attachment pieces Towlines and mooring lines may be of wire, natural or
A spare pear-shaped lugless end shackle or a spare synthetic fibre or a mixture of wire and fibre. For synthetic
attachment piece is to be provided for use when the spare fibre ropes it is recommended to use lines with reduced risk
anchor is fitted in place. of recoil (snap-back) to mitigate the risk of injuries or
fatalities in the case of breaking mooring lines.
3.5 Towlines and mooring lines The breaking loads defined in Tab 3, Tab 4 and App 2 refer
to steel wires or natural fibre ropes.
3.5.1 General (1/1/2022)
Steel wires and fibre ropes are to be tested in accordance
The requirements of [3.5] apply for the determination of the
with the applicable requirements in Pt D, Ch 4, Sec 1.
characteristics of towlines and mooring lines. The
equipment number EN is to be calculated in compliance 3.5.6 Length of mooring lines (1/7/2018)
with [2]. Deck cargoes at the ship nominal capacity The length of mooring lines for ships with EN of less than or
condition is to be included for the determination of side- equal to 2000 may be taken from Tab 4. For ships with EN >
projected area A. 2000 the length of mooring lines may be taken as 200 m.
[3.5.3] and [3.5.4] specify the minimum number and The lengths of individual mooring lines may be reduced by
minimum strength of mooring lines. As an alternative to up to 7% of the above given lengths but the total length of
[3.5.3] and [3.5.4], the direct mooring analysis in line with mooring lines is not to be less than would have resulted had
the procedure given in App 3 may be carried out. all lines been of equal length.
The designer is to consider verifying the adequacy of
mooring lines based on assessments carried out for the 3.5.7 Equivalence between the breaking loads of
individual mooring arrangement, expected shore-side synthetic and natural fibre ropes (1/1/2022)
mooring facilities and design environmental conditions for Generally, fibre ropes are to be made of polyamide or other
the berth. equivalent synthetic fibres (e.g. polyester, polypropylene).
The equivalence between the breaking loads of synthetic
3.5.2 Towlines (1/1/2022) fibre ropes BLS and of natural fibre ropes BLN is to be
The towlines having the characteristics defined in Tab 3 are obtained, in kN, from the following formula:
intended as those belonging to the ship to be towed by a tug
BLS = 7,4  BLN8/9 without being less than 1,2 BLN
or another ship.
where:
The designer should consider verifying the adequacy of
towing lines based on assessment carried out for the  : elongation to breaking of the synthetic fibre
individual towing arrangement. rope.
For other synthetic ropes different from those mentioned
3.5.3 Mooring lines for ships with EN  2000 above (e.g. aramid fiber, Ultra High Molecular Weight Poly-
(1/7/2018) Ethylene) the breaking load is to be taken equal to 1,1 BLN.
Mooring lines for ships having an Equipment Number EN of
less than or equal to 2000 are given in Tab 4. 3.5.8 Length of mooring lines for supply vessels
For ships having the ratio A/EN > 0,9 additional mooring For ships with the service notation supply vessel, the length
lines are required in addition to the number of mooring of mooring lines may be reduced. The reduced length  is to
lines defined in Tab 4. be not less than that obtained, in m, from the following
The number of these additional mooring lines is defined in formula:
Tab 6.  = L + 20
Table 3 : Towlines (1/1/2022)
Equipment number EN
Towline (1)
A< EN  B
Ship Design
A B Minimum length, in m
Minimum Breaking load, in kN
50 70 180 98
70 90 180 98
90 110 180 98
110 130 180 98
(1) The towline is not compulsory. It is recommended for ships having length not greater than 180 m.

Pt B, Ch 10, App 1
APPENDIX 1 C RITERIA FOR D IRECT C ALCULATION OF

R UDDER L OADS
Symbols
10, 20, 30, 40 : lengths, in m, of the individual girders of 1.1.2 Load calculation (1/7/2016)
the rudder system The loads in [1.1.1] are to be calculated through direct
50 : length, in m, of the solepiece (see Fig 34) calculations depending on the type of rudder.
J10, J20, J30, J40 : moments of inertia about the x axis, in cm4, They are to be used for the stress analysis required in:
of the individual girders of the rudder system • Sec 1, [4], for the rudder stock
having lengths 10, 20, 30, 40. For rudders
supported by a solepiece only, J20 indicates the • Sec 1, [6], for the rudder pintles and the pintle bearings
moment of inertia of the pintle in the sole piece • Sec 1, [7] for the rudder blade
J50 : moment of inertia about the z axis, in cm4, of • Sec 1, [8] for the solepiece and the rudder trunk.
the solepiece (see Fig 34)
CR : rudder force, in N, acting on the rudder blade, 1.2 Data for the direct calculation
defined in Sec 1, [2.1.1]
CR1, CR2 : rudder forces, in N, defined in Sec 1, [2.2.3] 1.2.1 Forces per unit length (1/7/2016)
E : Young’s modulus, in N/m2 The force per unit length pR (see Fig 1) acting on the rudder
body is to be obtained in N/m, from the following formula:
E = 2,06 1011 N/m2
G : Shear elasticity modulus, in N/m2 C
p R = -----R-
G = 7,85 1010 N/m2 l 10
1.2.2 Moments and forces (1/7/2024)

1 Criteria for direct calculation of the
For spade rudders, the results of direct calculations carried
loads acting on the rudder structure
out in accordance with [1.1.2] may be expressed in an
analytical form. The loads in [1.1.1] may therefore be
1.1 General obtained from the following formulae (See Fig 1):
• maximum bending moment MB in the rudder stock, in
1.1.1 Application (1/7/2016)
N.m:
The requirements of this Appendix apply to the following
 10  2C 1 + C 2 
types of rudders: M B = C R   20 + ---------------------------------
-
 3  C1 + C2  
• spade rudders (see Fig 1)
where C1 and C2 are the lengths, in m, defined in Fig 1
• spade rudders with trunk (see Fig 2 and Fig 3)
• 2 bearing rudders with solepiece (see Fig 34) • support forces, in N:
• 2 bearing semi-spade rudders with rudder horn (see Fig M

F A3 = ------B-
45)  30
• semi-spade rudders with 2-conjugate elastic support F A1 = C R + F A3

(see Fig 79)
• maximum shear force in the rudder body, in N:
The requirements of this Appendix provide the criteria for
calculating the following loads: QR = CR
• bending moment MB in the rudder stock
The maximum moment, MC, in top of the cone coupling as
• support forces FA shown in Fig 1 is applicable for the connection between the
rudder and the rudder stock.
• bending moment MR and shear force QR in the rudder
body
RINA Rules 2024 163

Pt B, Ch 10, App 1
Figure 1 : Spade rudders (1/7/2016)

FA1
MB
FA3
l30 J30
l20 J20
C2
J10 PR
l10
C1
Load M Q
Figure 1 : Spade rudders (1/7/2024)
1.3 Spade rudders with trunk 1.3.2 Moments and forces (1/7/2024)
For a spade rudder with trunk extending inside the rudder,
1.3.1 Force per unit length (1/7/2016) the strength is to be checked against the following two
The force per unit length pR (see Fig 2 and Fig 3) acting on cases:
the rudder body is to be obtained, in N/m, from the
following formula: a) pressure applied on the entire rudder area
CR b) pressure applied only on rudder area below the middle
p R = -------------------
 10 +  20 of neck bearing.
For spade rudders with trunk, tThe moments and forces for
the two cases defined above results of direct calculations
carried out in accordance with [1.1.2] may be determined
according to Fig 2 and 3 respectivelyexpressed in an
164 RINA Rules 2024

Pt B, Ch 10, App 1
analytical form. The loads in [1.1.1] may therefore be

obtained from the following formulae (see Fig 2):
Figure 2 : Full rudder force CR = CR1+CR2 and total rudder torque QR = QR1 + QR2 with rudders stock bending
moment Mb = MCR2 - MCR1 (1/7/2024)
Figure 3 : Rudder force CR2 corresponding to rudder torque QR2 acting at rudder blade area A2 with rudders stock
bending moment Mb = MCR2 (1/7/2024)
MCR2 = CR2 (10 - CG2) CG2 : Vertical position of the centre of gravity of the
MCR1 = CR1 (CG1 - 10) rudder blade area A2 from base
where: CR = CR1+ CR2
CR1 : Rudder force over the rudder blade area A1 Support forces FA2 and FA3, in N:
CR2 : Rudder force over the rudder blade area A2
FA3 = (MCR2 - MCR1)/(20 - 30)
CG1 : Vertical position of the centre of gravity of the
rudder blade area A1 from base FA2 = CR + FA3
RINA Rules 2024 165

• Bending moment MR for the scantling of the rudder CG1 : Vertical position of the centre of gravity of
blade, in N.m, shall be taken as the greatest of the the rudder blade area A1 from base
following values: CG2 : Vertical position of the centre of gravity of
MCR2 = CR2 (10 - CG2) the rudder blade area A2 from base
• CR = CR1+ CR2
MCR1 = CR1 (CG1 - 10)
• Support forces FA2 and FA3, in N:
where: FA3 = (MCR2 - MCR1)/(20 - 30)
CR1 : Rudder force over the rudder blade area A1 FA2 = CR + FA3
CR2 : Rudder force over the rudder blade area A2
Figure 4 : Spade rudder with trunk (1/7/2019)
______________________________________________________________________________________________
...OMISSIS...
Pt B, Ch 10, App 1
Figure 9 : Rudder horn geometry (Two bearing semi-spade rudder) (1/7/2016)
1.6.2 Shear force (1/7/2016) T : torsional stress to be obtained for the hollow
The shear force QH acting on the generic section of the rudder horn, in N/mm2, from the following
rudder horn is to be obtained, in N, from the following formula:
formula: –3
M T  10
 T = ----------------------
Q H = F A2 2A T t H
For solid rudder horn, T is to be considered by
FA2 : force, in N, defined in [1.6.1]. the Society on a case by case basis
1.6.3 Torque (1/7/2016) MT : torque, in N m, defined in [1.6.3]
The torque acting on the generic section of the rudder horn AT : area of the horizontal section enclosed by the
is to be obtained, in N, from the following formula: rudder horn, in m2
tH : plate thickness of the rudder horn, in mm.
M T = F A2 e  z 
1.7 Semi-spade rudders with 2-conjugate
where:
elastic support
FA2 : force, in N, defined in [1.6.1]
e(z) : torsion lever, in m, defined in Fig 67. 1.7.1 Force per unit length (1/7/2016)
The force per unit length pR10 and pR20 (see Fig 78) acting on
1.6.4 Stress calculations (1/7/2019) the rudder body is to be obtained, in N/m, from the
For the generic section of the rudder horn, the following following formulae:
stresses are to be calculated:
C
B : bending stress to be obtained, in N/mm2, from p R10 = -----R-
 10
C
M p R20 = -----R-
 B = -------H-  20
MX
MH : bending moment at the section considered, in 1.7.2 Support stiffness properties (1/7/2024)
N m, defined in [1.6.1] The 2-conjugate elastic supports (see Fig 78) are defined in
WX : section modulus, in cm3, around the horizontal terms of horizontal displacements yi by the following
axis X (see Fig 67) equations:
S : shear stress to be obtained, in N/mm2, from the • At the lower rudder horn bearing:
following formula:
F A2 y 1 = K 12 F A2 – K 22 F A1
 S = -------
AH • At the upper rudder horn bearing:
FA2 : force, in N, defined in [1.6.1]
y 2 = K 11 F A2 – K 12 F A1
AH : effective shear sectional area of the rudder horn
in Y direction, in mm2 where:
RINA Rules 2024 169

Pt B, Ch 10, App 1
y1, y2 : Horizontal displacements, in m, at the lower and assuming a hollow cross-section for this
and upper rudder horn bearings, respectively. part.
FA1, FA2 : Horizontal support forces, in N, at the lower e : Rudder horn torsion lever, in m, as defined in
and upper rudder horn bearings, respectively Fig 89 and Fig 910 (value taken as z = d/2)
K11, K212, K122, :Rudder horn compliance constants obtained, J1h : Moment of inertia of rudder horn about the x
in m/N, from the following formulae: axis, in m4, for the region above the upper
rudder horn bearing. Note that J1h is an average
value over the length see Fig 910)
 e 
3 2
K 11 = 1 3  ------------- + ------------ J2h : Moment of inertia of rudder horn about the x
3EJ 1h GJ th
axis, in m4, for the region between the upper
and lower rudder horn bearings. Note that J2h is
   d –  e 
2 2 2
K 12 = 1 3  ------------- + --------------------------- + ------------ an average value over the length d - λ (see
3EJ 1h 2EJ 1h GJ th Fig 910)
Jth : Torsional stiffness factor of the rudder horn, in
m4.
   d –    d –  d –  For any thin wall closed section:
2 2 2 3 2
e d
K 22 = 1 3  ------------- + --------------------------- + --------------------------- + ------------------- + ----------
3EJ 1h EJ 1h EJ 2h 3EJ 2h GJ th
2
4F
J th = ---------T-
where: u
 i ----i
d : Height of the rudder horn, in m, defined in ti
Fig 89 and Fig 910. This value is measured FT : Mean of areas enclosed by outer
downwards from the upper rudder horn end, at and inner boundaries of the thin
the point of curvature transition, till the mid-line walled section of rudder horn, in m2
of the lower rudder horn pintle
ti : Length, in mm, of the individual
λ : Length, in m, as defined in Fig 89 and Fig 910. plates forming the mean horn
This length is measured downwards from the sectional area
upper rudder horn end, at the point of curvature
ui : Thickness, in mm, of the individual
transition, till the mid-line of the upper rudder
horn bearing. For  = 0, the above formulae plates mentioned above
converge to those of spring constant Z for a rud- Note that the Jth value is taken as an average
der horn with 1-elastic support (see [1.5.2]), value, valid over the rudder horn height.
Figure 10 : Semi-spade rudders with 2-conjugate elastic support
170 RINA Rules 2024

...OMISSIS...
Pt B, Ch 10, App 4
APPENDIX 4 D IRECT F ORCE C ALCULATION F OR

A NCHORING E QUIPMENT
1 General k : Coefficient equal to:
C bWL
1.1 k = 0 017 + 20  -----------------------------------------------
– 0 5
-
– 1 5
L WL  T  B WL
2
1.1.1 (1/7/2024)
As an alternative to the prescriptive approach described in With CbWL, block coefficient at waterline:
Sec 4, [2] direct force calculation may be performed to
determine the necessary anchoring equipment for monohull 
C bWL = ---------------------------------------------------
ships with length less than 90m. 1 025  L WL  B WL  T
where:
2 Total force FEN
 : Moulded displacement at waterline, in m3
2.1 General Sm : Total wetted surface of the part of the hull under
2.1.1 (1/7/2024) draught, in m2. The value of Sm is to be given by the
The total force (static + dynamic) FEN , in kN, induced by Designer. When this value is not available, Sm is to be taken
wind and current acting on monohull in anchoring equal to 6.2/3
condition as defined in Sec 4, [1] is to be calculated as
follows: Vc : Speed of the current, in m/s, as defined in Sec 4, [1]
FEN = 2 (FSLPH + FSH + FSS)
where: 2.3 Static force on hull FSH
FSLPH : Static force on wetted part of the hull due to current, 2.3.1 (1/7/2024)
as defined in [2.2] of this Appendix
The theoretical static force induced by wind applied on the
FSH : Static force on hull due to wind, as defined in [2.3] of upper part of the hull, in kN, is defined according to the
this Appendix following formula:
FSS : Static force on superstructures due to wind, as defined
1 –3
F SH = ---     C hfr  S hfr + 0 02  S hlat   V W  10
2
[2.4] of this Appendix.
2
2.2 Static force on wetted part of hull FSLPH where:
2.2.1 (1/7/2024)  : Air density, equal to 1,22 kg/m3

The theoretical static force induced by current applied on
VW : Speed of the wind, in m/s, as defined in Sec 4, [1]
the wetted part of the hull, in kN, is defined according to
Shfr : Front surface of hull and bulwark if any, in m2,
1 –3
projected on a vertical plane of the ship situated aft of the
F SLPH = ---    C f  S m  V c  10
2
2 aft end of the ship and perpendicular to the longitudinal
axis of the ship
where:
Shlat : Partial lateral surface of one single side of the hull and
 : Water density, equal to 1025 kg/m3
bulwark if any, in m2, through the overall length of the ship,
Cf : Coefficient equal to: projected on a vertical plane parallel to the longitudinal
axis of the ship and delimited according to Fig 1
0 075
C f =  1 + k   ------------------------------2
 log R e – 2  Chfr : 0,8 sin , with  defined in Fig 1.
With Re, Reynolds number: In Fig 1, B is the breadth of the hull, in m.
 V c  L WL  The upper part of the hull is the part extending from side to
R e = ------------------------------
-
–6 side to the uppermost continuous deck extending over the
1 054  10
ship length.
174 RINA Rules 2024

Pt B, Ch 10, App 4
Figure 1 : (1/7/2024)
2.4 Static forces FSS on superstructures and 1

 C
–3
F SS = ---     S hfri + 0 08  S slati   V W  10
2
deckhouses 2 hfr i
where:
2.4.1 General Case (1/7/2024)
The theoretical static force induced by wind applied on the Shfri : Front surface of tier i of the superstructure, in m2,
superstructures and deckhouses, in kN, is defined as the projected on a vertical plane of the ship situated aft of the
sum of the forces applied to each superstructure and aft end of the ship and perpendicular to the longitudinal
deckhouse tier according to the following formula: axis of the ship
1 Chfri : Chfri=0,8 sins, with s as defined for in Fig 1 and

C
–3
F SS = ---     S sfri + 0 08  S slati   V W  10
2
2 sfr i measured at mid height of the superstructure tier located in
the front of the hull
where:
 VW, Sslati : as defined in [2.4.1].
 : Air density, equal to 1,22 kg/m3
The static force is to be added to the static force calculated
VW : Speed of the wind, in m/s, as defined in [2.3] for the other superstructures and deckhouses according to
[2.4.1].
Ssfri : Front surface of tier i (superstructure or deckhouse,
including bulwark if any), in m2, projected on a vertical
plane of the ship situated aft of the aft end of the ship and
3 Anchor weight
perpendicular to the longitudinal axis of the ship
Sslati : Partial lateral surface of one single side of tier i
3.1 General
(superstructure or deckhouse, including bulwark if any), in 3.1.1 (1/7/2024)
m2, projected on a vertical plane parallel to the longitudinal The individual mass of anchor, in kg, is to be at least equal
axis of the ship and delimited according to Fig 1 to:
When 4hi  lsi, Sslati is to be taken equal to 0 for ordinary anchor: P = (FEN / 7) * 102
Csfri : 0,8 sin i, with i defined in Fig 1 without being for high holding power anchor: P = (FEN / 10) * 102
greater than 90°
for very high holding power: P = (FEN / 15) * 102
2.4.2 Superstructures in the forward part of the
ship (1/7/2024) 4 Chain cable
When superstructures are located in the front of the hull
with front and side walls of superstructures in the continuity
4.1 Stud link chain cable scantling
of the side shell, the static force induced by wind applied
on these superstructures, in KN, is defined as the sum of the 4.1.1 (1/7/2024)
forces applied to each superstructure tier according to the Chain cable diameters are to be selected from Pt D, Ch 4,
following formula: Sec 1, Tab 9, based on the minimum breaking load BL and
RINA Rules 2024 175

Pt B, Ch 10, App 4
proof load PL of steel grades, in kN, calculated according to the value of FEN to take into account in the present Article
the following formulae: for the calculation of BL and PL is to be deduced from the
• for steel Grade 1: actual mass of the anchor according to the formulae in [3].
BL = 6 FEN
4.2 Length of individual chain cable
PL = 0,7 BL
4.2.1 (1/7/2024)
• for steel Grade 2:
The length of chain cable Lcc, in m, linked to each anchor is
BL = 6.8 FEN
to be at least equal to:
PL = 0,7 BL • When P<180:
• for steel Grade 3: Lcc = 30 ln(P) - 42
BL = 7.5 FEN • When P180:
PL = 0,7 BL Lcc to be selected according to Sec 4, Tab 1
The chain cable scantling is to be consistent with the mass where:

of the associated anchor. In case the anchor on board is P : Anchor weight, in kg, defined in [3] for an ordinary
heavier by more than 7% from the mass calculated in [3], anchor according to the considered case.
176 RINA Rules 2024

Pt C, Ch 1, Sec 2
SECTION 2 DIESEL ENGINES
1 General submitting a comparison list of the production drawings

to the previously approved engine design drawings
referenced in [1.2.1]
1.1 Application
1.1.1 (1/7/2024) • forwarding the relevant production drawings and
comparison list for the use of the Surveyors at the
Diesel engines listed below are to be designed, constructed,
manufacturing plant and shipyard if necessary
installed, tested and certified in accordance with the
requirements of this Section, under the supervision and to • engine's components testing and engine works trials
the satisfaction of the Society’s Surveyors:
• the issuance of an engine certificate upon satisfactorily
a) main propulsion engines meeting the Rule requirements.
b) engines driving electrical generators and other
auxiliaries essential for safety and navigation and cargo 1.4 Documentation
pumps in tankers, when they develop a power of 110
kW and over. 1.4.1 Document flow for obtaining a type approval
All other engines are to be designed and constructed certificate (1/7/2016)
according to sound marine practice, with the equipment
a) For the initial engine type, the engine designer is to
required in [4.3.4], [4.5.2], [4.7.2] [4.7.3], [4.7.5] and
submit to the Society the documentation in accordance
[4.7.8] and delivered with the relevant works’ certificate
with requirements in Tab 1 and Tab 2.
(see Pt D, Ch 1, Sec 1, [4.2.3]).
Additional requirements for control and safety systems for b) Upon review and approval of the submitted
dual fuel engines supplied with high pressure methane gas documentation (evidence of approval), it will be re-
are given in App 2. turned to the engine designer.
Additional requirements for trunk pistoninternal c) The engine designer arranges for a Surveyor to attend an
combustion engines supplied with low pressure natural gas engine type test
are given in App 12 and App 17.
d) Upon satisfactory testing and examination of relevant
In addition to the requirements of this Section, those given reports, the Society issues a type approval certificate.
in Sec 1 apply.
1.4.2 Document flow for engine certificate
1.2 Type approval certificate (1/7/2016)
1.2.1 (1/7/2016) a) The engine type must have a type approval certificate.
For each type of engine that is required to be certified, a For the first engine of a type, process and the engine
type approval certificate is to be obtained by the engine certification process (ECP) may be performed
designer. simultaneously.
The type approval process consists of: b) Engines to be installed in specific applications may
• drawing and specification approval, require the engine designer/licensor to modify the
• conformity of production, design or performance requirements. The modified
drawings are forwarded by the engine designer to the
• approval of type testing programme,
engine builder/licensee to develop production
• type testing of engines, documentation for use in the engine manufacture in
• review of the obtained type testing results, accordance with Tab 3.
• evaluation of the manufacturing arrangements, c) The engine builder/licensee develops a comparison list
• issue of a type approval certificate upon satisfactorily of the production documentation to the documentation
meeting the Rule requirements. listed in Tab 1 and Tab 2. An example comparison list is
provided in App 10. If there are differences in the
1.3 Engine certificate technical content on the licensee's production
drawings/documents compared to the corresponding
1.3.1 (1/7/2016) licensor's drawings, the licensee must obtain agreement
Each diesel engine manufactured for a shipboard to such differences from the designer using the template
application per [1.1.1] is to have an engine certificate: in App 11.
The certification process consists of: If the designer agreement is not confirmed, the engine is
• the engine builder/licensee obtaining design approval of to be regarded as a different engine type and is to be
the engine application specific documents, if any, by

Pt C, Ch 1, Sec 2
7 Certification of engine components, that the Surveyor also witnesses the testing, batch or
Workshop inspections and trials individual, unless an ACS provides other arrangements.
c) The manufacturer is not exempted from responsibility

7.1 General for any relevant tests and inspections of those parts for
7.1.1 (1/1/2020) which documentation is not explicitly requested by the
The engine manufacturer is to have a quality control system Society. The manufacturing process and equipment is to
that is suitable for the actual engine types to be certified by be set up and maintained in such a way that all
the Society. The quality control system is also to apply to materials and components can be consistently
any sub-suppliers. The Society re-serves the right to review produced to the required standard. This includes
the system or parts thereof. Materials and components are production and assembly lines, machining units, special
to be produced in compliance with all the applicable
tools and devices, assembly and testing rigs as well as
production and quality instructions specified by the engine
all lifting and transportation devices.
manufacturer. The Society requires that certain parts are
verified and documented by means of Society Certificate
(SC), Work Certificate (W) or Test Report (TR). 7.2 Parts to be documented
a) The documents above are used for product
documentation as well as for documentation of single 7.2.1 (1/7/2016)
inspections such as crack detection, dimensional check,
The extent of parts to be documented depends on the type
etc. If agreed to by the Society, the documentation of
of engine, engine size and criticality of the part.
single tests and inspections may also be arranged by
filling in results on a control sheet following the A summary of the required documentation for the engine
component through the production.
components is listed in Tab 8.
b) The Surveyor is to review the TR and W for compliance
with the agreed or approved specifications. SC means Symbols used are listed in Tab 9.
Table 8 : Summary of required documentation for engine components (1/7/2024)
Dimensional
Material Non-destruc- Hydro- inspection, Visual Compo-
Applicable to
Item Part (5) (6) (7) (8) proper- tive examina- static test including inspection nent certifi-
engines:
ties (1) tion (2) (3) surface condi- (surveyor) cate
tion
1 Welded bedplate W(C+M) W(UT+CD) fit-up + post- All SC
welding
2 Bearing transverse W(C+M) W(UT+CD) X All SC
girders GS
3 Welded frame W(C+M) W(UT+CD) fit-up + post- All SC
box welding
(1) Material properties include chemical composition and mechanical properties, and also surface treatment such as surface
hardening (hardness, depth and extent), peening and rolling (extent and applied force).
(2) Non-destructive examination means e.g. ultrasonic testing, crack detection by MPI or DP. When certain NDE method on the
finished component is impractical (for example UT for items 12/13), the NDE method can be performed at earlier appropriate
stages in the production of the component, see [1.5.4].
(3) Hydrostatic test is applied on the water/oil side of the component. Items are to be tested by hydraulic pressure at the pressure
equal to 1.5 times the maximum working pressure. High pressure parts of the fuel injection system are to be tested by hydraulic
pressure at the pressure equal to 1.5 maximum working pressure or maximum working pressure plus 300 bar, whichever is the
less. Where design or testing features may require modification of these test requirements, special consideration may be given.
(4) Material certification requirements for pumps and piping components are dependent on the operating pressure and
temperature. Requirements given in this Table apply except where alternative requirements are explicitly given elsewhere in the
Rule requirements.
(5) For turbochargers, see Sec 14.
(6) Crankcase explosion relief valves are to be type tested in accordance with App 5 and documented according to [4.3.4].
(7) Oil mist detection systems are to be type tested in accordance with Appendix 6 and documented according to [4.3.5].
(8) For Speed governor and overspeed protective devices, see [4.7.3] to [4.7.6].
(9) Charge air coolers need only be tested on the water side.
(10) Hydrostatic test is also required for those parts filled with cooling water and having the function of containing the water which
is in contact with the cylinder or cylinder liner.
60 RINA Rules 2024

...OMISSIS...
Pt C, Ch 1, Sec 10
SECTION 10 PIPING SYSTEMS
1 General • [21] for their certification, inspection and testing.

b) Specific requirements for ship piping systems and
1.1 Application machinery piping systems are given in Articles [6] to
[19].
1.1.1
a) General requirements applying to all piping systems are 1.2 Documentation to be submitted
contained in:
1.2.1 Documents
• [2] for their design and construction
The documents listed in Tab 1 are to be submitted.
• [3] for the welding of steel pipes
• [4] for the bending of pipes 1.2.2 Additional information
• [5] for their arrangement and installation The information listed in Tab 2 is also to be submitted.
Table 1 : Documents to be submitted (1/7/2006)
No. I/A (1) Document (2)

1 A Drawing showing the arrangement of the sea chests and ship side valves
2 A Diagram of the bilge and ballast systems (in and outside machinery spaces)
3 A Specification of the central priming system intended for bilge pumps, when provided
4 A Diagram of the scuppers and sanitary discharge systems
5 A Diagram of the air, sounding and overflow systems
6 A Diagram of cooling systems (sea water and fresh water)
7 A Diagram of fuel oil system
8 A Drawings of the fuel oil tanks not forming part of the ship‘s structure
9 A Diagram of the lubricating oil system
10 A Diagram of the thermal oil system
11 A Diagram of the hydraulic systems intended for essential services or located in machinery spaces
12 A Diagram of steam system, including safety valve exhaust and drain pipes
13 For high temperature steam pipes:
A • stress calculation note
I • drawing showing the actual arrangement of the piping in three dimensions
14 A Diagram of the boiler feed water and condensate system
15 A Diagram of the compressed air system
16 A Diagram of the hydraulic and pneumatic remote control systems
17 A Diagram of the remote level gauging system
18 I Diagram of the exhaust gas system
19 A Diagram of drip trays and gutterway draining system
20 A Diagram of the oxyacetylene welding system
21 A Drawings and specification of valves and accessories, where required in [2.7]
(1) A = to be submitted for approval, in four copies;
I = to be submitted for information, in duplicate.
(2) Diagrams are also to include, where applicable, the (local and remote) control and monitoring systems and automation sys-
tems.

Pt C, Ch 1, Sec 10
7.3 Ballast Water Management Systems 2) the pumping arrangements take account of the
requirements for any fixed pressure water-spraying
7.3.1 (1/1/2017)
fire-extinguishing system
When a Ballast water Management (treatment) system is
installed on board, the requirements in App 8 are to be 3) water contaminated with petrol or other dangerous
complied with. substances is not drained to machinery spaces or
other spaces where sources of ignition may be
present, and
8 Scuppers and sanitary discharges
4) where the enclosed cargo space is protected by a
8.1 Application carbon dioxide fire-extinguishing system, the deck
scuppers are fitted with means to prevent the escape
8.1.1 of the smothering gas.
a) This Article applies to: b) suitable sanitary tanks in the case of sanitary discharges.
• scuppers and sanitary discharge systems, and
8.3.2 Alternative arrangement (1/7/2017)
• discharges from sewage tanks.
The scuppers and sanitary discharges may be led overboard
b) Discharges in connection with machinery operation are provided that:
dealt with in [2.8].
• the freeboard deck edge is not immersed when the ship
Note 1: Arrangements not in compliance with the provisions of
heels 5°, and
this Article may be considered for the following ships:
• ships of less than 24 m in length • the inboard end of the discharge is located above the
load waterline formed by a 5° heel, to port or starboard,
• cargo ships of less than 500 tons gross tonnage
at a draft corresponding to the assigned summer
• ships to be assigned restricted navigation notations
freeboard, and,
• non-propelled units.
• the pipes are fitted with efficient means of preventing
water from passing inboard in accordance with [8.6]
8.2 Principle and [8.7].
8.2.1 (1/7/2017)
a) Scuppers, sufficient in number and suitable in size, are 8.4 Drainage of superstructures or
to be provided to permit the drainage of water likely to deckhouses not fitted with efficient
accumulate in the spaces which are not located in the weathertight doors
ship's bottom. The Society may permit the means of 8.4.1 (1/7/2017)
drainage to be dispensed with in any particular
Scuppers leading from superstructures or deckhouses not
compartment if it is satisfied that, by reason of size or
fitted with doors complying with the requirements of Pt B,
internal subdivision of such space, the safety of the ship
Ch 9, Sec 6 are to be led overboard, and subject to [8.3.2].
is not impaired.
b) The number of scuppers and sanitary discharge
openings in the shell plating is to be reduced to a
8.5 Drainage of cargo spaces, other than ro-
minimum either by making each discharge serve as ro spaces, intended for the carriage of
many as possible of the sanitary and other pipes, or in motor vehicles with fuel in their tanks
any other satisfactory manner. for their own propulsion
8.3 Drainage from spaces below the 8.5.1 Prevention of build-up of free
surfaces (1/7/2011)
freeboard deck or within enclosed
In cargo spaces, other than ro-ro spaces, intended for the
superstructures and deckhouses on the
carriage of motor vehicles with fuel in their tanks for their
freeboard deck own propulsion and fitted with a fixed pressure water-
8.3.1 Normal arrangement (1/7/2017) spraying fire-extinguishing system, the drainage
arrangement is to be in compliance with the requirements
Scuppers and sanitary discharges from spaces below the
contained in the guidelines developed by IMO (see Note 1)
freeboard deck or from within superstructures and
such as to prevent the build-up of free surfaces.
deckhouses on the freeboard deck fitted with doors
complying with the provisions of Pt B, Ch 9, Sec 6 are to be Note 1: see resolution MSC.1/Circ. 1320 "Guidelines for the
led to: drainage of fire-fighting water from closed vehicle and ro-ro spaces
and special category spaces of passenger and cargo ships".
a) a suitable space, or spaces, of appropriate capacity,
having a high water level alarm and provided with 8.5.2 Scupper draining
suitable pumping arrangements for discharge Scuppers from cargo spaces, other than ro-ro spaces,
overboard. In addition, it is to be ensured that: intended for the carriage of motor vehicles with fuel in their
1) the number, size and arrangement of the scuppers tanks for their own propulsion are not to be led to
are such as to prevent unreasonable accumulation machinery spaces or other places where sources of ignition
of free water, may be present.
RINA Rules 2024 199

Pt C, Ch 1, Sec 10
8.6 Arrangement of discharges - General If the inboard non-return valve is not according to the
above, a valve with positive means of closing controlled
8.6.1 Arrangement of discharges through the shell locally is to be fitted in between the shell plating and the
more than 450 mm below the freeboard deck inboard valve.
or less than 600 mm above the summer load
waterline (1/7/2017) 8.7.3 Alternative arrangement when the inboard
Scupper and discharge pipes originating at any level and end of the discharge pipe is above the
penetrating the shell either more than 450 millimetres summer waterline by more than 0,02 L
below the freeboard deck or less than 600 millimetres Where the vertical distance from the summer load waterline
above the summer load waterline are to be provided with a to the inboard end of the discharge pipe exceeds 0,02 L, a
non-return valve at the shell. Unless required by [8.7], this single automatic non-return valve without positive means of
valve may be omitted if the piping is of substantial closing may be accepted subject to the approval of the
thickness, as per Tab 232. Society.
Note 1: This requirement does not apply to ships for which the
8.6.2 Arrangement of discharges through the shell notation chemical tanker or liquefied gas carrier is requested.
less than 450 mm below the freeboard deck
and more than 600 mm above the summer 8.7.4 Arrangement of discharges through manned
load waterline (1/7/2017) machinery spaces (1/7/2017)
Scupper and discharge pipes penetrating the shell less than Where sanitary discharges and scuppers are lead overboard
450 millimetres below the freeboard deck and more than through the shell in way of manned machinery spaces, the
600 millimetres above the summer load waterline are not fitting at the shell of a locally operated positive closing
required to be provided with a non-return valve at the shell, valve together with a non-return valve inboard may be
except for the cases indicated in [8.7]. accepted. The operating position of the valve will be given
special consideration by the Society.
8.7 Arrangement of discharges from
enclosed spaces below the freeboard 8.8 Summary table of overboard discharge
deck or on the freeboard deck arrangements
8.8.1 (1/7/2024)
8.7.1 Normal arrangement (1/7/2017)
The various arrangements acceptable for scuppers and
Each separate discharge led though the shell plating from
sanitary overboard discharges are summarised in Table 22.1
enclosed spaces below the freeboard deck is to be provided
of Regulation 22 of the 1966 Convention on Load Line
with one automatic non-return valve fitted with positive
shown in Fig 3.
means of closing it from above the freeboard deck or one
automatic non-return valve and one sluice valve controlled
from above the freeboard deck. 8.9 Valves and pipes
The requirements for non-return valves are applicable only 8.9.1 Materials
to those discharges which remain open during the normal a) All shell fittings and valves are to be of steel, bronze or
operation of the ship; For discharges which are to be kept other ductile material. Valves of ordinary cast iron or
closed at sea (such as gravity drain from topside ballast similar material are not acceptable. All scupper and
tanks), a single screw down valve operated from above the discharge pipes are to be of steel or other ductile
freeboard deck is acceptable. material. Refer to [2.1].
Where a valve with positive means of closing is fitted, the b) Plastic is not to be used for the portion of discharge line
operating position above the freeboard deck shall always from the shell to the first valve.
be readily accessible and means shall be provided for
indicating whether the valve is open or closed. 8.9.2 Thickness of pipes (1/7/2017)
The position of the inboard end of discharges is related to a) The thickness of scupper and discharge pipes led to the
the timber summer load waterline when a timber freeboard bilge or to draining tanks is not to be less than that
is assigned. required in [2.2].
b) The thickness of scupper and discharge pipes led to the
8.7.2 Alternative arrangement when the inboard shell is not to be less than the minimum thickness given
end of the discharge pipe is above the in Tab 22 and Tab 232, for the part between the shell
summer waterline by more than 0,01
plating and the outermost valve.
L (1/7/2017)
Where the vertical distance from the summer load waterline 8.9.3 Operation of the valves
to the inboard end of the discharge pipe exceeds 0,01 L, the a) Where valves are required to have positive means of
discharge may have two automatic non-return valves closing, such means is to be readily accessible and
without positive means of closing, provided that the provided with an indicator showing whether the valve is
inboard valve: open or closed.
• is above the deepest subdivision load line, and b) Where plastic pipes are used for sanitary discharges and
• is always accessible for examination under service scuppers, the valve at the shell is to be operated from
conditions. outside the space in which the valve is located.
200 RINA Rules 2024

Pt C, Ch 1, Sec 10
Where such plastic pipes are located below the summer 8.10.1 Overboard discharges and valve connections
waterline (timber summer load waterline), the valve is to a) Overboard discharges are to have pipe spigots
be operated from a position above the freeboard deck. extending through the shell plate and welded to it, and
Refer also to App 3. are to be provided at the internal end with a flange for
connection to the valve or pipe flange.
8.10 Arrangement of scuppers and sanitary b) Valves may also be connected to the hull plating in
discharge piping accordance with the provisions of [2.8.3], item c).
Figure 3 : Overboard discharge arrangement (1/7/2017)

Discharges coming from enclosed spaces below the
Discharge coming from other spaces
freeboard deck or on the freeboard deck
Discharges
General requirement Alternatives (Reg. 22(1)) where inboard end outboard end > 450
through
Reg. 22(1) where machinery mm below FB deck or Otherwise
inboard end ≤ 0.01L above SWL spaces ≤ 600 mm above SWL Reg. 22(5)
>0,01L above SWL >0,02L above
SWL Reg. 22(4)
FB FB
FB Deck FB Deck FB Deck FB Deck Deck Deck
ML
TWL
SWL SWL SWL SWL SWL SWL SWL
*
Symbols:
non return valve without positive
inboard end of pipes remote control
means of closing
outboard end of pipes non return valve with positive means normal thickness
of closing controlled locally
pipes terminating on the
open deck valve controlled locally substantial thickness
Table 22 : Thickness of scupper and discharge pipes led to the shell, according to their location
Applicable
requirement 
[8.8.6]
[8.7.1] [8.7.2] [8.8.2] [8.8.3] [8.8.4] [8.8.5] with [8.8.6] without valve [8.8.7]
Pipe location
 valve
Between the shell Thickness according to Tab 23, column 1, or 0,7 times that NA NA
and the first valve of the shell side plating, whichever is the greater (1)
Between the first Thickness according to Tab 23, column 2 NA NA
valve and the
inboard end
Below the NA Thickness according Thickness according
freeboard deck to Tab 23, column 1 to Tab 23, column 2
Above the NA Thickness according Thickness according

freeboard deck to Tab 23, column 2 to Tab 23, column 2
(1) However, this thickness is not required to exceed that of the plating.
Note 1: NA = not applicable
Column 1 Column 2
Table 223 : Minimum thickness of scupper External diameter
substantial thick- normal thickness
and discharge pipes led to the shell of the pipe d (mm)
ness (mm) (mm)
220 12,50 5,80
Column 1 Column 2
External diameter 230 d 12,50 6,00
substantial thick- normal thickness
of the pipe d (mm)
ness (mm) (mm) Note 1: Intermediate sizes may be determined by interpola-
tion.
d 80,0 7,00 4,50
155 9,25 4,50
8.10.2 Passage through cargo spaces
180 10,00 5,00
Where scupper and sanitary discharge pipes are led through
Note 1: Intermediate sizes may be determined by interpola- cargo spaces, the pipes and the valves with their controls
tion. are to be adequately protected by strong casings or guards.
RINA Rules 2024

...OMISSIS... 201
Pt C, Ch 1, Sec 10
of the ship, and the protection of these tanks and Note 1: For the location of the remote controls, refer to [11.11.4],
bunkers against any abnormal rise in temperature. item c).
e) Attention is drawn to the requirements of Pt E, Ch 7, b) Such valves and cocks are also to include local control
Sec 4 regarding the segregation of fuel bunkers from the and on the remote and local controls it is to be possible
cargo area. to verify whether they are open or shut. (See [2.7.3].)
c) In the special case of deep tanks situated in any shaft or
11.5.2 Use of free-standing fuel oil tanks pipe tunnel or similar space, valves are to be fitted on
a) In general the use of free-standing fuel oil tanks is to be the tank but control in the event of fire may be effected
avoided except on cargo ships, where their use is by means of an additional valve on the pipe or pipes
permitted in category A machinery spaces. outside the tunnel or similar space. If such additional
valve is fitted in the machinery space it is to be operated
b) For the design and the installation of independent tanks,
from a position outside this space.
refer to App 4.
11.6.5 Drain pipes (1/7/2020)
11.6 Design of fuel oil tanks and bunkers Where fitted, drain pipes are to be provided with self-
closing valves or cocks.
11.6.1 General (1/7/2024)
A tank drain cock is not to be considered as a sampling
Tanks such as collector tanks, de-aerator tanks etc. are to be point.
considered as fuel oil tanks for the purpose of application of
this sub-article, and in particular regarding the valve 11.6.6 Air and overflow pipes (1/7/2020)
requirements. Air and overflow pipes are to comply with [9.1] and [9.3].
Tanks with a volume lower than 500 l will be given special As far as practicable, the Service tank overflow return line
consideration by the Society. to the settling tank is to be drawn from near the bottom of
A sufficient number of Mmain bunker tanks are to be the service tank to the top of the settling tank to ensure any
arranged to limit the need to mix newly bunkered fuel with accumulating sediment in the service tank bottom is
fuel already on-board. For this purpose at least 2 storage minimized.
fuel oil tanks are to be provided. In this connection special
11.6.7 Sounding pipes and level gauges
consideration will be given in case of vessels lower than
200 GT and classed for restricted navigation. a) Safe and efficient means of ascertaining the amount of
fuel oil contained in any fuel oil tank are to be provided.
11.6.2 Scantlings b) Sounding pipes of fuel oil tanks are to comply with the
a) The scantlings of fuel oil tanks and bunkers forming part provisions of [9.2].
of the ship's structure are to comply with the c) Oil-level gauges complying with [2.9.2] may be used in
requirements stated in Part B, Chapter 7. place of sounding pipes.
b) Scantlings of fuel oil tanks and bunkers which are not d) Gauge cocks for ascertaining the level in the tanks are
part of the ship's structure are to comply with App 4. For not to be used.
cases which are not contained in the Tables of that
appendix, scantlings will be given special consideration 11.7 Design of fuel oil heating systems
by the Society.
11.7.1 General
11.6.3 Filling and suction pipes a) Where heavy fuel oil is used, a suitable heating system
a) All suction pipes from fuel oil tanks and bunkers, is to be provided for storage tanks, settling tanks and
including those in the double bottom, are to be service tanks in order to ensure that the fuel oil has the
provided with valves. correct fluidity and the fuel pumps operate efficiently.
b) For storage tanks, filling pipes may also be used for b) Where necessary for pumping purposes, storage tanks
suction purposes. containing heavy fuel oil are to be provided with
c) Where the filling pipes to fuel oil bunkers and tanks are heating systems.
not led to the upper part of the such bunkers and tanks, c) Where necessary, pumps, filters, pipes and fittings are to
they are to be provided with non-return valves at their be provided with heat tracing systems.
ends, unless they are fitted with valves arranged in d) Where main or auxiliary engines are supplied with fuel
accordance with the requirements stated in [11.6.4]. oil which needs to be heated, arrangements are to be
made so that the engines can still operate if one oil
11.6.4 Remote control of valves (1/7/2004) heating system or the heating power source is out of
a) Every fuel oil pipe which, if damaged, would allow oil action. Such arrangements may consist of an alternative
to escape from a storage, settling or daily service tank supply of the engines in accordance with [11.10.2].
having a capacity of 500 l and above situated above the
double bottom, is to be fitted with a cock or valve 11.7.2 Tank heating systems (1/7/2004)
directly on the tank capable of being closed from a safe a) Fuel oil in storage tanks is not to be heated to
position outside the space in which such tanks are temperatures within 10°C below the flashpoint of the
situated in the event of a fire occurring in such space. fuel oil. Fuel oil in service tanks, settling tanks and any
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other tanks in the supply system may be heated above c) The capacity and arrangements of the fuel oil treatment
this limit, provided: system are to be suitable for ensuring availability of
• the length of the vent pipes from such tanks and/or a treated fuel oil for the Maximum Continuous Rating of
cooling device is sufficient for cooling the vapours the propulsion plant and normal operating load at sea of
to at least 10°C below the flashpoint of the fuel oil the generator plant.
and a temperature sensor is fitted in the vent pipe d) The capacity and arrangements of the fuel oil treatment
and adjusted to give an alarm if the temperature system are to be determined on the basis of the
should exceeds a limit set at 10°C below the requirements of the oil fuelled machinery manufacturer
flashpoint of the fuel, or the outlet of the vent pipes and the types of fuel (e.g. heavy fuel oil and marine
is located 3 m away from a source of ignition diesel oil) to be bunkered to the ship.
• the vent pipes are fitted with suitable flame screens
11.8.2 Drains (1/7/2020)
• there are no openings from the vapour space of the
fuel tanks into machinery spaces (bolted manholes a) Settling tanks and daily service tanks, are to be provided
are acceptable) with drains permitting the evacuation of water and
impurities likely to accumulate in the lower part of such
• enclosed spaces are not located directly over such
tanks.
fuel tanks, except for well ventilated cofferdams
If settling tanks are not provided, the fuel oil daily
• electrical equipment is not fitted in the vapour space
of the tanks, unless it is certified to be intrinsically service tanks are to be designed and constructed in such
a way as to direct water and sludge towards a drainage
safe.
outlet.
b) The temperature of the heating medium is not to exceed
220°C. b) Efficient means are to be provided for draining oily
water escaping from the drains.
c) Automatic control sensors are to be provided for each
heated tank to maintain the temperature of the fuel oil 11.8.3 Purifiers (1/7/2024)
below the limits prescribed in a) above.
a) Where fuel oil needs to be purified, at least two purifiers
d) Heated tanks are to be provided with temperature are to be installed on board, each capable of efficiently
measuring systems. purifying the amount of fuel oil necessary for the normal
operation of the engines.
11.7.3 Fuel oil heaters
Note 1: On ships with a restricted navigation notation where fuel
a) Where steam heaters or heaters using other heating oil needs to be purified, one purifier only may be accepted.
media are provided in fuel oil systems, they are to be
b) Subject to special consideration by the Society, the
fitted with at least a high temperature alarm or a low
capacity of the standby purifier may be less than that
flow alarm in addition to a temperature control, except
required in a), depending on the arrangements made for
where temperatures dangerous for the ignition of the
the fuel oil service tanks to satisfy the requirement in
fuel oil cannot be reached.
[11.10.2].
b) Electric heating of fuel oil is to be avoided as far as
practicable. c) The standby purifier may also be used for other services.
c) However, when electric heaters are fitted, means are to d) Each purifier is to be provided with an alarm in case of
be provided to ensure that heating elements are failures likely to affect the quality of the purified fuel oil.
permanently submerged during operation. In all cases a e) The amount of water reaching the oil fuelled
safety temperature switch is to be fitted in order to avoid machineryengine is to be not more than 0.3 % v/v or
a surface temperature of 220°C and above. It is to be: according to engine maker's recommendations.
• independent from the automatic control sensor f) Every attempt is to be made to reduce the amount of
• designed to cut off the electrical power supply in the catalyst fines to the lowest possible levels. The amount
event of excessive temperature of catalyst fines reaching the engine is normally not to
• provided with manual reset. exceed 10 ppm Al+Si. Exceptionally, this might rise to
15 ppm for short periods (i.e. few hours)Fuel treatment
d) Fuel oil heaters are to be fitted with relief valves leading system performance in the removal of catfines and
back to the pump suction concerned or to any other water is recommended to be regularly assessed, by
place deemed satisfactory. drawing and analyzing samples from before and after
the purifier plant and after the service tank to ensure
11.8 Design of fuel oil treatment systems that the catfines and water levels dot not exceed
maximum engine entry levels recommended by engine
11.8.1 General (1/7/2020) manufacturers.
a) Heavy fuel oils used in diesel engines are to be purified Note: Particle size has a significant influence on the
and filtered according to the engine manufacturer’s capacity of the centrifugal separators to lower the level
requirements. of catalyst fines in the fuel, with particles of 2 microns
b) Provisions are to be made to avoid inadvertent entry of or less being particularly difficult to remove. The
non-purified heavy fuel into the daily service tanks, in presence of particles of 2 microns size or lower may
particular through the overflow system. cause difficulties in achieving the 10 ppm limit. Engine
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manufacturer recommendations are also to be referred propulsion and electrical generating purposes where the
to for any further system specific recommendations. fuel conditioning system is installed between fuel oil
g) Centrifugal separators are to be certified for a flow rating service tanks and the inlet to the combustion system.
in accordance with a recognised standard, e.g. EN
11.10.2 Fuel oil service tanks (1/7/2022)
17763:2022, Centrifuges - Marine fuel centrifuges -
Determination of particle separation performance and a) Two fuel oil service tanks for each type of fuel used on
certified flow rate (CFR) under defined test conditions, board necessary for propulsion and vital systems, or
CEN Workshop Agreement (CWA) 15375 (latest equivalent arrangements, are to be provided on each
revision). new ship, with a capacity of at least 8 h at maximum
continuous rating of the propulsion plant and normal
h) Centrifugal separators are to meet the safety
operating load at sea of the generator plant.
requirements of a recognized standard, e.g. EN 12547,
Centrifuges - Common safety requirements. b) Where main engines, auxiliary engines and boilers are
operated with heavy fuel oil, the following equivalent
arrangements may be accepted for fuel oil service tanks:
11.9 Fuel oil pumps
• one heavy fuel oil service tank with a capacity of at
11.9.1 General (1/7/2020) least 8 h at maximum continuous rating of the
Fuel pump capacity is to ensure that fuel flow rate through propulsion plant and normal operating load at sea of
the fuel system is sufficient to maintain the installed oil the generator plant and of the auxiliary boiler
fuelled machinery's fuel consumption during normal • one marine diesel oil service tank with a capacity of
operation at maximum continuous rating of the propulsion at least 8 h at maximum continuous rating of the
plant and normal operating load at sea of the generator propulsion plant and normal operating load at sea of
plant. the generator plant and of the auxiliary boiler.
Satisfactory fuel pump operation is to be verified according c) Where main engine and auxiliary boilers are operated
to the Society requirements after installation on board. with heavy fuel oil and auxiliary engines are operated
with marine diesel oil, the following equivalent
11.9.2 Fuel oil pumps arrangement (1/7/2020)
arrangements may be accepted for fuel oil service tanks:
The fuel oil pumps used in fuel oil treatment and transfer
systems and operating on RMF and DMF are to comply with • one heavy fuel oil service tank with a capacity of at
the requirements in [11.9.3] that are applicable to primary least 8 h at maximum continuous rating of the
and secondary essential services fuel oil pumps (main and propulsion plant and normal operating load at sea of
stand-by) which include: separator fuel oil supply pumps; the auxiliary boiler
booster pumps; feeder pumps; fuel valve cooling pumps (in • two marine diesel oil service tanks, each with a
systems which use fuel oil for this service); and fuel oil capacity of at least the higher of:
transfer pumps. • 8 h at normal operating load at sea of the
auxiliary engines and auxiliary boilers
11.9.3 Requirements for fuel oil pumps arrangement
(1/7/2024) • 4 h at maximum continuous rating of the
propulsion plant and normal operating load at
For ships intending to use RMF and/or DMF in non-
sea of the generator plant and of the auxiliary
restricted areas and marine fuels with a Sulphur content not
boiler.
exceeding 0.10 % m/m and minimum viscosity of 2.0 cSt in
emission control areas, the fuel oil pumps arrangement is to d) The above calculated capacities are to be increased by
be in compliance with SOLAS regulation II-I/26.3.4 as the volume below the suction pipe due to the
interpreted by MSC.1/Circ.1467 (reflecting IACS UI SC255). requirement in [11.10.4] a).
Note 1: The requirement in [11.10.2] need not be applied to cargo
11.10 Design of fuel supply systems ships of less than 500 tons gross tonnage:
• intended for restricted service or
11.10.1 General (1/7/2024) • having engines declared suitable for prolonged operation on
a) In ships where heavy fuel oil and marine diesel oil are untreated fuel oil.
used, a change-over system from one fuel to the other is
to be provided. This system is to be so designed as to 11.10.3 Fuel oil supply to boilers (1/7/2011)
avoid: a) In ships where boilers burning oil under pressure are
• overheating of marine diesel oil installed to supply steam for propulsion purposes and
• inadvertent ingress of heavy fuel oil into marine essential services (such as propulsion machinery,
diesel oil tanks. machinery serving essential services or systems essential
for propulsion and other essential services, e.g. heavy
b) When necessary, arrangements are to be made for fuel oil heating system), the fuel oil supply system is to
cooling the marine diesel oil from engine return lines. include at least two units, each one comprising:
c) The fuel oil treatment system is to be provided with • a suction filter
redundancy so that failure of one system will not render
• an independent pump
the other system(s) inoperative. Arrangements are to
ensure that any single failure in the system will not • a heater in the case of heavy fuel oil
interrupt the supply of clean fuel to machinery used for • a discharge filter.
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b) Alternative arrangements using double filters are Valves or cocks used for this purpose are to be fitted
acceptable provided the element of one such filter can with drain pipes led to a safe location.
be cleaned while the other operates. d) Oil filters are to be so located that in the event of a
c) The fuel oil supply system is to be capable of supplying leakage the fuel oil cannot be pulverised onto the
the fuel oil necessary to generate enough steam for exhaust manifold.
propulsion purposes and essential services with one unit e) When a fuel oil booster pump is fitted which is essential
out of action. to the operation of the main engine, a standby pump,
d) A quick-closing valve is to be provided on the fuel connected ready for immediate use, is to be provided.
supply to the burners of each boiler, arranged to be The standby pump may be replaced by a complete spare
easily operated in case of emergency, either directly or pump of appropriate capacity ready to be connected, in
by remote control. the following cases:
e) The fuel supply to the burners is to be capable of being • where two or more main engines are fitted, each
automatically cut off when required under Sec 3, with its own booster pump
[5.1.8].
• in ships having main engines each with an output
f) Burners are to comply with Section Sec 3, [2.2.5]. not exceeding 375 kW.
g) Where burners are provided with fuel oil flow-back to For ships intending to use Heavy Fuel Oil (HFO) or
the pump suctions or other parts under pressure, non- Marine Diesel Oil (MDO) in some areas and marine
return devices are to be provided to prevent fuel oil fuels with a lower viscosity in other areas, either:
from flowing back to the burners when the oil supply is • each of the fuel oil pumps (main one and stand-by
cut off. one) is suitable to supply both types of fuel at the
h) For the starting-up of boilers, an auxiliary fuel oil unit required capacity for normal operation of
not requiring power from shore is to be provided. propulsion machinery, or
i) Where fuel oil is supplied to the burners by gravity, a • each of the fuel oil pumps (main one and stand-by
double filter satisfying the provisions of a) is to be one) is suitable to supply both types of fuel but one
provided in the supply line. pump alone is not capable of delivering at the
j) Fuel oil supply systems are to be entirely separate from required capacity, then both pumps may operate in
feed, bilge, ballast and other piping systems. parallel to achieve the required capacity for normal
operation of propulsion machinery but one
11.10.4 Fuel oil supply to internal combustion additional (third) fuel oil pump shall be fitted. The
engines (1/7/2024) additional pump shall, when operating in parallel
a) The suctions of engine fuel pumps are to be arranged at with one of the other pumps, be suitable for and
an appropriate distance above the fuel-oil treatment capable of delivering fuel at the required capacity
tank drain point in order to prevent accumulated water for normal operation of the propulsion machinery
and sludge being drawn into the fuel oil treatment • two separate fuel oil pumps (one main and one
system (e.g. 5% of the tank volume is below the suction stand-by) are to be fitted, each capable of and
pipe). suitable for supplying low viscosity fuels at the
b) Suitable filters are to be provided on the fuel oil line to required capacity for normal operation of
the injection pumps. propulsion machinery.
Fuel filters are to reduce the level of contaminants (i.e. f) Where fuel oils require pre-heating in order to have the
metallic particles / sediments etc.) in the fuel to a level appropriate viscosity when being injected in the engine,
commensurate with the downstream equipment the following equipment is to be provided in the fuel oil
manufacturers' requirements. line:
Internal combustion engines intended for main • one viscosity control and monitoring system
propulsion are to be fitted with at least two filters, or • two pre-heaters, one serving as a standby for the
similar devices, so arranged that one of the filters can other.
be overhauled while the other is in use.
g) In case of unrestricted navigation, automatic viscosity
Note 1: Where the propulsion plant consists of: controllers are to be maintained as the primary means to
• two or more engines, each one with its own filter, or control required injection viscosity, with automatic
• one engine with an output not exceeding 375 kW, temperature control being only a secondary back up
the second filter may be replaced by a readily accessible and option. In case of restricted navigation, manual
easily replaceable spare filter. temperature control can be accepted.
c) Oil filters fitted in parallel are to be so arranged as to h) Excess fuel oil from pumps or injectors is to be led back
minimise the possibility of a filter under pressure being to the service or settling tanks, or to other tanks
opened by mistake. intended for this purpose.
Filter chambers are to be provided with suitable means i) De-aeration tanks fitted in pressurised fuel oil return
for: lines are to be equipped with at least:
• ventilating when put into operation • an automatic venting valve or equivalent device
• de-pressurising before being opened. discharging to the daily service tank
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Pt C, Ch 1, Sec 10
c) Low pressure lines (i.e. lines between pressure reducing • for gas bottles, against sunrays and atmospheric agents, by
devices and distribution stations) are to comply with the means of watertight covers,
following provisions: • for the associated valves, piping and fittings, by means of steel
• pipes are to be of seamless steel covers, metal grids or similar devices.
Such means of protection are to be easily removable to allow bottle
• piping is to have a thickness of not less than:
removal, when necessary.
- 2,5 mm when installed in the open air,
When the total number of bottles exceeds 8, acetylene bottles are
- 2 mm otherwise. to be separated from oxygen bottles.
• supply lines to each distribution station are to
include, at the station inlet: 19.4.2 Distribution stations
Distribution stations are to be located in the engine room or
- a stop valve to be kept shut when the station is
in the workshop, in a well-ventilated position and protected
not working,
against possible mechanical damage.
- devices to protect the supply lines from back
Note 1: On pontoons and service working ships, distribution
flow of gas or flame passage. stations may be installed in the open air, enclosed in a cabinet with
d) Safety valves are to be provided on the low pressure a locked door, or in controlled access areas, to the satisfaction of
side of the pressure reducing devices and led to the the Society.
open air at least 3 m above the deck in a safe location
where no source of ignition is present. 19.4.3 Piping
a) Piping is not to be led through accommodation or
19.4 Arrangement of oxyacetylene welding service spaces.
systems b) Piping is to be protected against any possible
mechanical damage.
19.4.1 Gas bottle rooms (1/7/2010)
c) In way of deck or bulkhead penetrations, piping is to be
a) The gas bottle room is to be located in an independent
suitably enclosed in sleeves so arranged as to prevent
space over the highest continuous deck and provided
any fretting of the pipe with the sleeve.
with direct access from outside. The limiting bulkheads
and decks are to be made of steel. The limiting 19.4.4 Signboards
bulkheads and decks between the room and other Signboards are to be posted on board the ship in
enclosed spaces are to be gas-tight. accordance with Tab 33.
b) When the total number of gas bottles, including
Table 33 : Signboards
possible spare bottles which are not connected to the
plant, does not exceed 8, acetylene and oxygen bottles
may be installed in the same room. Otherwise, Location of the signboard Signboard to be posted
acetylene and oxygen bottles are to be separated by a in the gas bottle room diagram of the oxyacetylene
gas-tight bulkhead. plant
c) The bottle room is to be adequately insulated and fitted “no smoking”
with ventilation systems capable of providing at least six
in way of: “to be kept shut when distribu-
air changes per hour based on the gross volume of the tion stations are not working”
• bottle stop valves
room. The ventilation system is to be independent of
• distribution station
ventilation systems of other spaces. The space within 3
stop valves
m from the mechanical ventilation exhaust or 1 m from
the natural ventilation exhaust is to be considered a in way of the pressure indication of the maximum
hazardous area. The fan is to be of non-sparking reducing devices allowable pressure at the pres-
construction. Small storage spaces provided with sure reducing device outlet
sufficiently large openings for natural ventilation need in way of the safety valve “no smoking”
not be fitted with mechanical ventilation. discharge outlet
Electrical equipment installed within the storage room,
including the ventilation fan motor, is to be of the 20 Exhaust gas treatment systems
certified safe type.
Where no storage room is provided, the gas cylinders 20.1 Application
may be placed in an open storage area. In such cases
20.1.1 (1/1/2018)
they are to be shaded from heat sources and protected
against mechanical, weather and se damage. This Article applies to:
• exhaust gas cleaning systems (scrubbers)
d) The gas bottle room is not to be used for other services
on board. Flammable oil or gas piping, except that • selective catalytic reduction (SCR) systems.
related to the oxyacetylene welding plant, is not to be
20.1.2 Applicability of other Rules (1/4/2021)
led through this room.
Exhaust gas treatment systems are regarded as non-essential
Note 1: On pontoons and service working ships, gas bottles may
be installed on open deck in a safe position to the satisfaction of the
services, therefore:
Society. In such case, appropriate protection is to be provided: • redundancy is not necessary, and
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Pt C, Ch 1, Sec 10
• when they are adjacent to the urea integral tanks and such case, type approved plastic piping may be accepted
there are possible leak points (e.g. manhole, fittings) even if it has not passed a fire endurance test. Reductant
from these tanks; or tanks and pipes/piping systems are to be made with a
material compatible with reductant or coated with
• when the urea piping systems pass through these
appropriate anti-corrosion coating.
compartments, unless the piping system is made of steel
or other equivalent material with melting point above For the protection of crew members, the ship is to have on
925 degrees C and with fully welded joints. board suitable personnel protective equipment. Eyewash
are to be provided, the location and number of these
Alternatively, where a urea storage tank is located within an eyewash stations and safety showers are to be derived from
engine room a separate ventilation system is not required the detailed installation arrangements.
when the general ventilation system for the space is
Urea storage tanks are to be arranged so that they can be
arranged so as to provide an effective movement of air in
emptied of urea and ventilated by means of portable or
the vicinity of the storage tank and is to be maintained in
permanent systems.
operation continuously except when the storage tank is
empty and has been thoroughly ventilated.
20.7 Use of aqueous solution of NaOH or
Each urea storage tank is to be provided with temperature
and level monitoring arrangements. High and low level Ca(OH)2 in exhaust gas cleaning
alarms together with high and low temperature alarms are systems
also to be provided.
20.7.1 General (1/7/2022)
Where urea based ammonia solution is stored in integral
tanks, the following are to be considered during the design In this context, the term “chemical treatment fluid” means
and construction: the aqueous solution of sodium hydroxide (NaOH) or
calcium hydroxide (Ca(OH)2) that has corrosive properties
• These tanks may be designed and constructed as
or are considered to represent a hazard to personnel (see
integral part of the hull, (e.g. double bottom, wing
[20.7.2]).
tanks).
For exhaust gas cleaning systems using chemicals other
• These tanks are to be coated with appropriate anti-
than the above, safety measures are to be taken according
corrosion coating and cannot be located adjacent to any
to the result of a risk assessment to be conducted to analyze
fuel oil and fresh water tank.
the risks, in order to eliminate or mitigate the hazards to
• These tanks are to be designed and constructed as per personnel brought by the use of such exhaust gas cleaning
the structural requirements applicable to hull and systems, to an extent equivalent to systems complying with
primary support members for a deep tank construction. [20.7.2] a) to [20.7.2] p).
• These tanks are to be included in the ship's stability
calculation. 20.7.2 Requirements (1/7/2024)
The reductant piping and venting systems are to be a) The storage tank for chemical treatment fluids is to be
independent of other ship service piping and/or systems. arranged so that any leakage will be contained and
Reductant piping systems are not to be located in prevented from making contact with heated surfaces.
accommodation, service spaces, or control stations. The All pipes or other tank penetrations are to be provided
vent pipes of the storage tank are to terminate in a safe with manual closing valves attached to the tank. In
location on the weather deck and the tank venting system is cases where such valves are provided below top of tank,
to be arranged to prevent entrance of water into the urea they are to be arranged with quick acting shutoff valves
tank. which are to be capable of being remotely operated
from a position accessible even in the event of chemical
Reductant tanks are to be of steel or other equivalent treatment fluid leakages. Tank and piping arrangements
material with a melting point above 925 degrees C. are to be approved.
Note 1:
b) The storage tank is to be protected from excessively high
Material requirement “to be of steel or other equivalent material”
or low temperatures applicable to the particular
with a melting point above 925 degrees C is not applicable for
concentration chemical treatment fluids. Depending on
integral tanks on FRP vessels such as those listed below, provided
that the integral tanks are coated and/or insulated with a self- the operational area of the ship, this may necessitate the
extinguishing material. fitting of heating and/or cooling systems.
• FRP vessels complying with Regulation 17 of SOLAS Chapter c) If a storage tank for chemical treatment fluids is installed
II-2 based upon its associated IMO guidelines in a closed compartment, the area is to be served by an
(MSC.1/Circ.1574), and effective mechanical ventilation system of extraction
• FRP vessels exempted from the application of SOLAS e.g., type providing not less than 6 air changes per hour
yachts, fast patrol, navy vessels, etc., generally of less than 500 which is independent from the ventilation system of
gross tonnage, subject to yacht codes or flag regulations. other spacesaccommodation, service spaces, or control
Pipes/piping systems are to be of steel or other equivalent stations. The ventilation system is to be capable of being
material with melting point above 925 degrees C, except controlled from outside the compartment. A warning
downstream of the tank valve, provided this valve is metal notice requiring the use of such ventilation before
seated and arranged as fail-to-closed or with quick closing entering the compartment is to be provided outside the
from a safe position outside the space in the event of fire; in compartment adjacent to each point of entry.
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d) The storage tank may be located within the engine arranged to prevent entrance of water into the tank for
room. In this case, the requirements of [20.7.2], c) are to chemical treatment fluids.
be complied with, except that a separate ventilation j) Storage tanks and pipes/piping systems and drip trays for
system is not required when the general ventilation chemical treatment fluids which transfer undiluted
system for the space providing not less than 6 air chemical treatment fluids are to be of steel or other
changes per hour is arranged so as to provide an equivalent material with a melting point above 925
effective movement of air in the vicinity of the storage degrees C.
tank and is maintained in operation continuously except
when the storage tank is empty and has been thoroughly k) Storage tanks and pipes/piping systems for chemical
ventilated. treatment fluids are to be made with a material
compatible with chemical treatment fluids, or coated
e) Each storage tank for chemical treatment fluids is to be
with appropriate anticorrosion coating.
provided with level monitoring arrangements and
high/low level alarms. In cases where heating and/or Note 1: Several metals are incompatible with the chemical
cooling systems are provided, high and/or low treatment fluids, e.g. NaOH is incompatible with zinc,
temperature alarms or temperature monitoring are also aluminum, etc.
to be provided accordingly. l) Regardless of design pressure and temperature, piping
f) The storage tanks are to have sufficient strength to systems containing chemical treatment fluids only are to
withstand a pressure corresponding to the maximum comply with the requirements applicable to Class I
height of a fluid column in the overflow pipe, with a piping systems. As far as practicable, e.g. except for the
minimum of 2,4 m above the top plate taking into flange connections that connect to tank valves, the
consideration the specific density of the treatment fluid. piping systems are to be joined by welding.
g) Where chemical treatment fluid is stored in integral m) The following connections are to be screened and fitted
tanks, the following are to be considered during the with drip trays to prevent the spread of any spillage
design and construction: where they are installed:
1) These tanks may be designed and constructed as 1) Detachable connections between pipes (flanged
integral part of the hull, (e.g. double bottom, wing connections and mechanical joints, etc.);
tanks). 2) Detachable connections between pipes and
2) These tanks are to be coated with appropriate anti- equipment such as pumps, strainers, heaters, valves;
corrosion coating and are to be segregated by and
cofferdams, void spaces, pump rooms, empty tanks 3) Detachable connections between equipment
or other similar spaces so as to not be located mentioned in the above subparagraph.
adjacent to accommodation, cargo spaces
The drip trays are to be fitted with drain pipes which
containing cargoes which react with chemical
lead to appropriate tanks, such as residue tanks, which
treatment fluids in a hazardous manner as well as
are fitted with high level alarm, or are to be fitted with
any food stores, oil tanks and fresh water tanks.
alarms for leak detection. In cases where such tank is an
3) These tanks are to be designed and constructed as integral tank, [20.7.2] g), 1) and [20.7.2] g), 2) are to
per the structural requirements applicable to hull be applied to the tank.
and primary support members for a deep tank
n) For the protection of crew members, the ship is to have
construction.
on board suitable personnel protective equipment. The
4) These tanks are to be included in the ship’s stability number of personnel protective equipment carried
calculation. onboard is to be appropriate for the number of
h) The requirements specified in [20.7.2] c) also apply to personnel engaged in regular handling operations or
closed compartments normally entered by persons: that may be exposed in the event of a failure; but in no
1) when they are adjacent to the integral storage tank case is there to be less than two sets available onboard.
for chemical treatment fluids and there are possible o) Personnel protective equipment is to consist of
leak points (e.g. manhole, fittings) from these tanks; protective clothing, boots, gloves and tight-fitting
or goggles.
2) when the treatment fluid piping systems pass Eyewash and safety showers are to be provided, the
through these compartments, unless the piping location and number of these eyewash stations and
system is made of steel or other equivalent material safety showers are to be derived from the detailed
with melting point above 925 degrees C and with installation arrangements. As a minimum, the following
fully welded joints. stations are to be provided:
i) The chemical treatment fluid piping and venting systems 1) In the vicinity of transfer or treatment pump
are to be independent of other ship service piping locations. If there are multiple transfer or treatment
and/or systems. The chemical treatment fluid piping pump locations on the same deck then one eyewash
systems are not to be located in accommodation, and safety shower station may be considered for
service spaces, or control stations. The vent pipes of the acceptance provided that the station is easily
storage tank are to terminate in a safe location on the accessible from all such pump locations on the
weather deck and the tank venting system is to be same deck.
232 RINA Rules 2024

Pt C, Ch 1, Sec 10
2) An eyewash station and safety shower is to be c) Where residue tanks used in closed loop chemical
provided in the vicinity of a chemical bunkering treatment systems are also used as the overflow tanks for
station on-deck. If the bunkering connections are chemical treatment fluids storage tank, the requirements
located on both port and starboard sides, then for storage tanks apply.
consideration is to be given to providing two
eyewash stations and safety showers, one for each 21 Certification, inspection and testing
side.
of piping systems
3) An eyewash station and safety shower is to be
provided in the vicinity of any part of the system
where a spillage/drainage may occur and in the 21.1 Application
vicinity of system connections/components that
21.1.1 This Article defines the certification and workshop
require periodic maintenance.
inspection and testing programme to be performed on:
p) Storage tanks for chemical treatment fluids are to be
• the various components of piping systems,
arranged so that they can be safely emptied of the fluids
and ventilated by means of portable or permanent • the materials used for their manufacture.
systems. On board testing is dealt with in Sec 16.
20.7.3 Requirement for Exhaust Gas Cleaning 21.2 Type tests
Systems discharge water pipeline (1/7/2024)
a) Overboard discharges from exhaust gas cleaning system 21.2.1 Type tests of flexible hoses and expansion
(EGCS) are not to be interconnected to other systems. joints (1/1/2006)
b) Due consideration is to be given to the location of a) Type approval tests are to be carried out on flexible
overboard discharges with respect to vessel propulsion hoses or expansion joints of each type and of sizes to be
features, such as thrusters, propellers or to prevent any agreed with the Society, in accordance with Tab 34 (see
discharge water onto survival craft during also the "Rules for the type approval of flexible hoses
abandonment. and expansion joints").
c) The piping material for the EGCS discharge water b) The flexible hoses or expansion joints subjected to the
pipeline system is to be selected based on the corrosive tests are to be fitted with their connections.
nature of the liquid media. Table 34 : Type tests to be performed for
d) Special attention is to be paid to the corrosion resistivity flexible hoses and expansion joints (1/7/2001)
of EGCS overboard discharge piping. Where applicable,
adequate arrangements are to be provided to prevent Flexible hoses Flexible hoses
galvanic corrosion due to the use of dissimilar metals. and expansion and expansion
e) In case distance piece is fitted between the outboard Test joints in joints in
discharge valve and the shell plating, it is to be made of non-metallic metallic
corrosion resistant material steel or be coated with an material material
anti-corrosive material suitable for the operating bursting test X X
environment. The thickness of the distance piece is to fire-resistance test X (1) NR
be at least the minimum values specified in 1) and 2) as vibration test (2) X X
below; otherwise Sch.160 thickness specified in piping pressure impulse test X (6) NR
standards is, as far as practicable, to be used. flexibility test X (3) NR
1) 12 mm in cases where complete pipe is made of elastic deformation test NR X
corrosion resistant material steel. cyclic expansion test (4) NR X
2) 15 mm of mild steel in cases where the inside the resistance of the material X X
pipe is treated with an anticorrosive coating or fitted (5)
with a sleeve of corrosion resistant material. (1) only for flexible hoses and expansion joints used in
flammable oil systems and, when required, in sea water
20.7.4 Miscellaneous (1/7/2022)
systems.
Tanks for residues generated from the exhaust gas cleaning
(2) the Society reserves the right to require the vibration test
process are to satisfy the following requirements: in case of installation of the components on sources of
a) The tanks are to be independent from other tanks, high vibrations.
except in cases where these tanks are also used as the (3) only for flexible hoses conveying low temperature flu-
over flow tanks for chemical treatment fluids storage ids.
tank. (4) the Society reserves the right to require the cyclic
b) Tank capacities are to be decided in consideration of the expansion test for piping systems subjected to expan-
number and kinds of installed exhaust gas cleaning sion cycles
systems as well as the maximum number of days (5) internal to the conveyed fluid to be demonstrated by
between ports where residue can be discharged ashore. suitable documentation and / or tests.
In the absence of precise data, a figure of 30 days is to (6) only for flexible hoses.
be used. Note 1: X = required, NR = not required.
RINA Rules 2024

...OMISSIS... 233
Pt C, Ch 1, Sec 14
SECTION 14 TURBOCHARGERS
1 General • cross sectional drawing with principal dimensions and

materials of housing components for containment
evaluation;
1.1 Application
• documentation of containment in the event of disc
1.1.1 (1/7/2016)
fracture;
These Rules apply to turbochargers with regard to design
• operational data and limitations as;
approval, type testing and certification and their matching
on engines. • maximum permissible operating speed (rpm);
1.1.2 (1/7/2016) • alarm level for over-speed;
Turbochargers are to be type approved, either separately or • maximum permissible exhaust gas temperature before
as a part of an engine. The requirements are written for turbine;
exhaust gas driven turbochargers, but apply in principle • alarm level for exhaust gas temperature before turbine;
also for engine driven chargers. • minimum lubrication oil inlet pressure;
The requirements escalate with the size of the • lubrication oil inlet pressure low alarm set point;
turbochargers. The parameter for size is the engine power
• maximum lubrication oil outlet temperature;
(at MCR) supplied by a group of cylinders served by the
actual turbocharger, (e.g. for a V-engine with one • lubrication oil outlet temperature high alarm set point;
turbocharger for each bank the size is half of the total • maximum permissible vibration levels, i.e. self- and
engine power). externally generated vibration.
1.1.3 (1/7/2016) (Alarm levels may be equal to permissible limits but
Turbochargers are categorized in three groups depending shall not be reached when operating the engine at
on served power by cylinder groups with: 110% power or at any approved intermittent overload
be-yond the 110%);
• Category A: < 1000 kW
• Category B: > 1000 kW and < 2500 kW • arrangement of lubrication system, all variants within a
range;
• Category C: > 2500 kW
• type test reports;
1.1.4 In the case of special types of turbochargers, the • test program.
Society reserves the right to modify the requirements of this
Section, demand additional requirements in individual 1.2.4 (1/7/2016)
cases and require that additional plans and data be For Category C turbochargers:
submitted. • drawings of the housing and rotating parts including
1.1.5 (1/1/2023) details of blade fixing;
Turbochargers with an existing type approval on 1 January • material specifications (chemical composition and
2023 are not required to be re-type approved in accordance mechanical properties) of all parts mentioned above;
with this Section until the current Type Approval reaches its • welding details and welding procedure of above
expiry date. mentioned parts, if applicable;
• documentation of safe torque transmission when the
1.2 Documentation to be submitted disc is connected to the shaft by an interference fit, see
1.2.1 (1/7/2016) [2.2.4];
The Manufacturer is to submit to the Society the following • information on expected lifespan, considering creep,
documents. low cycle fatigue and high cycle fatigue;
1.2.2 (1/7/2016) • operation and maintenance manuals (see Note 1).
For Category A turbochargers: Note 1: Applicable to two sizes in a generic range of turbochargers.
On request: 1.2.5 (1/7/2016)
• containment test report; When the turbochargers are manufactured by a licensee on
• cross sectional drawing with principal dimensions and the basis of a previously type approved licensor design, but
names of components; using parts manufactured outside of the licensor premises
• test program. and making use of other than the original licensor drawings
and specifications, the licensee is to submit, for each
turbocharger type, a list of all the drawings specified above,
1.2.3 (1/7/2016) indicating for each drawing the relevant number and
For Category B and C turbochargers: revision status from both licensor and licensee.
262 RINA Rules 2024

Pt C, Ch 1, Sec 14
Where the licensee proposes design modifications to Note 1: A generic range means a series of turbocharger which are
components, the associated documents are to be submitted of the same design, but scaled to each other.
by the licensee to the Society for approval, with a Licensor c) The minimum test speeds, relative to the maximum
statement confirming acceptance of the changes. permissible operating speed, are:
In all cases, the licensee is to provide the Surveyor entrusted • for the compressor:120%
to carry out the testing, with a complete set of the • for the turbine: 140% or the natural burst speed,
documents specified above. whichever is lower.
d) Containment tests shall be performed at workinga
2 Design and construction temperature which is not lower than the maximum
allowable temperature of the turbocharger to be
2.1 Application specified by the manufacturer.
2.1.1 (1/7/2016) e) Manufacturers are to determine whether cases more
critical than those defined in [2.3.3], c) and [2.3.3], d)
The turbochargers shall be designed to operate under
exist with respect to containment safety. Where such a
conditions given in Sec 1, [2.4] and Sec 1, [2.5].
case is identified, evidence of containment safety is also
The component lifetime and the alarm level for speed shall to be provided for that case.
be based on 45°C air inlet temperature.
f) A numerical analysis (simulation) such as Finite Element
Method (FEM) of sufficient containment integrity of the
2.2 Materials casing based on calculations by means of a simulation
2.2.1 (1/7/2016) model may be accepted in lieu of the practical
The requirements of Sec 5, [2.1.1] are to be complied with, containment test, provided that:
as far as applicable, at the Society’s discretion. • the numerical simulation model has been tested and
its suitability/accuracy has been proven by direct
comparison between calculation results and the
2.3 Design
practical containment test for a reference
2.3.1 Stress analyses (1/7/2016) application (reference containment test). This test
shall be performed at least once by the manufacturer
a) For Category B and C turbochargers, the manufacturer is
for acceptance of the numerical simulation method
to submit a calculation report concerning the stresses on
in lieu of tests;
each rotor under the most severe service conditions.
• the corresponding numerical simulation for the
b) The results of previous in-service experience on similar containment is performed for the same speeds as
applications may be considered by the Society as an specified for the containment test;
alternative to item a) above.
• material properties for high-speed deformations are
Data on the design service life and test results used to to be applied in the numeric simulation. The
substantiate calculation assumptions are also to be correlation between normal properties and the
provided. properties at the pertinent deformation speed are to
be substantiated;
2.3.2 Vibrations (1/7/2016)
• the design of the turbocharger regarding geometry
The range of service speeds is not to give rise to
and kinematics is to be similar to the turbocharger
unacceptable vibrations affecting the rotor and blades.
that was used for the reference containment test. In
Calculations of the critical speeds including details of their general, totally new designs will call for a new
basic assumptions are to be submitted for Category B and C reference containment test.
turbochargers. g) In cases where a totally new design is adopted for a
turbocharger for which an application for type approval
2.3.3 Containment (1/7/2024)
certification has been requested, new reference
a) Turbochargers shall fulfil containment in the event of a containment tests are to be performed.
rotor burst. This means that at a rotor burst no part may
Note 2: Totally new design means the principal differences
penetrate the casing of the turbocharger or escape between a new turbocharger and previous ones are related to
through the air intake. For documentation purposes geometry and kinematics. The turbochargers are to be regarded
(test/calculation), it shall be assumed that the discs as having a totally new design if the structure and/or material of
disintegrate in the worst possible way. the turbocharger casings are changed, or any of, but not limited
to, the following items is changed from the previous design.
b) For category B and C, containment shall be documented
by testing. Fulfilment of this requirement can be • Maximum permissible exhaust gas temperature
awarded to a generic range of turbochargers based on • Number of bearings
testing of one specific unit. Testing of a large unit is • Number of turbine blades
preferred as this is considered conservative for all • Number of turbine wheels and/or compressor wheels
smaller units in the generic range. In any case, it must • Direction of inlet air and/or exhaust gas (e.g., axial flow
be documented (e.g. by calculation) that the selected orientation, radial flow orientation)
test unit really is representative for the whole generic • Type of the turbocharger drive (e.g., axial turbine type,
range. radial turbine type, mixed flow turbine type).
RINA Rules 2024 263

Pt C, Ch 1, Sec 14
2.3.4 Disc-shaft shrinkage fit (1/7/2016) The manufacturer's requirements relative to the welding of
For Category C turbochargers, in cases where the disc is turbine rotors or major forged or cast pieces, where
connected to the shaft with interference fit, calculations permitted, are to be readily identifiable by the Society in the
shall substantiate safe torque transmission during all plans submitted for approval.
relevant operating conditions such as maximum speed, Requirements relative to fabrication, welding, heat
maximum torque and maximum temperature gradient treatments, examinations, testing and acceptance will be
combined with minimum shrinkage amount. stipulated on a case by case basis.
In general, all welding is to be carried out by qualified
2.3.5 Bearings (1/7/2013) welders in accordance with qualified welding procedures
a) Turbine bearings are to be so located that their using approved consumables.
lubrication is not impaired by overheating from hot
gases or adjacent hot parts. 2.4 Alarms and Monitoring
b) Lubricating oil is to be prevented from dripping on high 2.4.1 (1/7/2016)
temperature parts. For all turbochargers of Categories B and C, indications and
alarms as listed in Tab 1 are required.
c) Roller bearings are to be identifiable and are to have a
life adequate for their intended purpose. 2.4.2 (1/7/2016)
Indications may be provided at either local or remote
2.3.6 Welded fabrication (1/7/2013) locations.
Table 1 (1/7/2016)
Category of Turbochargers
Pos. Monitored Parameters B C Notes
Alarm Indication Alarm Indication
1 Speed High (4) X (4) High (4) X (4)
2 Exhaust gas at each High (1) X (1) High X High temp. alarms for each cylinder at engine is
turbocharger inlet, acceptable (2)
temperature
3 Lub. oil at turbo- High X If not forced system, oil temperature near bear-
charger outlet, temper- ings
ature
4 Lub. oil at turbo- Low X Low X Only for forced lubrication systems (3)
charger outlet, temper-
ature
(1) For Category B turbochargers, the exhaust gas temperature may be alternatively monitored at the turbocharger outlet, provided
that the alarm level is set to a safe level for the turbine and that correlation between inlet and outlet temperatures is substanti-
ated.
(2) Alarm and indication of the exhaust gas temperature at turbocharger inlet may be waived if alarm and indication for individual
exhaust gas temperature is provided for each cylinder and the alarm level is set to a value safe for the turbocharger.
(3) Separate sensors are to be provided if the lubrication oil system of the turbocharger is not integrated with the lubrication oil sys-
tem of the diesel engine or if it is separated by a throttle or pressure reduction valve from the diesel engine lubrication oil sys-
tem.
(4) On turbocharging systems where turbochargers are activated sequentially, speed monitoring is not required for the turbo-
charger(s) being activated last in the sequence, provided all turbo-chargers share the same intake air filter and they are not fitted
with waste gates.
3 Type tests, material tests, workshop The type test for a generic range of turbochargers may be
carried out either on an engine (for which the turbocharger
inspection and testing, certification is foreseen) or in a test rig.
3.1.3 (1/7/2024)
3.1 Type testing
Turbochargers for the low, medium, and high-speed engines
3.1.1 (1/7/2016) are to be subjected to at least 500 load cycles at the limits
of operation. This test may be waived if the turbocharger
Applicable to Categories B and C.
together with the engine is subjected to this kind of low
3.1.2 (1/7/2016) cycle testing, according to Sec 2 The suitability of the
264 RINA Rules 2024

Pt C, Ch 1, Sec 14
turbocharger for such kind of operation is to be housing with the corresponding pressure ratio. The over-
preliminarily stated by the manufacture. speed test may be waived for forged wheels that are
3.1.4 (1/7/2016) individually controlled by an approved non-destructive
The rotor vibration characteristics shall be measured and method.
recorded in order to identify possible sub-synchronous
vibrations and resonances. 3.3 Type approval certificate and its validity
3.1.5 (1/7/2016) 3.3.1 (1/7/2016)
The type test shall be completed by a hot running test at Subject to the satisfactory outcome of the type tests
maximum permissible speed combined with maximum specified in [3.1] and a factory audit specified in [3.2.1], the
permissible temperature for at least one hour. After this test, Society will issue to the turbocharger Manufacturer a Type
the turbo-charger shall be opened for examination, with Approval Certificate valid for all turbochargers of the same
focus on possible rubbing and the bearing conditions. type.
3.1.6 (1/7/2016) Where changes are made to a turbocharger and upon
Normally the surveyor's presence during the various parts of satisfactory review of documents as per [1.2.2], the
the type tests is required. extension to the modified turbocharger of the validity of the
type tests and containment test previously carried out will
3.2 Workshop inspections and testing be evaluated on a case by case basis.
3.2.1 (1/7/2016)
3.4 Testing certification
The manufacturer shall adhere to a quality system designed
to ensure that the designer's specifications are met, and that 3.4.1 (1/7/2024)
manufacturing is in accordance with the approved Turbochargers shall be delivered with:
drawings; the verification of compliance with this
• For category C, a society certificate, which atas a
requirement is within the scope of a Type approval.
minimum cites the applicable type approval and the
3.2.2 (1/7/2024) Alternative Certification Scheme (ACS), when ACS
For category C, this shall be verified by means of periodic appliescable.
product audits of an Alternative Certification Scheme (ACS; • For category B, a work's certificate, which atas a
see RINA Rules for testing and certification of marine minimum cites the applicable type approval, which
materials and equipment, Chapter 2, [4]) by the Society. includes production assessment according to [3.2.1].
These audits shall focus on:
3.4.2 (1/7/2016)
• chemical composition of material for the rotating parts;
The same applies to replacement of rotating parts and
• mechanical properties of the material of a representative casing.
specimen for the rotating parts and the casing;
3.4.3 (1/7/2016)
• UT and crack detection of rotating parts;
Rotating parts of category C turbochargers are to be marked
• dimensional inspection of rotating parts;
for easy identification with the appropriate certificate.
• rotor balancing;
• hydraulic testing of cooling spaces to 4 bars or 1.5 times 3.4.4 (1/7/2016)
maximum working pressure, whichever is higher; Alternatively to the Alternative Certification Scheme and
• overspeed test of all compressor wheels for a duration of periodic product audits according to [3.2.2] individual
3 minutes at either 20% above alarm level speed at certification of a turbocharger and its parts may be made at
room temperature or 10% above alarm level speed at the discretion of the Society. However, such individual
45°C inlet temperature when tested in the actual certification of category C turbocharger and its parts shall
also be based on test requirements specified in [3.2.2].
RINA Rules 2024 265

Pt C, Ch 1, App 1
APPENDIX 1 CHECK FOR SCANTLINGS OF CRANKSHAFTS

FOR DIESEL ENGINES
1 General stress) (see [5]). This equivalent alternating stress is then

compared with the fatigue strength of the selected crank-
shaft material (see [6]). This comparison will show whether
1.1 Application or not the crankshaft concerned is dimensioned adequately
(see [7]).
1.1.1 (1/1/2007)
a) The requirements for the check of scantlings of crank- 2 Calculation of stresses

shaft given in this Appendix apply to diesel engines as
per Sec 2, [5.1.1] a) and b) capable of continuous oper-
ation of their maximum continuous power P as defined 2.1 Calculation of alternating stresses due
in Sec 2, [1.5.3], at the nominal maximum speed n. to bending moments and radial forces
Where a crankshaft design involves the use of surface
treated fillets, or when fatigue parameter influences are 2.1.1 Assumptions (1/1/2007)
tested, or when working stresses are measured, the rele-
vant documents with calculations/analysis are to be The calculation is based on a statically determined system,
submitted to the Society in order to demonstrate equiva- composed of a single crankthrow supported in the centre of
lence to these requirements. adjacent main journals and subject to gas and inertia forces.
The bending length is taken as the length between the two
b) The requirements of this Appendix apply only to solid main bearing mid-points (distance L3, see Fig 1).
forged and semi-built crankshafts of forged or cast steel,
with one crankthrow between main bearings. The bending moments MBR, MBT are calculated in the rele-
vant section based on triangular bending moment diagrams
due to the radial component FR and tangential component
1.2 Documentation to be submitted FT of the connecting rod force, respectively (see Fig 1a)).
1.2.1 (1/1/2007) For crankthrows with two connecting rods acting upon one
Required data for the check of the scantlings are indicated crankpin, the relevant bending moments are obtained by
in the specific Society form as per item 1) of Sec 2, Tab 1. superposition of the two triangular bending moment dia-
grams according to phase (see Fig 1b)).
1.3 Principles of calculation a) Bending moments and radial forces acting in web
1.3.1 (1/1/2007) The bending moment MBRF and the radial force QRF are
taken as acting in the centre of the solid web (distance
The design of crankshafts is based on an evaluation of safety
L1) and are derived from the radial component of the
against fatigue in the highly stressed areas.
connecting rod force.
The calculation is also based on the assumption that the
The alternating bending and compressive stresses due to
areas exposed to highest stresses are:
bending moments and radial forces are to be related to
• fillet transitions between the crankpin and web as well the cross-section of the crank web. This reference sec-
as between the journal and web, tion results from the web thickness W and the web
width B (see Fig 2).
• outlets of crankpin oil bores.
Mean stresses are disregarded.
When journal diameter is equal to or larger than crankpin
diameter, the outlets of main journal oil bores are to be b) Bending acting in outlet of crankpin oil bore
formed in a similar way to the crankpin oil bores; otherwise, The two relevant bending moments are taken in the
separate documentation of fatigue safety may be required. crankpin cross-section through the oil bore (see Fig 3).
Calculation of crankshaft strength consists initially in deter- The alternating stresses due to these bending moments
mining the nominal alternating bending (see [2.1]) and are to be related to the cross-sectional area of the axially
nominal alternating torsional stresses (see [2.2]) which, bored crankpin.
multiplied by the appropriate stress concentration factors
(see [3]), result in an equivalent alternating stress (uni-axial Mean bending stresses are disregarded.

Pt C, Ch 1, App 1
The maximum equivalent Von Mises stress 3P in the journal residual stresses in the fillets, this approach cannot be
fillet is evaluated. The SCF in the journal fillet can be deter- applied.
mined in two ways as shown in a) and b) below. One advantage of this approach is the rather high number
a) Method 1 of specimens which can be then manufactured. Another
The results from 3-point and 4-point bending are com- advantage is that the tests can be made with different stress
bined as follows: ratios (R-ratios) and/or different modes e.g. axial, bending
and torsion, with or without a notch. This is required for
3P = N3P x B + Q3P x Q
evaluation of the material data to be used with critical plane
where: criteria.
3P : as found by the FE calculation
10.1.3 Full-size crank throw testing (1/7/2018)
N3P : Nominal bending stress in the web centre
For crankshafts with surface treatment the fatigue strength
due to the force F3P [N] applied to the
can only be determined through testing of full size crank
centreline of the actual connecting rod; see
throws. For cost reasons, this usually means a low number
Fig 10
of crank throws. The load can be applied by hydraulic actu-
B : as determined in [9.3.3] ators in a 3- or 4- point bending arrangement, or by an
Q3P : Q3P / (BW) where Q3P is the radial (shear) exciter in a resonance test rig. The latter is frequently used,
force in the web due to the force F3P [N] although it usually limits the stress ratio to R = -1.
applied to the centreline of the actual con-
necting rod; see also Fig 1. 10.2 Evaluation of test results
b) Method 2
10.2.1 Principles (1/7/2018)
In a statically determined system with one crank throw
Prior to fatigue testing the crankshaft must be tested as
supported by two bearings, the bending moment and
required by quality control procedures, e.g. for chemical
radial (shear) force are proportional. Therefore the jour-
composition, mechanical properties, surface hardness,
nal fillet SCF can be found directly by the 3-point bend-
hardness depth and extension, fillet surface finish, etc.
ing FE calculation.
The SCF is then calculated according to: The test samples should be prepared so as to represent the
"lower end" of the acceptance range e.g. for induction hard-
ened crankshafts this means the lower range of acceptable
 3P hardness depth, the shortest extension through a fillet, etc.
 BQ = ----------
-
 N3P Otherwise the mean value test results should be corrected
with a confidence interval: a 90% confidence interval may
For symbols, see item a) above.
be used both for the sample mean and the standard devia-
When using this method, the radial force and stress tion.
determination become superfluous. The alternating
The test results, when applied in this App 1, shall be evalu-
bending stress in the journal fillet as per [2.1.3] is then
ated to represent the mean fatigue strength, with or without
evaluated:
taking into consideration the 90% confidence interval as
mentioned above. The standard deviation should be consid-
 BG =   BQ   BFN ered by taking the 90% confidence into account. Subse-
quently the result to be used as the fatigue strength is then
Note that the use of this method does not apply to the
the mean fatigue strength minus one standard deviation.
crankpin fillet and that this SCF must not be used in
connection with calculation methods other than those If the evaluation aims to find a relationship between (static)
assuming a statically determined system. mechanical properties and the fatigue strength, the relation
must be based on the real (measured) mechanical proper-
ties, not on the specified minimum properties.
10 Guidance for Evaluation of Fatigue
The calculation technique presented in Chapter 2.4 was
Tests developed for the original staircase method. However, since
there is no similar method dedicated to the modified stair-
10.1 Introduction case method the same is applied for both.
10.1.1 (1/7/2018)
10.2.2 Staircase method (1/7/2018)
Fatigue testing can be divided into two main groups; testing
In the original staircase method, the first specimen is sub-
of small specimens and full-size crank throws. Testing can
jected to a stress corresponding to the expected average
be made using the staircase method or a modified version
thereof which is presented in this document. Other statisti- fatigue strength. If the specimen survives 107 cycles, it is
cal evaluation methods may also be applied. discarded and the next specimen is subjected to a stress that
is one increment above the previous, i.e. a survivor is
10.1.2 Small specimen testing (1/7/2018) always followed by the next using a stress one increment
For crankshafts without any fillet surface treatment, the above the previous. The increment should be selected to
fatigue strength can be determined by testing small speci- correspond to the expected level of the standard deviation.
mens taken from a full-size crank throw. When other areas When a specimen fails prior to reaching 107 cycles, the
in the vicinity of the fillets are surface treated introducing obtained number of cycles is noted and the next specimen

Pt C, Ch 1, App 1
10.4 Full size testing Furthermore, it is important that the test rig provides bound-
ary conditions as defined in [9.3.2] to [9.3.4].
10.4.1 Hydraulic pulsation (1/7/2018)
A hydraulic test rig can be arranged for testing a crankshaft The (static) mechanical properties are to be determined as
in 3-point or 4-point bending as well as in torsion. This stipulated by the quality control procedures.
allows for testing with any R-ratio.
Although the applied load should be verified by strain 10.4.2 Resonance tester (1/7/2018)
gauge measurements on plain shaft sections for the initia-
tion of the test, it is not necessarily used during the test for A rig for bending fatigue normally works with an R-ratio of -
controlling load. It is also pertinent to check fillet stresses 1. Due to operation close to resonance, the energy con-
with strain gauge chains. sumption is moderate. Moreover, the frequency is usually
relatively high, meaning that 107 cycles can be reached
within some days. Fig 14 shows a layout of the testing
arrangement.
The applied load should be verified by strain gauge meas-

urements on plain shaft sections. It is also pertinent to check
fillet stresses with strain gauge chains.
Figure 14 : Example of testing arrangement of the resonance tester for bending loading (1/7/2018)
Clamping around the journals must be arranged in a way A rig for torsion fatigue can also be arranged as shown in
that prevents severe fretting which could lead to a failure Figure 15. When a crank throw is subjected to torsion, the
under the edges of the clamps. If some distance between twist of the crankpin makes the journals move sideways. If
the clamps and the journal fillets is provided, the loading is one single crank throw is tested in a torsion resonance test
consistent with 4-point bending and thus representative for
rig, the journals with their clamped-on weights will vibrate
the journal fillets also.
heavily sideways.
In an engine, the crankpin fillets normally operate with an
R-ratio slightly above -1 and the journal fillets slightly This sideway movement of the clamped-on weights can be
below -1. If found necessary, it is possible to introduce a reduced by having two crank throws, especially if the
mean load (deviate from R = -1) by means of a spring cranks are almost in the same direction. However, the jour-
preload. nal in the middle will move more.
296 RINA Rules 2024

Pt C, Ch 1, App 1
Figure 15 : Example of testing arrangement of the resonance tester for torsion loading with double crank throw
section (1/7/2018)
Since sideway movements can cause some bending τDWCT : fatigue strength by torsion testing
stresses, the plain portions of the crankpins should also be for other parameters see items [2.1.3], [2.2.3] and [4]
provided with strain gauges arranged to measure any possi-
Related to crankpin oil bore:
ble bending that could have an influence on the test results.
Similarly, to the bending case the applied load shall be veri-
fied by strain gauge measurements on plain shaft sections. It  DWOT 9  TO 2
 v = ---   BO   1 + 2  1 + ---   --------
1
Q = --------------- ; -
is also pertinent to check fillet stresses with strain gauge v 3  4   BO 
chains as well.
where:
10.4.3 Use of results and crankshaft DWOT : fatigue strength by means of largest principal
acceptability (1/7/2024) stress from torsion testing
In order to combine tested bending and torsion fatigue Related toAt the journal diameterfillet:
strength results in calculation of crankshaft acceptability,
see [7], the Gough-Pollard approach and the maximum
–1
principal equivalent stress formulation can be applied for  BG  2   G  2
Q =   ------------- + ------------
the following cases:    DWJT   DWJT 
Related toAt the crankpin diameterfillet:
–1
 BG +  add 2   G  2
Q =   ------------------------
- + ------------
 BH  2   BH   2 –1    DWJT    DWJT 
Q =   --------------
- + --------------
   DWCT   DWCT 
where:
σDWJT : fatigue strength by bending testing
–1 τDWJT : fatigue strength by torsion testing
 BH +  add 2   H  2
Q =   ------------------------
- + -------------- for other parameters see items [2.1.3], [2.2.3] and [4]
   DWCT    DWCT 
In case increase in fatigue strength due to the surface treat-
where: ment is considered to be similar between the above cases, it
DWCT : fatigue strength by bending testing is sufficient to test only the most critical location according
RINA Rules 2024 297

...OMISSIS...
Pt C, Ch 1, App 17
APPENDIX 17 TYPE TESTING PROCEDURE OF EXPLOSION

RELIEF DEVICES FOR COMBUSTION AIR INLET
AND EXHAUST GAS MANIFOLDS OF I.C.
ENGINES USING GAS AS FUEL
1 General 2 Tests
1.1 Scope 2.1 Test specimens
1.1.1 (1/7/2024) 2.1.1 (1/7/2024)

The ERD used for the explosion test is to be selected from
Aim of this Appendix is to specify testing procedure for
the manufacturer’s production line by a representative of
explosion relief devices for combustion air inlet manifold
the Society:
and exhaust gas manifold of internal combustion engines
using gas as fuel. • as a finished certified component itself, or
• on samples taken from earlier stages in the production
1.2 Definitions of the component, when applicable.
If necessary, an additional ERD may need to be selected for
1.2.1 (1/7/2024) the demonstration of the opening pressure. The selected
Definitions addressing gas as fuel as given in the App 12. ERD has to be clearly marked.
Explosion relief device (ERD) means a device to protect a If applicable, the selected ERD is to be representative for the
component against a determined overpressure in the event type range and operating conditions, for example:
of a gas explosion. The device is fitted with a flame arrester • kind of ERD (valve, rupture disc, etc.),
and may be a valve, a rupture disc or other, as applicable. • mounting orientation (vertical, horizontal)
• design of ERD (e.g., spring design, sealing)
1.3 Documents • design of flame arrester
• ERD intended to be fitted to the air inlet or exhaust gas
1.3.1 (1/7/2024)
manifold of an engine having a turbocharger with
Prior to testing, the following documentation for the ERD is characteristics as per the testing conditions in [2.3.2].
to be submitted for approval:
The selection of the representative ERD is subject to
• drawings (sectional drawings, details, assembly etc.)
approval by the Society.
• specification data sheet including operating conditions
and design limits such as: 2.2 Demonstration of opening pressure
- maximum permissible operating pressure, resulting
from maximum charging air or exhaust gas back 2.2.1 (1/7/2024)
pressure The ERD which has been selected is to be subjected to a
pressure test at the manufacturer’s works to demonstrate
- maximum permissible operating temperature,
that the static opening pressure is kept within the
resulting from maximum charging air or exhaust gas
manufacturer’s specification and that the ERD is air tight at
temperature
the maximum permissible operating pressure for at least 30
- static opening pressure, resulting from maximum seconds.
charging air or exhaust gas back pressure
- maximum explosion pressure, i.e. maximum 2.3 Explosion test
pressure that the device can withstand
2.3.1 Test facility (1/7/2024)
- geometric relief area
The test facilities are to be accredited to a national or
• product marking international standard, e.g. ISO/IEC 17025:2017, and are to
be acceptable to the Society.
• installation and operation manual
The test facilities are to be equipped so that they can
• test program
perform and record explosion testing in accordance with
• specification of test vessel. this procedure.
480 RINA Rules 2024

Pt C, Ch 1, App 17
The test facilities are to have equipment for controlling and 2.3.3 Explosion test process (1/7/2024)
measuring a methane gas concentration within a test vessel The explosion testing is to be performed in two stages
to an accuracy of ± 0.1%. according to [2.3.4] and [2.3.5] for each ERD that is
The test facilities are to be capable of effective point-located required to be approved as type tested.
ignition of a methane/air mixture. The explosion testing is to be witnessed by a Society
The test facility arrangements are to be capable of surveyor.
measuring and recording the pressure changes throughout Calibration records for the instrumentation used to collect
an explosion test at a frequency recognizing the speed of data are to be presented to, and reviewed by, the attending
the events during an explosion (10 kHz or above). surveyor.
The explosion test (see [2.3.5]) is to be documented by high 2.3.4 Reference test – Explosion test without
speed (250 frames/s or above) video recording. The video ERD (1/7/2024)
recording is to be provided with a time stamp. Two explosion tests are to be carried out in the test vessel
without ERD. The test vessel configuration is shown in Fig 1.
2.3.2 Test vessel (1/7/2024)
The aim of this test is to establish a reference pressure level
The test vessel is a simplified model of the air inlet or
in the test vessel which can be used for determination of the
exhaust gas manifold. The free area of the connected turbo
capability of a relief valve in terms of pressure relief.
charger (compressor or turbine wheel) is to be considered.
The test vessel is to comply with the following 2.3.5 ERD test – Explosion test with ERD (1/7/2024)
requirements: Two explosion tests are to be carried out in the test vessel
• The shape of the test vessel is to correspond to a pipe with the same ERD at the required position. If the ERD is a
with L/D  10. rupture disc with flame arrester, the rupture disc is to be
replaced.
• The test vessel is to be equipped with a rupture disc at
one front end to simulate the turbo charger. The relief If shielding arrangements to deflect the emission of
area of the rupture disc is to be in relationship to the test explosion combustion products at the ERD are intended,
vessel diameter based on turbocharger manufacturer the ERD are to be tested with the shielding arrangements
data for an equivalent free area of compressor or turbine fitted.
wheel. The opening pressure is to be ±10% of the static The test vessel configuration is shown in Fig 2 or Fig 3.
opening pressure of the ERD.
2.3.6 Explosion test method (1/7/2024)
• The volume of the test vessel is to comply with the The test conditions are to comply with the intended use of
specific relief area of the ERD of 700 cm2/m3 ±15%. the ERD, such as:
• The test vessel is to be provided with all necessary • pipe diameter
flanges and connection to mount the ERD in the • operating pressure
intended position, to mount a rupture disc as turbo
• operating temperature
charger simulation, to connect the Methane-air mixture
supply and the measurement equipment. • installation orientation.
• The ignition is to be made at the middle of the test All explosion tests are to be carried out using an air and
vessel. methane mixture with a volumetric methane concentration
of 9.5% ± 0.5%. A homogeneous air / methane mixture
• The test vessel is to be designed to verify a
inside the test vessel is to be verified. The concentration of
homogeneous air / methane mixture inside the vessel.
methane is not to differ by more than 0.5%.
• The test vessel is to have connections for measuring the
The initial pressure in the test vessel is to be the specified
pressure in the test vessel in at least two positions, one
maximum operating pressure of the ERD.
at the ERD and the other at the test vessel center.
The initial temperature in the test vessel is to be the
• The test vessel is to have a design pressure of not less specified maximum operating temperature of the ERD.
than the maximum explosion pressure of a
If the initial pressure and/or initial temperature deviate from
stoichiometric air / methane mixture at test conditions in
the design limits, the ERD manufacturer is to prove the
[2.3.6].
acceptability of this deviation either using standards or
• The test vessel configuration is subject to approval by generally applicable calculation methods.
the Society.
The ignition is to be made using an explosive charge of 50 -
Typical test vessel configurations: 100 Joule.
All test vessel configurations to be equipped with a rupture Successive explosion testing to establish an ERD
disc (1) (turbo charger simulation) at one front end. The functionality is to be carried out as quickly as possible
ignition is in the centre of the test vessel (↯). The pressure during stable weather conditions.
sensors are mounted at the valve flanges (p1) and at the test The pressure rise and decay during all explosion testing is to
vessel centre (p2). The measuring of the methane be recorded.
concentration to verify a homogeneous air / methane The effect of an ERD in terms of pressure relief following an
mixture can be performed at both ends of the test vessel, explosion is ascertained from maximum pressure recorded
e.g. (c1) and (c2). at the centre of the test vessel during the two stages. The
RINA Rules 2024 481

Pt C, Ch 1, App 17
pressure relief within the test vessel due to the installation of maximise the potential for flame/combustion detection. The
an ERD is the difference between average pressure of the use of a dark, ideally matt finish, background and an
two explosions of the reference test (see [2.3.4]) and the avoidance of direct light onto the video camera monitored
average of the two explosions of the ERD test (see [2.3.5]). area are recommended.
For acceptance of correct functioning of the flame arrester,
there is to be no indication of flame or combustion outside After each ERD test (see [2.3.5]), the external condition of
of the ERD during its testing (see [2.3.5]). This is to be the flame arrester to be examined for signs of damage
monitored by a high-speed video camera (see [2.3.1]), for and/or deformation that may affect the operation of the
which ambient light conditions are to be considered to ERD.
Figure 1 : Configuration without ERD (flanges for ERDs closed (2)) (1/7/2024)
Figure 2 : Configuration with ERD (3) mounted at the front end of the test vessel (1/7/2024)
Figure 3 : Configuration with ERD (3) mounted on top of the test vessel (1/7/2024)
2.4 Check of ERD components • the demonstration of opening pressure (see [2.2]) and
• the explosion test (see [2.3]).
2.4.1 (1/7/2024)
After completing the explosion tests, the ERDs are to be The reports is to include respective information according
dismantled and the condition of all components are to be to the requirements in [2], as applicable:
ascertained and documented. • test specimens
• test facility, including measuring equipment and test
3 Report, Assessment and Approval vessel
• measuring results (pressures, temperatures, flame
3.1 Test report velocities, volumetric methane concentration, ambient
conditions etc.)
3.1.1 (1/7/2024) • video documentation of explosion tests
A complete test report has to be submitted to the Society for • photo documentation of ERD components
482 RINA Rules 2024

Pt C, Ch 1, App 17
3.2 Assessment • The functioning of the flame arresters is considered

satisfactory if there is no indication of flame or
3.2.1 (1/7/2024) combustion outside the ERD during the explosion tests.
To verify compliance with this requirement the assessment
has to address the following:
3.3 Approval
• Function and mechanical integrity of the ERD.
- After dismantling of the ERD, the flame arrester is 3.3.1 (1/7/2024)
not to show signs of damage or any deformation that
may affect the operation of the ERD. The approval of an ERD is at the discretion of the Society
- If a valve is used any indication of valve sticking or based on the appraisal of plans and particulars and the test
uneven opening during the explosion that may affect report of type testing.
subsequent operation of the valve has to be The type approval is valid only for an ERD fitted to the air
considered. inlet or exhaust gas manifold of an engine having a
- The mechanical integrity of the ERD is proven up to turbocharger with compressor or turbine wheel
a maximum explosion pressure (as average of the characteristics corresponding to those required in [2.3.2] for
two explosions) of the ERD tests in [2.3.5]. the test vessel rupture disc in terms of free area.
RINA Rules 2024 483

Pt C, Ch 2, Sec 3
SECTION 3 SYSTEM DESIGN
1 Supply systems and characteristics 1.1.4 The requirement of [1.1.3] does not preclude under
conditions approved by the Society the use of:
of the supply
a) impressed current cathodic protective systems,
1.1 Supply systems
b) limited and locally earthed systems, or
1.1.1 The following distribution systems may be used: c) insulation level monitoring devices provided the circu-
a) on d.c. installations: lation current does not exceed 30 mA under the most
• two-wire insulated unfavourable conditions.
• two-wire with one pole earthed Note 1: Limited and locally earthed systems such as starting and
b) on a.c. installations: ignition systems of internal combustion engines are accepted pro-
vided that any possible resulting current does not flow directly
• three-phase three-wire with neutral insulated
through any dangerous spaces.
• three-phase three-wire with neutral directly earthed
or earthed through an impedance 1.1.5 For the supply systems of ships carrying liquid devel-
• three-phase four-wire with neutral directly earthed oping combustible gases or vapours, see Pt E, Ch 7, Sec 5,
or earthed through an impedance Pt E, Ch 8, Sec 10 or Pt E, Ch 9, Sec 10.
• single-phase two-wire insulated
• single-phase two-wire with one phase earthed. 1.1.6 For the supply systems in HV Installations, see
Sec 13.
1.1.2 Distribution systems other than those listed in [1.1.1]
(e.g. with hull return, three-phase four-wire insulated) will
be considered by the Society on a case by case basis. 1.2 Maximum voltages
1.1.3 The hull return system of distribution is not to be 1.2.1 The maximum voltages for both alternating current
used for power, heating or lighting in any ship of 1600 tons and direct current low-voltage systems of supply for the
gross tonnage and upwards. ship’s services are given in Tab 1.
Table 1 : Maximum voltages for various ship services
Use Maximum voltage, in V

For permanently installed Power equipment 1000
and connected to fixed Heating equipment (except in accommodation spaces) 500
wiring Cooking equipment 500
Lighting 250
Space heaters in accommodation spaces 250
Control (1), communication (including signal lamps) and instrumentation 250
equipment
For permanently installed Power and heating equipment, where such connection is necessary because 1000
and connected by flexi- of the application (e.g. for moveable cranes or other hoisting gear)
ble cable
For socket-outlets supply- Portable appliances which are not hand-held during operation (e.g. refriger- 1000
ing ated containers) by flexible cables
Portable appliances and other consumers by flexible cables 250
Equipment requiring extra precaution against electric shock where an iso- 250
lating transformer is used to supply one appliance (2)
Equipment requiring extra precaution against electric shock with or without 50
a safety transformer (2).
(1) For control equipment which is part of a power and heating installation (e.g. pressure or temperature switches for start-
ing/stopping motors), the same maximum voltage as allowed for the power and heating equipment may be used provided that
all components are constructed for such voltage. However, the control voltage to external equipment is not to exceed 500 V.
(2) Both conductors in such systems are to be insulated from earth.

Pt C, Ch 2, Sec 3
The protective devices are to be placed as near as possible 9 Electrical cables

to the tapping from the supply.
The secondary side of current transformers is not to be pro- 9.1 General
tected.
9.1.1 All electrical cables and wiring external to equipment
7.13.2 Control circuits and control transformers are to be shall be at least of a flame-retardant type, in accordance
protected against overload and short-circuit by means of with IEC Publication 60332-1.
multipole circuit-breakers or fuses on each pole not con-
nected to earth. 9.1.2 In addition to the provisions of [9.1.1], when cables
are laid in bundles, cable types are to be chosen in compli-
Overload protection may be omitted for transformers with a
ance with IEC Publication 60332-3 Category A, or other
rated current of less than 2 A on the secondary side.
means (see Sec 12) are to be provided such as not to impair
The short-circuit protection on the secondary side may be their original flame-retarding properties.
omitted if the transformer is designed to sustain permanent
short-circuit current. 9.1.3 Where necessary for specific applications such as
radio frequency or digital communication systems, which
7.13.3 Where a fault in a pilot lamp would impair the require the use of particular types of cables, the Society may
operation of essential services, such lamps are to be pro- permit the use of cables which do not comply with the pro-
tected separately from other circuits such as control circuits. visions of [9.1.1] and [9.1.2].
Note 1: Pilot lamps connected via short-circuit-proof transformers 9.1.4 (1/1/2007)
may be protected in common with control circuits.
Cables which are required to have fire-resisting characteris-
7.13.4 Circuits whose failure could endanger operation, tics are to comply with the requirements stipulated in [9.6].
such as steering gear control feeder circuits, are to be pro-
tected only against short-circuit. 9.2 Choice of insulation
7.13.5 The protection is to be adequate for the minimum 9.2.1 The maximum rated operating temperature of the
cross-section of the protected circuits. insulating material is to be at least 10°C higher than the
maximum ambient temperature liable to occur or to be pro-
7.14 Protection of transformers duced in the space where the cable is installed.
9.2.2 The maximum rated conductor temperature for nor-

7.14.1 The primary winding side of power transformers is
mal and short-circuit operation, for the type of insulating
to be protected against short-circuit and overload by means
compounds normally used for shipboard cables, is not to
of multipole circuit-breakers or switches and fuses.
exceed the values stated in Tab 4. Special consideration will
Overload protection on the primary side may be dispensed be given to other insulating materials.
with where it is provided on the secondary side or when the
total possible load cannot reach the rated power of the 9.2.3 PVC insulated cables are not to be used either in
transformer. refrigerated spaces, or on decks exposed to the weather of
ships classed for unrestricted service.
7.14.2 The protection against short-circuit is to be such as
to ensure the selectivity between the circuits supplied by 9.2.4 Mineral insulated cables will be considered on a
the secondary side of the transformer and the feeder circuit case by case basis.
of the transformer.
9.3 Choice of protective covering
7.14.3 When transformers are arranged to operate in par-
allel, means are to be provided so as to trip the switch on 9.3.1 The conductor insulating materials are to be
the secondary winding side when the corresponding switch enclosed in an impervious sheath of material appropriate to
on the primary side is open. the expected ambient conditions where cables are installed
in the following locations:
8 System components • on decks exposed to the weather,
• in damp or wet spaces (e.g. in bathrooms),
8.1 General • in refrigerated spaces,
8.1.1 The components of the electrical system are to be • in machinery spaces and, in general,
dimensioned such as to withstand the currents that can pass • where condensation water or harmful vapour may be
through them during normal service without their rating present.
being exceeded.
9.3.2 Where cables are provided with armour or metallic
8.1.2 The components of the electrical system are to be braid (e.g. for cables installed in hazardous areas), an over-
designed and constructed so as to withstand for the admissi- all impervious sheath or other means to protect the metallic
ble duration the thermal and electrodynamic stresses elements against corrosion is to be provided; see Sec 9,
caused by possible overcurrents, including short-circuit. [1.5].
RINA Rules 2024

...OMISSIS... 51
Pt C, Ch 2, Sec 3
9.8 Internal wiring of switchboards and tective covering (e.g. both armoured and non-armoured
other enclosures for equipment cables).
9.8.1 For installation in switchboards and other enclosures 9.9.3 Values other than those shown in Tab 5 to Tab 9 may
for equipment, single-core cables may be used without fur- be accepted provided they are determined on the basis of
ther protection (sheath). calculation methods or experimental values approved by
Other types of flame-retardant switchboard wiring may be the Society.
accepted at the discretion of the Society.
9.9.4 When the actual ambient temperature obviously dif-
fers from 45°C, the correction factors shown in Tab 10 may
9.9 Current carrying capacity of cables
be applied to the current carrying capacity in Tab 5 to
9.9.1 The current carrying capacity for continuous service Tab 9.
of cables given in Tab 5 to Tab 9 is based on the maximum
permissible service temperature of the conductor also indi- 9.9.5 Where more than six cables are bunched together in
cated therein and on an ambient temperature of 45°C. such a way that there is an absence of free air circulating
around them, and the cables can be expected to be under
9.9.2 The current carrying capacity cited in [9.9.1] is full load simultaneously, a correction factor of 0,85 is to be
applicable, with rough approximation, to all types of pro- applied.
Figure 3 (1/1/2007)
Table 4 : Maximum rated conductor temperature (1/7/2024)
Maximum rated conductor

Abbreviated
Type of insulating compound temperature, in °C
designation
Normal operation Short-circuit
a) Thermoplastic:
- based upon polyvinyl chloride or copolymer of vinyl chloride and vinyl acetate PVC/A 670 150
b) Elastomeric or thermosetting:
- based upon ethylene-propylene rubber or similar (EPM or EPDM) EPR 8590 250
- based upon high modulus or hardgrade ethylene propylene rubber HEPR 8590 250
- based upon cross-linked polyethylene XLPE 8590 250
- based upon rubber silicon S 95 95 350 (2)
- based upon ethylene-propylene rubber or similar (EPM or EPDM) halogen free HF EPR 8590 250
- based upon high modulus or hardgrade halogen free ethylene propylene rubber HF HEPR 8590 250
- based upon cross-linked polyethylene halogen free HF XLPE 8590 250
- based upon rubber silicon halogen free HF S 95 95 350 (2)
- based upon cross-linked polyolefin material for halogen free cable (1) HF 8590 8590 250
(1) Used on sheathed cable only
(2) This temperature is applicable only to power cables and not appropriate for tinned copper conductors
RINA Rules 2024 53

Pt C, Ch 2, Sec 3
Nominal section Number of conductors

Table 5 : Current carrying capacity, in A, in continu-
mm2 1 2 3 or 4
ous service for cables based on maximum conductor
operating temperature of 60°C (ambient temperature 50 15038 12817 10597
45°C) (1/7/2024)
70 19071 16245 13320
Nominal section Number of conductors 95 23007 1976 16145
mm2 1 2 3 or 4 120 27039 23003 18967
1 8 7 6 150 310275 2634 217193
1,5 1210 109 8 185 35013 29866 24519
7 240 415369 35314 29158
2,5 17 14 12 300 47524 404360 333297
4 2223 19 1516 400 d.c.:500 d.c.:425 d.c.:350
20 a.c.:490 a.c.:417 a.c.:343
6 29 25 20 500 d.c.:580 d.c.:493 d.c.:406
10 40 34 28 a.c.:550 a.c.:468 a.c.:385
16 54 46 38 600 d.c.:670 d.c.:570 d.c.:467
25 71 60 50 a.c.:610 a.c.:519 a.c.:427
35 87 7475 6162
88
50 105110 89 7477 Table 7 : Current carrying capacity, in A, in continu-
94 ous service for cables based on maximum conductor
operating temperature of 805°C (ambient temperature
70 135 115 95
45°C) (1/7/2024)
95 1654 14039 1165
120 19089 1621 1332 Nominal section Number of conductors
150 22018 1875 1543 mm2 1 2 3 or 4
185 25048 2131 1754 1 15 13 11
240 2902 2478 2034 1,5 1921 168 135
300 3356 2856 235 2,5 268 224 1820
400 d.c.:390 d.c.:332 d.c.:273 4 358 302 257
a.c.:380 a.c.:323 a.c.:266 6 459 3842 324
500 d.c.:450 d.c.:383 d.c.:315 10 637 547 447
a.c.:430 a.c.:366 a.c.:301
16 8491 717 5964
600 d.c.:520 d.c.:442 d.c.:364
25 1120 94102 7784
a.c.:470 a.c.:400 a.c.:329
35 1408 11926 98104
50 16584 14056 11629
ous service for cables based on maximum conductor 70 21528 18394 15160
operating temperature of 750°C (ambient temperature 95 26076 22135 18293
45°C) (1/7/2024) 120 30019 25571 21023
Nominal section Number of conductors 150 34067 289312 23857

mm2 1 2 3 or 4 185 390418 33255 2793
1 13 11 9 240 46092 391418 32244
1,5 175 143 121 300 53065 4580 37196
2,5 241 2018 175 400 d.c.:650 d.c.:553 d.c.:455
a.c.:630 a.c.:536 a.c.:441
4 3229 275 220
500 d.c.:740 d.c.:629 d.c.:518
6 4137 351 296
a.c.:680 a.c.:578 a.c.:476
10 571 483 4036
600 d.c.:840 d.c.:714 d.c.:588
16 7668 6558 5348 a.c.:740 a.c.:629 a.c.:518
25 1090 8577 7063
35 12511 10694 878
54 RINA Rules 2024

Pt C, Ch 2, Sec 3
Table 8 : Current carrying capacity, in A, in continu- Nominal section Number of conductors

ous service for cables based on maximum conductor mm2 1 2 3 or 4
operating temperature of 8590°C (ambient tempera-
95 310 264 217
ture 45°C) (1/7/2024)
120 36059 3065 2521
Number of conductors 150 4102 34950 28788

Nominal section
mm2 1 2 3 or 4 185 470 400 329
1 16 14 11 240 57053 48570 39987
1,5 203 1720 146 300 66036 56041 46245
2,5 2840 246 201 400 d.c.:760 d.c.:646 d.c.:532

a.c.:725 a.c.:616 a.c.:508
4 3851 324 278
500 d.c.:875 d.c.:744 d.c.:612
6 4852 414 346
a.c.:810 a.c.:689 a.c.:567
10 6772 5761 4750
600 d.c.:1010 d.c.:859 d.c.:707
16 906 7782 637 a.c.:900 a.c.:765 a.c.:630
25 1207 1028 849
35 14557 1233 10210 9.9.6 Where a cable is intended to supply a short-time
50 18096 15367 12637 load for 1/2-hour or 1-hour service (e.g. mooring winches
or bow thruster propellers), the current carrying capacity
70 22542 191206 15869
obtained from Tab 5 to Tab 9 may be increased by applying
95 27593 23449 193205 the corresponding correction factors given in Tab 11.
120 32039 27288 22437 In no case is a period shorter than 1/2-hour to be used,
150 36589 31031 25672 whatever the effective period of operation.
185 41544 35377 291311
9.9.7 For supply cables to single services for intermittent
240 490522 41744 34365
loads (e.g. cargo winches or machinery space cranes), the
300 560601 476511 392421 current carrying capacity obtained from Tab 5 to Tab 9 may
400 d.c.:690 d.c.:587 d.c.:483 be increased by applying the correction factors given in
a.c.:670 a.c.:570 a.c.:469 Tab 12.
500 d.c.:780 d.c.:663 d.c.:546 The correction factors are calculated with rough approxi-
a.c.:720 a.c.:612 a.c.:504 mation for periods of 10 minutes, of which 4 minutes with a
600 d.c.:890 d.c.:757 d.c.:623 constant load and 6 minutes without load.
a.c.:780 a.c.:663 a.c.:546
9.10 Minimum nominal cross-sectional area
of conductors
ous service for cables based on maximum conductor 9.10.1 In general the minimum allowable conductor
operating temperature of 95°C (ambient temperature cross-sectional areas are those given in Tab 13.
45°C) (1/7/2024)
9.10.2 The nominal cross-sectional area of the neutral
Nominal section Number of conductors conductor in three-phase distribution systems is to be equal
mm2 1 2 3 or 4
to at least 50% of the cross-sectional area of the phases,
unless the latter is less than or equal to 16 mm2. In such
1 20 17 14 case the cross-sectional area of the neutral conductor is to
1,5 246 202 178 be equal to that of the phase.
2,5 32 27 22
9.10.3 For the nominal cross-sectional area of:
4 423 367 2930
6 55 47 39 • earthing conductors, see Sec 12, [2.3]
10 756 645 53 • earthing connections for distribution systems, see
16 1002 857 701 Sec 12, [2.5].
25 135 115 95
35 1656 1401 116 9.11 Choice of cables
50 2008 1707 1406
9.11.1 The rated voltage of any cable is to be not lower
70 2556 2178 179 than the nominal voltage of the circuit for which it is used.
RINA Rules 2024 55

Pt C, Ch 2, Sec 3
9.11.2 The nominal cross-sectional area of each cable is to 9.11.3 The highest continuous load carried by a cable is to
be sufficient to satisfy the following conditions with refer- be calculated on the basis of the power requirements and of
ence to the maximum anticipated ambient temperature: the diversity factor of the loads and machines supplied
through that cable.
• the current carrying capacity is to be not less than the
highest continuous load carried by the cable 9.11.4 When the conductors are carrying the maximum
nominal service current, the voltage drop from the main or
• the voltage drop in the circuit, by full load on this cir- emergency switchboard busbars to any point in the installa-
cuit, is not to exceed the specified limits tion is not to exceed 6% of the nominal voltage.
• the cross-sectional area calculated on the basis of the For battery circuits with supply voltage less than 55 V, this
above is to be such that the temperature increases value may be increased to 10%.
which may be caused by overcurrents or starting tran- For the circuits of navigation lights, the voltage drop is not
sients do not damage the insulation. to exceed 5% of the rated voltage under normal conditions.
Table 10 : Correction factors for various ambient air temperatures (Reference ambient temperature of
45°C) (1/7/2024)
Maximum rated Correction factors for ambient air temperature of :

conductor
temperature, in °C 35°C 40°C 45°C 50°C 55°C 60°C 65°C 70°C 75°C 80°C 85°C
60 1,29 1,15 1,00 0,82 - - - - - - -

65 1,22 1,12 1,00 0,87 0,71 - - - - - -
70 1,18 1,10 1,00 0,89 0,77 0,63 - - - - -
75 1,15 1,08 1,00 0,91 0,82 0,71 0,58 - - - -
80 1,13 1,07 1,00 0,93 0,85 0,76 0,65 0,53 - - -
85 1,12 1,06 1,00 0,94 0,87 0,79 0,71 0,61 0,50 - -
90 1,10 1,05 1,00 0,94 0,88 0,82 0,74 0,67 0,58 0,47 -
95 1,10 1,05 1,00 0,95 0,89 0,84 0,77 0,71 0,63 0,55 0,45
Table 11 : Correction factors for short-time loads
½ -hour service 1-hour service

Sum of nominal cross-sectional areas of all conductors in Sum of nominal cross-sectional areas of all conductors in
the cable, in mm2 the cable, in mm2 Correlation
Cables with non-metallic Cables with non-metallic

Cables with metallic sheath Cables with metallic sheath
sheath and non-armoured sheath and non-armoured factor
and armoured cables and armoured cables
cables cables
up to 20 up to 75 up to 80 up to 230 1,06
21-41 76-125 81-170 231-400 1,10
41-65 126-180 171-250 401-600 1,15
66-95 181-250 251-430 601-800 1,20
96-135 251-320 431-600 - 1,25
136-180 321-400 601-800 - 1,30
181-235 401-500 - - 1,35
236-285 501-600 - - 1,40
286-350 - - - 1,45

Pt C, Ch 2, Sec 8
SECTION 8 SWITCHGEAR AND CONTROLGEAR ASSEMBLIES
1 Constructional requirements for 1.1.9 Where it is necessary to make provision for the
opening of the doors of the switchboard, this is to be in
main and emergency switchboards accordance with one of the following requirements:
a) opening is to necessitate the use of a key or tool (e.g.
1.1 Construction when it is necessary to replace a lamp or a fuse-link)
b) all live parts which can be accidentally touched after
1.1.1 (1/1/2021) the door has been opened are to be disconnected before
Construction is to be in accordance with IEC Publication the door can be opened
60092-302-2. c) the switchboard is to include an internal barrier or shut-
ter with a degree of protection not less than IP2X shield-
1.1.2 (1/1/2021) ing all live parts such that they cannot accidentally be
touched when the door is open. It is not to be possible
Switchboard manufactured and tested to standards other
to remove this barrier or shutter except by the use of a
than those specified in [1.1.1] will be accepted provided key or tool.
they are in accordance with an acceptable international or
national standard of an equivalent or higher safety level. 1.1.10 All parts of the switchboard are to be readily acces-
sible for maintenance, repair or replacement. In particular,
1.1.3 Where the framework, panels and doors of the fuses are to be able to be safely inserted and withdrawn
from their fuse-bases.
enclosure are of steel, suitable measures are to be taken to
prevent overheating due to the possible circulation of eddy 1.1.11 Hinged doors which are to be opened for operation
currents. of equipment on the door or inside are to be provided with
fixing devices for keeping them in open position.
1.1.4 Insulating material for panels and other elements of
1.1.12 Means of isolation of the circuit-breakers of genera-
the switchboard is at least to be moisture-resistant and
tors and other important parts of the installation are to be
flame-retardant.
provided so as to permit safe maintenance while the main
busbars are alive.
1.1.5 Switchboards are to be of dead front type, with
enclosure protection according to Sec 3, Tab 2. 1.1.13 Where components with voltage exceeding the
safety voltage are mounted on hinged doors, the latter are to
be electrically connected to the switchboard by means of a
1.1.6 Switchboards are to be provided with insulated
separate, flexible protective conductor.
handrails or handles fitted in an appropriate position at the
front of the switchboard. Where access to the rear is neces- 1.1.14 All measuring instruments and all monitoring and
sary for operational or maintenance purposes, an insulated control devices are to be clearly identified with indelible
handrail or insulated handles are to be fitted. labels of durable, flame-retardant material.
1.1.15 The rating of each circuit, together with the rating

1.1.7 Where the aggregate capacity of generators con- of the fuse or the appropriate setting of the overload protec-
nected to the main busbars exceeds 100 kVA, a separate tive device (circuit-breaker, thermal relay etc.) for each cir-
cubicle for each generator is to be arranged with flame- cuit is to be permanently indicated at the location of the
retardant partitions between the different cubicles. Similar fuse or protective device.
partitions are to be provided between the generator cubi-
cles and outgoing circuits. 1.2 Busbars and bare conductors
1.1.8 Instruments, handles or push-buttons for switchgear 1.2.1 Busbars are to be of copper or of copper-surrounded
operation are to be placed on the front of the switchboard. aluminium alloy if suitable for use in the marine environ-
ment and if precautions are taken to avoid galvanic corro-
All other parts which require operation are to be accessible
sion.
and so placed that the risk of accidental touching of live
parts, or accidental making of short-circuits and earthings, 1.2.2 All connections are to be so made as to inhibit corro-
is reduced as far as practicable. sion.
72 RINA Rules 2024

Pt C, Ch 2, Sec 8
1.2.3 Busbars are to be dimensioned in accordance with 1.3 Internal wiring

IEC Publication 60092-302-2.
1.3.1 Insulated conductors for internal wiring of auxiliary
The mean temperature rise of busbars is not to exceed 45°C
circuits of switchboards are to be constructed in accord-
under rated current condition with an ambient air tempera-
ance with Sec 9, [1.1.5].
ture of 45°C (see Sec 2, [1.2.5]) and is not to have any
harmful effect on adjacent components. Higher values of 1.3.2 All insulated conductors provided for in [1.3.1] are
temperature rise may be accepted to the satisfaction of the to be of flexible construction and of the stranded type.
Society.
1.3.3 Connections from busbars to protective devices are
1.2.4 The cross-section of neutral connection on an a.c. to be as short as possible. They are to be laid and secured in
three-phase, four-wire system is to be at least 50% of the such a way to minimise the risk of a short-circuit.
cross-section for the corresponding phases.
1.3.4 All conductors are to be secured to prevent vibration
1.2.5 Bare main busbars, excluding the conductors and are to be kept away from sharp edges.
between the main busbars and the supply side of outgoing
units, are to have the minimum clearances and creepage 1.3.5 Connections leading to indicating and control instru-
distances given in Tab 1. ments or apparatus mounted in doors are to be installed
such that they cannot be mechanically damaged due to
The values shown apply to clearances and creepage dis-
movement of the doors.
tances between live parts as well as between live parts and
exposed conductive parts. 1.3.6 Non-metallic trays for internal wiring of switch-
boards are to be of flame-retardant material.
Table 1 : Clearance and creepage distances
1.3.7 Control circuits are to be installed and protected
Rated insulation volt- Minimum Minimum creep- such that they cannot be damaged by arcs from the protec-
age a.c. r.m.s. or d.c. clearance age distance tive devices.
V mm mm
1.3.8 Where foreseen, fixed terminal connectors for con-
 250 15 20 nection of the external cables are to be arranged in readily
> 250 to  690 20 25 accessible positions.
> 690 25 35
1.4 Switchgear and controlgear, protective
Note 1: Clearance is the distance between two conductive parts devices
along a string stretched the shortest way between such parts.
Creepage distance is the shortest distance along the surface of an 1.4.1 (1/7/2013)
insulating material between two conductive parts. Switchgear and controlgear are to comply with IEC 60947
series adjusted as necessary for the ambient air reference
1.2.6 Reduced values as specified in IEC Publication temperature specified in Sec 2, Tab 1 and to be type tested
60092-302-2 may be accepted for type tested and partially or type approved when required in accordance with
type tested assemblies. Sec 15.
The reference values for the evaluation of the minimum
1.4.2 The characteristics of switchgear, controlgear and
clearances and creepage distances for these assemblies are
protective devices for the various consumers are to be in
based on the following:
compliance with Sec 3, [7].
• pollution degree 3 (conductive pollution occurs, or dry
1.4.3 (1/7/2015)
non-conductive pollution occurs which becomes con-
For high voltage switchgear and controlgear see Sec 13, [7].
ductive due to condensation which is expected)
1.4.4 (1/7/2014)
• overvoltage category III (distribution circuit level) For materials and construction, see Sec 2, [4] and Sec 2,
• inhomogenous field conditions (case A) [5].
• rated operational voltage 1000 V a.c., 1500 V d.c. 1.4.5 (1/7/2014)
• group of insulating material IIIa. Power-driven circuit-breakers are to be equipped with an
additional separate drive operated by hand.
Special consideration is to be given to equipment located in 1.4.6 (1/7/2014)
spaces where a pollution degree higher than 3 is applica- Power circuit-breakers with a making capacity exceeding
ble, e.g. in diesel engine rooms. 10 kA are to be equipped with a drive which performs the
make operation independently of the actuating force and
1.2.7 Busbars and other bare conductors with their sup-
speed.
ports are to be mechanically dimensioned and fixed such
that they can withstand the stresses caused by short-circuits. 1.4.7 (1/7/2014)
Where the conditions for closing the circuit-breaker are not
1.2.8 Busbars and bare conductors are to be protected, satisfied (e.g. if the undervoltage trip is not energised), the
where necessary, against falling objects (e.g. tools, fuses or closing mechanism is not to cause the closing of the con-
other objects). tacts.
RINA Rules 2024

...OMISSIS... 73
Pt C, Ch 3, Sec 2
SECTION 2 DESIGN REQUIREMENTS
1 General 2.1.4 (1/7/2020)

In addition to what above, the automation systems are to be
1.1 continuously powered by means of batteries or pneumatic
or hydraulic accumulators.
1.1.1 All control systems essential for the propulsion, con- 2.1.5 (1/7/2020)
trol and safety of the ship shall be independent or designed The capacity of the batteries, or pneumatic or hydraulic
such that failure of one system does not degrade the perfor- accumulators is to be sufficient to allow the normal opera-
mance of another system. tion of the alarm and safety system for at least half an hour.
1.1.2 Controlled systems are to have manual operation.
Failure of any part of such systems shall not prevent the use 3 Control systems
of the manual override.
3.1 General
1.1.3 Automation systems are to have constant perfor-
mance. 3.1.1 In the case of failure, the control systems used for
essential services are to remain in their last position they
1.1.4 Safety functions are to be independent of control and had before the failure.
monitoring functions. As far as practicable, control and
monitoring functions are also to be independent. 3.2 Local control
1.1.5 Control, monitoring and safety systems are to have
3.2.1 Each system is to be able to be operated manually
self-check facilities. In the event of failure, an alarm is to be
from a position located so as to enable visual control of
activated.
operation. For detailed instrumentation for each system,
In particular, failure of the power supply of the automation refer to Chapter 1and Chapter 2.
system is to generate an alarm.
It shall also be possible to control the auxiliary machinery,
1.1.6 When a programmable electronic system is used for essential for the propulsion and safety of the ship, at or near
control, alarm or safety systems, it is to comply with the the machinery concerned.
requirements of Sec 3.
3.3 Remote control systems
2 Power supply of automation sys- 3.3.1 When several control stations are provided, control
tems of machinery is to be possible at one station at a time.
3.3.2 At each location there shall be an indicator showing

2.1 General
which location is in control of the propulsion machinery.
2.1.1 (1/7/2020)
Automation systems are to pebe powered from two sources 3.3.3 Remote control is to be provided with the necessary
of power by means of two independent feeders. Failure of instrumentation, in each control station, to allow effective
each of these power supplies is to generate an alarm. control (correct function of the system, indication of control
Batteries or pneumatic or hydraulic accumulators, installed station in operation, alarm display).
to allow the system to be continuously powered, are not 3.3.4 When transferring the control location, no significant
considered as a duplication of the power supply. alteration of the controlled equipment is to occur. Transfer
Note 1: batteries constituting the emergency source of electrical of control is to be protected by an audible warning and
power may be considered as one of the two required sources. acknowledged by the receiving control location. The main
2.1.2 (1/7/2020) control location is to be able to take control without
Power supply circuits are to be such that no direct connec- acknowledgement.
tions to any point of the ship's main power supply system
are provided (e.g. by means of isolating transformers). 3.4 Automatic control systems
2.1.3 (1/7/2020)
3.4.1 Automatic starting, operational and control systems
Each automation system is to be have separate power sup-
shall include provisions for manually overriding the auto-
plies with short circuit and overload protection.
matic controls.
Safety systems are to have power supplies as far as possible
separate from control and alarm system, or an equivalent 3.4.2 Automatic control is to be stable in the range of the
safety level is to be ensured. controller in normal working conditions.
RINA Rules 2024

...OMISSIS... 131
Pt D, Ch 2, Sec 1
SECTION 1 ROLLED STEEL PLATES, SECTIONS AND BARS
1 General The suitability of each grade of steel for forming and

welding is to be demonstrated during the initial approval
tests at the steelworks. Approval of the steel works is to
1.1 Application
follow a scheme accepted by the Society.
1.1.1 General (1/7/2022) Provisions for the approval are given in the “Rules for the
The requirements of this Section apply to hot rolled plates, approval of Manufacturers of materials”.
strips, sections and bars intended for hull, structural
applications, boilers, pressure vessels and parts of 1.4 Quality of materials
machinery.
Article [1] specifies the requirements common to all the 1.4.1 All products are to have a workmanlike finish and to
above-mentioned steel products, while the appropriate be free from surface or internal defects which may impair
specific requirements are indicated in Articles [2] to [9]. their proper workability and use.
In the case of applications involving the storage and 1.4.2 (1/7/2011)

transport of liquefied gases in bulk and the use of gases or The responsibility for storage and maintenance of the
other low-flashpoint fuels, the additional requirements in delivered product(s) with acceptable level of surface
App 67 apply. conditions rests with the shipyard before the products are
used in fabrication.
1.1.2 Weldability
Steels in accordance with these Rules are weldable subject 1.5 Visual, dimensional and non-destructive
to the use of suitable welding processes and, where examinations
appropriate, to any conditions stated at the time of
approval. 1.5.1 Visual, dimensional and, as appropriate, non-
destructive examinations are to be performed by the
1.1.3 Products with through thickness properties Manufacturer on the materials supplied prior to delivery, as
For products intended for welded construction which may required.
be subject to particular stress in the thickness direction, it is The general provisions indicated in Ch 1, Sec 1, [3.6] and
suggested, and may be required, that the material satisfies specific requirements for the various products as specified
the through thickness properties indicated in Article [9]. in the relevant Articles of this Section apply.
For steels specified in Article [9], a further symbol Z is to be In the case of doubt about defects [1.4.1], suitable methods
added to the steel designation. of non-destructive examinations may be required by the
Surveyor.
1.2 Manufacture 1.5.2 (1/7/2011)
1.2.1 Steel is to be manufactured by the electric furnace, The thickness of the plates and strips is to be measured at
basic oxygen or open hearth processes. locations of a product or products as defined in the Articles
relevant to the various products. In any case, the distance of
The use of other processes may be specially approved by
the locations from the transverse or longitudinal edges of
the Society.
the product is to be not less than 10 mm.
1.2.2 The steel is to be cast in ingot moulds or by a Automated method or manual method is applied to the
continuous casting process. thickness measurements.
Provision is to be made for sufficient discard such as to The procedure and the records of measurements are to be
ensure: made available to the Surveyor and copies provided on
• at both ends of the ingots, the soundness of the material request.
• at the transitory zones of continuous casting material, a The tolerances on nominal thickness are indicated in the
homogeneous chemical composition along the Articles relevant to the various products.
longitudinal axis.
The tolerances on nominal thickness are not applicable to
areas repaired by grinding, which are to be in accordance
1.3 Approval with a recognised standard.
1.3.1 (1/1/2001) The responsibility for verification and maintenance of the
The manufacturing process is to be approved by the Society production within the required tolerances rests with the
for individual steelmakers, grade of steel and products, as Manufacturer. The Surveyor may require to witness some
specified in the applicable Articles. measurements.

Pt D, Ch 2, Sec 1
Table 31 : Brittle crack arrest steel requirement in function of structural members and thickness (1/1/2021)
Structural Members plating (1) Thickness (mm) Brittle crack arrest steel requirement
Upper deck 50  t  100

Steel grade YP36 or 40 with suffix BCA1
50  t  80
Steel grade YP 40 or 47 with suffix BCA1
Hatch coaming side
80  t  100
Steel grade YP 40 or 47 with suffix BCA2
(1) Excluding their attached longitudinals
11 YP47 Steels and Brittle Crack Arrest YP47 steels outside scope of the said thickness range,
special consideration is to be given by the Society.
Steels
11.1.3 Brittle crack arrest steels (1/1/2021)
11.1 Scope The brittle crack designation can be assigned to YP36 and
11.1.1 General (1/1/2021) YP40 steels specified in [2] and YP47 steels specified in this
This Article defines the requirements on YP47 steels and Article, which meet the additional brittle crack arrest
brittle crack arrest (BCA) steels as required in [10]. requirements and properties defined in this Article.
Unless otherwise specified in this Article, requirements in The application of brittle crack arrest steels is to comply
[2] are to be followed. with [10], which covers longitudinal structural members in
the upper deck region of container carriers (such as hatch
11.1.2 YP47 steels (1/1/2021) side coaming, upper deck, hatch coaming top and the
Steels designated as YP47 refer to steels with a specified attached longitudinals, etc.).
minimum yield point of 460 N/mm2. The thickness range of brittle crack arrest steels is over
The YP47 steel can be applied to longitudinal structural 50mm and not greater than 100mm as specified in Tab 34.
members in the upper deck region of container carriers
(such as hatch side coaming, hatch coaming top and the
11.2 Material specifications
attached longitudinals). Special consideration is to be given
to the application of YP47 steel plate for other hull 11.2.1 YP47 steels (1/1/2021)
structures.
Material specifications for YP47 steels are specified in
This Article gives the requirements for YP47 steels in Tab 32 and Tab 33.
thickness greater than 50mm and not greater than 100mm
intended for the upper deck region of container carriers. For
Table 32 : Chemical composition and deoxidation practice for YP47 steels without specified brittle crack arrest
properties (1/1/2021)
Grade EH47
Deoxidation Practice Killed and fine grain treated
Chemical Composition % (ladle samples)(6)(7)

C max. 0,18
Mn 0,90 - 2,00
Si max. 0,55
P max 0,020
S max. 0,020
Al (acid soluble min) 0,015 (1)(2)
Nb 0,02 - 0,05 (2)(3)
V 0,05 - 0,10 (2)(3)

Pt D, Ch 2, Sec 1
Table 34 : Requirement of brittle crack arrest properties for brittle crack arrest steels (1/7/2024)
Brittle crack arrest properties (2) (6)

Suffix to the steel Thickness range
grade (1) Brittle Crack Arrest Toughness Crack Arrest Temperature
(mm)
Kca at -10 °C (N/mm3/2) (2) (3) CAT (°C) (4)
BCA1 50 < t  100 6,000 min. -10 or below

BCA2 80 < t  100 (7) 8,000 min. (5)
Note 1:
t : thickness (mm)
(1) Suffix "BCA1" or "BCA2" is to be affixed to the steel grade designation (e.g. EH40-BCA1, EH47-BCA1, EH47-
BCA2, etc.).
(2) Brittle crack arrest properties for brittle crack arrest steels are to be verified by either the brittle crack arrest
toughness Kca or Crack Arrest Temperature (CAT).
(3) Kca value is to be obtained by the brittle crack arrest test specified in App 4 .
(4) CAT is to be obtained by the test method specified in App 5.
(5) Criterion of CAT for brittle crack arrest steels corresponding to Kca=8,000 N/mm3/2 is to be approved by the
Society.
(6) Where small-scale alternative tests are used for product testing (batch release testing), these test methods are to
be approved by the Society in accordance with App 6.
(7) Lower thicknesses may be approved at the discretion of the Society.
Table 35 : Chemical composition and deoxidation practice for brittle crack arrest steels (1/1/2021)
Grade EH36-BCA EH40-BCA EH47-BCA

Deoxidation Practice Killed and fine grain treated
Chemical Composition % (ladle samples) (1) (7) (8)
C max. 0,18 0,18
Mn 0,90 - 2,00 0,90 - 2,00
Si max. 0,50 0,55
P max 0,020 0,020
S max. 0,020 0,020
Al (acid soluble min) 0,015 (2) (3) 0,015 (2) (3)
Nb 0,02 - 0,05 (3) (4) 0,02 - 0,05 (3) (4)
V 0,05 - 0,10 (3) (4) 0,05 - 0,10 (3) (4)
Ti max. 0,02 (4) 0,02 (4)

Cu max. 0,50 0,50
Cr max. 0,25 0,50
Ni max. 2,0 2,0
Mo max. 0,08 0,08
Ceq max. (5) 0,47 0,55
0,49 for EH40-BCA
RINA Rules 2023 87

Pt D, Ch 2, Sec 1
Grade EH36-BCA EH40-BCA EH47-BCA

Pcm max. (6) - 0,24
Notes:
(1) Chemical composition of brittle crack arrest steels shall comply with Tab 35, regardless of chemical composition specified
in [2] and Tab 32.
(2) The total aluminium content may be determined instead of the acid soluble content. In such cases the total aluminium
content is to be not less than 0,020%.
(3) The steel is to contain aluminium, niobium, vanadium or other suitable grain refining elements, either singly or in any
combination. When used singly the steel is to contain the specified minimum content of the grain refining element. When
used in combination, the specified minimum content of a fine graining element is not applicable.
(4) The total niobium, vanadium and titanium content is not to exceed 0,12%.
(5) The carbon equivalent Ceq value is to be calculated from the ladle analysis using the following formula:
Mn C r + Mo + V Ni + Cu
C eq = C + --------- + ------------------------------
- + --------------------- (%)
6 5 15
(6) Cold cracking susceptibility Pcm value is to be calculated using the following formula:
Si Mn Cu Ni Cr Mo V
P cm = C + ------ + --------- + ------- + ------ + ------ + --------- + ------ + 5B (%)
30 20 20 60 20 15 10
(7) Where additions of any other element have been made as part of the steelmaking practice subject to approval by the Soci-
ety, the content is to be indicated on product inspection certificate.
(8) Variations in the specified chemical composition may be allowed subject to approval of the Society
11.3 Manufacturing approval Hardness test to be carried out according to Ch 5, Sec 4,

[2.1.10]. Measurement points are to include mid-thickness
11.3.1 (1/1/2021) position in addition to those required in Ch 5, Sec 4,
Provisions for the approval of YP47 steels and brittle crack [2.1.10]. The results of hardness tests are not to exceed 350
arrest steels are given in the "Rules for the approval of HV.
Manufacturers of materials". Tensile strength in transverse tensile test is to be not less
than 570 N/mm2.
11.4 Welding of YP47 steels Deep notch test or CTOD test may be required.
11.4.1 Welding procedure qualification (1/1/2021) 11.4.2 Welders (1/1/2021)
Approval test items, test methods and acceptance criteria Welders engaged in YP47 welding work are to possess
are to be in accordance with Ch 5, Sec 4 except for the welder's qualifications specified in Ch 5, Sec 6.
provisions of this Article.
11.4.3 Welding consumables (1/7/2024)
Approval range is to be in accordance with Ch 5, Sec 4, Approval procedure, approval test items, test methods and
[2.7]. acceptance criteria not specified in this Article are to be in
Impact test to be carried out according to Ch 5, Sec 4, accordance with Ch 5, Sec 2.
[2.1.8]. Minimum average absorbed energy of 64J at -20°C Specifications of welding consumables for YP47 steel plates
is to be satisfied. are to be in accordance with Tab 36.
Table 36 : Mechanical properties for deposited metal tests for welding consumables (1/1/2021)
Mechanical Properties Impact test

Yield Tensile Test
Elongation Average Impact
Strength Strength Temp.
(%) min Energy(J) min.
(N/mm2) min. (N/mm2) (°C)
460 570 - 720 19 -20°C 64
Consumables tests for butt weld assemblies are to be in

accordance with Tab 37.
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Table 37 : Mechanical properties for butt weld tests for welding consumables (1/1/2021)
Charpy V-notch impact tests

Tensile Strength Bend test ratio: Test
(N/mm2) D/t Average absorbed
Temp.
energy (J) min.
(°C)
570 - 720 4 -20°C 64
11.4.4 Production welding (1/1/2021) 12 Normal and higher strength

Short bead length for tack and repairs of welds by welding corrosion resistant steels for cargo
are not to be less than 50mm. oil tanks
In the case where Pcm is less than or equal to 0,19, 25mm
12.1 Scope
of short bead length may be adopted with approval of the
12.1.1 (1/1/2014)
Society.
The requirements of this Article [12] apply to normal and
Preheating is to be 50°C or over when air temperature is higher strength corrosion resistant steels when such steel is
5°C or below. used as the alternative means of corrosion protection for
cargo oil tanks as specified in the IMO performance
In the case where Pcm is less than or equal to 0,19 and the standard MSC.289 (87) of Regulation 3-11, Part A-1,
air temperature is below 5°C but above 0°C, alternative Chapter II-1 of the SOLAS Convention (Corrosion
protection of cargo oil tanks of crude oil tankers).
preheating requirements may be adopted with approval of
the Society. 12.1.2 (1/1/2014)
The requirements are primarily intended to apply to steel
Special care is to be paid to the final welding so that products with a thickness as follows:
harmful defects do not remain. For steel plates and wide flats:
• All Grades: up to 50 mm in thickness
Jig mountings are to be completely removed with no defects
in general, otherwise the treatment of the mounting is to be For sections and bars
accepted by the Society. • All Grades: up to 50 mm in thickness.
12.1.3 (1/1/2014)
11.5 Welding of brittle crack arrest steels Normal and higher strength corrosion resistant steels as
defined in this Article, are steels whose corrosion resistance
11.5.1 Welding procedure qualification (1/7/2024) performance in the bottom or top of the internal cargo oil
tank is tested and approved to satisfy the requirements in
Where Welding Procedure Specification (WPS) for the non- IMO MSC.289 (87) in addition to other relevant
BCA steels has been approved by the Society, the said WPS requirements for ship material, structural strength and
is applicable to the same welding procedure applied to the construction. It is not intended that such steels be used for
same grade with suffix "BCA1" or "BCA2" specified in corrosion resistant applications in other areas of a vessel
Tab 34 except high heat input processes over 50kJ/cm. that are outside of those specified in the IMO performance
The requirements for welding procedure qualification test standard MSC.289 (87) of Regulation 3-11, Part A-1,
Chapter II-1 of the SOLAS Convention.
for brittle crack arrest steels is to be in accordance with the
relevant requirements for each steel grade excluding suffix 12.1.4 (1/1/2014)
"BCA1" or "BCA2" specified in Tab 34, with the following Since corrosion resistant steels are similar to the ship steels
exception for hardness test. For YP47 steels with brittle as specified in this Sec 1, the basic requirements of this
Section apply to these steels except where modified by this
crack arrest properties, HV10, as defined in Ch 5, Sec 4,
Article [12].
[2.1.10], is to be not more than 380. and Mmeasurement
points are to include mid-thickness position in addition to 12.1.5 (1/1/2014)
the points required in Ch 5, Sec 4, [2.1.10]. The weldability of corrosion resistant steels is similar to that
given in this Sec 1, therefore welding requirements
specified in Ch 5, Sec 2 and Ch 5, Sec 4 also apply except
11.5.2 Welding work (1/7/2024) as modified by this Article [12].
Welding work (such as relevant welder's qualification, short
bead, preheating, selection of welding consumables, etc.) 12.2 Approval
for brittle crack arrest steels is to be in accordance with the 12.2.1 (1/1/2014)
relevant requirements for each steel grade excluding suffix All materials are to be manufactured at works which have
"BCA1" or "BCA2" specified in Tab 34. been approved by the Society.

Pt D, Ch 2, App 4
APPENDIX 4 TEST METHOD FOR BRITTLE CRACK ARREST

TOUGHNESS, KCA
1 General reporting of test results, etc. are to be in accordance with

ISO 20064: 2019.
1.1 Application As a methodThe following specifies the testing machine
needed for conducting the initiating a brittle crack arrest
1.1.1 (1/1/2021)
test. Testing machine, a secondary loading mechanism can
Setting a temperature gradient in the width direction of a be used in accordance with Annex D of ISO 20064: 2019,
test specimen, and applying uniform stress to the test except that the first sentence in Annex B.2.4 of ISO 20064:
specimen, strike the test specimen to initiate a brittle crack 2019 is used to apply tensile forcerevised to an integrated
from the mechanical notch at the side of the test specimen specimen, and impact equipment is used to generate a
and causes crack arrest (temperature gradient type arrest brittle crack on the test specimen”Obtain the value of
testing). Using the stress intensity factor, calculate the brittle (Kca/K0)exp(c/TK) for each data point”.
crack arrest toughness, Kca, from the applied stress and the
arrest crack length. This value is the brittle crack arrest
toughness at the temperature of the point of crack arrest
2.2 Testing machine
(arrest temperature). To obtain Kca at a specific temperature
2.2.1 Loading method (1/1/2021)
followed by the necessary evaluation, the method specified
in Annex A in [8] of this Appendix can be used. As a Tensile load to an integrated specimen is to be hydraulically
method for initiating a brittle crack, a secondary loading applied.
mechanism can also be used (see Annex B in [9] of this The loading method to an integrated specimen using the
Appendix ). testing machine is to be of a pin type. The stress distribution
in the plate width direction is to be made uniform by
1.2 Scope aligning the centres of the loading pins of both sides and the
neutral axis of the integrated specimen.
1.2.1 (1/7/2024)
ISO20064: 2019 provides a test method for the 2.2.2 Loading directions (1/1/2021)
determination of brittle crack arrest toughness of steel by The loading directions are to be either vertical or
using wide plates with a temperature gradient. horizontal. In the case of the horizontal direction, test
This Appendix specifies the test methodprocedures for specimen surfaces are to be placed either perpendicular to
brittle crack arrest toughness (i.e. Kca) of steel using fracture the ground.
mechanics parameter and determination method of Kca at a
2.2.3 Distance between the loading pins (1/1/2021)
specific temperature which are specified in ISO
20064:2019. Additionally, this Appendix specifies the The distance between the loading pins is to be
evaluation method of Kca of test plate. This Appendix is approximately 3,4W or more, where W is the width of the
test specimen. Since the distance between the loading pins
applicable to hull structural steels with the thickness over
sometimes has an effect on the load drop associated with
50 mm and not greater than 100 mm specified in Sec 1, [2]
crack propagation, the validity of the test results is
or Sec 1, [11].
determTab 1ined by the judgment method described in
[6.1].
1.3 Symbols and their significance
1.3.1 (1/1/2021) 2.3 Impact equipment
The symbols and their significance used in this Appendix
are shown in Tab 1. 2.3.1 Impact methods (1/1/2021)
Methods to apply an impact load to an integrated specimen
2 Testing equipmentProcedures are to be of a drop weight type or of an air gun type.
The wedge is to be hard enough to prevent significant
2.1 General plastic deformation caused by the impact. The wedge
thickness is to be equal to or greater than that of the test
2.1.1 (1/7/2024) specimen, and the wedge angle is to be greater than that of
The test procedures including testing equipment, test the notch formed in the test specimen and have a shape
specimens, test methods, determination of arrest toughness, capable of opening up the notch of the test specimen.
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Table 1 : Symbols and their significance (1/1/2021)
Symbol Unit Significance

a mm Crack length or arrest crack length
E N/mm2 Modulus of longitudinal elasticity
Ei J Impact energy
Es J Strain energy stored in a test specimen
Et J Total strain energy stored in tab plates and pin chucks
F MN Applied load
K N/mm3/2 Stress intensity factor
Kca N/mm3/2 Arrest toughness
L mm Test specimen length

Lp mm Distance between the loading pins
Lpc mm Pin chuck length

Ltb mm Tab plate length
T °C Temperature or arrest temperature
t mm Test specimen thickness
ttb mm Tab plate thickness
tpc mm Pin chuck thickness
W mm Test specimen width
Wtb mm Tab plate width
Wpc mm Pin chuck width
xa mm Coordinate of a main crack tip in the width direction
xbr mm Coordinate of the longest branch crack tip in the width direction
ya mm Coordinate of a main crack tip in the stress loading direction
ybr mm Coordinate of the longest branch crack tip in the stress loading
direction
 N/mm2 Applied stress
Y0 N/mm2 Yield stress at room temperature
3 Test specimens Figure 1 : Standard test specimen shape (1/1/2021)
3.1 Test specimen shapes

3.1.1 (1/1/2021)
The standard test specimen shape is shown in Fig 1. Tab 2
shows the ranges of test specimen thicknesses, widths and
width-to-thickness ratios.The test specimen length is to be,
in principle, equal to or greater than its width.
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Table 2 : Dimensions of test specimens (1/1/2021) 3.2 Shapes of tab plates and pin chucks
3.2.1 (1/1/2021)
Test specimen thickness, t 50 mm  t  100 mm The definitions of the dimensions of the tab plates and pin
Test specimen width, W 350 mm  W  1000 mm chucks are shown in Fig 2. Typical examples are shown in
(Standard width: W = 500 Fig 3 and Fig 4.
mm)
Test specimen width/test W/t 
specimen thickness, W/t
Figure 2 : Definitions of dimensions of tab plates and pin chucks (1/1/2021)
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Figure 3 : Examples of the shapes of tab plates and pin chucks (1/1/2021)
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Pt D, Ch 2, App 4
Figure 4 : Examples of the shapes of tab plates and pin chucks (1/1/2021)
3.2.2 Tab plates (1/1/2021) The pin chucks are to be designed to have a sufficient load
bearing strength. When pin chucks attached to both ends of
The tolerances of tab plate dimensions are shown in Tab 3.
an integrated specimen are asymmetric, the length of the
When the lengths of the tab plates attached to both ends of
shorter one is to be used as the pin chuck length, Lpc.
a test specimen are different, the shorter length is to be used
as the tab length, Ltb.
The distance between the pins, Lp, is obtained from the
equation (1). In the case as shown in Fig 4 (e), example 5,
Table 3 : Tolerances of tab plate Lp is obtained by setting Lpc = 0.
dimensions (1/1/2021)
Lp = L + 2Ltb +2Lpc (1)
Tab plate thickness, ttb 0,8t  ttb  1,5t

3.3 Welding of test specimen and tab plates
Tab plate width, Wtb W  Wtb  2W
3.3.1 (1/1/2021)
Total length of a test speci- L+2Ltb 3,0W Test specimen, tab plates, and pin chucks are to be
men and tab plates, L + 2Ltb (L+Ltb 2,0W) connected by welding. The welds are to have a sufficient
(Total length of a test speci- force bearing strength.
men and a single tab plate L
+ Ltb) As shown in Fig 5 (a), the flatness (angular distortion, linear
misalignment) of the weld between a test specimen and a
Tab plate length (Lt)/Tab plate Ltb/W  1,0 tab plate is to be 4 mm or less per 1 m. In the case of
width, (W) preloading, however, it is acceptable if the value after
preloading satisfies this condition. As shown in Fig 5 (b), the
3.2.3 Pin chucks (1/1/2021) accuracy of the in-plane loading axis is to be 0,5% or less of
the distance between the pins, and the accuracy of the out-
The pin chuck width, Wpc, is to be in principle equal to or of-plane loading axis is to be 0,4% or less of the distance
more than the tab plate width, Wtb. between the pins.
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Figure 5 : Dimensional accuracy of weld between test specimen and tab plate (1/1/2021)
4 Test methods the gradient is larger than 0,35 °C/mm, the obtained
arrest toughness may be too conservative
4.1 General b) At the test specimen width centre position (i.e., 0,5W),
and in the range of ±100 mm in the test specimen
4.1.1 (1/1/2021) length direction, the deviation from the temperature at
the centre position in the length direction is to be
The following specifies methods for conducting the arrest
controlled within ±5 °C. However, when temperature
toughness test. measurement is not performed at the centre position in
the length direction, the average temperature at the
4.2 Temperature control methods closest position is to be used as the temperature at the
centre position in the length direction
4.2.1 (1/1/2021)
c) At the same position in the width direction, the
A predetermined temperature gradient is to be established deviation of the temperature on the front and back
across a test specimen width by soldering at least nine surfaces is to be controlled within ±5 °C.
thermocouples to the test specimen for temperature
measurement and control.
4.3 Crack initiation methods
Temperature gradient is to be established in accordance
4.3.1 (1/1/2021)
with the following conditions:
Impact energy is to be applied to a test specimen to initiate
a) A temperature gradient of 0,25 - 0,35 °C/mm is to be
a crack. However, if the energy is excessive, it may
established in a test specimen width range of 0,3W - influence on the test results. In that case, the results are to
0,7W. When measuring the temperatures at the centre be treated as invalid data in accordance with the judgment
position of the test specimen thickness, it is to be kept criteria specified in [6.2]. It is desirable to use equation (2)
within ±2 °C for 10 minutes or more, whereas when and Fig 6 as guides for obtaining valid data.
measuring the temperatures on the front and back
surface positions of the test specimen, it is to be kept Ei / t min(1,2 - 40,200) (2)
within ±2 °C for (10+0,1t [mm]) minutes or more taking
account of the time needed for soaking to the centre. If Where the variables have the following units: Ei [J], t [mm],
the temperature gradient at 0,3W - 0,7W is less than and  [N/mm2], and min means the minimum of the two
0,25 °C/mm, crack arrest may become difficult, and if values.
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Figure 6 : Recommended range of impact Applied stress is to be within the range shown by
energy (1/1/2021) equation:
 Y0 (3)
As a guide, a value equal to 1/6 of Y0 or more is
desirable. If applied stress is larger than that
specified by equation (3), the test may give a non-
conservative result
g) To initiate a crack, the notch may be cooled further
immediately before impact on the condition that the
cooling does not disturb the temperature in the range of
0,3W - 0,7W. The test temperature in this case is to be
the measured temperature obtained from the
temperature record immediately before the further
notch cooling
h) Record the force value measured by a force recorder.
5 Test procedures 5.3 Loading procedures

5.3.1 (1/1/2021)
5.1 General
a) After holding a predetermined force for 30 seconds or
5.1.1 (1/1/2021) more, apply an impact to the wedge using the impact
The following specifies the procedures for testing brittle apparatus. If a crack initiates autonomously and the
crack arrest toughness. exact force value at the time of the crack initiation
cannot be obtained, the test is invalid
5.2 Pretest procedures b) After the impact, record the force value measured by the
5.2.1 (1/1/2021) force recorder
a) Install an integrated specimen in the testing machine c) When the force after the impact is smaller than the test
force, consider that crack initiation has occurred
b) Mount a cooling device on the test specimen. A heating
device may also be mounted on the test specimen Note 1: An increase in the number of times of impact may cause a
change in the shape of the notch of the test specimen. Since the
c) Install an impact apparatus specified in [2.3], on the number of impact has no effect on the value of brittle crack
testing machine. Place an appropriate reaction force arrest toughness, no limit is specified for the number of impact.
receiver as necessary However, because the temperature gradient is often distorted
Note 1: The above procedures (1) through (3) do not necessarily by impact, the test is to be conducted again, beginning from
specify the order of implementation, and they may be temperature control when applying repeated impact to the
completed, for example, on the day before the test wedge.
d) After checking that all measured values of the d) When crack initiation, propagation, and arrest are
thermocouples indicate room temperature, start observed, remove the force.
cooling. The temperature distribution and the holding
time is to be as provided in the specifications in [4.2] 5.4 Procedures after testing
e) Set an impact apparatus, as specified in [2.3] so that it 5.4.1 (1/1/2021)
can supply predetermined energy to the test specimen a) Remove the impact apparatus
f) Apply force to the test specimen until it reaches the b) Remove the cooling device, thermocouples, and strain
predetermined value. This force is applied after gauges
temperature control to prevent autonomous crack
c) Return the temperature of the test specimen to room
initiation during force increase. Alternatively,
temperature. For that purpose, the test specimen may be
temperature control may be implemented after loading.
heat-tinted using a gas burner or the like. If it is
The loading rate and applied stress are to satisfy the
necessary to prevent heating of the fracture surface, this
conditions (a) and (b) described below, respectively:
method is to be avoided
1) Loading rate
d) After gas-cutting an uncracked ligament, use the testing
There is no specification of loading rate, but it is to machine to cause ductile fracture, as necessary.
be determined considering that an excessively slow Alternatively, it is also possible to gas-cut the uncracked
loading rate may prolong the temperature control ligament after using the testing machine to develop a
period, thereby allowing the temperature ductile crack to a sufficient length.
distribution to depart from the desired condition and
an excessively fast loading rate may cause over-
5.5 Observation of fracture surfaces
shooting of the load
2) Applied stress/yield stress ratio 5.5.1 (1/1/2021)
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a) Photograph the fracture surfaces and propagation path In the case where a crack deviates from the direction
b) Measure the longest length of the arrest crack tip in the vertical to the loading direction, the length projected
plate thickness direction, and record the result as the to the plane vertical to the loading line is defined as
arrest crack length. The arrest crack length is to include the arrest crack length. Similarly, in the case of crack
the notch length. In the case where a crack deviates branching, the length of the longest branch crack
from the direction vertical to the loading direction, the projected to the plane vertical to the loading line is
length projected to the plane vertical to the loading line defined as the branch crack length. More
is defined as the arrest crack length. In the following specifically, from the coordinates (xa, ya) of the
cases, however, judge the results according to the arrest crack tip position and the coordinates (xbr, ybr)
methods described for each case: of the branch crack tip position shown in Fig 7,
1) Crack re-initiation obtain the angle  from the x-axis and define xa as
In the case where a brittle crack has re-initiated from the arrest crack length, a. Here, x is the coordinate
an arrested crack, the original arrest position is in the test specimen width direction, and the side
defined as the arrest crack position. Here re- face of the impact side is set as x = 0; y is the
initiation is defined as the case where a crack and coordinate in the test specimen length direction,
re-initiated cracks are completely separated by a and the notch position is set as y = 0
stretched zone and brittle crack initiation from the c) Prepare a temperature distribution curve (line diagram
stretched zone can be clearly observed. In the case showing the relation between the temperature and the
where a crack continuously propagates partially in distance from the test specimen top side) from the
the thickness direction, the position of the longest thermocouple measurement results, and obtain the
brittle crack is defined as the arrest position arrest temperature T corresponding to the arrest crack
2) Crack branching length.
Figure 7 : Measurement methods of main crack and branch crack lengths (1/1/2021)
6 Determination of arrest toughness When an arrested crack satisfies all of the conditions (a)
through (d) below as shown in Fig 8, the length of the
arrested crack determined by [5.5] is valid. If any of the
6.1 Judgment of arrested crack conditions is not met, the arrest toughness calculated from
6.1.1 (1/1/2021) [6.3] is invalid
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Figure 8 : Necessary conditions of arrest crack d) Conditions for crack branching:

position (1/1/2021) (xbr/xa)  (9)
Figure 9 : Allowable range of main crack propagation

path (1/1/2021)
a) Conditions for crack propagation path:

All of the crack path from crack initiation to arrest is to
be within the range shown in Fig 9. However, in the
case where a main crack tip lies within this range but a
part of the main crack passes outside the range, the
arrest toughness may be assessed as valid if the 6.2 Assessment of impact energy
temperature at the most deviated position of the main
crack in the y direction is lower than that at y = 0, and 6.2.1 Impact energy is to satisfy equation (10). If it does
also K for the main crack falls within ± 5% of K for a not satisfy the equation, the value of arrest toughness
straight crack of the same a. The calculation method of calculated from the equations in [6.3] is invalid.
Ks for the main crack and a straight crack is obtained Conditions for impact energy:
from equation (4).
Ei 5a – 1050 + 1 4W
-  ------------------------------------------------ where 0,3   ------  0 7
a
-------------- (10)
Es + Et 0 7W – 150  W
where the variables have the following units: a [mm], and

 3
 2
 W [mm]. Ei is impact energy calculated from the equation
K = K I  cos  --- + 3  K II  cos  ---  sin  --- (4)
 2  2  2 (11). Es and Et are calculated from equations (12) and (13),
respectively.
Note 1: If equation (10) is not satisfied, the influence of impact
energy on the stress intensity factor is too large to obtain an
accurate arrest toughness.
b) Conditions for arrest crack length: Note 2: In the case where the tab plates are multistage as shown in
0,3 (a/W)  Fig 3 (b), calculate and total the strain energy of each tab plate
using equation (12).
(a/t) 
Note 3: In the case where tab plate widths are tapered as shown in
(a/Lp)  Fig 4 (d), calculate the strain energy based on elastostatics.
Note 1: Equation (7) ensures minimal influence of force drop at the Ei = mgh (11)
centre of the specimen which might be caused by crack
propagation and reflection of the stress wave at the two ends of
10  F
9 2
the specimen. However, application of equation (7) is not L
E s = ------------------  -------- (12)
necessarily required if the strain and the crack length have 2  E Wt
been dynamically measured and the value of the strain at the
time of arrest is 90% or more of the static strain immediately
before crack initiation.
c) Conditions for crack straightness:
|ya|  mm (8) 10  F
9 2
L tb L pc 
E t = ------------------   --------------
- + ---------------
- (13)
E  W tb t tb W pc t pc
In the case where 50 mm < |ya|  100 mm and || 
30°, the result is valid only when the temperature at x =
0,5W and y = ±100 mm falls within ± 2,5 C of that at x
= 0,5W and y = 0.
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where the variables have the following units: Es [J], Et [J], F 7.1.1 (1/1/2021)
[MN], E [N/mm2], L [mm], W [mm], and t [mm]. Using Tab 4, the following items are to be reported:
a) Test material: Steel type and yield stress at room
6.3 Calculation of arrest toughness temperature
6.3.1 (1/1/2021) b) Testing machine: Capacity of the testing machine
The arrest toughness, Kca, at the temperature, T, is to be c) Test specimen dimensions: Thickness, width, length,
calculated from equation (14) using the arrest crack length, angular distortion, and linear misalignment
a, and the applied stress, s, judged by [6.1]. Calculate s
d) Integrated specimen dimensions: Tab plate thickness,
from equation (15).
tab plate width, integrated specimen length including
the tab plates, and distance between the loading pins
1
---
a
=   a  ---------  tan  ---------
2W 2
e) Test conditions: Applied force, applied stress,
K ca (14)
a  2W temperature gradient, impact energy, and the ratio of
impact energy to the strain energy stored in the
integrated specimen (sum of test specimen strain energy
and tab plate strain energy)
f) Test results:
10  F
6
1) Judgment of arrest: Crack length, presence or
 = ---------------- (15)
Wt absence of crack branching, main crack angle,
presence or absence of crack re-initiation, and arrest
temperature
2) Arrest toughness value
where the variables have the following units: F [MN], W g) Temperature distribution at moment of impact:
[mm], and t [mm]. Thermocouple position, temperature value, and
If the conditions specified in [6.1] and [6.2] are not temperature distribution
satisfied, the Kca calculated from equation (14) is invalid. h) Test specimen photographs: Crack propagation path
(one side), and brittle crack fracture surface (both sides)
7 Reporting i) Dynamic measurement results: History of crack
propagation velocity, and strain change at pin chucks.
7.1 General Note 1: Item (9) is to be reported as necessary.
Table 4 : Report sheet for brittle crack arrest test results (1/1/2021)
Condi-
Details Valid/
Item Symbol tions/ Unit
Invalid
Results
(1) Test material Steel type - - -
Yield stress at room temperature Y0 N/mm2 -
(2) Test equipment Testing machine capacity - MN -
(3) Test specimen Thickness t mm
dimensions Width W mm
Length L mm
Angular distortion + linear misalignment - mm/m
(4) Integrated spec- Tab plate thickness ttb mm

imen dimensions
Tab plate width Wtb mm
Test specimen length including a tab plate L + Ltb mm
Distance between loading pins Lp mm
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Pt D, Ch 2, App 4
Condi-
Details Valid/
Item Symbol tions/ Unit
Invalid
Results
(5) Test conditions Applied force F MN
Applied stress  N/mm2
Temperature gradient - °C/mm
Impact energy Ei J
Ratio of impact energy to strain energy Ei / (Es+Et) -
stored in integrated specimen
(6) Test results Judgment of crack Crack length a mm
propagation/arrest Presence/absence of - - -
crack branching
Ratio of branch crack xbr/xa -
length to main crack
Main crack angle  degree (°)
Presence/absence of - -
crack re-initiation
Temperature at crack T °C
arrest position
Arrest toughness value Kca N/mm3/2
(7) Temperature Temperature measurement position - Attached - -
distribution at Temperature at each temperature measure- - Attached °C -
moment of impact ment position
Temperature distribution curve - Attached -
(8) Test specimen Crack propagation path - Attached -

photographs Brittle crack fracture surface (both sides) - Attached -
(9) Dynamic meas- History of crack propagation velocity - Attached -

urement results Strain change at pin chucks - Attached -
38 ANNEX A: Method for obtaining

Kca at a specific temperature and
the evaluation
K ca = K 0  exp  -----
c
(16)
 T K
38.1 GeneralMethod
38.1.1 (1/7/2024)
This Article specifies the method for conducting multiple
tests specified in this Appendix to obtain Kca value at a a) Obtain at least four valid Kca data
specific temperature is to be in accordance with Annex B of
b) Approximating logKca by a linear expression of 1/TK,
ISO 20064: 2019TD.
determine the coefficients logK0 and c for the data
described in item a) by using the least square method
8.2 Method
8.2.1 (1/1/2021) 1
log K ca = log K 0 + c  ----- (17)
A number of experimental data show dependency of Kca on TK
arrest temperature, as expressed by equation 16, where TK
[K] (= T [°C]+273), c and K0 are constants. c) Obtain the value of (Kca/K0)exp(c/TK) for each data item.
When the number of data outside the range of 0,85
through 1,15 does not exceed, the least square method
The arrest toughness at a required temperature TD [K] can used in item b) is considered valid. Here is an integer
be obtained by following the procedures below: obtained by rounding down the value of (number of all
162 RINA Rules 2023

Pt D, Ch 2, App 4
data divided by 6). If this condition is not met, conduct Figure 211 : Example for evaluation of temperature
additional tests to add at least two data and apply the corresponding to the required Kca (1/1/2021)
procedure in item b) to the data
d) The value of K0 exp(c/TD) is defined as the estimated
value of Kca at TD. The estimated value for the
temperature corresponding to a specific value of Kca can
be obtained from TK = c/log(Kca/K0). If the condition
specified in item c) is not met, these estimated values
are treated as reference values.
38.23 Evaluation
38.23.1 (1/7/2024)
The straight-line approximation of Aarrhenius plot for valid
Kca data by interpolation method are to comply with either
the following:
a) The evaluation temperature of Kca (i.e. - 10 degree C) is
located between the upper and lower limits of the arrest If both of a) and b) above are not satisfied, conduct
temperature, with the Kca corresponding to the additional tests to satisfy this condition.
evaluation temperature not lower than the required Kca
(e.g. 6,000 N/mm3/2 or 8,000 N/mm3/2), as shown in 9 ANNEX B: Double tension type
Fig. 10 arrest test
b) The temperature corresponding to the required Kca (e.g.
6,000 N/mm3/2 or 8,000 N/mm3/2) is located between 9.1 Features of this test method
the upper and lower limits of the arrest temperature, 9.1.1 (1/1/2021)
with the temperature corresponding to the required Kca A double tension type arrest test specimen consists of a
not higher than the evaluation temperature (i.e. -10 main plate and a secondary loading tab. The main plate is a
test plate for evaluating brittle crack arrest toughness. The
degree C), as shown in Fig 211. secondary loading tab is a crack starter plate for assisting a
Figure 10 : Example for evaluation of Kca at - 10 brittle crack to run into the main plate. After applying a
degree C (1/1/2021) predetermined tension force and a temperature gradient to
the main plate, a secondary force is applied to the
secondary loading tab by a secondary loading device to
cause a brittle crack to initiate and run into the main plate.
The arrest toughness is evaluated from the arrest
temperature and the crack length in the main plate.
The narrow connection part of the main plate and the

secondary loading tab in this test suppress the flow of the
tension stresses of the secondary loading tab into the main
plate. The values of arrest toughness obtained by this
method can be considered the same as the results obtained
by the brittle crack arrest toughness test specified in this
Appendix.
The specifications described in this Appendix are to be

applied to conditions not mentioned in this Article.
9.2 Test specimen shapes

9.2.1 (1/1/2021)
The recommended shapes of the entire double tension type
arrest test specimen and the secondary loading tab are
shown in Fig 12 and Fig 13, respectively. The requirements
in [3.2] apply to the shapes of the tab plates and pin chucks
Note 1: Because of the narrowness of the connection part, slight
crack deviation may lead to failure of the crack to enter the main
plate. The optimum shape design of the secondary loading tab
depends on the type of steel and testing conditions.
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Pt D, Ch 2, App 4
Figure 12 : Example of shape of entire test

specimen (1/1/2021)
Figure 13 : Example of shape of secondary loading tab (1/1/2021)
9.3 Temperature conditions and • Holding methods of secondary loading device

temperature control methods To avoid applying unnecessary force to the integrated
9.3.1 (1/1/2021) specimen, the secondary loading device must be held in
Establish a temperature gradient in the main plate in order an appropriate way. Suspension type or floor type
to evaluate its brittle crack arrest toughness. The holding methods can be used. In the suspension type
specifications for temperature gradients and methods for method, the secondary loading device is suspended and
establishing the temperature gradient are described in [4]. held by using a crane or a similar device. In the floor
In addition, in the double tension type arrest test, the type method, the secondary loading device is lifted and
secondary loading tab must be cooled. The secondary held by using a frame or a similar device
loading tab is cooled without affecting the temperature • Loading system
gradient of the main plate. As in the cooling method for test A hydraulic type loading system is most suitable for
specimens described in this Appendix, cooling may be applying a force to the secondary loading tab. However,
applied using a cooling box and a coolant. The temperature other methods may be used. The requirements in [3.2]
of the secondary loading tab can be measured using apply to the shapes of the tab plates and pin chucks
thermocouples as described in this Appendix. • Loading method
The method of loading the secondary loading tab is to
9.4 Secondary loading method be a pin type loading method. A loading method other
9.4.1 (1/1/2021) than a pin type may be used by agreement among the
A secondary loading device is used to apply force to the parties concerned. The loading rate is not specifically
secondary loading tab. The secondary loading device is to specified because it does not have a direct influence on
satisfy the conditions below: the crack arrest behavior of the main plate.
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Pt D, Ch 2, App 5
APPENDIX 5 OUTLINE OF REQUIREMENTS FOR UNDERTAKING

ISOTHERMAL CRACK ARREST TEMPERATURE
(CAT) TEST
1 General 2 Testing equipment
1.1 Scope 2.1 General

2.1.1 (1/1/2021)
1.1.1 (1/1/2021)
The test equipment to be used is to be of the hydraulic type
This Appendix is to be applied according to the scope of sufficient capacity to provide a tensile load equivalent to
defined in Sec 1, [11]. 2/3 of SMYS of the steel grade to be approved
1.1.2 (1/1/2021) 2.1.2 (1/1/2021)
This Appendix specifies the requirements for test The temperature control system is to be equipped to
procedures and test conditions when using the isothermal maintain the temperature in the specified region of the
crack arrest test to determine a valid test result under specimen within ±2°C from Ttarget
isothermal conditions and in order to establish the crack 2.1.3 (1/1/2021)
arrest temperature (CAT). This Appendix is applicable to Methods for initiating the brittle crack may be of drop
steels with thickness over 50mm and not greater than weight type, air gun type or double tension tab plate type
100mm. 2.1.4 (1/7/2024)
1.1.3 (1/7/2024) The detailed requirements for testing equipment are
specified in App 4, [2]to be in accordance with ISO 20064:
This method uses an isothermal temperature in the test
2019.
specimen being evaluated. Unless otherwise specified in
this Appendix, the other test parameters are to be in
accordance with App 4ISO 20064: 2019. 3 Test specimens
1.1.4 (1/1/2021)
3.1 Impact type crack initiation
Sec 1, Tab 34 gives the relevant requirements for the brittle
3.1.1 (1/7/2024)
crack arrest property described by the crack arrest
temperature (CAT). Test specimens are to be in accordance with App 4, [3]ISO
20064: 2019, unless otherwise specified in this Appendix
1.1.5 (1/1/2021) 3.1.2 (1/1/2021)
The manufacturer is to submit the test procedure to the Specimen dimensions are shown in Fig 1. The test specimen
Society for review prior to testing. width, W is to be 500mm. The test specimen length, L is to
be equal to or greater than 500mm
1.2 Symbols and their significance 3.1.3 (1/1/2021)
V-shape notch for brittle crack initiation is machined on the
1.2.1 (1/7/2024) specimen edge of the impact side. The whole machined
Tab 1 supplements App 4, Table 1 in ISO 20064: 2019 with notch length is to be equal to 29mm with a tolerance range
specific symbols for the isothermal test. of ±1mm
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Pt D, Ch 2, App 5
Table 1 : Nomenclature supplementary to Table 1 of Appendix 4in ISO 20064: 2019 (1/7/2024)
Symbol Unit Significance

t mm Test specimen thickness
L mm Test specimen length
W mm Test specimen width

aMN mm Machined notch length on specimen edge
mm Side groove length on side surface from the specimen edge. LSG
LSG is defined as a groove length with constant depth except a curved
section in depth at side groove end
dSG mm Side groove depth in section with constant depth
mm Minimum length between specimen edge and electron beam re-
LEB - min
melting zone front
mm Length between specimen edge and electron beam re-melting
LEB-s1, -s2
zone front appeared on both specimen side surfaces
LLTG mm Local temperature gradient zone length for brittle crack runway
aarrest mm Arrested crack length
Ttarget °C Target test temperature

Ttest °C Defined test temperature
Tarrest °C Target test temperature at which valid brittle crack arrest
behaviour is observed
 N/mm2 Applied test stress at cross section of W x t
SMYS N/mm2 Specified minimum yield strength of the tested steel grade to be
approved
CAT °C Crack arrest temperature, the lowest temperature, Tarrest, at
which running brittle crack is arrested
3.1.4 (1/1/2021)
Requirements for side grooves are described in [3.4].
Figure 1 : Test specimen dimensions for an impact type specimen (1/1/2021)
Note 1: Saw cut notch radius may be machined in the range 3.2.2 (1/1/2021)
0,1mm R and 1mm R in order to control a brittle crack initiation at In a double tension type test, the secondary loading tab
test. plate may be subject to further cooling to enhance an easy
brittle crack initiation.
3.2 Double tension type crack initiation
3.3 Embrittled zone setting
3.2.1 (1/7/2024)
3.3.1 (1/1/2021)
Reference is to be made to Annex BD in App 4, [9]in ISO An embrittled zone is to be applied to ensure the initiation
20064: 2019 for the shape and sizes in secondary loading of a running brittle crack. Either Electron Beam Welding
tab and secondary loading method for brittle crack (EBW) or Local Temperature Gradient (LTG) may be
initiation adopted to facilitate the embrittled zone
166 RINA Rules 2023

Pt D, Ch 2, App 5
3.3.2 (1/1/2021) 3.4 Side grooves

In EBW embrittlement, electron beam welding is applied 3.4.1 (1/1/2021)
along the expected initial crack propagation path, which is Side grooves on side surface can be machined along the
the centre line of the specimen in front of the machined V- embrittled zone to keep brittle crack propagation straight.
notch Side grooves are to be machined in the specified cases as
specified in this section.
3.3.3 (1/1/2021)
3.4.2 (1/1/2021)
The complete penetration through the specimen thickness is
In EBW embrittlement, side grooves are not necessarily
required along the embrittled zone. One side EBW
mandatory. Use of EBW avoids the shear lips. However,
penetration is preferable, but dual sides EB penetration may
when shear lips are evident on the fractured specimen, e.g.
be also adopted when the EBW power is not enough to
shear lips over 1mm in thickness in either side then side
achieve the complete penetration by one side EBW
grooves should be machined to suppress the shear lips.
3.3.4 (1/1/2021) 3.4.3 (1/1/2021)
The EBW embrittlement is recommended to be prepared In LTG embrittlement, side grooves are mandatory. Side
before specimen contour machining grooves with the same shape and size are to be machined
on both side surfaces.
3.3.5 (1/1/2021)
3.4.4 (1/7/2024)
In EBW embrittlement, zone is to be of an appropriate The length of side groove, LSG is to be no shorter than the
quality sum of the required embrittled zone length of 150mm.
Note 1: EBW occasionally behaves in an un-stable manner at start 3.4.5 (1/1/2021)
and end points. EBW line is recommended to start from the When side grooves would be introduced, the side groove
embrittled zone tip side to the specimen edge with an increasing
depth, the tip radius and the open angle are not regulated,
power control or go/return manner at start point to keep the stable
but are adequately selected in order to avoid any shear lips
EBW.
over 1mm thickness in either side. An example of side
3.3.6 (1/1/2021) groove dimensions are shown in Fig 2.
In LTG system, the specified local temperature gradient 3.4.6 (1/1/2021)
between machined notch tip and isothermal test region is Side groove end is to be machined to make a groove depth
regulated after isothermal temperature control. LTG gradually shallow with a curvature larger than or equal to
temperature control is to be achieved just before brittle groove depth, dSG. Side groove length, LSG is defined as a
crack initiation, nevertheless the steady temperature groove length with constant depth except a curved section
gradient through the thickness is to be ensured. in depth at side groove end.
Figure 2 : Side groove configuration and dimensions (1/1/2021)
3.5 Nominal length of embrittled zone between specimen edge and EBW front line, and LEB-s1
and LEB-s2.
3.5.1 (1/7/2024)
The length of embrittled zone is to be nominally equalat 3.5.3 (1/1/2021)
least to 150mm in both systems of EBW and LTG. The minimum length between specimen edge and EBW
3.5.2 (1/1/2021) front line, LEB-min should be no smaller than 150mm.
EBW zone length is regulated by three measurements on However, it can be acceptable even if LEB-min is no smaller
the fracture surface after test as shown in Fig 3 , LEB-min than 150mm-0,2t, where t is specimen thickness. When
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Pt D, Ch 2, App 5
LEB-min is smaller than 150mm, a temperature safety LEB-s1 and LEB-s2. Both of LEB-s1 and LEB-s2 are to be no
margin is to be considered into Ttest (See [7.1.2]) smaller than 150mm.
3.5.4 (1/1/2021)
3.5.5 (1/1/2021)
Another two are the lengths between specimen edge and
EBW front appeared on both side surfaces, as denoted with In LTG system, LLTG is set as 150mm.
Figure 3 : Definition of EBW length (1/1/2021)
3.6 Tab plate / pin chuck details and welding be applied at higher temperature than ambient temperature
of test specimen to tab plates when brittle crack initiation is expected at preloading
process. However, the specimen is to not be subjected to
3.6.1 (1/7/2024)
temperature higher than 100°C.
The configuration and size of tab plates and pin chucks is to
be referred to App 4, [3.2]ISO 20064: 2019. The welding
distortion in the integrated specimen, which is welded with 4.2 Temperature measurement and control
specimen, tab plates and pin chucks, is to be also within the
4.2.1 (1/1/2021)
requirement in App 4, [3.3]ISO 20064: 2019.
Temperature control plan showing the number and position
4 Test method of thermocouples is to be in accordance with this section.
4.2.2 (1/1/2021)
4.1 Preloading Thermocouples are to be attached to both sides of the test
4.1.1 (1/1/2021) specimen at a maximum interval of 50mm in the whole
Preloading at room temperature can be applied to avoid width and in the longitudinal direction at the test specimen
unexpected brittle crack initiation at test. The applied load centre position (0,5 W) within the range of ±100mm from
value is to be no greater than the test stress. Preloading can the centreline in the longitudinal direction, refer to Fig 4.
Figure 4 : Locations of temperature measurement (1/1/2021)
4.2.3 (1/1/2021) directions are to be controlled within ± 2°C of the target

For EBW embrittlement: test temperature, Ttarget
• The temperatures of the thermocouples across the range • When all measured temperatures across the range of
of 0,3W~0,7W in both width and longitudinal 0,3W~0,7W have reached Ttarget, steady temperature
control is to be kept at least for 10 + 0,1 x t [mm]
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Pt D, Ch 2, App 5
minutes to ensure a uniform temperature distribution control is to be kept at least for 10 + 0,1 x t [mm]
into mid-thickness prior to applying test load minutes to ensure a uniform temperature distribution
• The machined notch tip can be locally cooled to easily into mid-thickness, then the test load is applied
initiate brittle crack. Nevertheless, the local cooling is to d) LTG is controlled by local cooling around the machined
not disturb the steady temperature control across the notch tip. LTG profile is to be recorded by the
range of 0,3W~0,7W. temperature measurements from A0 to A3 shown in
4.2.4 (1/7/2024) Fig 6
For LTG embrittlement: e) LTG zone is established by temperature gradients in
a) In LTG system, in addition to the temperature three zones, Zone I, Zone II and Zone III. The
measurements shown in Fig 4, the additional acceptable range for each temperature gradient is listed
temperature measurement at the machine notch tip, A0 Tab 2
and B0 is required. Thermocouples positions within LTG f) Two temperature measurements at A2, B2 and A3, B3 are
zone are shown in Fig 5. to be satisfied the following requirements:
Figure 5 : Detail of LTG zone and additional T at A3, T at B3 < Ttarget - 2°C
thermocouple A0 (1/1/2021)
T at A2 < T at A3 - 5°C
T at B2 < T at B3 - 5°C
g) No requirements for T at A0 and T at A1 temperatures

when T at A3 and T at A2 satisfy the requirements
above. Face B is the same
h) The temperatures from A0, B0 to A3, B3 should be
decided at test planning stage refer to Tab 2 which gives
the recommended temperature gradients in three zones,
Zone I, Zone II and Zone III in LTG zone
b) The temperatures of the thermocouples across the range i) The temperature profile in LTG zone mentioned above
of 0,3W~0,7W in both width and longitudinal is to be ensured after holding time at least for 10 + 0,1 x
directions are to be controlled within ± 2°C of the target t [mm] minutes to ensure a uniform temperature
test temperature, Ttarget. However, the temperature distribution into mid-thickness before brittle crack
measurement at 0,3W (location of A3 and B3) is to be in initiation
accordance with f) below j) The acceptance of LTG in the test is to be decided from
c) Once the all measured temperatures across the range of Tab 2 based on the measured temperatures from A0 to
0,3W~0,7W have reached Ttarget, steady temperature A3.
Figure 6 : Schematic temperature gradient profile in LTG zone (1/1/2021)
Table 2 : Acceptable LTG range (1/1/2021)
Location from
Zone Acceptable range of temperature gradient
edge
Zone I 29mm - 50mm 2,00 °C/mm - 2,30 °C/mm
Zone II 50mm - 0,25 °C/mm - 0,60 °C/mm
100mm
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Pt D, Ch 2, App 5
Location from
Zone Acceptable range of temperature gradient
edge
Zone III (1) 100mm - 0,10 °C/mm - 0,20 °C/mm
150mm
(1) The Zone III arrangement is mandatory
Figure 7 : Allowable range of main crack propagation

4.2.5 (1/7/2024)
path (1/1/2021)
For double tension type crack initiation specimen
Temperature control and holding time at steady state are to
be the same as the case of EBW embrittlement specified in
[4.2.3] or the case of LTG embrittlement specified in
[4.2.4].
4.3 Loading and brittle crack initiation

4.3.1 (1/1/2021)
Prior to testing, a target test temperature (Ttarget) is to be
selected.
4.3.2 (1/7/2024)
Test procedures are to be in accordance with App4, [5]ISO
20064: 2019 except that the applied stress is to be 2/3 of
SMYS of the steel grade tested.
4.3.3 (1/1/2021) 5.3 Fracture surface examination, crack
The test load is to be held at the test target load or higher for length measurement and their validation
a minimum of 30 seconds prior to crack initiation. 5.3.1 (1/1/2021)
4.3.4 (1/1/2021) Fracture surface is to be observed and examined. The crack
Brittle crack can be initiated by impact or secondary tab "initiation" and "propagation" are to be checked for validity
plate tension after all of the temperature measurements and and judgements recorded. The crack "arrest" positions are to
the applied force are recorded. be measured and recorded.
5.3.2 (1/1/2021)
5 Measurements after test and test When crack initiation trigger point is clearly detected at
validation judgement side groove root, other than the V-notch tip, the test is to be
invalid.
5.1 Brittle crack initiation and validation 5.3.3 (1/1/2021)
In EBW embrittlement setting, EBW zone length is
5.1.1 (1/1/2021)
quantified by three measurements of LEB-s1, LEB-s2 and
If brittle crack spontaneously initiates before the test force is LEB-min, which are defined in [3.5]. When either or both of
achieved or the specified hold time at the test force is not LEB-s1 and LEB-s2 are smaller than 150mm, the test is to be
achieved, the test is to be invalid. invalid. When LEB-min is smaller than 150mm-0,2t, the test
5.1.2 (1/1/2021) is to be invalid.
If brittle crack spontaneously initiates without impact or 5.3.4 (1/1/2021)
secondary tab tension but after the specified time at the test When the shear lip with thickness over 1mm in either side
force is achieved, the test is considered as a valid initiation. near side surfaces of embrittled zone are visibly observed
The following validation judgments of crack path and independent of the specimens with or without side grooves,
fracture appearance is to be examined. the test is to be invalid.
5.3.5 (1/1/2021)
5.2 Crack path examination and validation In EBW embrittlement setting, the penetration of brittle
5.2.1 (1/1/2021) crack beyond the EBW front line is to be visually examined.
When brittle crack path in embrittled zone deviates from When any brittle fracture appearance area continued from
EBW line or side groove in LTG system due to crack the EB front line is not detected, the test is to be invalid.
deflection and/or crack branching, the test is to be 5.3.6 (1/1/2021)
considered as invalid. The weld defects in EBW embrittled zone are to be visually
5.2.2 (1/1/2021) examined. If detected, it are to be quantified. A projecting
All of the crack path from embrittled zone end is to be length of defect on the thickness line through EB weld
within the range shown in Fig 7. If not, the test is to be region along brittle crack path is to be measured, and the
considered as invalid. total occupation ratio of the projected defect part to the
total thickness is defined as defect line fraction (see Fig 8).
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Pt D, Ch 2, App 5
When the defects line fraction is larger than 10 %, the test is meeting of dual fusion lines is visibly detected at an
to be invalid overlapped line of dual side penetration, the test is to be
5.3.7 (1/1/2021) invalid.
In EBW embrittlement by dual sides' penetration, a gap on
embrittled zone fracture surface which is induced by miss
Figure 8 : Counting procedure of defect line fraction (1/1/2021)
6 Judgement of "arrest" or 7 Ttest, Tarrest and CAT determination

"propagate"
7.1 Ttest determination
6.1 General 7.1.1 (1/1/2021)
6.1.1 (1/7/2024) It is to be ensured on the thermocouple measured record
that all temperature measurements across the range of 0,3W
The final test judgment of "arrest", "propagate" or "invalid" is ~ 0,7W in both width and longitudinal direction are in the
decided by the following requirements: range of Ttarget ±2°C at brittle crack initiation. If not, the test
a) If initiated brittle crack is arrested and the tested is to be invalid. However, the temperature measurement at
specimen is not broken into two pieces, the fracture 0,3W (location of A3 and B3) in LTG system is to be
surfaces should be exposed with the procedures exempted from this requirement.
specified in App 4, [5.4] and [5.5]ISO 20064: 2019 7.1.2 (1/1/2021)
b) When the specimen was not broken into two pieces If LEB-min in EBW embrittlement is no smaller than
during testing, the arrested crack length, aarrest is to be 150mm, Ttest can be defined to equal with Ttarget. If not, Ttest
measured on the fractured surfaces. The length from the is to be equaled with Ttarget + 5°C.
specimen edge of impact side to the arrested crack tip 7.1.3 (1/1/2021)
(the longest position) is defined as aarrest In LTG embrittlement, Ttest can be equaled with Ttarget.
c) For LTG and EBW, aarrest is to be greater than LLTG and 7.1.4 (1/1/2021)
LEB-s1, LEB-s2 or LEB-min. If not, the test is to be The final arrest judgment at Ttest is concluded by at least two
considered as invalid tests at the same test condition which are judged as "arrest".
d) Even when the specimen was broken into two pieces 7.2 Tarrest determination
during testing, it can be considered as "arrest" when
brittle crack re-initiation is clearly evident. Even in the 7.2.1 (1/1/2021)
fracture surface all occupied by brittle fracture, when a When at least repeated two "arrest" tests appear at the same
part of brittle crack surface from embrittled zone is Ttarget, brittle crack arrest behaviour at Ttarget will be decided
continuously surrounded by thin ductile tear line, the (Tarrest = Ttarget). When a "propagate" test result is included in
test can be judged as re-initiation behaviour. If so, the the multiple test results at the same Ttarget, the Ttarget cannot
maximum crack length of the part surrounded tear line to be decided as Tarrest.
can be measured as aarrest. If re-initiation is not visibly
evident, the test is judged as "propagate" 7.3 CAT determination
e) The test is judged as "arrest" when the value of aarrest is 7.3.1 (1/1/2021)
no greater than 0,7W. If not, the test is judged as When CAT is determined, one "propagate" test is needed in
"propagate". addition to two "arrest" tests. The target test temperature,

Pt D, Ch 2, App 6
APPENDIX 6 APPROVAL SCHEME OF SMALL-SCALE TEST

METHODS FOR BRITTLE CRACK ARREST
STEELS
1 General f) Data records which validate the correlation between

small-scale test results and the large brittle crack arrest
test results of brittle crack arrest steels whose number
1.1 Scope
can satisfy the requirement for minimum data number
1.1.1 (1/7/2024) gi.ven in [3.3]
This Appendix specifies the approval scheme of small-scale
g) Proposed test plan for approval
test methods which are used for product testing (batch
release testing) of brittle crack arrest steels specified as Sec 2.1.2 (1/7/2024)
1, Tab 34. Small-scale test procedure specification is to be prepared in
1.1.2 (1/7/2024) accordance with [3].
Unless otherwise specified in this Appendix, Ch 2, Sec 1, 2.1.3 (1/7/2024)
[10] and/or Ch 2, Sec 1, [11] of the Rules for the Approval Where the manufacturer proposes to change any part of the
of Manufacturers of Materials are to be followed. approved small-scale test procedure specification, then the
manufacturer is to submit to the Society the documents
2 Approval Application which can cover all items specified in [2.1.1].
2.1.4 (1/7/2024)
2.1 General The documents confirming the reason for the change are to
2.1.1 (1/7/2024) be submitted to identify the impact of those changes on the
existing procedure, and the proposed actions to address any
The manufacturer is to submit to the Society the following
such impacts.
documents:
a) Application for approval of small-scale test procedure
specification 3 Establishment of Procedure
b) Small-scale test procedure specification including the Specification for Small-scale Testing
following items at least:
• Applicable material grades, thickness range, 3.1 General
deoxidation practice, heat treatment, etc. 3.1.1 (1/7/2024)
• Types and methods of small-scale tests Small-scale test methods are to be determined based on the
• Sampling positions in plate thickness direction and manufacturer’s own technical philosophy with regard to
final rolling direction of test specimens achieving the brittle crack arrest properties of brittle crack
• Size and dimension of test specimens arrest steels. Furthermore, description of an appropriate
correlation between large scale brittle crack arrest
• Number of test specimens
properties and small-scale test results is to be required, and
• Test conditions, such as test temperature the acceptance criterion of the small-scale test are to be
• Acceptance criterion determined, based on the followings:
• Example of format of test report • Mechanism of achieving the suitable brittle crack arrest
• Example of product inspection certificate including properties
small-scale test results • Sampling position and direction
• Handling of the products when small-scale test • Frequency of sampling
results do not satisfy the criterion
• Small-scale test methodology
c) Mechanism of achieving the brittle crack arrest
• Demonstrated correlation between brittle crack arrest
properties of brittle crack arrest steels
test results and small-scale test results
d) Technical background for enabling the evaluation of
• Derivation of small scale testing acceptance criterion
brittle crack arrest properties by small-scale test
based on the statistical analysis.
methods considering the mechanism specified in above
c) 3.1.2 (1/7/2024)
e) Procedure of the evaluation for the brittle crack arrest The manufacturer is to prepare the small-scale test
properties of brittle crack arrest steels by small-scale test procedure specification in accordance with the following
results [3.2] through [3.5].
RINA Rules 2024 165

Pt D, Ch 2, App 6
3.2 Types and Methods of Testing combination of thickness range and heat sample to
include:
3.2.1 (1/7/2024)
Types, methods, dimension and positions as well as • The intended maximum and minimum plate
direction of test specimens, etc. of small-scale tests are to be thickness
specified by the manufacturer, and approved in accordance • Different heats are to be chosen for each thickness.
with Sec 1, [11], App 4, this Appendix or Ch 2, Sec 1, [10] Furthermore, the above test plates are to include a fixed
and [11] of the Rules for the Approval of Manufacturers of number of steel plate(s) whose brittle crack arrest
Materials. properties (i.e. brittle crack arrest test results) do not
3.2.2 (1/7/2024) comply with the requirements specified in Sec 1, Tab
34. Such a number should be at least one, but not
In general, the test method should reproduce the crack
exceeding one quarter of all test plates. Manufacturing
initiation, propagation and arrest feature by such as the
process of these test plates can be different (or
following test method.
intentionally altered from the approved manufacturing
• Combination of test methods, e.g. NRL drop weight test process) from that of the brittle crack arrest steels to
and V-notch Charpy impact test which the small-scale test method is applied. It is
• One test method, e.g. press-notch Charpy impact test or recommended that the strength grade of these test plates
side-section drop weight test (non-compliant with the relevant requirements of brittle
crack arrest properties) are similar to that of the brittle
3.2.3 (1/7/2024)
crack arrest steels.
In general, brittle crack arrest properties of brittle crack
Where the manufacturer has requested approval for
arrest steels are to be predicted using a regression equation
only a single thickness, the thickness of test plates can
on the relationship between small scale test result (e.g.
be only a single thickness. In this case, at least four steel
transition temperature obtained by small scale tests) and
plates for each combination of thickness (single
large scale brittle crack arrest test result (e.g. Kca or
thickness) and heats (three different heats) should be
temperature corresponding to the specific brittle crack used, and the applicable thickness of the small scale test
arrest properties). is only that single thickness condition.
Other approaches can be used subject to the approval of
d) Brittle crack arrest steels used for the approval test of
the Society.
manufacturing process of these steels (and its approval
Note 1: Tab 1, Tab 2 and Tab 3 give the examples of small scale test test results) can also be used as the test plates specified
methods.
in [3.3.1], c).
3.2.4 (1/7/2024) e) Brittle crack arrest test specimens and small-scale test
For determination of test methods, the manufacturer should specimens are to be taken from the same test plate.
confirm the applicability of these test methods to their
f) A decrease of the total of the indicated number of test
brittle crack arrest steels theoretically taking into account
plates may be accepted by the Society in the following
the methodology of test methods, their own mechanism of
1) or 2) cases:
achieving the brittle crack arrest properties, and sampling
positions of test specimens (See [3.1.1]). Then, the 1) When the manufacturer applies a small-scale test
manufacturer should also submit the technical background procedure specification to multiple material grades,
for determination of small-scale test methods to the Society and the manufacturing process and mechanism to
as given in [2.1]. ensure the brittle crack arrest properties of these
different material grades are the same.
3.3 Testing Data 2) When a small-scale test procedure specification is
already approved by the Society for one or some
3.3.1 Selection of test plates (1/7/2024) material grades, and the manufacturer applies
a) Brittle crack arrest tests and small-scale tests are to be similar small-scale test procedure specification to
conducted for each material grade (including all the other material grade(s), and the manufacturing
suffixes) of brittle crack arrest steels in accordance with process and mechanism to ensure the brittle crack
[3.3.1]. arrest properties of these different material grades
are same.
b) Brittle crack arrest tests and small-scale tests are to be
carried out on at least 12 test plates, in accordance with 3.3.2 Brittle crack arrest tests (1/7/2024)
[3.3.1], c), by which these test results can reliably
a) Brittle crack arrest tests are to be carried out for each test
estimate brittle crack arrest properties of brittle crack
plate in accordance with Ch 2, Sec 1, [11.3.3] of the
arrest steels.
Rules for the Approval of Manufacturers of Materials.
Note 1: “One test plate” means “the rolled product from a single
slab or ingot if this is rolled directly into plates” as defined in b) Where brittle crack arrest tests are carried out for
Sec 1, [2]. evaluation of Kca, Kca at a specific temperature is to be
c) In order to ensure appropriate correlation between obtained in accordance with App 4, [3].
small-scale test results and brittle crack arrest properties c) Where brittle crack arrest tests are carried out for
with various manufacturing conditions of steel plates, evaluation of CAT, deterministic (actual) CAT is to be
the steel plates should be representative for each obtained in accordance with App 5, [7.3].
166 RINA Rules 2024

Pt D, Ch 2, App 6
3.3.3 Small-scale tests (1/7/2024) 3.5 Acceptance Criterion

a) Small-scale tests are to be carried out in accordance
with small-scale test procedure specification to be 3.5.1 (1/7/2024)
approved for each test plate. Acceptance criterion of brittle crack arrest steels by the
b) In general, the test specimens of small-scale tests are to small-scale tests is to be proposed by the manufacturer
be taken with their longitudinal axis parallel to the final based on the regression equation which is assured in the
rolling direction of the test plates. correlation with brittle crack arrest properties in [3.4]. The
c) The test specimens of small-scale tests are to be taken criterion is to be determined so that regression equation can
from the specified positions in plate thickness direction predict brittle crack arrest properties on safety side,
of the test plates, as given in [3.2.3]. considering the scatter of brittle crack arrest properties from
the predicted value by the regression equation.
3.4 Validation of Correlation 3.5.2 (1/7/2024)
3.4.1 (1/7/2024) Unless otherwise agreed by the Society, an acceptance
A regression equation on the relationship between brittle criterion of small-scale tests is to be determined by
crack arrest property obtained from brittle crack arrest test following procedures:
and single or multiple small-scale test results is to be a) For correlation by means of temperature
established. For brittle crack arrest properties, a specific
temperature (e.g. TKca6000 in BCA1, TKca8000 in BCA2 or 1) The required temperature (see Fig 1) is obtained by
CAT) or the Kca value at -10°C may be used. subtracting 2 (°C) from the brittle crack arrest steel
specification in Sec 1, Tab 34, that is -10-2 (°C),
3.4.2 (1/7/2024) where 2 is given in [3.4.2].
The validity of the regression equation is to be examined to TKca6000 and TKca8000 in Fig 1 are the temperatures
predict brittle crack arrest properties with enough accuracy. at which the Kca value of steel plates equals
The correlation in brittle crack arrest properties between the
calculated values from small scale tests and the brittle crack 6,000N/mm3/2 and 8,000N/mm3/2, respectively.
arrest test results is to be assured by using the value of twice 2) The temperature predicted from the small-scale test
the standard deviation (2). When using temperature for results through the regression equation is to be no
brittle crack arrest property, 2 is not to be greater than higher than the value of -10-2(°C).
20°C. In other cases (e.g. Kca value at -10°C), an upper limit
b) For correlation by means of brittle crack arrest
of 2 is to be established with the agreement of the Society.
toughness (Kca):
Note 1: Calculation procedure of the standard deviation () is
given as follows: 1) The required Kca (see Fig 2) is obtained by adding 2
(N/mm3/2) to the brittle crack arrest steel
n
1 specification in Sec 1, Tab 34, that is either
 = ----------------- 
 y – x 
2
n – 1 i i
6,000+2(N/mm3/2) in BCA1 or
i=1 3/2
8,000+2(N/mm ) in BCA2, where 2 is given in
Where: [3.4.2].
n: number of test plates
yi: brittle crack arrest property obtained from brittle crack arrest test 2) The Kca value predicted from the small-scale test
for one test plate results through the regression equation is to be no
xi: brittle crack arrest property estimated from small scale tests for smaller than the value of 6000+2(N/mm3/2) for
one test plate BCA1, or 8000+2(N/mm3/2) for BCA2.
RINA Rules 2024 167

Pt D, Ch 2, App 6
Figure 1 : Example for determination of acceptance criterion of small-scale test for correlation by means of
temperature (1/7/2024)
Note 1: Fig 1 is only a schematic and may not represent the actual data obtained
Figure 2 : Example for determination of acceptance criteria of small-scale test for correlation by means of brittle
crack arrest toughness (Kca) (1/7/2024)
Note 2: Fig 2 is only a schematic and may not represent the actual data obtained
168 RINA Rules 2024

Pt D, Ch 2, App 6
4 Approval Tests 4.3 Type of tests

4.3.1 Brittle crack arrest tests (1/7/2024)
4.1 General a) Brittle crack arrest tests are to be carried out in
accordance with Ch 2, Sec 1, [11.3.3] of the Rules for
4.1.1 (1/7/2024) the Approval of Manufacturers of Materials.
b) Where brittle crack arrest tests are carried out for
In order to confirm the validity of the submitted technical
evaluation of Kca, Kca at a specific temperature (TKca6000
documents specified in [2.1.1], approval tests are to be
or TKca8000) is to be obtained in accordance with App 4,
carried out.
[3].
4.1.2 (1/7/2024) c) Where brittle crack arrest tests are carried out for
Approval test plan is to be approved by the Society prior to evaluation of CAT, deterministic CAT is to be obtained in
testing. accordance with App 5, [7.3].
4.3.2 Small-scale tests (1/7/2024)
4.1.3 (1/7/2024) Small-scale tests are to be carried out in accordance with
[3.3.3].
Considering the contents of the submitted technical
documents specified in [2.1.1], the Society may require
additional tests in the following cases: 5 Results
a) When the Society determines that the number of brittle 5.1 General
crack arrest tests or small-scale tests is too few to
adequately confirm the validity of the acceptance 5.1.1 (1/7/2024)
criterion of small-scale tests (See [3.3.1]); Results of test items and the procedures are to comply with
the test program approved by the Society.
b) When the Society determines that the testing data 5.1.2 (1/7/2024)
obtained for setting the acceptance criterion of small- For the brittle crack arrest test results, the manufacturer is to
scale tests varies too widely (See [3.4.2]), or that the submit to the Society the brittle crack arrest test reports in
data is clustered producing a biased correlation curve; accordance with App 4 for Kca and App 5 for CAT.
c) When the Society determines that the validity of brittle 5.1.3 (1/7/2024)
crack arrest test results or small-scale test results for For small-scale test results, the manufacturer is to submit to
setting the acceptance criterion of small-scale tests is the Society the small-scale test reports in accordance with
insufficient, or has some flaws during tests and/or for the example of format of test reports submitted as specified
test results (See [3.3.2] and [3.3.3]); and in [2.1.1], b).
d) Others as deemed necessary by the Society.

6 Approval
4.2 Extent of the approval tests 6.1 General

6.1.1 (1/7/2024)
4.2.1 (1/7/2024)
Upon satisfactory completion of the survey and tests, and
Extent of the approval tests is to be in accordance with Ch satisfactory confirmation of the submitted technical
2, Sec 1, [10.2.1] and Ch 2, Sec 1, [11.3.1] of the Rules for documents, the approval for small scale test procedure
the Approval of Manufacturers of Materials. specification is granted by the Society.
RINA Rules 2024 169

Pt D, Ch 2, App 6
Table 1 : Example of small-scale test method using NRL drop weight test and V-notch Charpy impact test
(Informative) (1/7/2024)
Test type: NRL drop weight test and V-notch Charpy impact test
Standard: ASTM E208:2020 and ISO 148-1:2016
Sampling positions of test specimens: NRL drop weight test: at surface
V-notch charpy impact test: 1/4 of thickness
Length direction of test specimen: Parallel to the final rolling direction of test plate
Regression equation:
1
------
T Kca =    NDTT + 10  +   vTrs + 153   t – 5  – 170 5
13
Where:
TKca: Temperature at Kca of 6,000N/mm3/2 or Kca of 8,000N/mm3/2, (°C)
NDTT: Nil-ductility transition temperature (°C)
vTrs: Transition temperature of the absorbed energy (°C)
t: thickness
, (1): constant
Notes:
(1)  and  are determined by comparing small-scale test results with brittle crack arrest test results.
Table 2 : Example of small-scale test method using pressed-notch Charpy impact test (Informative) (1/7/2024)
Test type: Pressed-notch Charpy impact test

Standard: Dimension, shape, introducing method of notch: Manufacturer’s proposal
Others: ISO148-1:2016
Sampling positions of test specimens: 1/2 of thickness
T Kca =   pTE  J + 
Where:
pTEJ:Test temperature at absorbed energy of  (J), (°C)
, (1): constant
: Absorbed energy at brittle fracture surface ratio of  (%),(J) (1)
Notes:
(1)  ,  ,  and  are determined by comparing small-scale test results with brittle crack arrest test results.
170 RINA Rules 2024

Pt D, Ch 2, App 6
Table 3 : Example of small-scale test method using Side-section drop weight test (Informative) (1/7/2024)
Test type: Side-section drop weight test

Standard: Dimension: P-2 type of ASTM E 208 2020
Sampling positions of test specimens: 1/2 of thickness and side-section
1 5
T Kca =  +   T NDT +   t
side
Where:
side
T NDT : Nil-ductility transition temperature obtained by side-section drop weight test,
(°C)
t: thickness
, , (1): constant
Notes:
(1)  ,  and  are determined by comparing small-scale test results with brittle crack arrest test results.
RINA Rules 2024 171

Pt D, Ch 4, Sec 1
SECTION 1 EQUIPMENT
1 Anchors The lateral movement of the shank is not to exceed 3

degrees (see Fig 1).
1.1 Application
Table 1 (1/1/2007)
1.1.1 General
The requirements of this Article apply to anchors and asso- Anchor mass (t) Clearance (mm)
ciated components (heads, shanks and shackles) made of
cast or forged steel, or fabricated by welding from rolled Up to 3 3
steel. Over 3 up to 5 4
1.1.2 Modified testing procedure for anchors of Over 5 up to 7 6
small mass
Over 7 12
For anchors having mass lower than 100 kg, or 75 kg in the
case of high holding power anchors, continuously pro-
duced by Manufacturers who have been approved by the Figure 1 (1/1/2007)
Society for this purpose, a batch testing procedure is admit-
ted, with random execution of the checks required for nor-
mal testing.
The composition of the batches is to be judged appropriate
as regards the homogeneity of material, manufacturing,
heat treatment and dimensions.
1.2 Design - Manufacture

1.2.1 General (1/2/2007)
Anchors are to be manufactured by recognised Manufactur-
ers, according to approved plans or recognised standards;
see Pt B, Ch 10, Sec 4, [3.2].
For approval and/or acceptance of high holding power
(HHP) and super high holding power (SHHP) anchors , the
type tests indicated in Pt B, Ch 10, Sec 4, [3.2] are to be
carried out.
Steel forgings and castings for anchors is to comply with the
applicable requirements of Ch 2, Sec 3 and Ch 2, Sec 4,
respectively, and are to be manufactured by recognised
Manufacturers.
1.2.2 Tolerances (1/1/2007)

1.2.3 Welded anchors (1/1/2007)
If not otherwise specified on standards or on drawings
demonstrated to be appropriate, the following assembly and Welded anchors are to be manufactured in accordance with
fitting tolerances are to be applied. approved procedures.
The clearance either side of the shank within the shackle
jaws is to be in accordance with Tab 1 depending on the 1.2.4 Heat treatment (1/1/2007)
anchor mass. Components for forged or cast anchors are to be properly
The shackle pin is to be a push fit in the eyes of the shackle, heat treated in accordance with the applicable require-
which are to be chamfered on the outside to ensure a good ments of Ch 2, Sec 3 and Ch 2, Sec 4, respectively.
tightness when the pin is clenched over on fitting. Fabricated anchors may require stress relief after welding
The shackle pin to hole tolerance is to be no more than depending upon weld thickness.
0,5mm for pins up to 57mm and 1,0 mm for pins of larger
diameter. Stress relief is to be carried out as indicated in the approved
welding procedure.
The trunnion pin is to be a snug fit within the chamber and
be long enough to prevent horizontal movement. The gap is Stress relief temperatures are not to exceed the tempering
to be no more than 1% of the chamber length. temperature of the base material.
RINA Rules 2024

...OMISSIS... 195
Pt D, Ch 4, Sec 1
4.5 Identification marking and certification The required tests and examinations are to be performed
with the appropriate machinery, equipment and procedures
4.5.1 Upon satisfactory completion of the required tests recognised by the Society; the testing machine is to be cali-
and examinations, the ropes, packed in the required length brated.
for supply, are to be tagged with lead seals stamped with the In particular the dynamometer is to be of a type allowing a
Society’s brand and further indications, as necessary for constant rate of traverse of the moving element (see
identification with the respective test certificates. [5.4.4]). Other types of dynamometer may be considered by
the Society in each case.
4.5.2 The certificates are to contain the essential elements
relevant to the rope characteristics, the results of the test 5.2.4 Quality of ropes - Dimensional tolerances
and the stamps and markings mentioned in [4.5.1]. Ropes are to be free from harmful material or manufactur-
Special marking and certification methods may be agreed ing defects. As regards lengths, tolerances, marking and
upon for supplies by Manufacturers granted the use of an packaging, reference is to be made to the requirements
alternative testing procedure. specified in the applied standards and in the purchase
order.
5 Fibre ropes
5.3 Type of ropes
5.1 Application 5.3.1 (1/7/2024)
In general, ropes should have either 3-4 strands (plain
5.1.1 General ropes) or 8 strands (plaited ropes); however, other types of
The requirements of this Article apply to natural and syn- construction may be considered for acceptance by the Soci-
thetic fibre ropes, intended for towing and mooring lines, ety.
cargo handling gear or similar applications. The diameter of mooring lines is to be not less than 20mm.
5.1.2 Continuous productions Ropes may be made of hemp, manila, sisal or synthetic
fibres (see [5.2.2]).
In the case of continuous production, the Manufacturers
may adopt an alternative procedure for testing and inspec- The following types and qualities of ropes, complying with
tion subject to the approval of the Society. recognised standards, are acceptable:
• three- or four-strand hemp ropes, EN 1261
5.2 Manufacture • three, four- and eight-strand manila and sisal ropes, ISO
1181
5.2.1 General • three-strand polyamide ropes, ISO 1140
Fibre ropes are to be manufactured in accordance with • three-strand polyester ropes, ISO 1141
national or international standards recognised by the Soci-
• three, four- and eight-strand polypropylene ropes, ISO
ety (see [5.3]).
1346.
The type and size of ropes are to be in accordance with the
requirements specified for each application by the relevant 5.4 Sampling and testing
part of the Rules or the approved plans relative to each
installation. 5.4.1 Sampling
Acceptance tests are be performed on each rope length
5.2.2 Rope materials (1/7/2007) (defined as either one single length or multiple lengths man-
Ropes are to be manufactured with natural or synthetic ufactured with continuity).
fibre; the natural fibre is to be of suitable type and consist-
Where the rope length is greater than 2000 m, the accept-
ency, free from defects or harmful imperfections. Synthetic
ance tests are to be carried out for every portion of 2000 m.
fibres are to be of a type and quality which have been rec-
ognised as suitable for the intended application. When the base material used has the same origin and char-
acteristics, the acceptance tests required in [5.4] for each
5.2.3 Manufacturing process and facilities rope length may be performed for each rope construction
The manufacturing procedures and relevant facilities are to and diameter.
be suitable and such as to ensure production of the required Suitable sampling and identification procedures are to be
quality. adopted, to the Surveyor’s satisfaction.
The manufacturing process is to be recognised as appropri- The tests and examinations under [5.4.2], [5.4.3] and
ate by the Society. [5.4.4] or [5.4.5] are to be performed for acceptance.
No addition of other materials is to be made and treatments 5.4.2 Visual examination and check of the diameter
intended to increase the mass of the finished rope are not to and construction
be used; additions of suitable lubricants are to be kept to an The check of diameter is to be performed during the break-
absolute minimum. ing test. The sample is to be arranged on the testing
Treatments intended to prevent decaying and moisture machine and the diameter of rope (diameter of the circum-
absorption are not to impair the quality of the fibre or the scribed circumference) is to be measured under the refer-
strength of the rope. ence load specified in Tab 17.
RINA Rules 2024 215

Pt D, Ch 4, Sec 1
The visual examination and the check of correct construc- 5.4.4 Breaking test on full size specimen (1/7/2024)
tion and twist are to be performed by the Manufacturer,
The breaking load is to be determined by testing to destruc-
while random checks are carried out by the Surveyor to the
tion a sample of rope of sufficient length; in general, the
extent deemed necessary.
gauge length of the sample is to be not less than 1800 and
The results are to comply with the applicable standards. 900 mm for vegetable fibre ropes and synthetic fibre ropes,
respectively.
5.4.3 Check of the linear mass After the visual and dimensional examination performed at
the prescribed load (see [5.4.2]), the sample is subjected to
The linear mass m is given by the formula:
a tension load, steadily increased until fracture occurs.
m Depending upon the type of fibre used in manufacturing the
m = ------0-
L ropes, the rate of application of the test load is to be 120-
180 mm/min for vegetable fibre ropes and 50-100 mm/min
where:
for synthetic fibre ropes.
m0 : Mass, in grams, of the test piece In the case of synthetic fibre ropes for mooring, the value of
L : Length, in metres, of the test piece under the elongation A, expressed in percent as given by the follow-
reference load (see Tab 17), equal to: ing formula, is also to be checked:
Df – Di
Dp L0
L = -----------
- A = ----------------
-
D0 Di
where:
with:
Df : Distance between marks, on the test specimen,
D0 : Initial distance (at least 0,5 m) between the ref- under a load equal to 75% of the minimum
erence marks spaced symmetrically about the specified breaking strength.
mid-point of the test piece when this is laid out
by hand on a flat surface Df may be determined by stopping, for as short
a time as possible, the action of the moving ele-
Dp : Distance between these marks measured under ment, when the tensile load has reached 75% of
the reference load specified in Tab 17 the minimum specified breaking strength
L0 : Initial total length of the test piece (laid out by Di : Distance between marks measured under the
hand on a flat surface). initial reference load.
Table 17 : Load to be applied to ropes for the measurement of the linear mass and diameter (1/1/2011)
Reference load (kN) Nominal diameter Reference load (kN)

Nominal diameter (mm)
Tolerance:  5% (mm) Tolerance:  5%
4 0,020 32 1,28
6 0,045 36 1,62
8 0,080 40 2,00
9 0,101 44 2,42
10 0,125 48 2,88
12 0,180 52 3,38
14 0,245 56 3,92
16 0,320 60 4,50
18 0,405 64 5,12
20 0,500 68 5,78
22 0,605 72 6,48
24 0,720 76 7,22
26 0,845 80 8,00
28 0,980 88 9,68
30 1,13 96 11,5
216 RINA Rules 2024

Pt D, Ch 4, Sec 1
Alternative types of test pieces and testing procedures, in Manufacturing procedures are to be of appropriate type, to
accordance with recognised standards, may be considered the Surveyor’s satisfaction.
by the Society.
6.2.2 Frame materials
The measured breaking load is to be not less than those of
the standards listed in [5.3.1]. Materials are to be of appropriate type and properties, as
required in the approved plans or applicable standards.
If the test piece breaks at the terminals (clamp or splice), the
They are to comply with the requirements of Chapter 2, in
test requirements are considered to have been met if the
relation to the type of material and the nature of the prod-
measured break occurs at a load not less that 90% of the
uct.
minimum breaking load given by the reference standard. It
is not to be assumed that the actual breaking load of the Subject to approval for each case or application, the follow-
specimen is represented by multiplying the result by 10/9. ing types of material and products are generally regarded as
appropriate:
The value of elongation A, for which no minimum require-
ments are given, is used only for determination of the equiv- • hull steel plates, shapes and bars having Rm in the range
alence between synthetic and natural fibre ropes with the 400-490 N/mm²
formula given in Pt B, Ch 10, Sec 4, [3.5.7], and therefore • steel forgings and castings
for definition of the minimum breaking load of the synthetic • brass plates, shapes, bars and castings
fibre ropes for mooring, in relation to the Equipment Num-
ber of the ship. • light alloy castings and semi-finished products, of cate-
gory Al-Mg or Al-Mg-Si.
5.4.5 Breaking test on individual yarns (1/1/2011)
Subject to approval in individual cases, nodular cast iron of
When the breaking test on full size test pieces cannot be type GS400 or GS370 may also be used.
performed, alternative test procedures may be considered
and, if used, they are to be reported in the relevant testing 6.2.3 Glass panes
documentation. The glass panes are to be of appropriate type and quality,
To this end, the procedure outlined in Annex B to ISO manufactured in accordance with suitable procedures, to
Standard 2307 is appropriate. the satisfaction of the Society, by recognised Manufactur-
ers.
5.5 Identification, marking and certification 6.2.4 Quality of materials
5.5.1 Upon satisfactory completion of the required tests The product is to be free from detrimental defects.
and examinations, the ropes, packed in the required length
for supply, are to be tagged with lead seals stamped with the 6.3 Inspections and tests
Society’s brand and further indications, as necessary for
identification with the respective test certificates. 6.3.1 Frame material tests
Materials are to comply with the applicable requirements
5.5.2 The certificates are to contain the essential elements and to be tested or certified accordingly; depending on the
relevant to the rope characteristics, the results of the test individual cases, they are also to be submitted to the follow-
and the stamps and markings mentioned in [5.5.1]. ing additional tests :
Special marking and certification procedures may be agreed a bend test, as indicated below, depending on the type of
upon for supplies by Manufacturers granted the use of an material:
alternative testing procedure. • brass products: d1s   60°
• light alloy products: d3s   60°
6 Side scuttles, windows and their
• cast iron: d4s   60°
glass panes
where:
6.1 Application s : Thickness of the specimen (which, as far as pos-
sible, should be equal to the thickness of the
6.1.1 The requirements of this Article apply to fixed product)
frames, window frames, dead covers and glass panes. d : Diameter of the mandrel
The types of sidescuttles and windows which, in relation to  : Required bend angle, which is to be attained
their position, are to be tested are indicated in Pt B, Ch 9, without cracks or other defects.
Sec 9. For castings, as an alternative to the bend test performed on
specimens, it may be agreed to perform a bend test directly
6.2 Manufacture on a completed piece. Such test may also be required by
the Surveyor as an additional random check. When this test
6.2.1 General is performed as an alternative to that on specimens, the
Sidescuttles and windows which are subject to inspection number of pieces tested is to be one for every batch of not
are to be manufactured in accordance with approved plans more than 50 equal pieces (25 in the case of cast iron prod-
or standards and specifications recognised by the Society. ucts) originating from the same heat.

Part E
Service Notations
Chapter 4
BULK CARRIERS
SECTION 1 GENERAL
SECTION 2 SHIP ARRANGEMENT

SECTION 3 HULL AND STABILITY
SECTION 4 MACHINERY
APPENDIX 1 INTACT STABILITY CRITERIA FOR GRAIN LOADING

Pt E, Ch 4, Sec 3
Symbols
D1 : Distance, in m, from the base line to the free- 1.1.2 (1/4/2006)
board deck at side amidships (see Fig 13) Ships with the service notation bulk carrier ESP CSR are to
hDB : Height, in m, of the double bottom comply with the requirements in [2.1] and [2.2].
hLS : Mean height, in m, of the lower stool, measured
from the inner bottom 1.2 Loading manual and loading instru-
k : Material factor defined in Pt B, Ch 4, Sec 1, ments
[2.3]
tC : Corrosion addition, in mm, defined in Pt B, 1.2.1 The specific requirements in Pt B, Ch 11, Sec 2 for
Ch 4, Sec 2, Tab 2 ships with the service notation bulk carrier ESP and equal
 : Span, in m, of side frames; see [3.2.3] to or greater than 150 m in length are to be complied with.
d : Height, in mm, of side frame web; see [3.2.3]
C : Span, in m, of the corrugations of vertically cor- 2 Stability
rugated transverse watertight bulkheads; see
[3.5.2] 2.1 Definitions
sC : Spacing of corrugations, in m; see Fig 5
2.1.1 Grain
ReH : Minimum upper yield stress, in N/mm2, of the
material as defined in Pt B, Ch 4, Sec 1, [2] The term grain covers wheat, maize (corn), oats, rye, bar-
ley, rice, pulses, seeds and processed forms thereof, whose
E : Young’s modulus, in N/mm2, to be taken equal
behaviour is similar to that of grain in its natural state.
to:
• E = 2,06.105 N/mm2 for steels in general 2.1.2 Filled compartment trimmed
• E = 1,95.105 N/mm2 for stainless steels The term filled compartment trimmed refers to any cargo
B : Dry bulk cargo density, in t/m3; the following space in which, after loading and trimming as specified in
values may generally be taken: App 1, the bulk grain is at its highest possible level.
•  = 3,0 t/m3 for iron ore
2.1.3 Filled compartment untrimmed
•  = 1,3 t/m3 for cement
The term filled compartment untrimmed refers to a cargo
 : Angle of repose, in degrees, of the dry bulk space which is filled to the maximum extent possible in way
cargo carried; in the absence of more precise of the hatch opening but which has not been trimmed out-
evaluation the following values can be taken: side the periphery of the hatch opening.
•  = 30° in general
•  = 35° for iron ore 2.1.4 Partially filled compartment
• = 25° for cement The term partly filled compartment refers to any cargo
space where the bulk grain is not loaded in the manner pre-
 : Sea water density, in t/m3
scribed in [2.1.2] or [2.1.3].
hF, zF : Flooding head and distance, respectively, in m,
defined in [4.6.3] for transverse bulkheads and 2.1.5 Stowage factor
[4.7.3] for double bottoms The term stowage factor, for the purposes of calculating the
h B , zB : Level height of the dry bulk cargo and distance, grain heeling moment caused by a shift of grain, means the
respectively, in m, defined in [4.6.4] for trans- volume per unit weight of the cargo as attested by the load-
verse bulkheads and [7.2.6] for double bottoms ing facility, i.e. no allowance is to be made for lost space
g : Gravity acceleration, in m/s2, to be taken equal when the cargo space is nominally filled.
to 9,81 m/s2.
2.1.6 Specially suitable compartment
1 General The term specially suitable compartment refers to a cargo
space which is constructed with at least two vertical or slop-
ing, longitudinal, grain-tight divisions which are coincident
1.1 Application with the hatch side girders or are so positioned as to limit
1.1.1 (1/4/2006) the effect of any transverse shift of grain. If sloping, the divi-
The requirements of this Section apply to ships with the ser- sions are to have an inclination of not less than 30° to the
vice notation bulk carrier ESP. horizontal.
RINA Rules 2024 77

...OMISSIS...
Pt E, Ch 4, Sec 3
• for dry bulk cargoes, the lesser of: [3] against dynamic pressures due to bottom impact for the
Z + g  z F – 0 ,1D 1 – h F  condition specified in [4.3.2] at the minimum forward
X = ---------------------------------------------------------
- draught.

1 + -----  perm – 1 
B
X = Z + g  z F – 0 ,1D 1 – h F perm  9 Hatch covers, hatch coamings and
• for steel mill products: closing devices
Z + g  z F – 0 ,1D 1 – h F 
X = ---------------------------------------------------------
-
9.1 Application

1 – -----
B 9.1.1 (1/7/2024)
perm : Permeability of cargo, which need not be taken Refer to Tthe requirements for Type 2 ships of this Article
greater than 0,3 [9] apply to steel hatch covers in positions 1 and 2 on
Z : Pressure, in kN/m2, to be taken as the lesser of: weather decks, defined in Pt B, Ch 19, Sec 27, [3.16].
CH 9.1.2 Symbols used in Article [9] (1/7/2012)

Z = ------------
-
A DB ,H pS : Still water pressure, in kN/m2 (see [9.4])
CE pW : Wave pressure, in kN/m2 (see [9.4])
Z = -----------
-
A DB ,E s : Length, in m, of the shorter side of the plate
CH : Shear capacity of the double bottom, in kN, to panel
be calculated according to [7.2.2], considering,  : Length, in m, of the longer side of the plate
for each floor, the lesser of the shear strengths panel
SF1 and SF2 (see [7.2.4]) and, for each girder, the bP : Width, in m, of the plating attached to the ordi-
lesser of the shear strengths SG1 and SG2 (see nary stiffener or primary supporting member,
[7.2.5]) defined in [9.3]
CE : Shear capacity of the double bottom, in kN, to w : Net section modulus, in cm3, of the ordinary
be calculated according to [7.2.2], considering, stiffener or primary supporting member, with an
attached plating of width bp
for each floor, the shear strength SF1 (see [7.2.4])
and, for each girder, the lesser of the shear ASh : Net shear sectional area, in cm2, of the ordinary
strengths SG1 and SG2 (see [7.2.5]) stiffener or primary supporting member, to be
n
calculated as specified in Pt B, Ch 4, Sec 3,
[3.4], for ordinary stiffeners, and Pt B, Ch 4,
A DB ,H = S B i DB ,i Sec 3, [4.3], for primary supporting members
i=1 m : Boundary coefficient for ordinary stiffeners and
n
primary supporting members, taken equal to:
A DB ,E =  S Bi DB – s • m = 8 in the case of ordinary stiffeners and
i=1 primary supporting members simply sup-
n : Number of floors between stools (or transverse ported at both ends or supported at one end
bulkheads, if no stool is fitted) and clamped at the other
Si : Space of ith-floor, in m • m = 12 in the case of ordinary stiffeners and
primary supporting members clamped at
BDB,i : Length, in m, to be taken equal to : both ends
• BDB,i = BDB - s for floors for which SF1 < SF2 tC : Corrosion additions, in mm, defined in [9.1.5]
(see [7.2.4])
ReH : Minimum yield stress, in N/mm2, of the mate-
• BDB,i = BDB,h for floors for which SF1  SF2 rial, defined in Pt B, Ch 4, Sec 1, [2]
(see [7.2.4]) Rm : Minimum ultimate tensile strength, in N/mm2,
BDB : Breadth, in m, of double bottom between the of the material, defined in Pt B, Ch 4, Sec 1, [2]
hopper tanks (see Fig 17) Ry : Yield stress, in N/mm2, of the material, to be
BDB,h : Distance, in m, between the two openings con- taken equal to 235/k N/mm2, unless otherwise
sidered (see Fig 17) specified
s : Spacing, in m, of inner bottom longitudinal k : Material factor, defined in Pt B, Ch 4, Sec 1,
ordinary stiffeners adjacent to the hopper tanks. [2.3]
cS : Coefficient, taken equal to:
8 Fore part • cS = 1-(s/2) for ordinary stiffeners
• cS = 1 for primary supporting members
8.1 Reinforcement of the flat bottom for-
ward area
g = 9,81 m/s2.
8.1.1 Minimum forward draught (1/7/2003)
The structures of the bottom forward are to be strengthened 9.1.3 Materials (1/7/2012)
in accordance with the requirements in Pt B, Ch 9, Sec 1, a) Steel
RINA Rules 2024 95

Pt E, Ch 4, Sec 3
The formulae for scantlings given in the requirements in Table 5 : Corrosion additions tc for steel hatch
[9.5] are applicable to steel hatch covers. covers (1/7/2012)
Materials used for the construction of steel hatch covers
are to comply with the applicable requirements of Corrosion addition tc , in mm
Part D, Chapter 2.
Plating and stiffeners of single skin hatch cover 2,0
b) Other materials
Top and bottom plating of double skin hatch 2,0
The use of materials other than steel is considered by cover
the Society on a case by case basis, by checking that cri-
teria adopted for scantlings are such as to ensure Internal structures of double skin hatch cover 1,5
strength and stiffness equivalent to those of steel hatch
covers. 9.2 Arrangements
9.1.4 Net scantlings (1/7/2012) 9.2.1 Height of hatch coamings (1/7/2012)
As specified in Pt B, Ch 4, Sec 2, [1], all scantlings referred a) The height above the deck of hatch coamings closed by
to in this Section are net, i.e. they do not include any mar- portable covers is to be not less than:
gin for corrosion.
• 600 mm in position 1
The gross scantlings are obtained as specified in Pt B, Ch 4,
• 450 mm in position 2.
Sec 2.
b) The height of hatch coamings in positions 1 and 2
9.1.5 Partial safety factors (1/7/2012) closed by steel covers provided with gaskets and secur-
ing devices may be reduced with respect to the above
The partial safety factors to be considered for checking
values or the coamings may be omitted entirely.
hatch cover structures are specified in Tab 4.
In such cases the scantlings of the covers, their gasket-
ing, their securing arrangements and the drainage of
Table 4 : Hatch covers - Partial safety
recesses in the deck are considered by the Society on a
factors (1/7/2012)
case by case basis.
Partial safety factors c) Regardless of the type of closing arrangement adopted,
Ordinary the coamings may have reduced height or be omitted in
Partial safety factors
stiffeners way of openings in closed superstructures or decks
covering uncertainties
Symbol Plating and primary below the freeboard deck.
regarding:
supporting
members 9.2.2 Hatch covers (1/7/2012)
Still water pressure S2 1,00 1,00 a) Hatch covers on exposed decks are to be weathertight.
Wave pressure W2 1,20 1,20 Hatch covers in closed superstructures need not be
Material m 1,02 1,02 weathertight.
Resistance R 1,22 1,22 However, hatch covers fitted in way of ballast tanks, fuel
oil tanks or other tanks are to be watertight.
9.1.6 Corrosion additions (1/7/2012) b) The ordinary stiffeners and primary supporting members
a) Corrosion additions for hatch covers of the hatch covers are to be continuous over the
breadth and length of the hatch covers, as far as practi-
The corrosion addition to be considered for the plating cal. When this is impractical, sniped end connections
and internal members of hatch covers is the value speci- are not to be used and appropriate arrangements are to
fied in Tab 5 for the total thickness of the member under be adopted to ensure sufficient load carrying capacity.
consideration.
c) The spacing of primary supporting members parallel to
b) Corrosion additions for hatch coamings the direction of ordinary stiffeners is to be not greater
The corrosion addition to be considered for the hatch than 1/3 of the span of primary supporting members.
coaming structures and coaming stays is equal to 1,5 d) The breadth of the primary supporting member flange is
mm. to be not less than 40% of its depth for laterally unsup-
c) Corrosion additions for stainless steel ported spans greater than 3,0 m. Tripping brackets
attached to the flange may be considered as a lateral
For structural members made of stainless steel, the cor-
support for primary supporting members.
rosion addition tc is to be taken equal to 0.
e) The covers used in 'tweendecks are to be fitted with an
d) Corrosion additions for aluminium alloys appropriate system ensuring an efficient stowing when
For structural members made of aluminium alloys, the the ship is sailing with open 'tweendecks.
corrosion addition tc is to be taken equal to 0.
f) The ends of hatch covers are normally to be protected
by efficiently secured galvanised steel strips.
96 RINA Rules 2024

Pt E, Ch 4, Sec 3
g) Efficient retaining arrangements are to be provided to Securing arrangements and stiffening of hatch cover
prevent translation of the hatch cover under the action edges are to be such that weathertightness can be main-
of the longitudinal and transverse forces exerted by the tained in any sea condition.
stacks of containers on the cover. These retaining
At least one securing device is to be fitted at each side.
arrangements are to be located in way of the hatch
Circular hole hinges are considered equivalent to secur-
coaming side brackets.
ing devices.
Solid fittings are to be welded on the hatch cover where
the corners of the containers are resting. These parts are c) Hold accesses located on the weather deck are to be
intended to transmit the loads of the container stacks provided with watertight metallic hatch covers, unless
onto the hatch cover on which they are resting and also they are protected by a closed superstructure. The same
to prevent horizontal translation of the stacks by means applies to accesses located on the forecastle deck and
of special intermediate parts arranged between the sup- leading directly to a dry cargo hold through a trunk.
ports of the corners and the container corners. d) Accesses to cofferdams and ballast tanks are to be man-
Longitudinal stiffeners are to stiffen the hatch cover holes fitted with watertight covers fixed with bolts which
plate in way of these supports and connect at least the are sufficiently closely spaced.
nearest three transverse stiffeners. e) Hatchways of special design are considered by the Soci-
h) The width of each bearing surface for hatch covers is to ety on a case by case basis.
be at least 65 mm.
9.3 Width of attached plating
9.2.3 Hatch coamings (1/7/2012)
a) Coamings, stiffeners and brackets are to be capable of 9.3.1 Ordinary stiffeners (1/7/2012)
withstanding the local forces in way of the clamping The width of the attached plating to be considered for the
devices and handling facilities necessary for securing check of ordinary stiffeners is to be obtained, in m, from the
and moving the hatch covers as well as those due to following formulae:
cargo stowed on the latter.
• where the attached plating extends on both sides of the
b) Special attention is to be paid to the strength of the fore stiffener:
transverse coaming of the forward hatch and to the
bP = s
scantlings of the closing devices of the hatch cover on
this coaming. • where the attached plating extends on one side of the
stiffener:
c) Longitudinal coamings are to be extended at least to the
lower edge of deck beams. bP = 0,5 s
Where they are not part of continuous deck girders, lon-
9.3.2 Primary supporting members parallel to
gitudinal coamings are to extend for at least two frame
ordinary stiffeners (1/7/2012)
spaces beyond the end of the openings.
The width of the attached plating to be considered for the
Where longitudinal coamings are part of deck girders, yielding and buckling checks of primary supporting mem-
their scantlings are to be as required in Pt B, Ch 7, bers analysed through beam or grillage models is to be
Sec 3. obtained, in m, from the following formulae:
d) Transverse coamings are to extend below the deck at • where the plating extends on both sides of the primary
least to the lower edge of longitudinals. supporting member:
Transverse coamings not in line with ordinary deck bp = bp,1 + bp,2
beams below are to extend below the deck at least three
longitudinal frame spaces beyond the side coamings. • where the plating extends on one side of the primary
supporting member:
9.2.4 Small hatchways (1/7/2012) bp = bp,1
a) The height of small hatchway coamings is to be not less
than 600 mm if located in position 1, and 450 mm if where:
located in position 2. bp,1 = min (0,165 lP, Sp,1)
Where the closing appliances are in the form of hinged bp,2 = min (0,165 lP, Sp,2)
steel covers secured weathertight by gaskets and swing
bolts, the height of the coamings may be reduced or the lP : span, in m, of the primary supporting member
coamings may be omitted altogether. considered
b) Small hatch covers are to have strength equivalent to Sp,1, Sp,2 : half distance, in m, between the primary sup-
that required for main hatchways and are to be of steel, porting member considered and those adjacent,
weathertight and generally hinged. on the two sides.
RINA Rules 2024 97

Pt E, Ch 4, Sec 3
9.4 Load model e) Hatch covers carrying containers

The still water and wave loads are to be considered and
9.4.1 Lateral pressures and concentrated are defined in Pt B, Ch 5, Sec 6, [5].
loads (1/7/2012)
f) Hatch covers carrying wheeled cargoes
a) General The still water and wave loads are to be considered and
The still water and wave lateral pressures and concen- are defined in Pt B, Ch 5, Sec 6, [6].
trated loads, to be considered as acting on hatch covers, g) Hatch covers carrying special cargoes
are those in b) to g). In the case of carriage on the hatch covers of special
Each case in g) to f) is not necessarily exhaustive for cargoes (e.g. pipes, etc.) which may temporarily retain
any specific hatch cover; however, depending on the water during navigation, the lateral pressure to be
location of each cover and its intended use, the pres- applied is considered by the Society on a case by case
sures and loads to be considered as acting on it are to basis.
be calculated for one or more of these cases. For exam-
9.4.2 Wave pressure for hatch covers on exposed
ple, for a hatch cover located on an exposed deck and
decks (1/7/2012)
covering a ballast tank, the pressures in b) and c) are to
The wave pressure pW is defined in Tab 6 according to the
be separately considered. If the same hatch cover is also
hatch cover position.
intended to carry uniform cargoes, the pressures in d)
are to be individually considered, in addition to the two Where two or more panels are connected by hinges, each
above. individual panel is to be considered separately.
b) Hatch covers on exposed decks 9.4.3 Load point (1/7/2012)

The still water lateral pressure and loads are to be con- a) Wave lateral pressure for hatch covers on exposed
sidered when the hatch cover is intended to carry uni- decks:
form cargoes, wheeled cargoes or containers. In these The wave lateral pressure to be considered as acting on
cases, the still water lateral pressures and loads are to be each hatch cover is to be calculated at a point located:
calculated according to d) and e), as applicable. • longitudinally, at the hatch cover mid-length
The wave lateral pressure is to be considered and is • transversely, on the longitudinal plane of symmetry
defined in [9.4.2]. of the ship
• vertically, at the top of the hatch coaming.
c) Hatch covers in way of liquid cargo or ballast tanks
b) Lateral pressure other than the wave pressure:
The still water and wave lateral pressures are to be con-
The lateral pressure is to be calculated:
sidered and are defined in Pt B, Ch 5, Sec 6, [1].
• in way of the geometrical centre of gravity of the
d) Hatch covers carrying uniform cargoes plate panel, for plating
The still water and wave lateral pressures are to be con- • at mid-span, for ordinary stiffeners and primary sup-
sidered and are defined in Pt B, Ch 5, Sec 6, [4]. porting members.
Table 6 : Wave pressure on hatch covers (1/7/2012)
Wave pressure pW , in kN/m2

Freeboard length LLL, in m Hatchway location Position 1 Position 2
L LL  100 m 0  x  0 75 L LL 14 9 + 0 195L LL 11 3 + 0 142L LL
L LL 
- 1 – --- ------- – 3 6 -------
5 x x
0 75L LL  x  L LL 15 8 + ------
3  3 L LL L LL
L LL  100 m 0  x  0 75L LL 34,3 25,5
p FP – 34 3  x
34 3 + -------------------------- ------- – 0 75
0 75L LL  x  L LL 0 25  L LL 
(1)
(1) Where a position 1 hatchway is located at least one superstructure standard height, as specified in Pt B, Ch 1, Sec 2, Tab 2,
higher than the freeboard deck, where the pressure pW may be taken equal to 34,3 kN/m2.
Note 1:
pFP : pressure, in kN/m2, at the forward perpendicular, to be taken equal to:
• pFP = 49,1 + 0,0726 (LLL - 100) for Type B ships
• pFP = 49,1 + 0,356 (LLL - 100) for Type B-60 or Type B-100 ships
98 RINA Rules 2024

Pt E, Ch 4, Sec 3
9.5 Strength check mined through a grillage analysis or a Finite

Element analysis, as the case may be.
9.5.1 General and application (1/7/2012)
b) Minimum net thickness
a) Application
In addition to the requirements in a) above, the net
The strength check is applicable to rectangular hatch thickness, in mm, of hatch cover plating is to be not less
covers subjected to a uniform pressure, designed with than 1% of s or 6 mm, whichever is the greater.
primary supporting members arranged in one direction
or as a grillage of longitudinal and transverse primary c) Critical buckling stress check
supporting members. The compressive stress s in the hatch cover plating,
In the latter case, the stresses in the primary supporting induced by the bending of primary supporting mem-
members are to be determined by a grillage or a Finite bers, either parallel and perpendicular to the direction
Element analysis. It is to be checked that stresses of ordinary stiffeners, calculated according to [9.5.3] c)
induced by concentrated loads are in accordance with or determined through a grillage analysis or a Finite Ele-
the criteria in [9.5.3] d). ment analysis, as the case may be, is to comply with the
following formula:
b) Hatch covers supporting wheeled loads
 Cp
The scantlings of hatch covers supporting wheeled loads ---------- 
R m
are to be obtained in accordance with:
• the applicable requirements of Pt B, Ch 7, Sec 1 for where sCp is critical buckling stress, defined in Pt B,
plating Ch 7, Sec 1, [5.3.1].
• the applicable requirements of Pt B, Ch 7, Sec 2 for In addition, the bi-axial compression stress in the hatch
ordinary stiffeners cover plating, when calculated by means of Finite Ele-
• the applicable requirements of Pt B, Ch 7, Sec 3 for ment analysis, is to comply with the requirements in
primary supporting members. Pt B, Ch 7, Sec 1, [5.4.5].
c) Hatch covers subjected to concentrated loads 9.5.3 Ordinary stiffeners and primary supporting
For hatch covers supporting concentrated loads, ordi- members (1/7/2012)
nary stiffeners and primary supporting members are a) General
generally to be checked by direct calculations, taking The flange outstand of the primary supporting members
into account the stiffener arrangements and their rela- is to be not greater than 15 times the flange thickness.
tive inertia. It is to be checked that stresses induced by
concentrated loads are in accordance with the criteria The net dimensions of the flat bar ordinary stiffeners and
in [9.5.3] d). buckling stiffeners are to comply with the following
requirement:
d) Covers of small hatchways
hW
The thickness of covers is to be not less than 8 mm. This -------  15 k
tW
thickness is to be increased or an efficient stiffening fit-
ted to the Society's satisfaction where the greatest hori- where hw and tw are the height and thickness, in mm, of
zontal dimension of the cover exceeds 0,6 m. the ordinary stiffener, respectively.
b) Application
9.5.2 Plating (1/7/2012)
a) Net thickness The requirements in [9.5.3] c) to g) apply to:
The net thickness of steel hatch cover top plating is to be • ordinary stiffeners
not less than the value obtained, in mm, from the fol- • primary supporting members which may be ana-
lowing formula: lysed through isolated beam models.
pS + pW Primary supporting members whose arrangement is of a
t = F p 15 ,8 s ---------------------
- grillage type and which cannot be analysed through iso-
0 95R eH
lated beam models are to be checked by direct calcula-
where: tions, using the checking criteria in [9.5.3] d).
Fp : factor for combined membrane and bending
c) Normal and shear stress
response, equal to:
1) Where the grillage analysis or Finite Element analy-
• FP = 1,50 in general
sis is not carried out according to the requirements
• FP = 2,375 s/ReH for s/ReH  0,64, for the in [9.5.1] a), the maximum normal stress s and shear
attached plating of primary supporting stress t in the ordinary stiffeners are to be obtained,
members. in N/mm2, from the following formulae:
pS : still water pressure, in kN/m2, to be calcu-
s  p S + p W l S 10
2 3
lated according to [9.4.1].  = -----------------------------------------

-
12w
pW : wave pressure, in kN/m2, defined in [9.4.2].
5s  p S + p W l S
s : normal stress, in N/mm2, in the attached  = ---------------------------------
-
A sh
plating of primary supporting members, cal-
culated according to [9.5.3] c) 1) or deter- where:
RINA Rules 2024 99

Pt E, Ch 4, Sec 3
S : ordinary stiffener span, in m, to be taken tp = net thickness, in mm, of the attached plating
as the spacing, in m, of primary support- hw, tw = height and thickness, in mm, of the ordi-
ing members or the distance between a nary stiffener, respectively
primary supporting member and the
kp = 1 - hp to be taken not less than zero; for flanged
edge support, as applicable. When
ordinary stiffeners, kp need not be taken less than
brackets are fitted at both ends of all
0,1
ordinary stiffener spans, the ordinary
stiffener span may be reduced by an 
 p = -------
amount equal to 2/3 of the minimum  Ep
bracket arm length, but not greater than s is calculated according to c) or determined
10% of the gross span, for each bracket. through a grillage analysis
pW : wave pressure, as defined in [9.4.2]. 2
tp 
 Ep = 3 6E  ---------------
-
2) Where the grillage analysis or Finite Element analy-  1000s
in [9.5.1] a), the maximum normal stress s and shear 3) Critical buckling stress check of the web panels of
stress t in the primary supporting members are to be the primary supporting members
obtained, in N/mm2, from the following formulae: The shear stress t in the web panels of the primary
supporting members, calculated according to c) or
s  p S + p W l m 10
2 3
 = ------------------------------------------
- determined through a grillage analysis or a Finite
mw Element analysis, as the case may be, is to comply
5s  p S + p W l m with the following formula:
 = ----------------------------------
-
A sh C
---------- 
where pw is the wave pressure, as defined in [9.4.2], m R
and lm is the span of the primary supporting mem- where tC is critical shear buckling stress, defined in
ber. Pt B, Ch 7, Sec 1, [5.3.2].
d) Checking criteria For primary supporting members parallel to the
1) Strength check direction of ordinary stiffeners, tC is to be calculated
The normal stress s and the shear stress t, calculated considering the actual dimensions of the panels
according to c) or determined through a grillage taken for the determination of the stress tC.
analysis or Finite Element analysis, as the case may For primary supporting members perpendicular to
be, are to comply with the following formulae: the direction of ordinary stiffeners or for hatch cov-
ers built without ordinary stiffeners, a presumed
R eH
----------  square panel of dimension d is to be taken for the
R m
determination of the stress tC. In such case, the aver-
R eH age shear stress t of the values calculated at the ends
0 57 ---------- 
m R of this panel is to be considered.
2) Critical buckling stress check of the ordinary stiffen- 4) Deflection limit
ers The vertical deflection of primary supporting mem-
The compressive stress s in the top flange of ordinary bers is to be not more than 0,0056 lmax, where lmax is
stiffeners, induced by the bending of primary sup- the greatest span of primary supporting members.
porting members, parallel to the direction of ordi- e) Net section modulus and net shear sectional area
nary stiffeners, calculated according to c) or
This requirement provides the minimum net section
determined through a grillage analysis or a Finite
modulus and net shear sectional area of an ordinary
Element analysis, as the case may be, is to comply
stiffener or a primary supporting member subjected to
with the following formula:
lateral pressure, complying with the checking criteria
 Cs indicated in d).
---------- 
m R
The net section modulus w, in cm3, and the net shear
where: sectional area ASh, in cm2, of an ordinary stiffener sub-
sCS =sES for sES £ ReH/2 jected to lateral pressure are to be not less than the val-
sCS =sES [1 - ReH / (4 sES)] for sES £ ReH/2 ues obtained from the following formulae:
s  p S + p W l S 10
2 3
sES =min (sE1, sE2)
w =  m  R -----------------------------------------
-
sE1 and sE2 are defined in Pt B, Ch 7, Sec 2, [4.3.1]. 12R eH
In calculating sE2, C0 is to be taken equal to: 5s  p S + p W l S
A Sh =  m  R ---------------------------------
-
0 57R eH
3
k p Et p
- 10 –3
C 0 = ----------------------------------------------------- The net section modulus w, in cm3, and the net shear
1 33k p k W t p 
3

3s 1 + ------------------------------- - sectional area Ash, in cm2, of a primary supporting mem-
 1000st W 
3
ber subject to lateral pressure are to be not less than the
where: values obtained from the following formulae:
100 RINA Rules 2024

Pt E, Ch 4, Sec 3
s  p S + p W l m 10
2 3 b) Coamings are to be stiffened on their upper edges with a
w =  m  R ------------------------------------------
- stiffener suitably shaped to fit the hatch cover closing
mR eH
appliances.
5s  p S + p W l m
A Sh =  m  R ----------------------------------
-
Moreover, when covers are fitted with tarpaulins, an
0 57R eH
angle or a bulb section is to be fitted all around coam-
f) Minimum net thickness of web ings of more than 3 m in length or 600 mm in height;
The net thickness of the ordinary stiffeners and primary this stiffener is to be fitted at approximately 250 mm
supporting members, in mm, is to be not less than the below the upper edge. The width of the horizontal
minimum values given in [9.5.2] b). flange of the angle is not to be less than 180 mm.
g) Ordinary stiffeners and primary supporting members of c) Where hatch covers are fitted with tarpaulins, coamings
variable cross-section are to be strengthened by brackets or stays with a spac-
ing not greater than 3 m.
The section modulus of ordinary stiffeners and primary
supporting members with a variable cross-section is to Where the height of the coaming exceeds 900 mm,
be not less than the greater of the values obtained, in additional strengthening may be required.
cm3, from the following formulae: However, reductions may be granted for transverse
w = w CS
coamings in protected areas.
3 ,2 –  – 0 ,8 d) When two hatches are close to each other, underdeck

w =  1 + ------------------------------------- w CS
 7 + 0 ,4  stiffeners are to be fitted to connect the longitudinal
coamings with a view to maintaining the continuity of
where: their strength.
wCS : Section modulus, in cm3, for a constant Similar stiffening is to be provided over 2 frame spacings
cross-section, obtained according to [9.5.2] at ends of hatches exceeding 9 frame spacings in length.
e). In some cases, the Society may require the continuity of
 coamings to be maintained above the deck.
 = ----1
0 e) Where watertight metallic hatch covers are fitted, other
w arrangements of equivalent strength may be adopted.
 = ------1
w0
9.6.2 Load model (1/7/2012)
1 : Length of the variable section part, in m,
(see Fig 15) a) The wave lateral pressure to be considered as acting on
the hatch coamings is that specified in b) and c).
0 : Span measured, in m, between end supports
(see Fig 15) b) The wave lateral pressure pWC, in kN/m2, on the No. 1
forward transverse hatch coaming is to be taken equal
w1 : Section modulus at end, in cm3 (see Fig 15) to:
w0 : Section modulus at mid-span, in cm3 (see pWC = 220 kN/m2, when a forecastle is fitted in accord-
Fig 15). ance with [12.1], Ch 5, Sec 3, [8.1] or Ch 6, Sec 3,
The use of this formula is limited to the determination of [11.1] applicable to ships with service notations bulk
the strength of ordinary stiffeners and primary support- carrier ESP, ore carrier ESP or combination carrier ESP,
ing members in which abrupt changes in the cross-sec- respectively.
tion do not occur along their length. pWC = 290 kN/m2, in other cases.
Figure 15 : Variable cross-section c) The wave lateral pressure pWC, in kN/m2, on the hatch
stiffener (1/7/2012) coamings other than the No. 1 forward transverse hatch
coaming is to be taken equal to:
pWC = 220 kN/m2.
9.6.3 Scantlings (1/7/2012)

a) Plating
In ships intended for the carriage of liquid cargoes, the
plate thickness of coamings is also to be checked under
liquid internal pressures.
1) Net thickness
9.6 Hatch coamings
The net thickness of the hatch comaing plate is to be
not less than the value obtained, in mm, from the
9.6.1 Stiffening (1/7/2012)
following formula:
a) The ordinary stiffeners of the hatch coamings are to be
continuous over the breadth and length of the hatch p WC
t = 16 4s --------
-
coamings. R eH
RINA Rules 2024 101

Pt E, Ch 4, Sec 3
2) Minimum net thickness tALL : allowable shear stress, in N/mm2, equal to 0,5 ReH
In addition to the requirements in a), the net thick- Unless otherwise stated, weld connections and materi-
ness of the hatch coaming plate is to be not less than als are to be dimensioned and selected in accordance
9,5 mm. with the requirements in Pt B, Ch 12, Sec 1 and Part D,
b) Ordinary stiffeners respectively.
The net section modulus w of the longitudinal or trans- Double continuous fillet welding is to be adopted for
verse ordinary stiffeners of hatch coamings is to be not the connections of stay webs with deck plating and the
less than the value obtained, in cm3, from the following weld throat thickness is to be not less than 0,44 tW,
formula: where tW is the gross thickness of the stay web.
1 2sp WC l 10
2 3 Toes of stay webs are to be connected to the deck plat-
w = -----------------------------------
- ing with full penetration double bevel welds extending
mc p R eH
over a distance not less than 15% of the stay width.
where:
e) Coamings of small hatchways
m = 16 in general
The coaming plate thickness is to be not less than the
m = 12 for the end span of stiffeners sniped at the coam- lesser of the following values:
ing corners
1) the thickness for the deck inside line of openings
cp = ratio of the plastic section modulus to the elastic
calculated for that position, assuming as spacing of
section modulus of the secondary stiffeners with an
stiffeners the lesser of the values of the height of the
attached plate breadth, in mm, equal to 40 t, where t is
coaming and the distance between its stiffeners, if
the plate net thickness
any, or
cp = 1,16 in the absence of more precise evaluation.
2) 10 mm.
c) Coaming stays
Coamings are to be suitably strengthened where their
The net section modulus w, in cm3, and the thickness tw, height exceeds 0,80 m or their greatest horizontal
in mm, of the coaming stays are to be not less than the dimension exceeds 1,20 m, unless their shape ensures
values obtained from the following formulae: an adequate rigidity.
1 05H C s c p WC 10
2 3
w = ----------------------------------------------
-
9.7 Weathertightness, closing arrangement
2R eH
3
and securing devices
H C s c p WC 10
t w = ------------------------------
-
0 5hR eH 9.7.1 Weathertightness (1/7/2012)
where: a) Where the hatchway is exposed and closed with a sin-
HC = stay height, in m gle panel, the weathertightness is to be ensured by gas-
kets and clamping devices sufficient in number and
sc = stay spacing, in m
quality.
h = stay depth, in mm, at the connection with deck
Weathertightness may also be ensured means of tarpau-
For calculating the section modulus of coaming stays, lins.
their face plate area is to be taken into account only
b) The mean spacing of swing bolts or equivalent devices
when it is welded with full penetration welds to the
is, in general, to be not greater than:
deck plating and adequate underdeck structure is fitted
to support the stresses transmitted by it. • 2,0 m for dry cargo holds
d) Local details • 1,5 m for ballast compartments
The design of local details is to comply with the require- • 1,0 m for liquid cargo holds.
ments in this Section for the purpose of transferring the
9.7.2 Gaskets (1/7/2012)
pressures on the hatch covers to the hatch coamings
and, through them, to the deck structures below. Hatch a) The weight of hatch covers and any cargo stowed
coamings and supporting structures are to be ade- thereon, together with inertia forces generated by ship
quately stiffened to accommodate the loading from motions, are to be transmitted to the ship’s structure
hatch covers in longitudinal, transverse and vertical through steel to steel contact.
directions. This may be achieved by continuous steel to steel con-
The normal stress s and the shear stress t, in N/mm2, tact of the hatch cover skirt plate with the ship’s struc-
induced in the underdeck structures by the loads trans- ture or by means of defined bearing pads.
mitted by stays are to comply with the following formu- b) The sealing is to be obtained by a continuous gasket of
lae: relatively soft elastic material compressed to achieve the
   ALL necessary weathertightness. Similar sealing is to be
arranged between cross-joint elements.
   ALL
Where fitted, compression flat bars or angles are to be
sALL : allowable normal stress, in N/mm2, equal to 0,95 well rounded where in contact with the gasket and to be
ReH made of a corrosion-resistant material.
102 RINA Rules 2024

Pt E, Ch 4, Sec 3
c) The gasket and the securing arrangements are to main- Arrangement and spacing are to be determined with
tain their efficiency when subjected to large relative due attention to the effectiveness for weathertightness,
movements between the hatch cover and the ship’s depending on the type and the size of the hatch cover,
structure or between hatch cover elements. as well as on the stiffness of the hatch cover edges
If necessary, suitable devices are to be fitted to limit between the securing devices.
such movements. At cross-joints of multipanel covers, (male/female) verti-
cal guides are to be fitted to prevent excessive relative
d) The gasket material is to be of a quality suitable for all
vertical deflections between loaded/unloaded panels.
environmental conditions likely to be encountered by
the ship, and is to be compatible with the cargoes trans- The location of stoppers is to be compatible with the rel-
ported. ative movements between hatch covers and the ship’s
structure in order to prevent damage to them. The num-
The material and form of gasket selected are to be con-
ber of stoppers is to be as small as possible.
sidered in conjunction with the type of hatch cover, the
securing arrangement and the expected relative move- c) Spacing
ment between the hatch cover and the ship’s structure. The spacing of the securing arrangements is to be gener-
The gasket is to be effectively secured to the hatch ally not greater than 6 m.
cover. The spacing of securing arrangements of tank hatch cov-
e) Coamings and steel parts of hatch covers in contact with ers in ‘tweendecks is to be not greater than 600 mm.
gaskets are to have no sharp edges. d) Construction
f) Metallic contact is required for an earthing connection Securing arrangements with reduced scantlings may be
between the hatch cover and the hull structures. If nec- accepted provided it can be demonstrated that the pos-
essary, this is to be achieved by means of a special con- sibility of water reaching the deck is negligible.
nection for the purpose. Securing devices are to be of reliable construction and
securely attached to the hatchway coamings, decks or
9.7.3 Closing arrangement, securing devices and hatch covers.
stoppers (1/7/2012)
Individual securing devices on each hatch cover are to
a) General have approximately the same stiffness characteristics.
Panel hatch covers are to be secured by appropriate e) Area of securing devices
devices (bolts, wedges or similar) suitably spaced along-
The net cross area of each securing device is to be not
side the coamings and between cover elements.
less than the value obtained, in cm2, from the following
The securing and stop arrangements are to be fitted formula:
using appropriate means which cannot be easily
f
A = 1 ,4S S  ----------
removed. 235
 R eH 
In addition to the requirements above, all hatch covers,
and in particular those carrying deck cargo, are to be where:
effectively secured against horizontal shifting due to the SS : Spacing, in m, of securing devices
horizontal forces resulting from ship motions.
f : Coefficient taken equal to:
Towards the ends of the ship, vertical acceleration
• 0,75 for ReH > 235 N/mm2,
forces may exceed the gravity force. The resulting lifting
forces are to be considered when dimensioning the • 1,00 for ReH  235 N/mm2.
securing devices according to e) to g). Lifting forces In the above calculations, ReH may not be taken greater
from cargo secured on the hatch cover during rolling are than 0,7 Rm.
also to be taken into account.
Between hatch cover and coaming and at cross-joints, a
Hatch coamings and supporting structure are to be ade- packing line pressure sufficient to obtain weathertight-
quately stiffened to accommodate the loading from ness is to be maintained by securing devices. For pack-
hatch covers. ing line pressures exceeding 5 N/mm, the net cross area
Hatch covers provided with special sealing devices, A is to be increased in direct proportion. The packing
insulated hatch covers, flush hatch covers and those line pressure is to be specified.
having coamings of a reduced height (see [9.2.1] ) are In the case of securing arrangements which are particu-
considered by the Society on a case by case basis. larly stressed due to the unusual width of the hatchway,
In the case of hatch covers carrying containers, the the net cross area A of the above securing arrangements
scantlings of the closing devices are to take into account is to be determined through direct calculations.
the possible upward vertical forces transmitted by the f) Inertia of edges elements
containers. The hatch cover edge stiffness is to be sufficient to main-
b) Arrangements tain adequate sealing pressure between securing
The securing and stopping devices are to be arranged so devices.
as to ensure sufficient compression on gaskets between The moment of inertia of edge elements is to be not less
hatch covers and coamings and between adjacent hatch than the value obtained, in cm4, from the following for-
covers. mula:
RINA Rules 2024 103

Pt E, Ch 4, Sec 3
4
I = 6p L S S giving support to battens and wedges and with edges
rounded so as to minimise damage to the wedges.
where:
b) Cleats are to be spaced not more than 600 mm from
pL : Packing line pressure, in N/mm, to be taken centre to centre and are to be not more than 150 mm
not less than 5 N/mm from the hatch corners.
SS : Spacing, in m, of securing devices. c) The thickness of cleats is to be not less than 9,5 mm for
angle cleats and 11 mm for forged cleats.
g) Diameter of rods or bolts
d) Where rod cleats are fitted, resilient washers or cushions
Rods or bolts are to have a net diameter not less than 19 are to be incorporated.
mm for hatchways exceeding 5 m2 in area. e) Where hydraulic cleating is adopted, a positive means is
h) Stoppers to be provided to ensure that it remains mechanically
locked in the closed position in the event of failure of
Hatch covers are to be effectively secured, by means of the hydraulic system.
stoppers, against the transverse forces arising from a
pressure of 175 kN/m2. 9.7.6 Wedges, battens and locking bars (1/7/2012)
With the exclusion of No. 1 hatch cover, hatch covers a) Wedges
are to be effectively secured, by means of stoppers, Wedges are to be of tough wood, generally not more
against the longitudinal forces acting on the forward end than 200 mm in length and 50 mm in width.
arising from a pressure of 175 kN/m2.
They are generally to be tapered not more than 1 in 6
No. 1 hatch cover is to be effectively secured, by means and their thickness is to be not less than 13 mm.
of stoppers, against the longitudinal forces acting on the b) Battens and locking bars
forward end arising from a pressure of 230 kN/m2. This
For all hatchways in exposed positions, battens or trans-
pressure may be reduced to 175 kN/m2 if a forecastle is
verse bars in steel or other equivalent means are to be
fitted in accordance with [12.1], Ch 5, Sec 3, [8.1] or
provided in order to efficiently secure the portable cov-
Ch 6, Sec 3, [11.1] applicable to ships with service
ers after the tarpaulins are battened down.
notations bulk carrier ESP, ore carrier ESP or combina-
tion carrier ESP, respectively. Portable covers of more than 1,5 m in length are to be
secured by at least two such securing appliances.
The equivalent stress in stoppers, their supporting struc-
tures and in the throat of the stopper welds is to be
equal to or less than the allowable value, equal to 0,8
9.8 Drainage
ReH.
9.8.1 Arrangement (1/7/2012)
9.7.4 Tarpaulins (1/7/2012) a) Drainage is to be arranged inside the line of gaskets by
means of a gutter bar or vertical extension of the hatch
Where weathertightness of hatch covers is ensured by side and end coaming.
means of tarpaulins, at least two layers of tarpaulins are to
be fitted. b) Drain openings are to be arranged at the ends of drain
channels and are to be provided with efficient means for
Tarpaulins are to be free from jute and waterproof and are preventing ingress of water from outside, such as non-
to have adequate characteristics of strength and resistance return valves or equivalent.
to atmospheric agents and high and low temperatures.
c) Cross-joints of multipanel hatch covers are to be
The mass per unit surface of tarpaulins made of vegetable arranged with drainage of water from the space above
fibres, before the waterproofing treatment, is to be not less the gasket and a drainage channel below the gasket.
than: d) If a continuous outer steel contact is arranged between
2
• 0,65 kg/m for waterproofing by tarring the cover and the ship’s structure, drainage from the
space between the steel contact and the gasket is also to
• 0,60 kg/m2 for waterproofing by chemical dressing be provided.
• 0,55 kg/m2 for waterproofing by dressing with black oil.
10 Hull outfitting
In addition to tarpaulins made of vegetable fibres, those of
synthetic fabrics or plastic laminates may be accepted by 10.1 Forecastle
the Society provided their qualities, as regards strength,
waterproofing and resistance to high and low temperatures, 10.1.1 General (1/1/2004)
are equivalent to those of tarpaulins made of vegetable Ships with service notation bulk carrier ESP are to be fitted
fibres. with an enclosed forecastle on the freeboard deck.
The required dimensions of the forecastle are defined in
9.7.5 Cleats (1/7/2012)
[10.1.2].
a) The arrangements for securing the tarpaulins to hatch The structural arrangements and scantlings of the forecastle
coamings are to incorporate cleats of a suitable pattern are to comply with the requirements in Pt B, Ch 10, Sec 2.

Part E
Service Notations
Chapter 5
ORE CARRIERS
SECTION 1 GENERAL

APPENDIX 1 GUIDELINES FOR BALLAST LOADING CONDITIONS OF CARGO

VESSELS INVOLVING PARTIALLY FILLED BALLAST TANKS

Pt E, Ch 5, Sec 3
Symbols
Ry : Minimum yield stress, in N/mm2, of the mate- Figure 1 : Symmetrical gusset/shedder plates
rial, to be taken equal to 235/k N/mm2, unless
otherwise specified
k : Material factor for steel, defined in Pt B, Ch 4,
Sec 1, [2.3]
E : Young’s modulus, in N/mm2, to be taken equal
gusset
to: plate
• E = 2,06.105 N/mm2 for steels in general
• E = 1,95.105 N/mm2 for stainless steels. hg
1 General
1
Lower
1.1 Loading manual and loading instru- stool
ments
1.1.1 The specific requirements in Pt B, Ch 11, Sec 2 for

ships with the service notation ore carrier ESP and equal to
or greater than 150 m in length are to be complied with. Figure 2 : Asymmetrical gusset/shedder plates
2 Stability
2.1 Intact stability
2.1.1 General
The stability of the ship for the loading conditions in Pt B,
Ch 3, App 2, [1.2.5] is to be in compliance with the
requirements in Pt B, Ch 3, Sec 2. Where the ship is
gusset
intended also for the carriage of grain, the requirements in hg plate
Ch 4, Sec 3, [2.2.2] and Ch 4, Sec 3, [2.2.3] are to be com-
1
plied with.
lower
3 Design loads
stool
• ballast conditions; App 1 contains the guidance for par-

3.1 Hull girder loads tially filled ballast tanks in ballast loading conditions.
• short voyage conditions where the ship is to be loaded
3.1.1 Still water loads (1/1/2022) to maximum draught but with a limited amount of bun-
In addition to the requirements in Pt B, Ch 5, Sec 2, [2.1.2], kers
still water loads are to be calculated for the following load- • multiple port loading/unloading conditions
ing conditions, subdivided into departure and arrival condi- • deck cargo conditions, where applicable
tions as appropriate: • typical loading sequences where the ship is loaded from
• alternate light and heavy cargo loading conditions at commencement of cargo loading to reaching full dead-
maximum draught weight capacity, for homogeneous conditions, relevant
part load conditions and alternate conditions where
• homogeneous light and heavy cargo loading conditions applicable. Typical unloading sequences for these con-
at maximum draught ditions are also to be included. The typical load-

Pt E, Ch 5, Sec 3
 : Compressive stress, in N/mm2, obtained from a 6 Hatch covers, hatch coamings and
three dimensional finite element analysis, based
closing devices
on fine mesh modelling, according to Pt B,
Ch 7, Sec 3 and Pt B, Ch 7, App 1
6.1 Application
c : Critical stress, in N/mm2, defined in [5.3.2]
6.1.1 (1/7/2024)
R : Resistance partial safety factor:
Refer to Tthe requirements for Type 2 ships of this Article
R = 1,02 [6] apply to steel hatch covers in positions 1 and 2 on
m : Material partial safety factor: weather decks, defined in Pt B, Ch 19, Sec 27, [3.16].
m = 1,02 6.1.2 Symbols used in Article [6] (1/7/2012)

pS : Still water pressure, in kN/m2 (see [6.4])
5.3.2 The critical buckling stress of cross-ties is to be
obtained, in N/mm2, from the following formulae: pW : Wave pressure, in kN/m2 (see [6.4])
R s : Length, in m, of the shorter side of the plate

c = E for  E  -----y panel
2
Ry  R  : Length, in m, of the longer side of the plate
 c = R y  1 – --------
- for  E  -----y
 4 E 2 panel
where: bP : Width, in m, of the plating attached to the ordi-

nary stiffener or primary supporting member,
E = Min (E1, E2), defined in [6.3]
E1 : Euler flexural buckling stress, to be obtained, in w : Net section modulus, in cm3, of the ordinary
N/mm2, from the following formula: stiffener or primary supporting member, with an
attached plating of width bp
 2 EI
 E1 = ---------------------
4
10 A ct 
2 ASh : Net shear sectional area, in cm2, of the ordinary
stiffener or primary supporting member, to be
I : Min (Ixx, Iyy) calculated as specified in Pt B, Ch 4, Sec 3,
Ixx : Net moment of inertia, in cm4, of the cross-tie
Sec 3, [4.3], for primary supporting members
about the x axis defined in [5.2.1]
m : Boundary coefficient for ordinary stiffeners and
Iyy : Net moment of inertia, in cm4, of the cross-tie
primary supporting members, taken equal to:
about the y axis defined in [5.2.1]
• m = 8 in the case of ordinary stiffeners and
Act : Net cross-sectional area, in cm2, of the cross-tie primary supporting members simply sup-
 : Span, in m, of the cross-tie ported at both ends or supported at one end
and clamped at the other
E2 : Euler torsional buckling stress, to be obtained,
in N/mm2, from the following formula:
primary supporting members clamped at
 2 EI w both ends
-2 + 0 ,41 E ---J
 E2 = -----------------
4
10 I o  Io
tC : Corrosion additions, in mm, defined in [6.1.5]
4
Iw : Net sectorial moment of inertia, in cm , of the ReH : Minimum yield stress, in N/mm2, of the mate-
cross-tie, specified in Tab 5 for various types of rial, defined in Pt B, Ch 4, Sec 1, [2]
profiles
Rm : Minimum ultimate tensile strength, in N/mm2,
Io : Net polar moment of inertia, in cm4, of the of the material, defined in Pt B, Ch 4, Sec 1, [2]
cross-tie, Ry : Yield stress, in N/mm2, of the material, to be
I o = I xx + I yy + A ct  y o + e  2 taken equal to 235/k N/mm2, unless otherwise
specified
yo : Distance, in cm, from the centre of torsion to
k : Material factor, defined in Pt B, Ch 4, Sec 1,
the web of the cross-tie, specified in Tab 5 for
[2.3]
various types of profiles
cS : Coefficient, taken equal to:
e : Distance, in cm, from the centre of gravity to
the web of the cross-tie, specified in Tab 5 for • cS = 1-(s/2) for ordinary stiffeners
various types of profiles
• cS = 1 for primary supporting members
J : St. Venant’s net moment of inertia, in cm4, of the
cross-tie, specified in Tab 5 for various types of
profiles. g = 9,81 m/s2.
RINA Rules 2024 131

Pt E, Ch 5, Sec 3
6.1.3 Materials (1/7/2012) Table 3 : Corrosion additions tc for steel hatch

a) Steel covers (1/7/2012)
The formulae for scantlings given in the requirements in
[6.5] are applicable to steel hatch covers. Corrosion addition tc , in mm
Materials used for the construction of steel hatch covers Plating and stiffeners of single skin hatch cover 2,0
are to comply with the applicable requirements of
Top and bottom plating of double skin hatch 2,0
Part D, Chapter 2.
cover
b) Other materials
Internal structures of double skin hatch cover 1,5
The use of materials other than steel is considered by
6.2 Arrangements
teria adopted for scantlings are such as to ensure
strength and stiffness equivalent to those of steel hatch 6.2.1 Height of hatch coamings (1/7/2012)
covers.
a) The height above the deck of hatch coamings closed by
6.1.4 Net scantlings (1/7/2012) portable covers is to be not less than:
As specified in Pt B, Ch 4, Sec 2, [1], all scantlings referred • 600 mm in position 1
to in this Section are net, i.e. they do not include any mar- • 450 mm in position 2.
gin for corrosion. b) The height of hatch coamings in positions 1 and 2
The gross scantlings are obtained as specified in Pt B, Ch 4, closed by steel covers provided with gaskets and secur-
Sec 2. ing devices may be reduced with respect to the above
values or the coamings may be omitted entirely.
6.1.5 Partial safety factors (1/7/2012) In such cases the scantlings of the covers, their gasket-
The partial safety factors to be considered for checking ing, their securing arrangements and the drainage of
hatch cover structures are specified in Tab 2. recesses in the deck are considered by the Society on a
case by case basis.
Table 2 : Hatch covers - Partial safety c) Regardless of the type of closing arrangement adopted,
factors (1/7/2012) the coamings may have reduced height or be omitted in
way of openings in closed superstructures or decks
Partial safety factors below the freeboard deck.
Partial safety factors Ordinary
stiffeners 6.2.2 Hatch covers (1/7/2012)
covering uncertainties
regarding: Symbol Plating and primary a) Hatch covers on exposed decks are to be weathertight.
supporting Hatch covers in closed superstructures need not be
members weathertight.
Still water pressure S2 1,00 1,00 However, hatch covers fitted in way of ballast tanks, fuel
Wave pressure W2 1,20 1,20 oil tanks or other tanks are to be watertight.
Material m 1,02 1,02 b) The ordinary stiffeners and primary supporting members
of the hatch covers are to be continuous over the
Resistance R 1,22 1,22
breadth and length of the hatch covers, as far as practi-
cal. When this is impractical, sniped end connections
6.1.6 Corrosion additions (1/7/2012)
are not to be used and appropriate arrangements are to
a) Corrosion additions for hatch covers be adopted to ensure sufficient load carrying capacity.
The corrosion addition to be considered for the plating c) The spacing of primary supporting members parallel to
and internal members of hatch covers is the value speci- the direction of ordinary stiffeners is to be not greater
fied in Tab 3 for the total thickness of the member under than 1/3 of the span of primary supporting members.
consideration.
d) The breadth of the primary supporting member flange is
b) Corrosion additions for hatch coamings to be not less than 40% of its depth for laterally unsup-
The corrosion addition to be considered for the hatch ported spans greater than 3,0 m. Tripping brackets
coaming structures and coaming stays is equal to 1,5 attached to the flange may be considered as a lateral
mm. support for primary supporting members.
c) Corrosion additions for stainless steel e) The covers used in 'tweendecks are to be fitted with an
appropriate system ensuring an efficient stowing when
For structural members made of stainless steel, the cor- the ship is sailing with open 'tweendecks.
rosion addition tc is to be taken equal to 0.
f) The ends of hatch covers are normally to be protected
d) Corrosion additions for aluminium alloys by efficiently secured galvanised steel strips.
For structural members made of aluminium alloys, the g) Efficient retaining arrangements are to be provided to
corrosion addition tc is to be taken equal to 0. prevent translation of the hatch cover under the action
of the longitudinal and transverse forces exerted by the
132 RINA Rules 2024

Pt E, Ch 5, Sec 3
stacks of containers on the cover. These retaining they are protected by a closed superstructure. The same
arrangements are to be located in way of the hatch applies to accesses located on the forecastle deck and
coaming side brackets. leading directly to a dry cargo hold through a trunk.
Solid fittings are to be welded on the hatch cover where d) Accesses to cofferdams and ballast tanks are to be man-
the corners of the containers are resting. These parts are holes fitted with watertight covers fixed with bolts which
intended to transmit the loads of the container stacks are sufficiently closely spaced.
onto the hatch cover on which they are resting and also e) Hatchways of special design are considered by the Soci-
to prevent horizontal translation of the stacks by means ety on a case by case basis.
of special intermediate parts arranged between the sup-
ports of the corners and the container corners.
Longitudinal stiffeners are to stiffen the hatch cover
plate in way of these supports and connect at least the 6.3.1 Ordinary stiffeners (1/7/2012)
nearest three transverse stiffeners. The width of the attached plating to be considered for the
h) The width of each bearing surface for hatch covers is to check of ordinary stiffeners is to be obtained, in m, from the
be at least 65 mm. following formulae:
• where the attached plating extends on both sides of the
6.2.3 Hatch coamings (1/7/2012) stiffener:
a) Coamings, stiffeners and brackets are to be capable of bP = s
withstanding the local forces in way of the clamping
devices and handling facilities necessary for securing • where the attached plating extends on one side of the
and moving the hatch covers as well as those due to stiffener:
cargo stowed on the latter. bP = 0,5 s
b) Special attention is to be paid to the strength of the fore 6.3.2 Primary supporting members parallel to
transverse coaming of the forward hatch and to the ordinary stiffeners (1/7/2012)
scantlings of the closing devices of the hatch cover on The width of the attached plating to be considered for the
this coaming. yielding and buckling checks of primary supporting mem-
c) Longitudinal coamings are to be extended at least to the bers analysed through beam or grillage models is to be
lower edge of deck beams. obtained, in m, from the following formulae:
Where they are not part of continuous deck girders, lon- • where the plating extends on both sides of the primary
gitudinal coamings are to extend for at least two frame supporting member:
spaces beyond the end of the openings. bp = bp,1 + bp,2
Where longitudinal coamings are part of deck girders, • where the plating extends on one side of the primary
their scantlings are to be as required in Pt B, Ch 7, supporting member:
Sec 3.
bp = bp,1
d) Transverse coamings are to extend below the deck at
least to the lower edge of longitudinals. where:
Transverse coamings not in line with ordinary deck bp,1 = min (0,165 lP, Sp,1)
beams below are to extend below the deck at least three bp,2 = min (0,165 lP, Sp,2)
longitudinal frame spaces beyond the side coamings.
lP : span, in m, of the primary supporting member
6.2.4 Small hatchways (1/7/2012) considered
a) The height of small hatchway coamings is to be not less Sp,1, Sp,2 : half distance, in m, between the primary sup-
than 600 mm if located in position 1, and 450 mm if porting member considered and those adjacent,
located in position 2. on the two sides.
Where the closing appliances are in the form of hinged
steel covers secured weathertight by gaskets and swing 6.4 Load model
bolts, the height of the coamings may be reduced or the
6.4.1 Lateral pressures and concentrated
coamings may be omitted altogether.
loads (1/7/2012)
b) Small hatch covers are to have strength equivalent to a) General
that required for main hatchways and are to be of steel,
The still water and wave lateral pressures and concen-
weathertight and generally hinged.
trated loads, to be considered as acting on hatch covers,
Securing arrangements and stiffening of hatch cover are those in b) to g).
edges are to be such that weathertightness can be main-
Each case in g) to f) is not necessarily exhaustive for
tained in any sea condition.
any specific hatch cover; however, depending on the
At least one securing device is to be fitted at each side. location of each cover and its intended use, the pres-
Circular hole hinges are considered equivalent to secur- sures and loads to be considered as acting on it are to
ing devices. be calculated for one or more of these cases. For exam-
c) Hold accesses located on the weather deck are to be ple, for a hatch cover located on an exposed deck and
provided with watertight metallic hatch covers, unless covering a ballast tank, the pressures in b) and c) are to
RINA Rules 2024 133

Pt E, Ch 5, Sec 3
be separately considered. If the same hatch cover is also water during navigation, the lateral pressure to be
intended to carry uniform cargoes, the pressures in d) applied is considered by the Society on a case by case
are to be individually considered, in addition to the two basis.
above.
b) Hatch covers on exposed decks 6.4.2 Wave pressure for hatch covers on exposed
decks (1/7/2012)
The still water lateral pressure and loads are to be con-
sidered when the hatch cover is intended to carry uni- The wave pressure pW is defined in Tab 4 according to the
form cargoes, wheeled cargoes or containers. In these hatch cover position.
cases, the still water lateral pressures and loads are to be
calculated according to d) and e), as applicable. Where two or more panels are connected by hinges, each
individual panel is to be considered separately.
The wave lateral pressure is to be considered and is
defined in [6.4.2].
6.4.3 Load point (1/7/2012)
c) Hatch covers in way of liquid cargo or ballast tanks
a) Wave lateral pressure for hatch covers on exposed
The still water and wave lateral pressures are to be con- decks:
The wave lateral pressure to be considered as acting on
d) Hatch covers carrying uniform cargoes each hatch cover is to be calculated at a point located:
The still water and wave lateral pressures are to be con- • longitudinally, at the hatch cover mid-length
• transversely, on the longitudinal plane of symmetry
e) Hatch covers carrying containers
of the ship
The still water and wave loads are to be considered and
are defined in Pt B, Ch 5, Sec 6, [5].
b) Lateral pressure other than the wave pressure:
f) Hatch covers carrying wheeled cargoes
The still water and wave loads are to be considered and The lateral pressure is to be calculated:
are defined in Pt B, Ch 5, Sec 6, [6]. • in way of the geometrical centre of gravity of the
g) Hatch covers carrying special cargoes plate panel, for plating
In the case of carriage on the hatch covers of special • at mid-span, for ordinary stiffeners and primary sup-
cargoes (e.g. pipes, etc.) which may temporarily retain porting members.

L LL  100 m 0  x  0 75 L LL 14 9 + 0 195L LL 11 3 + 0 142L LL
L LL 
- 1 – --- ------- – 3 6 -------
5 x x
0 75L LL  x  L LL 15 8 + ------
3  3 L LL L LL
L LL  100 m 0  x  0 75L LL 34,3 25,5
p FP – 34 3  x
34 3 + -------------------------- ------- – 0 75
0 75L LL  x  L LL 0 25  L LL 
(1)
Note 1:
134 RINA Rules 2024

Pt E, Ch 5, Sec 3
6.5 Strength check mined through a grillage analysis or a Finite

Element analysis, as the case may be.
6.5.1 General and application (1/7/2012)
b) Minimum net thickness
a) Application
In addition to the requirements in a) above, the net
The strength check is applicable to rectangular hatch thickness, in mm, of hatch cover plating is to be not less
covers subjected to a uniform pressure, designed with than 1% of s or 6 mm, whichever is the greater.
primary supporting members arranged in one direction
or as a grillage of longitudinal and transverse primary c) Critical buckling stress check
supporting members. The compressive stress s in the hatch cover plating,
following formula:
b) Hatch covers supporting wheeled loads
 Cp
The scantlings of hatch covers supporting wheeled loads ---------- 
R m
are to be obtained in accordance with:
• the applicable requirements of Pt B, Ch 7, Sec 1 for where Cp is critical buckling stress, defined in Pt B,
c) Hatch covers subjected to concentrated loads 6.5.3 Ordinary stiffeners and primary supporting
For hatch covers supporting concentrated loads, ordi- members (1/7/2012)
nary stiffeners and primary supporting members are a) General
generally to be checked by direct calculations, taking The flange outstand of the primary supporting members
into account the stiffener arrangements and their rela- is to be not greater than 15 times the flange thickness.
tive inertia. It is to be checked that stresses induced by
concentrated loads are in accordance with the criteria The net dimensions of the flat bar ordinary stiffeners and
in [6.5.3] d). buckling stiffeners are to comply with the following
requirement:
d) Covers of small hatchways
hW
The thickness of covers is to be not less than 8 mm. This -------  15 k
tW
thickness is to be increased or an efficient stiffening fit-
ted to the Society's satisfaction where the greatest hori- where hw and tw are the height and thickness, in mm, of
zontal dimension of the cover exceeds 0,6 m. the ordinary stiffener, respectively.
b) Application
6.5.2 Plating (1/7/2012)
a) Net thickness The requirements in [6.5.3] c) to g) apply to:
The net thickness of steel hatch cover top plating is to be • ordinary stiffeners
not less than the value obtained, in mm, from the fol- • primary supporting members which may be ana-
lowing formula: lysed through isolated beam models.
pS + pW Primary supporting members whose arrangement is of a
t = F p 15 ,8 s ---------------------
- grillage type and which cannot be analysed through iso-
0 95R eH
lated beam models are to be checked by direct calcula-
where: tions, using the checking criteria in [6.5.3] d).
c) Normal and shear stress
response, equal to:
1) Where the grillage analysis or Finite Element analy-
• FP = 2,375 s/ReH for s/ReH 0,64, for the in [6.5.1] a), the maximum normal stress s and shear
attached plating of primary supporting stress t in the ordinary stiffeners are to be obtained,
members. in N/mm2, from the following formulae:
pS : still water pressure, in kN/m2, to be calcu-
s  p S + p W l S 10
2 3
lated according to [6.4.1].  = -----------------------------------------
-
12w
pW : wave pressure, in kN/m2, defined in [6.4.2].
5s  p S + p W l S
s : normal stress, in N/mm2, in the attached  = ---------------------------------
-
plating of primary supporting members, cal- A sh
culated according to [6.5.3] c) 1) or deter- where:
RINA Rules 2024 135

Pt E, Ch 5, Sec 3
primary supporting member and the
kp = 1 - hp to be taken not less than zero; for flanged
edge support, as applicable. When
ordinary stiffeners, kp need not be taken less than
brackets are fitted at both ends of all
0,1
stiffener span may be reduced by an 
 p = -------
amount equal to 2/3 of the minimum  Ep
bracket arm length, but not greater than  is calculated according to c) or determined
pW : wave pressure, as defined in [6.4.2]. tp  2
 Ep = 3 6E  ---------------
-
in [6.5.1] a), the maximum normal stress s and shear 3) Critical buckling stress check of the web panels of
stress t in the primary supporting members are to be the primary supporting members
s  p S + p W l m 10
2 3
 = ------------------------------------------
 = ----------------------------------
-
A sh C
---------- 
and m is the span of the primary supporting mem- where tC is critical shear buckling stress, defined in
ber. Pt B, Ch 7, Sec 1, [5.3.2].
d) Checking criteria For primary supporting members parallel to the
1) Strength check direction of ordinary stiffeners, tC is to be calculated
The normal stress s and the shear stress t, calculated considering the actual dimensions of the panels
according to c) or determined through a grillage taken for the determination of the stress tC.
analysis or Finite Element analysis, as the case may For primary supporting members perpendicular to
be, are to comply with the following formulae: the direction of ordinary stiffeners or for hatch cov-
R eH
----------  square panel of dimension d is to be taken for the
R m
R eH age shear stress t of the values calculated at the ends
0 57 ---------- 
m R of this panel is to be considered.
2) Critical buckling stress check of the ordinary stiffen- 4) Deflection limit
ers The vertical deflection of primary supporting mem-
The compressive stress s in the top flange of ordinary bers is to be not more than 0,0056 lmax, where lmax is
stiffeners, induced by the bending of primary sup- the greatest span of primary supporting members.
porting members, parallel to the direction of ordi- e) Net section modulus and net shear sectional area
nary stiffeners, calculated according to c) or
determined through a grillage analysis or a Finite
modulus and net shear sectional area of an ordinary
Element analysis, as the case may be, is to comply
stiffener or a primary supporting member subjected to
with the following formula:
lateral pressure, complying with the checking criteria
 Cs indicated in d).
---------- 
m R
where: sectional area ASh, in cm2, of an ordinary stiffener sub-
CS =ES for ES  ReH/2 jected to lateral pressure are to be not less than the val-
CS =ES [1 - ReH / (4 ES)] for ES  ReH/2 ues obtained from the following formulae:
ES =min (sE1, sE2) s  p S + p W l S 10
2 3
w =  m  R -----------------------------------------
-
E1 and E2 are defined in Pt B, Ch 7, Sec 2, [4.3.1]. 12R eH
In calculating E2, C0 is to be taken equal to: 5s  p S + p W l S

A Sh =  m  R ---------------------------------
-
0 57R eH
3
k p Et p
- 10 –3
C 0 = ----------------------------------------------------- The net section modulus w, in cm3, and the net shear

3
1 33k k t
3s  1 + -------------------------------
p W p 
- sectional area Ash, in cm2, of a primary supporting mem-
 1000st W 
3
where: values obtained from the following formulae:
136 RINA Rules 2024

Pt E, Ch 5, Sec 3
s  p S + p W l m 10
2 3 b) Coamings are to be stiffened on their upper edges with a
w =  m  R ------------------------------------------
- stiffener suitably shaped to fit the hatch cover closing
mR eH
appliances.
5s  p S + p W l m
A Sh =  m  R ----------------------------------
-
0 57R eH Moreover, when covers are fitted with tarpaulins, an
f) Minimum net thickness of web ings of more than 3 m in length or 600 mm in height;
The net thickness of the ordinary stiffeners and primary this stiffener is to be fitted at approximately 250 mm
supporting members, in mm, is to be not less than the below the upper edge. The width of the horizontal
minimum values given in [6.5.2] b). flange of the angle is not to be less than 180 mm.
g) Ordinary stiffeners and primary supporting members of c) Where hatch covers are fitted with tarpaulins, coamings
variable cross-section are to be strengthened by brackets or stays with a spac-
ing not greater than 3 m.
The section modulus of ordinary stiffeners and primary
supporting members with a variable cross-section is to Where the height of the coaming exceeds 900 mm,
be not less than the greater of the values obtained, in additional strengthening may be required.
cm3, from the following formulae: However, reductions may be granted for transverse
coamings in protected areas.
w = w CS
3 ,2 –  – 0 ,8 d) When two hatches are close to each other, underdeck
w =  1 + ------------------------------------- w CS stiffeners are to be fitted to connect the longitudinal
 7 + 0 ,4 
coamings with a view to maintaining the continuity of
where: their strength.
wCS : Section modulus, in cm3, for a constant Similar stiffening is to be provided over 2 frame spacings
cross-section, obtained according to [6.5.2] at ends of hatches exceeding 9 frame spacings in length.
e). In some cases, the Society may require the continuity of
 coamings to be maintained above the deck.
 = ----1
0 e) Where watertight metallic hatch covers are fitted, other
w arrangements of equivalent strength may be adopted.
 = ------1
w0
6.6.2 Load model (1/7/2012)
1 : Length of the variable section part, in m,
a) The wave lateral pressure to be considered as acting on
(see Fig 9)
the hatch coamings is that specified in b) and c).
b) The wave lateral pressure pWC, in kN/m2, on the No. 1
(see Fig 9)
w1 : Section modulus at end, in cm3 (see Fig 9) to:
w0 : Section modulus at mid-span, in cm3 (see pWC = 220 kN/m2, when a forecastle is fitted in accord-
Fig 9). ance with Ch 4, Sec 3, [12.1], [8.1] or Ch 6, Sec 3,
The use of this formula is limited to the determination of [11.1] applicable to ships with service notations bulk
the strength of ordinary stiffeners and primary support- carrier ESP, ore carrier ESP or combination carrier ESP,
ing members in which abrupt changes in the cross-sec- respectively.
tion do not occur along their length. pWC = 290 kN/m2, in other cases.
Figure 9 : Variable cross-section c) The wave lateral pressure pWC, in kN/m2, on the hatch
stiffener (1/7/2012) coamings other than the No. 1 forward transverse hatch
coaming is to be taken equal to:
pWC = 220 kN/m2.
6.6.3 Scantlings (1/7/2012)

a) Plating
In ships intended for the carriage of liquid cargoes, the
plate thickness of coamings is also to be checked under
liquid internal pressures.
1) Net thickness
6.6 Hatch coamings
The net thickness of the hatch comaing plate is to be
not less than the value obtained, in mm, from the
6.6.1 Stiffening (1/7/2012)
following formula:
a) The ordinary stiffeners of the hatch coamings are to be
continuous over the breadth and length of the hatch p WC
t = 16 4s --------
-
coamings. R eH
RINA Rules 2024 137

Pt E, Ch 5, Sec 3
2) Minimum net thickness tALL : allowable shear stress, in N/mm2, equal to 0,5 ReH
In addition to the requirements in a), the net thick- Unless otherwise stated, weld connections and materi-
ness of the hatch coaming plate is to be not less than als are to be dimensioned and selected in accordance
9,5 mm. with the requirements in Pt B, Ch 12, Sec 1 and Part D,
b) Ordinary stiffeners respectively.
The net section modulus w of the longitudinal or trans- Double continuous fillet welding is to be adopted for
verse ordinary stiffeners of hatch coamings is to be not the connections of stay webs with deck plating and the
less than the value obtained, in cm3, from the following weld throat thickness is to be not less than 0,44 tW,
formula: where tW is the gross thickness of the stay web.
Toes of stay webs are to be connected to the deck plat-
1 2sp WC l 10
2 3
w = -----------------------------------
- ing with full penetration double bevel welds extending
mc p R eH
over a distance not less than 15% of the stay width.
where:
e) Coamings of small hatchways
m = 16 in general
m = 12 for the end span of stiffeners sniped at the coam- lesser of the following values:
ing corners
1) the thickness for the deck inside line of openings
cp = ratio of the plastic section modulus to the elastic
calculated for that position, assuming as spacing of
attached plate breadth, in mm, equal to 40 t, where t is
coaming and the distance between its stiffeners, if
the plate net thickness
any, or
cp = 1,16 in the absence of more precise evaluation.
2) 10 mm.
c) Coaming stays
Coamings are to be suitably strengthened where their
The net section modulus w, in cm3, and the thickness tw, height exceeds 0,80 m or their greatest horizontal
in mm, of the coaming stays are to be not less than the dimension exceeds 1,20 m, unless their shape ensures
values obtained from the following formulae: an adequate rigidity.
1 05H C s c p WC 10
2 3
w = ----------------------------------------------
- 6.7 Weathertightness, closing arrangement
2R eH
3
and securing devices
H C s c p WC 10
t w = ------------------------------
-
0 5hR eH 6.7.1 Weathertightness (1/7/2012)
where: a) Where the hatchway is exposed and closed with a sin-
HC = stay height, in m gle panel, the weathertightness is to be ensured by gas-
kets and clamping devices sufficient in number and
sc = stay spacing, in m
quality.
h = stay depth, in mm, at the connection with deck
Weathertightness may also be ensured means of tarpau-
For calculating the section modulus of coaming stays, lins.
their face plate area is to be taken into account only
b) The mean spacing of swing bolts or equivalent devices
when it is welded with full penetration welds to the
is, in general, to be not greater than:
deck plating and adequate underdeck structure is fitted
to support the stresses transmitted by it. • 2,0 m for dry cargo holds
d) Local details • 1,5 m for ballast compartments
The design of local details is to comply with the require- • 1,0 m for liquid cargo holds.
ments in this Section for the purpose of transferring the
6.7.2 Gaskets (1/7/2012)
and, through them, to the deck structures below. Hatch a) The weight of hatch covers and any cargo stowed
coamings and supporting structures are to be ade- thereon, together with inertia forces generated by ship
quately stiffened to accommodate the loading from motions, are to be transmitted to the ship’s structure
hatch covers in longitudinal, transverse and vertical through steel to steel contact.
directions. This may be achieved by continuous steel to steel con-
The normal stress s and the shear stress t, in N/mm2, tact of the hatch cover skirt plate with the ship’s struc-
induced in the underdeck structures by the loads trans- ture or by means of defined bearing pads.
mitted by stays are to comply with the following formu- b) The sealing is to be obtained by a continuous gasket of
lae: relatively soft elastic material compressed to achieve the
   ALL necessary weathertightness. Similar sealing is to be
   ALL
sALL : allowable normal stress, in N/mm2, equal to 0,95 well rounded where in contact with the gasket and to be
ReH made of a corrosion-resistant material.
138 RINA Rules 2024

Pt E, Ch 5, Sec 3
c) The gasket and the securing arrangements are to main- Arrangement and spacing are to be determined with
tain their efficiency when subjected to large relative due attention to the effectiveness for weathertightness,
movements between the hatch cover and the ship’s depending on the type and the size of the hatch cover,
structure or between hatch cover elements. as well as on the stiffness of the hatch cover edges
If necessary, suitable devices are to be fitted to limit between the securing devices.
such movements. At cross-joints of multipanel covers, (male/female) verti-
cal guides are to be fitted to prevent excessive relative
d) The gasket material is to be of a quality suitable for all
vertical deflections between loaded/unloaded panels.
environmental conditions likely to be encountered by
the ship, and is to be compatible with the cargoes trans- The location of stoppers is to be compatible with the rel-
ported. ative movements between hatch covers and the ship’s
structure in order to prevent damage to them. The num-
The material and form of gasket selected are to be con-
ber of stoppers is to be as small as possible.
sidered in conjunction with the type of hatch cover, the
securing arrangement and the expected relative move- c) Spacing
ment between the hatch cover and the ship’s structure. The spacing of the securing arrangements is to be gener-
The gasket is to be effectively secured to the hatch ally not greater than 6 m.
cover. The spacing of securing arrangements of tank hatch cov-
e) Coamings and steel parts of hatch covers in contact with ers in ‘tweendecks is to be not greater than 600 mm.
gaskets are to have no sharp edges. d) Construction
f) Metallic contact is required for an earthing connection Securing arrangements with reduced scantlings may be
between the hatch cover and the hull structures. If nec- accepted provided it can be demonstrated that the pos-
essary, this is to be achieved by means of a special con- sibility of water reaching the deck is negligible.
nection for the purpose. Securing devices are to be of reliable construction and
securely attached to the hatchway coamings, decks or
6.7.3 Closing arrangement, securing devices and hatch covers.
stoppers (1/7/2012)
Individual securing devices on each hatch cover are to
a) General have approximately the same stiffness characteristics.
Panel hatch covers are to be secured by appropriate e) Area of securing devices
devices (bolts, wedges or similar) suitably spaced along-
The net cross area of each securing device is to be not
side the coamings and between cover elements.
less than the value obtained, in cm2, from the following
The securing and stop arrangements are to be fitted formula:
using appropriate means which cannot be easily
f
A = 1 ,4S S  ----------
removed. 235
 R eH 
Towards the ends of the ship, vertical acceleration
• 0,75 for ReH > 235 N/mm2,
forces are to be considered when dimensioning the • 1,00 for ReH  235 N/mm2.
also to be taken into account.
Between hatch cover and coaming and at cross-joints, a
Hatch covers provided with special sealing devices, A is to be increased in direct proportion. The packing
insulated hatch covers, flush hatch covers and those line pressure is to be specified.
having coamings of a reduced height (see [6.2.1]) are In the case of securing arrangements which are particu-
considered by the Society on a case by case basis. larly stressed due to the unusual width of the hatchway,
In the case of hatch covers carrying containers, the the net cross area A of the above securing arrangements
scantlings of the closing devices are to take into account is to be determined through direct calculations.
the possible upward vertical forces transmitted by the f) Inertia of edges elements
b) Arrangements tain adequate sealing pressure between securing
The securing and stopping devices are to be arranged so devices.
as to ensure sufficient compression on gaskets between The moment of inertia of edge elements is to be not less
hatch covers and coamings and between adjacent hatch than the value obtained, in cm4, from the following for-
covers. mula:
RINA Rules 2024 139

Pt E, Ch 5, Sec 3
4
I = 6p L S S giving support to battens and wedges and with edges
where: b) Cleats are to be spaced not more than 600 mm from
pL : Packing line pressure, in N/mm, to be taken centre to centre and are to be not more than 150 mm
not less than 5 N/mm from the hatch corners.
SS : Spacing, in m, of securing devices. c) The thickness of cleats is to be not less than 9,5 mm for
angle cleats and 11 mm for forged cleats.
g) Diameter of rods or bolts
d) Where rod cleats are fitted, resilient washers or cushions
Rods or bolts are to have a net diameter not less than 19 are to be incorporated.
mm for hatchways exceeding 5 m2 in area. e) Where hydraulic cleating is adopted, a positive means is
h) Stoppers to be provided to ensure that it remains mechanically
locked in the closed position in the event of failure of
Hatch covers are to be effectively secured, by means of the hydraulic system.
stoppers, against the transverse forces arising from a
pressure of 175 kN/m2. 6.7.6 Wedges, battens and locking bars (1/7/2012)
With the exclusion of No. 1 hatch cover, hatch covers a) Wedges
are to be effectively secured, by means of stoppers, Wedges are to be of tough wood, generally not more
against the longitudinal forces acting on the forward end than 200 mm in length and 50 mm in width.
arising from a pressure of 175 kN/m2. They are generally to be tapered not more than 1 in 6
No. 1 hatch cover is to be effectively secured, by means and their thickness is to be not less than 13 mm.
of stoppers, against the longitudinal forces acting on the b) Battens and locking bars
forward end arising from a pressure of 230 kN/m2. This For all hatchways in exposed positions, battens or trans-
pressure may be reduced to 175 kN/m2 if a forecastle is verse bars in steel or other equivalent means are to be
fitted in accordance with Ch 4, Sec 3, [12.1], [8.1] or provided in order to efficiently secure the portable cov-
Ch 6, Sec 3, [11.1] applicable to ships with service ers after the tarpaulins are battened down.
notations bulk carrier ESP, ore carrier ESP or combina- Portable covers of more than 1,5 m in length are to be
tion carrier ESP, respectively. secured by at least two such securing appliances.
tures and in the throat of the stopper welds is to be 6.8 Drainage
ReH. 6.8.1 Arrangement (1/7/2012)
a) Drainage is to be arranged inside the line of gaskets by
6.7.4 Tarpaulins (1/7/2012) means of a gutter bar or vertical extension of the hatch
Where weathertightness of hatch covers is ensured by side and end coaming.
means of tarpaulins, at least two layers of tarpaulins are to b) Drain openings are to be arranged at the ends of drain
be fitted. channels and are to be provided with efficient means for
preventing ingress of water from outside, such as non-
Tarpaulins are to be free from jute and waterproof and are
return valves or equivalent.
to have adequate characteristics of strength and resistance
to atmospheric agents and high and low temperatures. c) Cross-joints of multipanel hatch covers are to be
arranged with drainage of water from the space above
The mass per unit surface of tarpaulins made of vegetable the gasket and a drainage channel below the gasket.
fibres, before the waterproofing treatment, is to be not less
d) If a continuous outer steel contact is arranged between
than:
the cover and the ship’s structure, drainage from the
• 0,65 kg/m2 for waterproofing by tarring space between the steel contact and the gasket is also to
be provided.
• 0,60 kg/m2 for waterproofing by chemical dressing
• 0,55 kg/m2 for waterproofing by dressing with black oil. 7 Hull outfitting
In addition to tarpaulins made of vegetable fibres, those of
synthetic fabrics or plastic laminates may be accepted by 7.1 Forecastle
waterproofing and resistance to high and low temperatures, 7.1.1 General (1/1/2004)
are equivalent to those of tarpaulins made of vegetable Ships with service notation ore carrier ESP are to be fitted
fibres. with an enclosed forecastle on the freeboard deck.
The required dimensions of the forecastle are defined in
6.7.5 Cleats (1/7/2012) [7.1.2].
a) The arrangements for securing the tarpaulins to hatch The structural arrangements and scantlings of the forecastle
coamings are to incorporate cleats of a suitable pattern are to comply with the requirements in Pt B, Ch 10, Sec 2.

Part E
Service Notations
Chapter 6
COMBINATION CARRIERS
SECTION 1 GENERAL

SECTION 4 MACHINERY AND CARGO SYSTEMS

Pt E, Ch 6, Sec 3
Symbols
Ry : Minimum yield stress, in N/mm2, of the mate- corrections are to be based on the appropriate upright
rial, to be taken equal to 235/k N/mm2, unless free surface inertia moment.
otherwise specified c) The vessel is to be loaded with:
k : Material factor for steel, defined in Pt B, Ch 4, • all cargo tanks filled to a level corresponding to the
Sec 1, [2.3]
maximum combined total of vertical moment of vol-
E : Young’s modulus, in N/mm2, to be taken equal ume plus free surface inertia moment at 0° heel, for
to: each individual tank
• E = 2,06.105 N/mm2, for steels in general • cargo density corresponding to the available cargo
5 2
• E = 1,95.10 N/mm , for stainless steels. deadweight at the displacement at which transverse
KM reaches a minimum value
1 General • full departure consumable
• 1% of the total water ballast capacity. The maximum
1.1 Loading manual and loading instrument free surface moment is to be assumed in all ballast
tanks.
1.1.1 The specific requirements in Pt B, Ch 11, Sec 2 for
ships with either of the service notations combination car- 2.1.3 Alternative requirements for liquid transfer
rier/OBO ESP or combination carrier/OOC ESP and equal operation
to or greater than 150 m in length are to be complied with. As an alternative to the requirements in [2.1.2], simple sup-
plementary operational procedures are to be followed when
the ship is carrying oil cargoes or during liquid transfer
2 Stability
operations.
Simple supplementary operational procedures for liquid
2.1 Intact stability
transfer operations means written procedures made availa-
2.1.1 General ble to the Master which:
The stability of the ship for the loading conditions in Pt B, • are approved by the Society,
Ch 3, App 2, [1.2.5] is to be in compliance with the • indicate those cargo and ballast tanks which may, under
requirements in Pt B, Ch 3, Sec 2. Where the ship is any specific condition of liquid transfer and possible
intended also for the carriage of grain, the requirements in range of cargo densities, be slack and still allow the sta-
Ch 4, Sec 3, [2.2.2] and Ch 4, Sec 3, [2.2.3] are to be com- bility criteria to be met. The slack tanks may vary during
plied with. the liquid transfer operations and be of any combination
In addition, for the carriage of liquids, the requirements in provided they satisfy the criteria.
[2.1.3] are to be complied with. • are to be readily understandable to the officer-in-charge
of liquid transfer operations,
2.1.2 Liquid transfer operations
• provide for planned sequences of cargo/ballast transfer
Ships with certain internal subdivision may be subjected to
operations,
lolling during liquid transfer operations such as loading,
unloading or ballasting. In order to prevent the effect of loll- • allow comparisons of attained and required stability
ing, the design of oil tankers of 5000 t deadweight and using stability performance criteria in graphical or tabu-
above is to be such that the following criteria are complied lar form,
with: • require no extensive mathematical calculations by the
a) The intact stability criteria reported in b) are to be com- officer-in-charge,
plied with for the worst possible condition of loading • provide for corrective actions to be taken by the officer-
and ballasting as defined in c), consistent with good in-charge in the event of departure from the recom-
operational practice, including the intermediate stages mended values and in case of emergency situations,
of liquid transfer operations. Under all conditions the and,
ballast tanks are to be assumed slack.
• are prominently displayed in the approved trim and sta-
b) The initial metacentric height GMo, in m, corrected for bility booklet and at the cargo/ballast transfer control
free surface measured at 0° heel, is to be not less than station and in any computer software by which stability
0,15. For the purpose of calculating GMo, liquid surface calculations are performed.

Pt E, Ch 6, Sec 3
The forecastle height HF above the main deck is to be not w : Net section modulus, in cm3, of the ordinary
less than the greater of: stiffener or primary supporting member, with an
• the standard height of a superstructure, as specified in attached plating of width bp
Pt B, Ch 1, Sec 2, Tab 2, or ASh : Net shear sectional area, in cm2, of the ordinary
• HC + 0,5 m, where HC is the height of the forward trans- stiffener or primary supporting member, to be
calculated as specified in Pt B, Ch 4, Sec 3,
verse hatch coaming of cargo hold No.1.
All points of the aft edge of the forecastle deck are to be Sec 3, [4.3], for primary supporting members
located at a distance lF, in compliance with the following m : Boundary coefficient for ordinary stiffeners and
formula, from the hatch coaming plate in order to apply the primary supporting members, taken equal to:
reduced loading to the No.1 forward transverse hatch • m = 8 in the case of ordinary stiffeners and
coaming and No.1 hatch cover in applying [9.6.2] and primary supporting members simply sup-
[9.7.3], respectively: ported at both ends or supported at one end
and clamped at the other
lF  5 H F – H C
A breakwater may not be fitted on the forecastle deck with primary supporting members clamped at
the purpose of protecting the hatch coaming or hatch cov- both ends
ers. If fitted for other purposes, it is to be located such that tC : Corrosion additions, in mm, defined in [9.1.5]
its upper edge at centreline is not less than HB / tan20° for-
ReH : Minimum yield stress, in N/mm2, of the mate-
ward of the aft edge of the forecastle deck, where HB is the
rial, defined in Pt B, Ch 4, Sec 1, [2]
height of the breakwater above the forecastle (see Fig 10).
of the material, defined in Pt B, Ch 4, Sec 1, [2]
8 Machinery space
Ry : Yield stress, in N/mm2, of the material, to be
taken equal to 235/k N/mm2, unless otherwise
8.1 Extension of hull structures within the specified
machinery space k : Material factor, defined in Pt B, Ch 4, Sec 1,
[2.3]
8.1.1 Longitudinal bulkheads or inner side, as applicable,
carried through cofferdams are to continue within the cS : Coefficient, taken equal to:
machinery space and are to be used preferably as longitudi- • cS = 1-(s/2) for ordinary stiffeners
nal bulkheads for liquid cargo tanks. In any case, such • cS = 1 for primary supporting members
extension is to be compatible with the shape of the struc- g : Gravity acceleration, in m/s2:
tures of the double bottom, deck and platforms of the
machinery space. g = 9,81 m/s2.
Where topside tanks are fitted, their structures are to extend 9.1.3 Materials (1/7/2012)
as far as possible within the machinery space and to be ade- a) Steel
quately tapered.
The formulae for scantlings given in the requirements in
[9.5] are applicable to steel hatch covers.
9 Hatch covers, hatch coamings and Materials used for the construction of steel hatch covers
closing devices are to comply with the applicable requirements of
Part D, Chapter 2.
9.1 Application b) Other materials
9.1.1 (1/7/2024) The use of materials other than steel is considered by
Refer to Tthe requirements for Type 2 ships of this Article teria adopted for scantlings are such as to ensure
[9] apply to steel hatch covers in positions 1 and 2 on strength and stiffness equivalent to those of steel hatch
weather decks, defined in Pt B, Ch 19, Sec 27, [3.16]. covers.
9.1.2 Symbols used in Article [9] (1/7/2012) 9.1.4 Net scantlings (1/7/2012)
pS : Still water pressure, in kN/m2 (see [6.4]) As specified in Pt B, Ch 4, Sec 2, [1], all scantlings referred
pW : Wave pressure, in kN/m2 (see [6.4]) to in this Section are net, i.e. they do not include any mar-
gin for corrosion.
s : Length, in m, of the shorter side of the plate
panel The gross scantlings are obtained as specified in Pt B, Ch 4,
Sec 2.
 : Length, in m, of the longer side of the plate
panel 9.1.5 Partial safety factors (1/7/2012)
bP : Width, in m, of the plating attached to the ordi- The partial safety factors to be considered for checking
nary stiffener or primary supporting member, hatch cover structures are specified in Tab 2.
defined in [3]
180 RINA Rules 2024

Pt E, Ch 6, Sec 3
Table 2 : Hatch covers - Partial safety recesses in the deck are considered by the Society on a
factors (1/7/2012) case by case basis.
c) Regardless of the type of closing arrangement adopted,
Partial safety factors
the coamings may have reduced height or be omitted in
Partial safety factors Ordinary way of openings in closed superstructures or decks
covering uncertainties stiffeners below the freeboard deck.
regarding: Symbol Plating and primary
supporting 9.2.2 Hatch covers (1/7/2012)
members
a) Hatch covers on exposed decks are to be weathertight.
Still water pressure S2 1,00 1,00
Hatch covers in closed superstructures need not be
Wave pressure W2 1,20 1,20
weathertight.
Material m 1,02 1,02
However, hatch covers fitted in way of ballast tanks, fuel
Resistance R 1,22 1,22 oil tanks or other tanks are to be watertight.
b) The ordinary stiffeners and primary supporting members
9.1.6 Corrosion additions (1/7/2012)
of the hatch covers are to be continuous over the
a) Corrosion additions for hatch covers breadth and length of the hatch covers, as far as practi-
The corrosion addition to be considered for the plating cal. When this is impractical, sniped end connections
and internal members of hatch covers is the value speci- are not to be used and appropriate arrangements are to
fied in Tab 3 for the total thickness of the member under be adopted to ensure sufficient load carrying capacity.
consideration. c) The spacing of primary supporting members parallel to
b) Corrosion additions for hatch coamings the direction of ordinary stiffeners is to be not greater
than 1/3 of the span of primary supporting members.
The corrosion addition to be considered for the hatch
coaming structures and coaming stays is equal to 1,5 d) The breadth of the primary supporting member flange is
mm. to be not less than 40% of its depth for laterally unsup-
ported spans greater than 3,0 m. Tripping brackets
c) Corrosion additions for stainless steel attached to the flange may be considered as a lateral
For structural members made of stainless steel, the cor- support for primary supporting members.
rosion addition tc is to be taken equal to 0. e) The covers used in 'tweendecks are to be fitted with an
d) Corrosion additions for aluminium alloys appropriate system ensuring an efficient stowing when
the ship is sailing with open 'tweendecks.
For structural members made of aluminium alloys, the
corrosion addition tc is to be taken equal to 0. f) The ends of hatch covers are normally to be protected
by efficiently secured galvanised steel strips.
Table 3 : Corrosion additions tc for steel hatch g) Efficient retaining arrangements are to be provided to
covers (1/7/2012) prevent translation of the hatch cover under the action
of the longitudinal and transverse forces exerted by the
stacks of containers on the cover. These retaining
Corrosion addition tc , in mm
arrangements are to be located in way of the hatch
Plating and stiffeners of single skin hatch cover 2,0 coaming side brackets.
Top and bottom plating of double skin hatch 2,0 Solid fittings are to be welded on the hatch cover where
cover the corners of the containers are resting. These parts are
intended to transmit the loads of the container stacks
Internal structures of double skin hatch cover 1,5 onto the hatch cover on which they are resting and also
to prevent horizontal translation of the stacks by means
9.2 Arrangements of special intermediate parts arranged between the sup-
ports of the corners and the container corners.
9.2.1 Height of hatch coamings (1/7/2012) Longitudinal stiffeners are to stiffen the hatch cover
a) The height above the deck of hatch coamings closed by plate in way of these supports and connect at least the
portable covers is to be not less than: nearest three transverse stiffeners.
• 600 mm in position 1 h) The width of each bearing surface for hatch covers is to
• 450 mm in position 2. be at least 65 mm.
b) The height of hatch coamings in positions 1 and 2 9.2.3 Hatch coamings (1/7/2012)
closed by steel covers provided with gaskets and secur- a) Coamings, stiffeners and brackets are to be capable of
ing devices may be reduced with respect to the above withstanding the local forces in way of the clamping
values or the coamings may be omitted entirely. devices and handling facilities necessary for securing
In such cases the scantlings of the covers, their gasket- and moving the hatch covers as well as those due to
ing, their securing arrangements and the drainage of cargo stowed on the latter.
RINA Rules 2024 181

Pt E, Ch 6, Sec 3
b) Special attention is to be paid to the strength of the fore 9.3.2 Primary supporting members parallel to
transverse coaming of the forward hatch and to the ordinary stiffeners (1/7/2012)
scantlings of the closing devices of the hatch cover on The width of the attached plating to be considered for the
this coaming. yielding and buckling checks of primary supporting mem-
c) Longitudinal coamings are to be extended at least to the bers analysed through beam or grillage models is to be
lower edge of deck beams. obtained, in m, from the following formulae:
Where they are not part of continuous deck girders, lon- • where the plating extends on both sides of the primary
gitudinal coamings are to extend for at least two frame supporting member:
spaces beyond the end of the openings. bp = bp,1 + bp,2
Where longitudinal coamings are part of deck girders, • where the plating extends on one side of the primary
their scantlings are to be as required in Pt B, Ch 7, supporting member:
Sec 3. bp = bp,1
d) Transverse coamings are to extend below the deck at
where:
least to the lower edge of longitudinals.
bp,1 = min (0,165 lP, Sp,1)
Transverse coamings not in line with ordinary deck
beams below are to extend below the deck at least three bp,2 = min (0,165 lP, Sp,2)
longitudinal frame spaces beyond the side coamings. lP : span, in m, of the primary supporting member
considered
9.2.4 Small hatchways (1/7/2012)
Sp,1, Sp,2 : half distance, in m, between the primary sup-
a) The height of small hatchway coamings is to be not less
porting member considered and those adjacent,
than 600 mm if located in position 1, and 450 mm if
on the two sides.
located in position 2.
Where the closing appliances are in the form of hinged 9.4 Load model
steel covers secured weathertight by gaskets and swing
bolts, the height of the coamings may be reduced or the 9.4.1 Lateral pressures and concentrated
coamings may be omitted altogether. loads (1/7/2012)
b) Small hatch covers are to have strength equivalent to a) General
that required for main hatchways and are to be of steel, The still water and wave lateral pressures and concen-
weathertight and generally hinged. trated loads, to be considered as acting on hatch covers,
Securing arrangements and stiffening of hatch cover are those in b) to g).
edges are to be such that weathertightness can be main- Each case in g) to f) is not necessarily exhaustive for
tained in any sea condition. any specific hatch cover; however, depending on the
At least one securing device is to be fitted at each side. location of each cover and its intended use, the pres-
Circular hole hinges are considered equivalent to secur- sures and loads to be considered as acting on it are to
ing devices. be calculated for one or more of these cases. For exam-
c) Hold accesses located on the weather deck are to be ple, for a hatch cover located on an exposed deck and
provided with watertight metallic hatch covers, unless covering a ballast tank, the pressures in b) and c) are to
they are protected by a closed superstructure. The same be separately considered. If the same hatch cover is also
applies to accesses located on the forecastle deck and intended to carry uniform cargoes, the pressures in d)
leading directly to a dry cargo hold through a trunk. are to be individually considered, in addition to the two
above.
d) Accesses to cofferdams and ballast tanks are to be man-
holes fitted with watertight covers fixed with bolts which b) Hatch covers on exposed decks
are sufficiently closely spaced. The still water lateral pressure and loads are to be con-
sidered when the hatch cover is intended to carry uni-
e) Hatchways of special design are considered by the Soci-
form cargoes, wheeled cargoes or containers. In these
ety on a case by case basis.
cases, the still water lateral pressures and loads are to be
calculated according to d) and e), as applicable.
The wave lateral pressure is to be considered and is
9.3.1 Ordinary stiffeners (1/7/2012) defined in [9.4.2].
The width of the attached plating to be considered for the c) Hatch covers in way of liquid cargo or ballast tanks
check of ordinary stiffeners is to be obtained, in m, from the The still water and wave lateral pressures are to be con-
following formulae: sidered and are defined in Pt B, Ch 5, Sec 6, [1].
• where the attached plating extends on both sides of the d) Hatch covers carrying uniform cargoes
stiffener: The still water and wave lateral pressures are to be con-
bP = s sidered and are defined in Pt B, Ch 5, Sec 6, [4].
• where the attached plating extends on one side of the e) Hatch covers carrying containers
stiffener: The still water and wave loads are to be considered and
bP = 0,5 s are defined in Pt B, Ch 5, Sec 6, [5].
182 RINA Rules 2024

Pt E, Ch 6, Sec 3
f) Hatch covers carrying wheeled cargoes c) Hatch covers subjected to concentrated loads
The still water and wave loads are to be considered and For hatch covers supporting concentrated loads, ordi-
are defined in Pt B, Ch 5, Sec 6, [6]. nary stiffeners and primary supporting members are
g) Hatch covers carrying special cargoes generally to be checked by direct calculations, taking
into account the stiffener arrangements and their rela-
In the case of carriage on the hatch covers of special tive inertia. It is to be checked that stresses induced by
cargoes (e.g. pipes, etc.) which may temporarily retain concentrated loads are in accordance with the criteria
water during navigation, the lateral pressure to be in [9.5.3] d).
applied is considered by the Society on a case by case
basis. d) Covers of small hatchways
The thickness of covers is to be not less than 8 mm. This
9.4.2 Wave pressure for hatch covers on exposed thickness is to be increased or an efficient stiffening fit-
decks (1/7/2012) ted to the Society's satisfaction where the greatest hori-
The wave pressure pW is defined in Tab 4 according to the zontal dimension of the cover exceeds 0,6 m.
hatch cover position.
9.5.2 Plating (1/7/2012)
Where two or more panels are connected by hinges, each
individual panel is to be considered separately. a) Net thickness
The net thickness of steel hatch cover top plating is to be
9.4.3 Load point (1/7/2012) not less than the value obtained, in mm, from the fol-
a) Wave lateral pressure for hatch covers on exposed lowing formula:
decks: pS + pW
t = F p 15 ,8 s ---------------------
-
The wave lateral pressure to be considered as acting on 0 95R eH
each hatch cover is to be calculated at a point located:
where:
• longitudinally, at the hatch cover mid-length
• transversely, on the longitudinal plane of symmetry response, equal to:
of the ship
• FP = 2,375 s/ReH for s/ReH > 0,64, for the
b) Lateral pressure other than the wave pressure: attached plating of primary supporting
The lateral pressure is to be calculated: members.
• in way of the geometrical centre of gravity of the pS : still water pressure, in kN/m2, to be calcu-
plate panel, for plating lated according to [9.4.1].
• at mid-span, for ordinary stiffeners and primary sup- pW : wave pressure, in kN/m2, defined in [9.4.2].
porting members. s : normal stress, in N/mm2, in the attached
plating of primary supporting members, cal-
9.5 Strength check culated according to [9.5.3] c) 1) or deter-
mined through a grillage analysis or a Finite
9.5.1 General and application (1/7/2012) Element analysis, as the case may be.
a) Application b) Minimum net thickness
The strength check is applicable to rectangular hatch In addition to the requirements in a) above, the net
covers subjected to a uniform pressure, designed with thickness, in mm, of hatch cover plating is to be not less
primary supporting members arranged in one direction than 1% of s or 6 mm, whichever is the greater.
or as a grillage of longitudinal and transverse primary
c) Critical buckling stress check
supporting members.
The compressive stress s in the hatch cover plating,
b) Hatch covers supporting wheeled loads following formula:
The scantlings of hatch covers supporting wheeled loads  Cp
---------- 
are to be obtained in accordance with: R m
• the applicable requirements of Pt B, Ch 7, Sec 1 for where sCp is critical buckling stress, defined in Pt B,
RINA Rules 2024 183

Pt E, Ch 6, Sec 3
9.5.3 Ordinary stiffeners and primary supporting d) Checking criteria

members (1/7/2012) 1) Strength check
a) General The normal stress s and the shear stress t, calculated
The flange outstand of the primary supporting members according to c) or determined through a grillage
is to be not greater than 15 times the flange thickness. analysis or Finite Element analysis, as the case may
The net dimensions of the flat bar ordinary stiffeners and be, are to comply with the following formulae:
buckling stiffeners are to comply with the following R eH
requirement: ---------- 
R m
hW
-------  15 k R eH
tW 0 57 ---------- 
m R
where hw and tw are the height and thickness, in mm, of
2) Critical buckling stress check of the ordinary stiffen-
the ordinary stiffener, respectively.
ers
b) Application
The compressive stress s in the top flange of ordinary
The requirements in c) to g) apply to: stiffeners, induced by the bending of primary sup-
• ordinary stiffeners porting members, parallel to the direction of ordi-
• primary supporting members which may be ana- nary stiffeners, calculated according to c) or
lysed through isolated beam models. determined through a grillage analysis or a Finite
Primary supporting members whose arrangement is of a Element analysis, as the case may be, is to comply
grillage type and which cannot be analysed through iso- with the following formula:
lated beam models are to be checked by direct calcula-  Cs
---------- 
tions, using the checking criteria in d). m R
c) Normal and shear stress where:
1) Where the grillage analysis or Finite Element analy- sCS =sES for sES £ ReH/2
sis is not carried out according to the requirements sCS =sES [1 - ReH / (4 sES)] for sES £ ReH/2
in [9.5.1] a), the maximum normal stress s and shear
sES =min (sE1, sE2)
stress t in the ordinary stiffeners are to be obtained,
in N/mm2, from the following formulae: sE1 and sE2 are defined in Pt B, Ch 7, Sec 2, [4.3.1].
In calculating sE2, C0 is to be taken equal to:
s  p S + p W l S 10
2 3
 = -----------------------------------------
- 3
12w k p Et p
- 10 –3
C 0 = -----------------------------------------------------

3
1 33k k t
5s  p S + p W l S
 = ---------------------------------
- 3s  1 + -------------------------------
p W p
-
A sh  1000st W 
3
where: where:
primary supporting member and the kp = 1 - hp to be taken not less than zero; for flanged
edge support, as applicable. When ordinary stiffeners, kp need not be taken less than
brackets are fitted at both ends of all 0,1

stiffener span may be reduced by an  p = -------
 Ep
amount equal to 2/3 of the minimum
bracket arm length, but not greater than s is calculated according to c) or determined
pW : wave pressure, as defined in [9.4.2]. tp  2
 Ep = 3 6E  ---------------
-
3) Critical buckling stress check of the web panels of
in [9.5.1] a), the maximum normal stress s and shear
the primary supporting members
stress t in the primary supporting members are to be
s  p S + p W l m 10
2 3
 = ------------------------------------------
 = ----------------------------------
-
A sh C
---------- 
and lm is the span of the primary supporting mem- where tC is critical shear buckling stress, defined in
ber. Pt B, Ch 7, Sec 1, [5.3.2].
184 RINA Rules 2024

Pt E, Ch 6, Sec 3
For primary supporting members parallel to the g) Ordinary stiffeners and primary supporting members of
direction of ordinary stiffeners, tC is to be calculated variable cross-section
considering the actual dimensions of the panels The section modulus of ordinary stiffeners and primary
taken for the determination of the stress tC. supporting members with a variable cross-section is to
For primary supporting members perpendicular to be not less than the greater of the values obtained, in
the direction of ordinary stiffeners or for hatch cov- cm3, from the following formulae:
square panel of dimension d is to be taken for the w = w CS
3 ,2 –  – 0 ,8
w =  1 + ------------------------------------- w CS
age shear stress t of the values calculated at the ends  7 + 0 ,4 
of this panel is to be considered.
where:
4) Deflection limit
wCS : Section modulus, in cm3, for a constant
The vertical deflection of primary supporting mem-
cross-section, obtained according to [9.5.2]
bers is to be not more than 0,0056 lmax, where lmax is
e).
the greatest span of primary supporting members.

e) Net section modulus and net shear sectional area  = ----1
0
w
modulus and net shear sectional area of an ordinary  = ------1
stiffener or a primary supporting member subjected to w0
lateral pressure, complying with the checking criteria 1 : Length of the variable section part, in m,
indicated in d). (see Fig 11)
sectional area ASh, in cm2, of an ordinary stiffener sub-
(see Fig 11)
jected to lateral pressure are to be not less than the val-
ues obtained from the following formulae: w1 : Section modulus at end, in cm3 (see Fig 11)
s  p S + p W l S 10
2 3 w0 : Section modulus at mid-span, in cm3 (see
w =  m  R -----------------------------------------
- Fig 11).
12R eH
5s  p S + p W l S The use of this formula is limited to the determination of
A Sh =  m  R ---------------------------------
-
0 57R eH the strength of ordinary stiffeners and primary support-
ing members in which abrupt changes in the cross-sec-
tion do not occur along their length.
sectional area Ash, in cm2, of a primary supporting mem-
Figure 11 : Variable cross-section
values obtained from the following formulae:
stiffener (1/7/2012)
s  p S + p W l m 10
2 3
w =  m  R ------------------------------------------
-
mR eH
5s  p S + p W l m
A Sh =  m  R ----------------------------------
-
0 57R eH
f) Minimum net thickness of web
The net thickness of the ordinary stiffeners and primary
supporting members, in mm, is to be not less than the
minimum values given in [9.5.2] b).
RINA Rules 2024 185

Pt E, Ch 6, Sec 3

L LL  100 m 0  x  0 75 L LL 14 9 + 0 195L LL 11 3 + 0 142L LL
L LL 
- 1 – --- ------- – 3 6 -------
5 x x
0 75L LL  x  L LL 15 8 + ------
3  3 L LL L LL
L LL  100 m 0  x  0 75L LL 34,3 25,5
p FP – 34 3  x
34 3 + -------------------------- ------- – 0 75
0 75L LL  x  L LL 0 25  L LL 
(1)
Note 1:
9.6 Hatch coamings b) The wave lateral pressure pWC, in kN/m2, on the No. 1
9.6.1 Stiffening (1/7/2012) to:
a) The ordinary stiffeners of the hatch coamings are to be pWC = 220 kN/m2, when a forecastle is fitted in accord-
continuous over the breadth and length of the hatch ance with Ch 4, Sec 3, [12.1], Ch 5, Sec 3, [8.1] or
coamings. [11.1] applicable to ships with service notations bulk
b) Coamings are to be stiffened on their upper edges with a carrier ESP, ore carrier ESP or combination carrier ESP,
stiffener suitably shaped to fit the hatch cover closing respectively.
appliances. pWC = 290 kN/m2, in other cases.
Moreover, when covers are fitted with tarpaulins, an
c) The wave lateral pressure pWC, in kN/m2, on the hatch
ings of more than 3 m in length or 600 mm in height; coamings other than the No. 1 forward transverse hatch
this stiffener is to be fitted at approximately 250 mm coaming is to be taken equal to:
below the upper edge. The width of the horizontal pWC = 220 kN/m2.
flange of the angle is not to be less than 180 mm.
9.6.3 Scantlings (1/7/2012)
c) Where hatch covers are fitted with tarpaulins, coamings
are to be strengthened by brackets or stays with a spac- a) Plating
ing not greater than 3 m. In ships intended for the carriage of liquid cargoes, the
Where the height of the coaming exceeds 900 mm, plate thickness of coamings is also to be checked under
additional strengthening may be required. liquid internal pressures.
However, reductions may be granted for transverse 1) Net thickness
coamings in protected areas. The net thickness of the hatch comaing plate is to be
d) When two hatches are close to each other, underdeck not less than the value obtained, in mm, from the
stiffeners are to be fitted to connect the longitudinal following formula:
coamings with a view to maintaining the continuity of p WC
their strength. t = 16 4s --------
-
R eH
Similar stiffening is to be provided over 2 frame spacings
at ends of hatches exceeding 9 frame spacings in length. 2) Minimum net thickness
In some cases, the Society may require the continuity of In addition to the requirements in a), the net thick-
coamings to be maintained above the deck. ness of the hatch coaming plate is to be not less than
9,5 mm.
e) Where watertight metallic hatch covers are fitted, other
arrangements of equivalent strength may be adopted. b) Ordinary stiffeners
The net section modulus w of the longitudinal or trans-
9.6.2 Load model (1/7/2012) verse ordinary stiffeners of hatch coamings is to be not
a) The wave lateral pressure to be considered as acting on less than the value obtained, in cm3, from the following
the hatch coamings is that specified in b) and c). formula:
186 RINA Rules 2024

Pt E, Ch 6, Sec 3
1 2sp WC l 10
2 3 weld throat thickness is to be not less than 0,44 tW,
w = -----------------------------------
-
where tW is the gross thickness of the stay web.
mc p R eH
where: Toes of stay webs are to be connected to the deck plat-

ing with full penetration double bevel welds extending
m = 16 in general over a distance not less than 15% of the stay width.
m = 12 for the end span of stiffeners sniped at the coam- e) Coamings of small hatchways
ing corners
cp = ratio of the plastic section modulus to the elastic lesser of the following values:
attached plate breadth, in mm, equal to 40 t, where t is 1) the thickness for the deck inside line of openings
the plate net thickness calculated for that position, assuming as spacing of
cp = 1,16 in the absence of more precise evaluation. coaming and the distance between its stiffeners, if
c) Coaming stays any, or
The net section modulus w, in cm3, and the thickness tw, 2) 10 mm.
in mm, of the coaming stays are to be not less than the Coamings are to be suitably strengthened where their
values obtained from the following formulae: height exceeds 0,80 m or their greatest horizontal
dimension exceeds 1,20 m, unless their shape ensures
1 05H C s c p WC 10
2 3
w = ----------------------------------------------
- an adequate rigidity.
2R eH
9.7 Weathertightness, closing arrangement

3
H C s c p WC 10
t w = ------------------------------
-
0 5hR eH and securing devices
where:
9.7.1 Weathertightness (1/7/2012)
HC = stay height, in m
a) Where the hatchway is exposed and closed with a sin-
sc = stay spacing, in m gle panel, the weathertightness is to be ensured by gas-
h = stay depth, in mm, at the connection with deck kets and clamping devices sufficient in number and
quality.
For calculating the section modulus of coaming stays,
their face plate area is to be taken into account only Weathertightness may also be ensured means of tarpau-
when it is welded with full penetration welds to the lins.
deck plating and adequate underdeck structure is fitted b) The mean spacing of swing bolts or equivalent devices
to support the stresses transmitted by it. is, in general, to be not greater than:
d) Local details • 2,0 m for dry cargo holds
The design of local details is to comply with the require- • 1,5 m for ballast compartments
ments in this Section for the purpose of transferring the • 1,0 m for liquid cargo holds.
and, through them, to the deck structures below. Hatch 9.7.2 Gaskets (1/7/2012)
coamings and supporting structures are to be ade-
a) The weight of hatch covers and any cargo stowed
quately stiffened to accommodate the loading from
thereon, together with inertia forces generated by ship
hatch covers in longitudinal, transverse and vertical
motions, are to be transmitted to the ship’s structure
directions.
through steel to steel contact.
The normal stress s and the shear stress t, in N/mm2,
This may be achieved by continuous steel to steel con-
induced in the underdeck structures by the loads trans-
tact of the hatch cover skirt plate with the ship’s struc-
mitted by stays are to comply with the following formu-
ture or by means of defined bearing pads.
lae:
b) The sealing is to be obtained by a continuous gasket of
   ALL relatively soft elastic material compressed to achieve the
   ALL necessary weathertightness. Similar sealing is to be
sALL : allowable normal stress, in N/mm2, equal to 0,95
ReH
well rounded where in contact with the gasket and to be
tALL : allowable shear stress, in N/mm2, equal to 0,5 ReH made of a corrosion-resistant material.
Unless otherwise stated, weld connections and materi- c) The gasket and the securing arrangements are to main-
als are to be dimensioned and selected in accordance tain their efficiency when subjected to large relative
with the requirements in Pt B, Ch 12, Sec 1 and Part D, movements between the hatch cover and the ship’s
respectively. structure or between hatch cover elements.
Double continuous fillet welding is to be adopted for If necessary, suitable devices are to be fitted to limit
the connections of stay webs with deck plating and the such movements.
RINA Rules 2024 187

Pt E, Ch 6, Sec 3
d) The gasket material is to be of a quality suitable for all At cross-joints of multipanel covers, (male/female) verti-
environmental conditions likely to be encountered by cal guides are to be fitted to prevent excessive relative
the ship, and is to be compatible with the cargoes trans- vertical deflections between loaded/unloaded panels.
ported. The location of stoppers is to be compatible with the rel-
The material and form of gasket selected are to be con- ative movements between hatch covers and the ship’s
sidered in conjunction with the type of hatch cover, the structure in order to prevent damage to them. The num-
securing arrangement and the expected relative move- ber of stoppers is to be as small as possible.
ment between the hatch cover and the ship’s structure. c) Spacing
The gasket is to be effectively secured to the hatch The spacing of the securing arrangements is to be gener-
cover. ally not greater than 6 m.
e) Coamings and steel parts of hatch covers in contact with The spacing of securing arrangements of tank hatch cov-
gaskets are to have no sharp edges. ers in ‘tweendecks is to be not greater than 600 mm.
d) Construction
f) Metallic contact is required for an earthing connection
between the hatch cover and the hull structures. If nec- Securing arrangements with reduced scantlings may be
essary, this is to be achieved by means of a special con- accepted provided it can be demonstrated that the pos-
nection for the purpose. sibility of water reaching the deck is negligible.
Securing devices are to be of reliable construction and
9.7.3 Closing arrangement, securing devices and securely attached to the hatchway coamings, decks or
stoppers (1/7/2012) hatch covers.
a) General Individual securing devices on each hatch cover are to
have approximately the same stiffness characteristics.
Panel hatch covers are to be secured by appropriate
devices (bolts, wedges or similar) suitably spaced along- e) Area of securing devices
side the coamings and between cover elements. The net cross area of each securing device is to be not
The securing and stop arrangements are to be fitted less than the value obtained, in cm2, from the following
using appropriate means which cannot be easily formula:
f
removed.
A = 1 ,4S S  ----------
235
 R eH 
Towards the ends of the ship, vertical acceleration • 0,75 for ReH > 235 N/mm2,
• 1,00 for ReH  235 N/mm2.
forces are to be considered when dimensioning the
also to be taken into account. Between hatch cover and coaming and at cross-joints, a
A is to be increased in direct proportion. The packing
Hatch covers provided with special sealing devices, line pressure is to be specified.
insulated hatch covers, flush hatch covers and those
In the case of securing arrangements which are particu-
having coamings of a reduced height (see [9.2.1]) are
larly stressed due to the unusual width of the hatchway,
considered by the Society on a case by case basis.
the net cross area A of the above securing arrangements
In the case of hatch covers carrying containers, the is to be determined through direct calculations.
scantlings of the closing devices are to take into account
f) Inertia of edges elements
the possible upward vertical forces transmitted by the
tain adequate sealing pressure between securing
b) Arrangements devices.
The securing and stopping devices are to be arranged so The moment of inertia of edge elements is to be not less
as to ensure sufficient compression on gaskets between than the value obtained, in cm4, from the following for-
hatch covers and coamings and between adjacent hatch mula:
covers. 4
I = 6p L S S
Arrangement and spacing are to be determined with
where:
due attention to the effectiveness for weathertightness,
depending on the type and the size of the hatch cover, pL : Packing line pressure, in N/mm, to be taken
as well as on the stiffness of the hatch cover edges not less than 5 N/mm
between the securing devices. SS : Spacing, in m, of securing devices.
188 RINA Rules 2024

Pt E, Ch 6, Sec 3
g) Diameter of rods or bolts locked in the closed position in the event of failure of
Rods or bolts are to have a net diameter not less than 19 the hydraulic system.
mm for hatchways exceeding 5 m2 in area.
9.7.6 Wedges, battens and locking bars (1/7/2012)
h) Stoppers
Hatch covers are to be effectively secured, by means of a) Wedges
stoppers, against the transverse forces arising from a Wedges are to be of tough wood, generally not more
pressure of 175 kN/m2. than 200 mm in length and 50 mm in width.
With the exclusion of No. 1 hatch cover, hatch covers They are generally to be tapered not more than 1 in 6
are to be effectively secured, by means of stoppers, and their thickness is to be not less than 13 mm.
against the longitudinal forces acting on the forward end
b) Battens and locking bars
arising from a pressure of 175 kN/m2.
No. 1 hatch cover is to be effectively secured, by means For all hatchways in exposed positions, battens or trans-
of stoppers, against the longitudinal forces acting on the verse bars in steel or other equivalent means are to be
forward end arising from a pressure of 230 kN/m2. This provided in order to efficiently secure the portable cov-
pressure may be reduced to 175 kN/m2 if a forecastle is ers after the tarpaulins are battened down.
fitted in accordance with Ch 4, Sec 3, [12.1], Ch 5, Portable covers of more than 1,5 m in length are to be
Sec 3, [8.1] or [11.1] applicable to ships with service secured by at least two such securing appliances.
notations bulk carrier ESP, ore carrier ESP or combina-
tion carrier ESP, respectively.
9.8 Drainage
tures and in the throat of the stopper welds is to be 9.8.1 Arrangement (1/7/2012)
ReH. a) Drainage is to be arranged inside the line of gaskets by
means of a gutter bar or vertical extension of the hatch
9.7.4 Tarpaulins (1/7/2012) side and end coaming.
Where weathertightness of hatch covers is ensured by b) Drain openings are to be arranged at the ends of drain
means of tarpaulins, at least two layers of tarpaulins are to channels and are to be provided with efficient means for
be fitted. preventing ingress of water from outside, such as non-
Tarpaulins are to be free from jute and waterproof and are return valves or equivalent.
to have adequate characteristics of strength and resistance
c) Cross-joints of multipanel hatch covers are to be
to atmospheric agents and high and low temperatures.
arranged with drainage of water from the space above
The mass per unit surface of tarpaulins made of vegetable the gasket and a drainage channel below the gasket.
fibres, before the waterproofing treatment, is to be not less
than: d) If a continuous outer steel contact is arranged between
2
the cover and the ship’s structure, drainage from the
• 0,65 kg/m for waterproofing by tarring space between the steel contact and the gasket is also to
• 0,60 kg/m2 for waterproofing by chemical dressing be provided.
• 0,55 kg/m2 for waterproofing by dressing with black oil.
In addition to tarpaulins made of vegetable fibres, those of 10 Opening arrangement
synthetic fabrics or plastic laminates may be accepted by
10.1 Tanks covers
waterproofing and resistance to high and low temperatures,
are equivalent to those of tarpaulins made of vegetable
10.1.1 Covers fitted on all cargo tank openings are to be of
fibres.
sturdy construction, and to ensure tightness for hydrocarbon
9.7.5 Cleats (1/7/2012) and water.
a) The arrangements for securing the tarpaulins to hatch Aluminium is not permitted for the construction of tank
coamings are to incorporate cleats of a suitable pattern covers. The use of reinforced fibreglass covers is to be spe-
giving support to battens and wedges and with edges cially examined by the Society.
b) Cleats are to be spaced not more than 600 mm from 11 Hull outfitting
centre to centre and are to be not more than 150 mm
from the hatch corners.
11.1 Equipment
c) The thickness of cleats is to be not less than 9,5 mm for
angle cleats and 11 mm for forged cleats. 11.1.1 Emergency towing arrangement
d) Where rod cleats are fitted, resilient washers or cushions The specific requirements in Pt B, Ch 10, Sec 4, [4] for ships
are to be incorporated. with either of the service notations combination car-
e) Where hydraulic cleating is adopted, a positive means is rier/OBO ESP or combination carrier/OOC ESP and of
to be provided to ensure that it remains mechanically 20000 t deadweight and above are to be complied with.

Part E
Service Notations
Chapter 11
PASSENGER SHIPS
SECTION 1 GENERAL

SECTION 4 MACHINERY AND SYSTEMS
SECTION 5 ELECTRICAL INSTALLATIONS

Pt E, Ch 11, Sec 3
1 Stability [1.1.4] and [1.1.56], respectively. In this connection, a

value higher than four persons per square metre is not
1.1 Intact stability necessary.
1.1.1 General (1/1/2009) 1.1.4 Maximum turning angle (1/7/2010)

Every passenger ship regardless of size is to be inclined The angle of heel on account of turning may not exceed 10°
upon its completion and the elements of its stability when calculated using the following formula:
determined. The Master is to be supplied with such V0 
2
 KG – ---
d
M R = 0 200 --------
information satisfactory to the Society as is necessary to L WL  2
enable him by rapid and simple processes to obtain
accurate guidance as to the stability of the ship under where:
varying conditions of service. A copy of the stability MR : Heeling moment, in kNm
information is to be furnished to the Society. V0 : Service speed, in m/s
Where any alterations are made to a ship so as to materially LWL : Length of ship at waterline, in m
affect the stability information supplied to the Master,  : Displacement, in t
amended stability information is to be provided. If
d : Mean draught, in m
necessary the ship is to be re-inclined.
KG : Height of centre of gravity above keel, in m.
1.1.2 Standard requirements
In addition to PtB, Ch3, Sec2, [2] the requirements in 1.1.5 Where anti-rolling devices are installed in a ship, the
[1.1.3] to [1.1.5] are to be complied with for the loading Society is to be satisfied that the above criteria can be
conditions defined in PtB, Ch3, App2, [1.2.1] and PtB, maintained when the devices are in operation.
Ch3, App2, [1.2.9]. 1.1.6 Ships engaged in still waters (1/7/2024)
1.1.3 Crowding of passengers (1/7/2024) a) Loading conditions
The angle of heel due toon account of crowding of In addition to the loading conditions considered in Pt B,
passengers (see [1.1.6]) to one side as defined in Ch 3, App 2, [1.2.1] and Pt B, Ch 3, App 2, [1.2.9], the
[1.1.4] may is not to exceed 10° and any event the loading condition at arrival, without cargo, with
freeboard deck is not to be immersed. necessary water ballast, with all passengers, on all decks
For ships lesser than 20 m in length, the angle of heel is not assigned to them, crowded on the same side of the ship,
to be greater than the angle corresponding to a freeboard of is also to be considered.
0,1 m before the deck's immersion, or 12° if less. If in any real loading condition the stability of the ship is
In elaborating the stability booklet, the following is to be less favourable than in the requested conditions, the
assumed: stability requirements are also to be checked in such
real condition.
• A minimum weight of 75 kg for each passenger except
that this value may be increased subject to the approval In elaborating the stability booklet, the following is to be
of the Society. In addition, the mass and distribution of assumed:
the luggage is to be approved by the Society. • weight of each person equal to 75 kg;
• The height of the centre of gravity for passengers shall • centre of gravity of each person, both standing and
be assumed equal to: sitting, equal to 0,90 m above the upper surface of
• 1 m above deck level for passengers standing the relevant deck;
upright. Account may be taken, if necessary, of • maximum allowable number of persons equal to the
camber and sheer of deck; and number of sitting places plus two passengers/m2 in
• 0,3 m above the seat in respect of seated passengers. the areas available for passengers, clear from the
persons seated.
• Passengers and luggage shall be considered to be in the
spaces normally at their disposal, when assessing A higher number of standing persons may be assumed
compliance with the criteria given in Pt B, Ch 3, Sec 2, provided that the competent authority agrees.
[2.1.2] to [2.1.5]. In calculating the area in which the passengers are
• Passengers without luggage shall be considered as crowded among the benches, the distance between two
distributed to produce the most unfavourable of them may be reduced by 0,3 m x l (length of the
combination of passenger heeling moment and/or initial bench) to exclude the area obstructed by sitting
metacentric height, which may be obtained in practice, passengers.
when assessing compliance with the criteria given in b) Stability requirements in all required loading conditions
154 RINA Rules 2023

Pt E, Ch 11, Sec 3
The following stability requirements are to be complied appliances and essential service of the ship (e.g.
with: toilets, bar, etc.) is not impeded.
1) (r-a) to be not less than 0,30 m. Such devices are not to obstruct escape routes,
muster stations and embarkation points; are not to
To this end passengers are to be considered interfere with the safe abandonment of the ship; and
accommodated taking all the sitting places and are to be in place at all times during navigation.
areas assigned to them with 4 passengers/m2, During boarding, these devices can be temporarily
starting from the highest deck and proceeding to removed to ensure homogeneous distribution of
lower decks until the maximum allowable number boarding passengers, and are to be reinstalled
of passengers is exceeded; before the voyage starts. In the case of longitudinal
2) Distance between the upper surface of the main obstructions, such as seats, railings or nets, fitted to
deck, at side, from the waterline in the final prevent passengers from crowding on one side of
equilibrium status of heeled ship (residual minimum the ship, the Society may, at its discretion, relax the
freeboard) to be not less than 0,20 m. For this above-mentioned requirements, reducing the level
purpose, passengers are to be considered of crowding of standing persons. Such longitudinal
accommodated on one side of the ship only, from obstructions may be partially movable for the
the ship's centreline, taking all the sitting places and purpose of ensuring a suitable distribution of
areas assigned to them with 4 passengers/m2, embarking passengers; nevertheless, the crew
starting from the highest deck and proceeding to undertakes to put the longitudinal obstructions
lower decks until the maximum allowable number temporarily removed back in place, before the
of passengers is exceeded. voyage starts.
If the number of all the passengers on one side of the 5) To facilitate the calculations, it is permissible not to
ship does not reach the maximum allowable take into account both the shear and the camber of
number, the surplus of passengers is to be ignored in the ship, but to evaluate the vertical positions of all
calculating the transversal heeling of the ship. the centres of gravity referring to the section at ½ L.
3) The maximum allowable number of passengers is to 6) Any opening sidescuttles located below the upper
be the lower of 1 and 2 above. Such number may deck which, because of the transversal heeling of
be further reduced taking into account the the ship, may have their lowest point less than 0,20
following: m above the final waterline, are to be fitted with
efficient devices such that they can be effectively
• if the value calculated according to 1 leads to a closed and secured, under the Master's
value of (r-a) less than 0,30 m and this cannot be responsibility, while the passengers are on board.
avoided by the use of ballast of the ship, or by Such condition is to be noted in the ship's logbook.
other suitable operations, such number is to be It is allowable in the calculations that such
decreased in the calculation by unloading a sidescuttles are partially or fully submerged at the
suitable number of passengers, starting from the end of the heeling.
lower deck, until (r-a) not less than 0,30 m is
reached. Therefore, the resulting reduced 7) In the case of decked ships of length less than 20 m,
number of passengers is to replace the one item b) applies and the required residual freeboard
resulting from 1 on the side of passenger crowding, to be not less
than 0,20 m, is to correspond to a heeling angle not
• if the residual freeboard, calculated through the more than 15°. In the case of ships without decks,
passenger distribution according to 2, is less the residual freeboard after heeling due to the
than 0,20 m and it cannot be increased by crowding of passengers on one side of the ship is to
ballasting the ship, or by other suitable be not less than 0,30 m with an angle of heel not
operations, the number of passengers calculated greater than 15°.
according to 2 is to be decreased in the
calculation by unloading a suitable number of
passengers, starting from those standing closest 2 Structure design principles
to the midship plane on the lower deck.
Obviously, in such operation an upper deck is
not affected by unloading of passengers as far as 2.1 Hull structure
first all those standing, and then those sitting, in
the lower deck are unloaded. 2.1.1 Framing
The resulting reduced number of passengers is to In general, the strength deck and the bottom of passenger
replace the one resulting from 2. ships of more than 100 m in length are to be longitudinally
framed.
4) Chains, railings or similar devices, fitted to segregate
deck areas to prevent the presence of passengers Where a transverse framing system is adopted for such
during navigation, may be accepted by the Society ships, it is to be considered by the Society on a case-by-case
on condition that the safe access to life saving basis.
RINA Rules 2023 155

...OMISSIS...
Pt E, Ch 11, Sec 3
The design pressure p, in kN/m2 is in any case not to be 8.2 Design considerations
taken less than pmin as defined in Tab 8 where arrangement 8.2.1 (1/1/2020)
is in accordance to Pt B, Ch 9, Sec 9 or where arrangement
External glass balustrades are not to be located in areas
is in accordance to [7.3].
deemed essential for the operation of the ship. Such areas
include mooring decks, lifeboat decks, external muster
Table 8 : pmin (1/7/2020) stations and in the vicinity of davits. Where external glass
balustrades are not to be used, more traditional bulwarks or
Type of bulkhead location pmin in KN/m2 guard rails are to be fitted in accordance with Pt B, Ch 10,
Sec 2.
Lowest tier 30  25+0.1L  50
8.2.2 (1/1/2020)
Unprotect front 15 12.5+0.05L  External glass balustrades are to be not less than 1,0 m in
Second tier
25 height.
third tier 15 8.2.3 (1/1/2020)
Protect front, Lowest and sec- 15  12.5+0.05L  External glass balustrades are to provide water freeing areas
side and aft end ond tiers 25 in accordance with Pt B, Ch 9, Sec 9, [5].
8.3 Balustrade glasses

Table 9 : pmin for "alternative to deadlights / storm
8.3.1 (1/1/2020)
covers" arrangement and scantling in [7.3] (1/7/2020)
Railing with glass elements can be used provided they are
made of either:
tier pmin in KN/m2 • monolithic glass with a minimum thickness of 6.0 mm,
nd or
2 35
• laminated glass with a minimum thickness for each
3rd and above 15 glass pane equal to 4 mm.
8.3.2 (1/7/2024)
7.3 Alternative to deadlights/storm covers
When glass pane is supported along all four edges, tThe
7.3.1 (1/7/2020) thickness of the glass pane shall be calculated according to
In case the freeboard exceeds the minimum required [7.2.2] using the design pressures as specified in [7.2.4]
according to the applicable International Convention on multiplied by 0.5.
Load Lines, windows in the second tier and above may be When the glass is continuously supported only along two
fitted with a more robust glazing arrangement in alternative opposite sides, the coefficient same formula of above
to the deadlights/storm covers required in Pt B, Ch 9, Sec 9. applies with  in [7.2.2] is to be taken equal to 0.75.
The more robust glazing arrangement is to be either:
• one glazing of a thickness increased by at least 40% 8.4 Balustrade stanchions minimum
with respect to the value t calculated according to [7.2]; requirements
or
8.4.1 (1/10/2022)
• two glazing, each one of a thickness t calculated
according to [7.2]. Stanchions are to be fitted, not more than 1.5 m apart for
monolithic glass and 3.0 m apart for laminated glass. The
The supporting frames are to be strengthened comparably. stanchions are to have a minimum section modulus of 16
cm3 for a glass railing with 1.5 m stanchion distance and a
Other alternative arrangements of equivalent strength can
minimum section modulus of 32 cm3 for a glass railing with
be considered on case by case basis.
3.0 m stanchion distance. For intermediate distances, linear
7.3.2 (1/7/2020) interpolation is to be applied.
The Client is to ensure that the glazing arrangement in The stanchions are to be rigidly fixed at their lower ends to
alternative to the deadlights/storm covers is acceptable to resist rotational displacements.
the Administration.
These minimum requirements are intended for Grade A
steel; for different metallic materials, an equivalent section
8 External glass balustrades modulus is to be calculated.
8.1 Application 8.5 Balustrade top rail minimum

8.1.1 (1/1/2020)
requirements
The requirements of this paragraph apply solely to external 8.5.1 (1/1/2020)
glass balustrades, intended as barriers constructed with Balustrade top rail is to be effectively attached to balustrade
glass used on exposed decks. stanchions.
160 RINA Rules 2023

Pt E, Ch 11, Sec 3
8.5.2 (1/10/2022) glass pane for testing shall be supported with a similar
The top rail is to have a minimum section modulus Z in cm3 arrangement as the actual arrangement on board the ship.
calculated as follows: The test pressure shall be the design pressure specified in
[7.2.4] multiplied by 1.1. The test is considered successful if
Z = 1.06 l2
no visible damage occurs to the glass or its supporting
where l is the span of the top rail between stanchions, in m. arrangements. A test report shall be submitted to the
These minimum requirements are intended for Grade A Society.
steel; for different metallic materials, an equivalent section
modulus is to be calculated.
8.7 Impact Resistance and Containment
8.6 Glass supporting structures yielding 8.7.1 (1/7/2024)
check
External glass balustrades are to be subject to a prototype
8.6.1 (1/7/2024) pendulum impact test in accordance with "EN 13049:2003
For external glass balustrades, the glass supporting Windows - Soft and heavy body impact - Test method,
structures shall be calculated by direct calculations using safety requirements and classification" or an equivalent
the design pressures as specified in [7.2.4] and allowable National or International Standard, utilizing a drop height of
stresses according to Pt B, Ch 7, Sec 3. not less than 1.2 m. The test specimens including the
As an alternative to direct calculations, the glass supporting retaining arrangements are to be the same as the finished
structures shall be accepted upon issuance of Type installation. The report of the prototype pendulum impact
Approval Certificate (TA) based on testing. The balustrade test is to be submitted to the Society.
RINA Rules 2023 161

Part E
Service Notations
Chapter 13
SHIPS FOR DREDGING ACTIVITY
SECTION 1 GENERAL

SECTION 3 MACHINERY AND DREDGING SYSTEMS
189
...OMISSIS...
RINA Rules 2024
Pt E, Ch 13, Sec 2
Symbols
T : Navigation draught, in m, corresponding to the 1 Stability
international freeboard
TD : Dredging draught, in m, corresponding to the 1.1 Intact stability
dredging freeboard
1.1.1 General (1/7/2006)
C : Wave parameter defined in Pt B, Ch 5, Sec 2 or
Pt B, Ch 8, Sec 1, as applicable In addition to the requirements of Pt B, Ch 3, Sec 2,
dredgers are to comply with the provisions of [1.1.2] and
k : Material factor for steel, defined in Pt B, Ch 4, [1.1.3] as applicable.
Sec 1, [2.3]
n, n1 : Navigation coefficients, defined in Pt B, Ch 5, 1.1.2 Intact stability (1/7/2006)
Sec 1, [2.6] or Pt B, Ch 8, Sec 1, [1.5], as a) Loading conditions
applicable In the working condition, dredging equipment is to be
nD : Navigation coefficient in dredging situation, considered positioned so as to produce the most severe
defined in [3.3.1] combination of inclining moment and/or initial
metacentric height. In particular, for grab dredgers, the
s : Spacing, in m, of ordinary stiffeners
mass, in t, of the dredged materials contained in the
 : Specific gravity of the mixture of sea water and grab of volume V, in m3, is to be considered equal to 1,6
spoil, taken equal to: V; for bucket dredgers the mass, in t, contained in each
PD bucket of volume V, in m3, of the top of the chain is to
 = ------ be considered equal to 2 V. For suction pipes of trailing
VD
suction dredgers, the mass of the dredged spoil is to be
PD : Maximum mass, in t, of the spoil contained in considered equal to 1,3 t/m3.
the hopper space Bucket dredgers are generally not allowed to proceed to
VD : Volume of the hopper space, in m3, limited to sea without first dismantling the dredging equipment.
the highest weir level For the calculation of displacement, the volumes of
g : Gravity acceleration, in m/s2: hoppers and wells intended for the carriage of sand and
spoil, even if closed in their lower part by means of non-
g = 9,81 m/s2 watertight doors, are to be considered as part of the
p : Length, in m, of the hopper well ship's body and the weight of the water within, when
there is no cargo, is to be considered as additional
a : Distance from the bottom to the sealing joint cargo. On the other hand, wells for the arrangement of
located at the lower part of the hopper well, in bucket chains, cutter heads or ladder pumps are to be
m considered as buoyancy losses.
h1 : Distance, in m, from spoil level to base line b) Influence of free surfaces
when working at the dredging freeboard (see
Fig 8) 1) In the calculation of initial metacentric height, the
effects of free surfaces may be disregarded when the
h2 : Distance, in m, from spoil level to base line mass density of spoil is greater than 1 t/m3;
when working at the international freeboard otherwise, they are assumed to be fluid cargoes.
(see Fig 8)
2) In the calculation of righting levers, account is to be
h4 : Distance, in m, from the lowest weir level to taken of the shifting of cargo that occurs in way of
base line the various angles of heel of the dredger, considering
T3 : Navigation draught, in m, with well filled with any variation in displacement and the position of the
centre of gravity due to the discharge of mud and the
water up to waterline
re-entry of sea water. The angle of shifting of the
T4 : Navigation draught, in m, with well filled with cargo qR is to be assumed as a function of the angle
water up to the lowest weir level of heel qG and the mass density , in t/m3, according
ReH : Minimum yield stress, in N/mm2, of the material to the following formulas:

of the material.  R =  G for   1
192 RINA Rules 2024

...OMISSIS...
Pt E, Ch 13, Sec 2
PS : Pressure on the rod side of the jack pressure test at the greater of the values 1,4PS and 1,2Pm
corresponding to the greatest of forces FS, applied on the rod side and a pressure test at 1,4PC on the
defined in [9.3.7], and FP, defined in [9.3.3]. bottom side for the fully extended position.
10.5.3 The completed hydraulic circuit is to be subjected,

10.3 Arrangements
on board, to pressure tests at 1,4 times the relevant
10.3.1 When large ships are concerned, the following maximum service pressure for normal conditions or static
arrangements are generally to be provided: loads, for the part of the circuit considered.
• for each hydraulic jack, a measuring system of the
pressure in the cylinder is to be supplied 10.6 Relief valve setting
• this system, in addition to the indication of the pressure 10.6.1 At least one relief valve of appropriate capacity is to
at the bridge and at the dredging room, is to comprise a protect each part of the circuit which may be subject to
visual and audible alarm at the same locations, to be overpressure due to external loads or due to pump action;
activated when a certain limit is exceeded in general, relief valves on the rod side of each cylinder or
• the measuring system, the alarm activating limit as well group of cylinders are to be set at Pm, while PC applies to the
as the instructions to be followed after the alarm occurs bottom side for relief valve setting purposes.
are to be submitted to the Society for approval. Parts of the circuit possibly subject to overpressure from
pumps only are to be protected by relief valves set at
10.3.2 Special attention is to be paid to protection against
pressure PP.
corrosion.
10.4 Scantling of jacks 11 Rudders

10.4.1 For the pressure parts of hydraulic jacks made of 11.1 General
steel, the permissible stress related to the loading conditions
resulting in pressure PP or PS (whichever is the greater) 11.1.1 The rudder stock diameter obtained from Pt B,
acting on the cylinder rod side without pressure on the Ch 10, Sec 1, [4] is to be increased by 5%.
other side is to be taken as the smaller of ReH/1,8 and
Rm/2,7. 11.2 Additional requirements for split hopper
The allowable stress applicable to the cylindrical envelope, dredgers and split hopper units
for the loading conditions resulting in pressure Pm , may be
11.2.1 Each half-hull of ships with either of the service
taken as the smaller of ReH/1,5 and Rm/2,25.
notations split hopper unit or split hopper dredger is to be
10.4.2 The scantlings of the jack end cover on the rod side fitted with a rudder complying with the requirements of
are to be determined using Pm as design pressure. Pt B, Ch 10, Sec 1.
The scantlings of the jack end cover on the bottom side as 11.2.2 An automatic system for synchronising the
well as the mechanical connections (for example the bolts movement of both rudders is to be fitted.
between the cover and the cylinder or between the piston
and the rod) are to be based on Fm.
12 Equipment
The calculations justifying the proposed scantlings and, as
the case may be, the pre-stresses are to be submitted to the 12.1 General
Society for approval.
12.1.1 The requirements of this Article apply to ships
10.4.3 The scantlings of the rod are to be based on Fm and
having normal ship shape of the underwater part of the hull.
on the smaller value of ReH/2 and Rm/2,4, for the mean
For ships having unusual ship shape of the underwater part
permissible stress in traction. A calculation proving the
of the hull, the equipment is to be considered by the Society
adequate buckling strength of the rod is to be submitted to
on a case-by-case basis.
the Society for approval.
12.1.2 The equipment obtained from [12.1.4] or [12.1.5]
10.4.4 The scantlings of the lugs and the pins at each end
is independent of anchors, chain cables and ropes which
of the hydraulic cylinder are to be based on Fm.
may be needed for the dredging operations.
10.5 Inspection and testing 12.1.3 The Equipment Number EN is to be obtained from
10.5.1 In addition to inspections required in [10.1.2], 23
where applicable, welded joints connecting parts subject to EN = 1 ,5  LBD 
the load Fm are to fulfil the requirements for class 1 pressure When calculating EN, bucket ladders and gallows may not
vessels or equivalent. be included.
10.5.2 Completed cylinders and attached piping up to and 12.1.4 For ships equal to or greater than 80 m in length
including the first isolating valve are to undergo, at works, a and for ships with EN, calculated according to [12.1.3],
RINA Rules 2024 217

Pt E, Ch 13, Sec 2
equal to or greater than 795, the equipment is to be Where such ships are assigned one of the following
obtained from Pt B, Ch 10, Sec 4, [3], with EN calculated navigation notations:
according to Pt B, Ch 10, Sec 4, [2] and not being taken less
than 795, considering the following: • summer zone
• to apply the formula, the displacement considered is • tropical zone

that of the navigation draught, taking into account the
• coastal area,
cylinder housings and the free space between the two
half-hulls
the equipment is to be obtained by consulting Tab 17 one
• the chain cable diameter is to be read off after moving line higher.
to the next line below in the applicable Table.
Where such ships are assigned the navigation notation
12.1.5 For ships other than those defined in [12.1.4], the sheltered area, the equipment is to be obtained by
equipment is to be obtained from Tab 17. consulting Tab 17 two lines higher.
Table 17 : Ships for dredging activities - Equipment
Equipment number EN
Stockless anchors Stud link chain cables for anchors
A< EN  B
A B N Mass per anchor, in kg Total length, in m Diameter, in mm
35 45 2 120 110,0 16,0
45 60 2 140 110,0 17,5
60 80 2 220 110,0 19,0
80 92 2 260 137,5 20,5
92 102 2 290 137,5 22
102 112 2 320 165,0 24
112 130 2 350 165,0 24
130 155 2 430 165,0 26
155 185 2 500 165,0 28
185 210 2 600 165,0 30
210 250 2 700 165,0 32
250 285 2 800 220,0 34
285 315 2 900 220,0 36
315 350 2 1000 220,0 38
350 385 2 1100 220,0 38
385 415 2 1200 220,0 40
415 450 2 1300 220,0 40
450 485 2 1400 220,0 42
485 515 2 1500 220,0 44
515 550 2 1600 220,0 46
550 585 2 1700 220,0 48
585 635 2 1800 275,0 48
635 685 2 2000 275,0 50
685 715 2 2100 275,0 52
715 750 2 2200 275,0 54
750 795 2 2300 275,0 54
12.1.6 (1/7/2024) direct force calculation for anchoring equipment described

Dredgers with unusual design of the underwater part of the in Pt B, Ch 10, App 4.
hull are not covered by alternative methodology using

Part E
Service Notations
Chapter 14
TUGS
SECTION 1 GENERAL

SECTION 3 INTEGRATED TUG/BARGE COMBINATION
RINA Rules 2024

...OMISSIS... 223
Pt E, Ch 14, Sec 2
1 General 2.2 Stability
2.2.1 Openings (1/1/2021)

1.1 Application
a) Openings which cannot be closed weathertight:
1.1.1 (1/7/2022)
Openings in the hull, superstructures or deckhouses
The requirements of this Section apply to ships with one of which cannot be closed weathertight are to be
the following service notations: considered as unprotected openings and, consequently,
• tug, mainly intended for towing services, which are to as down-flooding points for the purpose of stability
comply with the requirements in [2] calculations (the lower edge of such openings is to be
taken into account).
• salvage tug, having specific equipment for salvage
b) Ventilation openings of machinery space and
services, which are to comply with the requirements in
emergency generator room:
[2] and [3]
It is recognised that for tugs, due to their size and
• escort tug, mainly intended for escort services such as
arrangement, compliance with the requirements of ICLL
for steering, braking and otherwise controlling escorted
Reg. 17(3) for ventilators necessary to continuously
ships, which are to comply with the requirements in [2]
supply the machinery space and the emergency
and [4].
generator room may not be practicable. Lesser heights
Ships with the additional service feature barge combined of the coamings of these particular openings may be
(units designed to be connected with barges) are to comply accepted if the openings:
with the applicable requirements in Sec 3. • are positioned as close to the centreline and as high
above the deck as practicable in order to maximise
Ships with the additional service feature rescue (units
the down-flooding angle and to minimise exposure
specially equipped for the rescue of shipwrecked persons
to green water
and for their accommodation) are to comply with the
requirements given in [2.11]. • are provided with weathertight closing appliances in
combination with suitable arrangements, such as
Ships with the additional service feature standby vessel separators fitted with drains
(units specially intended to perform rescue and standby
services) are to comply with the requirements given in • are equipped with efficient protective louvers and
[2.12]. mist eliminators
• have a coaming height of not less than 900 mm
Ships with the additional service feature anchor handling
above the deck
(units specially designed for anchor handling operations)
are to comply with the requirements given in Ch 15, Sec 2, • are considered as unprotected openings and,
[2.10], [8.3] and [8.5]. consequently, as down-flooding points for the
purpose of stability calculations.
Ships with the additional service feature anchor handling
stab (units specially designed and equipped for anchor 2.2.2 Stability booklet (1/1/2021)
handling operation and also fulfilling specific stability
The stability booklet for ships engaged in harbour, coastal
requirements related to this service) are to comply with the
or ocean going towing operations and/or escort operations
requirements given in Ch 15, Sec 2, [2.10], [3.4], [8.3] and
is to contain additional information on:
[8.6].
• maximum bollard pull
2 Tugs, salvage tugs and escort tugs • details on the towing arrangement, including location
and type of the towing point(s) such as towing hook,
staple, fairlead or any other point serving that purpose
2.1 General • recommendations on the use of roll reduction systems
2.1.1 In general, tugs are completely decked ships • If any wire, etc. is included as part of the lightship
provided with an ample drift surface and, where intended weight, clear guidance on the quantity and size is to be
for service outside sheltered areas, with a forecastle or half given
forecastle, or at least with a large sheer forward. • maximum and minimum draught for towing and escort
Tugs of unusual design are to be considered by the Society operations
on a case-by-case basis. • instructions on the use of the quick-release device
226 RINA Rules 2024

...OMISSIS...
Pt E, Ch 14, Sec 2
Escape hatch covers are to have hinges arranged 2.7.3 Anchors, chain cables and ropes (1/1/2017)
athwartship and are to be capable of being opened and
Tugs with notation unrestricted navigation or summer
closed watertight from either side.
navigation with equipment number EN calculated
2.5.3 Height of hatchway coamings according [2.7.1], are to be provided with equipment in
The height of the hatchway coamings is to be not less than anchors, chain cables and ropes obtained from Pt B, Ch 10,
300 mm. Hatch covers are to be fitted with efficient Sec 4.
securing devices. Tugs with notation unrestricted navigation or summer
navigation with equipment number EN calculated
2.6 Rudder and bulwarks according g [2.7.1] equal to or less than 205, may reduce
the number of anchor to one, and the mass of that anchor
2.6.1 Rudder can be reduced to half of the mass indicated in Pt B, Ch 10,
For tugs, the rudder stock diameter is to be increased by 5% Sec 4, Tab 1. In the case only one anchor is adopted, the
with respect to that calculated according to Pt B, Ch 10, total lenght of anchor chain cable may be reduced to half of
Sec 1, [4]. that indicated in Pt B, Ch 10, Sec 4, Tab 1. No reduction is
forseen for chain cable diameter.
2.6.2 Bulwarks Tugs with the navigation notation coastal area or sheltered
The bulwarks are to be sloped inboard to avoid distortions area with equipment number EN calculated according
likely to occur during contact. Their height may be reduced [2.7.2], are to be provided with equipment in anchors,
where required by operational necessities. chain cables and ropes obtained from Tab 1 and Tab 2.
2.7 Equipment 2.7.4 Additional equipment

Tugs are to be fitted with the additional equipment specified
2.7.1 Equipment number for tugs with the in Tab 3.
navigation notation “unrestricted
navigation” (1/7/2024) 2.7.5 Tugs under 45 m in length intended for towing
For tugs with the navigation notation unrestricted service only (1/7/2024)
navigation, the equipment number EN is to be obtained For tugs under 45 m in length intended for towing service
from Pt B, Ch 10, Sec 4, [2.1.2] where the following may be only, one anchor may be used onboard provided that the
substituted for the term 2hB.: second anchor and its relevant chain cable holds readily
available to be installed. In case of loss of anchor, the tug is
to remain in port until replace anchor equipment is
2  a  B + h  b n installed onboard.
 n

where a, B and hn are defined in Pt B, Ch 10, Sec 4, [2.1.2] 2.8 Towing arrangements
and bn is the breadth, in m, of the widest superstructure or
deckhouse of each tier n having a breadth greater than B/4. 2.8.1 General
In general, towing hooks and winches are to be arranged in
For tugs where the vertical extent of the superstructure is
way of the ship’s centreline, in such a position as to
much greater than usual, the Society may require an
increased equipment number EN. minimise heeling moments in normal working conditions.
2.8.2 Definitions (1/7/2021)

• Emergency release system: refers to the mechanism and
2.7.2 Equipment number for tugs with the
navigation notation coastal area or sheltered associated control arrangements that are used to release
area the load on the towline in a controlled manner under
For tugs with the navigation notation coastal area or both normal and black out conditions
sheltered area, the equipment number EN is to be obtained • Maximum design load: is the maximum load that can be
from the following formula: held by the winch as defined by the manufacturer (the
manufacturer’s rating)
EN = 2,51 (L B D)2/3
• Fleet angle: is the angle between the applied load
(towline force) and the towline as it is wound onto the
winch drum.
increased equipment number EN.
For tugs with total block coefficient CB less than 0,60, at a Figure 2 : Towline ’fleet angle’ (1/7/2021)
draught T equal to 0,85 D, the equipment number EN is to
be obtained from the following formulae:
EN = 1,76 (L B D)2/3
increased equipment number EN.
RINA Rules 2024

...OMISSIS... 229
Part E
Service Notations
Chapter 19
NON-PROPELLED UNITS
SECTION 1 GENERAL

SECTION 3 MACHINERY SYSTEMS
SECTION 4 ADDITIONAL REQUIREMENTS FOR MACHINERY AND CARGO

SYSTEMS OF BARGE-OIL

SYSTEMS OF BARGE-LIQUEFIED GAS

SYSTEMS OF BARGE-LNG BUNKER

SYSTEMS OF BARGE-CHEMICAL
RINA Rules 2024

...OMISSIS... 75
Pt E, Ch 19, Sec 2
Symbols
LG : Ship’s length, in m, measured at the maximum a) unmanned
load waterline
b) having a block coefficient not less than 0,9
s : Spacing, in m, of ordinary stiffeners.
c) having a breadth/depth ratio greater than 3,0
1 General d) having no hatchways in the deck except small manholes

closed with gasketed covers.
1.1 Application The requirements of item [2.1] also apply to barges that do
not comply with d).
1.1.1 General (1/6/2021) The intact stability of ships not having any one of the above
Unless otherwise specified, the requirements of this Section characteristics is to comply with Pt B, Ch 3, Sec 2, unless
apply to ships with one of the service notations barge, otherwise decided by the Society, on a case by case basis,
pontoon and pontoon - crane. taking into account the ship's characteristics. In this case,
an appropriate entry is made in the classification files of the
Specific requirements which apply only to ships with the
ship.
service notation barge or ships with the service notation
pontoon or pontoon - crane are indicated. Items [2.1.2] and [2.1.3] do not apply to barges.
Barges with the additional service feature tug combined are
2.1.2 Trim and stability booklet
also to comply with the applicable additional requirements
in Ch 14, Sec 3. In addition to the information to be included in the trim and
stability booklet specified in Pt B, Ch 3, App 2, [1.1],
Intact stability additional requirements for units with service simplified stability guidance, such as a loading diagram, is
notations barge-oil, barge-accommodation, barge-liquified to be submitted to the Society for approval, so that
gas, barge-LNG bulker and barge-chemical, are indicated pontoons may be loaded in compliance with the stability
in [2.3] to [2.6] respectively. criteria.
1.1.2 Main characteristics of non-propelled units
2.1.3 Stability calculations
The requirements of this Section are based on the following
Stability calculations may be carried out according to the
assumptions, relevant to the main characteristics of non-
following criteria:
propelled units:
• no account is to be taken of the buoyancy of deck cargo
• the structural configuration and proportions of non-
(except buoyancy credit for adequately secured timber)
propelled units are similar to those of propelled ships
• the cargo is homogeneously distributed. • consideration is to be given to such factors as water
absorption (e.g. timber), trapped water in cargo (e.g.
The scantlings of non-propelled units with unusual shapes pipes) and ice accretion
and dimensional proportions or carrying cargoes which are • in carrying out wind heel calculations:
not homogeneously distributed, such as containers or heavy
loads concentrated in limited areas, are to be considered by - the wind pressure is to be constant and for general
the Society on a case-by-case basis, taking into account the operations considered to act on a solid mass
results of direct calculations, to be carried out according to extending over the length of the deck and to an
Pt B, Ch 7, App 1. assumed height above the deck
- the centre of gravity of the cargo is to be assumed at
2 Stability a point mid-height of the cargo
- the wind lever arm is to be taken from the centre of
2.1 Intact stability for ships with service the deck cargo to a point at one half the draught
notation “barge”, “pontoon” or • calculations are to be carried out covering the full range
“pontoon-crane” of operating draughts
• the downflooding angle is to be taken as the angle at
2.1.1 Application (1/7/2012) which an opening through which progressive flooding
The requirements of this item [2.1] apply to seagoing ships may take place is immersed. This would not be an
with one of the service notations barge, pontoon and opening closed by a watertight manhole cover or a vent
pontoon-crane with the following characteristics: fitted with an automatic closure.

Pt E, Ch 19, Sec 2
5.2.2 Scantlings of plating, ordinary stiffeners and 6 Other structures

primary supporting members
In applying the formulae in Part B, Chapter 7 or Part B, 6.1 Reinforcement of the flat bottom
Chapter 8, as applicable, T is to be taken equal to the forward area of ships with one of the
maximum draught during the different stages of launching service notations “pontoon” and
and taking into account, where appropriate, the differential “pontoon - crane”
static pressure.
6.1.1 Application (1/7/2024)
5.2.3 Deck scantlings (1/1/2015) The requirements in this Article are applicable to barges,
pontoons and barge-shaped assisted propelled units with a
The net scantlings of decks are to be in accordance with navigation notation other than sheltered area.
Part B, Chapter 7 or Part B, Chapter 8, considering the
maximum loads acting on the launching cradle or grillage. For barges, pontoons and barge-shaped assisted propelled
units of less than 100 m in length, when a reduction of the
The net thickness of deck plating in way of launch ground speed is provided in relation with the sea state to avoid
ways is to be suitably increased if the cradle or grillage may bottom impact pressure for flat bottom area, the
be placed in different positions. requirements related to the bottom impact pressure are not
applicable.
The scantlings of decks in way of pivoting and end areas of
the cradle or grillage are to be obtained through direct 6.1.2 Area to be reinforced
calculations, to be carried out according to the criteria in The structures of the flat bottom forward area are to be able
Pt B, Ch 7, App 1. to sustain the dynamic pressure due to the bottom impact.
The flat bottom forward area is:
5.2.4 Launching cradles or grillage (1/1/2015) • longitudinally, over the bottom located from the fore
end to 0,15 L aft of the fore end
The launching cradles or grillage are to be adequately • transversely, over the whole flat bottom, and the
connected to deck structures and arranged, as far as adjacent zones up to a height, from the base line, not
possible, in way of longitudinal bulkheads or at least of less than 2L, in mm. In any case, this height need not be
girders. greater than 300 mm.
6.1.3 Bottom impact

5.3 Hull scantlings of non-propelled units The bottom dynamic impact pressure is to be considered if:
with service notation “pontoon - crane”
TF < 0,04 L,
5.3.1 Loads transmitted by the lifting appliances where TF is the minimum forward draught, in m, among
those foreseen in operation in ballast conditions or
The forces and moments transmitted by the lifting conditions of partial loading.
appliances to the ship’s structures, during both lifting If TF is less than 0,025 L, strengthening of the flat bottom
service and navigation, are to be obtained by means of forward is to be considered by the Society on a case-by-
criteria to be considered by the Society on a case-by-case case basis.
basis.
6.1.4 Partial safety factors
5.3.2 Ship’s structures The partial safety factors to be considered for checking the
reinforcements of the flat bottom forward area are specified
The ship’s structures, subjected to the forces transmitted by in Tab 4.
the lifting appliances, are to be reinforced to the Society’s
satisfaction. Table 4 : Reinforcements of the flat bottom forward
area - Partial safety factors
5.3.3 Lifting appliances
Partial safety factors Partial safety factors
The check of the behaviour of the lifting appliances at sea is covering uncertain- Ordinary
outside the scope of the classification and is under the ties regarding: Symbol Plating
stiffeners
responsibility of the Designer. However, where the
Still water pressure S2 1,00 1,00
requirements in [3.2.1] may not be complied with (i.e.
sailing with boom or derrick up) or where, exceptionally, Wave pressure W2 1,10 1,10
trips with suspended load are envisaged, the Designer is to Material m 1,02 1,02
submit the check of the lifting appliances during navigation
to the Society for information. Resistance R 1,30 1,15
The Society may check these calculations following a 6.1.5 Scantlings of plating and ordinary stiffeners
specific request, while also reserving the right to do so, Where TF is less than 0,03 L, the net scantlings of plating
when deemed necessary, without any such request. and ordinary stiffeners of the flat bottom forward area, as
RINA Rules 2024

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Part E
Service Notations
Chapter 25
OIL CARRIERS - ASSISTED PROPULSION
SECTION 1 GENERAL

SECTION 3 STABILITY
SECTION 4 MACHINERY AND CARGO SYSTEMS
SECTION 5 MACHINERY AND CARGO SYSTEMS FOR OIL CARRIER,

FLASHPOINT > 60°C
RINA Rules 2024

...OMISSIS... 237
Pt E, Ch 25, Sec 1
SECTION 1 GENERAL
1 General
Table 1 : Sections or Appendixes with requirements
applicable to ships having the Service Notations indi-
1.1 Application cated in [1.2.1] (1/5/2013)
1.1.1 Service notation oil carrier (1/5/2013)
Main subject Reference
a) The requirements of this Chapter apply to ships having
the service notations oil carriertanker, as defined in Pt A, Ship arrangement Sec 2
Ch 1, Sec 2, [4.5.2] Hull and stability Sec 3
As indicated in Pt A, Ch 1, Sec 2, [4.5.11] these units
Machinery and cargo system Sec 4 and Sec 5
are to be assigned with the additional service feature
assisted propulsion. Electrical installations Sec 6
Note 1: As recalled in Part A, Chapter 1, Sec 1, [3.1.1], the classifi-
Automation (1)
cation of a ship does not absolve the Interested Party from com-
pliance with any requirements issued by Administrations and Fire protection, detection and extinction (1)
any other applicable international and national regulations for
the safety of life at sea and protection of the marine environ- Devices to prevent the passage of flames Ch 7, App 1
ment. into cargo tanks
b) Departures are given for oil carriers that have the addi- Crude oil washing system Ch 7, App 2
tional service feature oil carriers, flashpoint > 60°C and
(1) No specific requirements are given in this Chapter.
are intended only for the carriage of bulk cargoes:
• at a temperature below and not within 15°C of their
1.3.2 Cargo pump room (1/5/2013)
flashpoint, or
Cargo pump room is a space containing pumps and their
• having a flashpoint above 100°C.
accessories for the handling of products covered by the ser-
c) The list of substances the carriage in bulk of which is vice notation granted to the ship.
covered by the service notations
• oil carrier 1.3.3 Cargo service spaces (1/5/2013)
• oil carrier, flashpoint > 60°C Cargo service spaces are spaces within the cargo area used
is the one in MARPOL 73/78 annex Convention , for workshops, lockers and storerooms of more than 2 m2 in
except “naphta solvent”, the carriage of which is subject area, intended for cargo handling equipment.
to compliance with Chapter 8.
1.3.4 Clean ballast (1/5/2013)
Clean ballast means the ballast in a tank which since oil
1.2 Summary tables
was last carried therein, has been so cleaned that the efflu-
1.2.1 (1/5/2013) ent therefrom if it were discharged from a ship which is sta-
Tab 1 indicates, for easy reference, the Sections or Appen- tionary into clean calm water on a clear day would not
dixes of this Chapter dealing with requirements applicable produce visible traces of oil on the surface of the water or
to ships having the following service notations: on adjoining shorelines or cause a sludge or emulsion to be
• oil carrier deposited beneath the surface of the water or upon adjoin-
• oil carrier, flashpoint > 60°C. ing shorelines. If the ballast is discharged through an oil dis-
charge monitoring and control system approved by the
Society, evidence based on such a system to the effect that
1.3 Definitions
the oil content of the effluent did not exceed 15 parts per
1.3.1 Cargo area (1/5/2013) million is to be determinative that the ballast was clean,
The cargo area is that part of the ship that contains cargo notwithstanding the presence of visible traces.
tanks as well as slop tanks, cargo pump rooms including
1.3.5 Crude oil (1/5/2013)
pump rooms, cofferdams, ballast or void spaces adjacent to
Crude oil means any liquid hydrocarbon mixture occurring
cargo tanks or slop tanks as well as deck areas throughout
naturally in the earth whether or not treated to render it suit-
the entire length and breadth of the part of the ship above
able for transportation and includes:
these spaces.
When independent tanks are installed in hold spaces, the a) crude oil from which certain distillate fractions have
cofferdams, ballast or void spaces at the after end of the been removed, and
aftermost hold space or at the forward end of the forward- b) crude oil to which certain distillate fractions may have
most hold space are excluded from the cargo area. been added.
RINA Rules 2024

...OMISSIS... 239
Pt F, Ch 3, Sec 1
SECTION 1 UNATTENDED MACHINERY SPACES (AUT-UMS)
1 General • fire detection system requirements given in [3.2] insofar

as the location of the spaces considered allows people
on board to detect fire outbreaks easily, and
1.1 Application
• requirement [3.4.4].
1.1.1 The additional class notation AUT-UMS is assigned
in accordance with Pt A, Ch 1, Sec 2, [6.4.2] to ships fitted 1.2.6 Fishing vessels of less than 75 m in length are
with automated installations enabling periodically exempted from the application of the requirements laid
unattended operation of machinery spaces, and complying down in [1.3.2], [3.1.3] and [3.3.1].
with the requirements of this Section.
Note 1: Machinery spaces are defined in Pt C, Ch 1, Sec 1, [1.4.2]. 1.3 Communication system
1.1.2 The arrangements provided shall be such as to 1.3.1 A reliable means of vocal communication shall be
ensure that the safety of the ship in all sailing conditions, provided between the main machinery control room or the
including manoeuvring, is equivalent to that of a ship propulsion machinery control position as appropriate, the
having the machinery spaces manned. navigation bridge and the engineer officers’
accommodation.
1.2 Exemptions This means of communication is to be foreseen in collective
or individual accommodation of engineer officers.
1.2.1 For ships whose gross tonnage is less than 500 and
propulsive power less than 1 MW, the requirements laid 1.3.2 Means of communication are to be capable of being
down in [1.3] and [5.4.3] do not apply. operated even in the event of failure of supply from the
main source of electrical power.
1.2.2 For ships whose gross tonnage is less than 500 and
propulsive power less than 1 MW, the requirements laid 2 Documentation
down in [4] do not apply. An alarm signal is to be activated
in the following circumstances:
2.1 Documents to be submitted
a) for diesel engine propulsion plant
• lubricating oil system low pressure 2.1.1 In addition to those mentioned in Pt C, Ch 3, Sec 1,
Tab 1, the documents in Tab 1 are required.
• cylinder coolant high temperature
• cylinder coolant low pressure or low flow rate Table 1 : Documents to be submitted
• cylinder coolant make up tank low level
• sea water cooling low pressure or low flow rate No. (1) Document
b) for auxiliary internal combustion engines intended for 1 A Means of communication diagram
electricity production of a power higher than 37 kW,
2 A Technical description of automatic engineer’s
supplying essential services: alarm and connection of alarms to accom-
• cylinder coolant high temperature modation and bridge, when applicable
• lubricating oil system low pressure.
3 A System of protection against flooding
1.2.3 For ships whose gross tonnage is less than 500 and 4 A Fire detection system: diagram, location and
propulsive power less than 1 MW, automatic stop is to be cabling
provided for lubricating oil failure of engines, reduction
gears, clutches and reversing gears. A possible override of (1) A : to be submitted for approval
this automatic stop is to be available at the control stations,
and an indication is to be provided at each control station, 3 Fire and flooding precautions
when override is activated.
3.1 Fire prevention
1.2.4 The requirements laid down in [3.3.1] do not apply
to cargo ships of less than 1 600 tons gross tonnage, insofar 3.1.1 The requirements regarding piping and arrangements
as the arrangements of the machinery space access make it of fuel oil and lubricating oil systems given in Pt C, Ch 1,
unnecessary. Sec 10 are applicable.
1.2.5 Fishing vessels of less than 45m in length are 3.1.2 Fuel oil and lubricating oil purifiers and the auxiliary
exempted from the application of: equipment and its fittings containing hot fuel oil are to be
• alarm system requirements given in [5.2.3] and [5.4.2] grouped in a special room or in locations ventilated by
RINA Rules 2024 81

...OMISSIS...
Pt F, Ch 3, Sec 1
Table 3 : Monitored parameter for main propulsion trunk piston diesel engine (1/1/2020)
Symbol convention
H = High, HH = High high, G = group alarm
L = Low, LL = Low low, I = individual alarm
X = function is required, R = remote
Automatic start of
Alarm Remote Slow-down Shut-down stand
Identification of system parameter
activation indication with alarm with alarm by pump with
alarm
Fuel oil system
• Fuel oil pressure after filter (engine inlet) L R
X
• Fuel oil viscosity before injection pumps or fuel oil H+L
temperature before injection pumps (for engine
running on heavy fuel)
• Leakage from high pressure pipes where required H
• Common rail fuel oil pressure L
Lubricating oil system
• Lubricating oil to main bearing and thrust bearing L R
pressure X
X
• Lubricating oil filter differential pressure H R
• Lubricating oil inlet temperature H R
• Activation of oil mist detection arrangements (or X X
activation of the temperature monitoring systems or
equivalent devices of:
- the engine main and crank bearing oil outlet; or
- the engine main and crank bearing) (1)
• Flow rate cylinder lubricator (each apparatus) L X
• Common rail servo oil pressure L
Turbocharger system
• Lubricating oil to turbocharger inlet pressure (2) L R
• Turbochanger lub oil temp. each bearing (4) H R
• Speed of turbocharger (5) H R
Sea water cooling system
• Sea water cooling pressure L R
X
Cylinder fresh cooling water system
• Cylinder water inlet pressure or flow L R X
X
(1) When required by Pt C, Ch 1, Sec 2, [4.3.5] or by SOLAS Reg.II-1/47.2.
For each engine one oil mist detector (or engine bearing temperature monitoring system or equivalent device) having two
independent outputs for initiating the alarm and shut-down would satisfy the requirement for independence between alarm
and shut-down system.
(2) Unless provided with a self-contained lubrificating oil system integrated with the turbocharger.
(3) For engine power > 500 kW/cyl.
(4) Where outlet temperature from each bearing cannot be monitored due to the engine/turbocharger design alternative
arrangements may be accepted. Continuous monitoring of inlet pressure and inlet temperature in combination with specific
intervals for bearing inspection in accordance with the turbocharger manufacturer’s instructions may be accepted as an
alternative.
(5) Only required for turbochargers of Categories B and C (see Pt C, Ch 1, Sec 14).

Pt F, Ch 4, Sec 1
SECTION 1 CENTRALISED NAVIGATION EQUIPMENT

(SYS-NEQ)
1 General International Maritime Organisation are complied with, in

particular:
1.1 Application a) Regulation 12, Chapter V of the 1974 “International

Convention for the Safety of Life at Sea” (SOLAS) and
1.1.1 The additional class notation SYS-NEQ is assigned, applicable amendments
in accordance with Pt A, Ch 1, Sec 2, [6.5.2], to ships fitted b) the international Regulations for Preventing Collisions at
with a centralised navigation control system so laid out and Sea and all other relevant Regulations relating to
arranged that it enables normal navigation and Radiotelegraphy, Radiotelephony and Safety of
manoeuvring operation of the ship by two persons in Navigation required by Chapters IV and V of SOLAS
cooperation. 1974, as amended
This notation is assigned when the requirements of Articles c) the Provisional Guidelines for the Conduct of Trials in
[1] to [5], [7] and [8] of this Section are complied with. which the Officer of the Navigational Watch acts as the
sole Lookout in Periods of Darkness (MSC Circular 566
1.1.2 The additional class notation SYS-NEQ-1 is assigned, of 2 July 1991)
in accordance with Pt A, Ch 1, Sec 2, [6.5.2], when, in d) IMO Performance Standards for navigational equipment
addition to [1.1.1] above, the installation is so arranged that applicable to:
the navigation and manoeuvring of the ship can be
• magnetic compasses (Resolution A382)
operated under normal conditions by one person for
periodical one man watches. This notation includes specific • gyrocompasses (Resolution A424)
requirements for prevention of accidents caused by the • radar equipment (Resolutions A222, A278, A477)
operator’s unfitness. • ARPA (Resolution A422)
This notation is assigned when the requirements of this • speed and distance measuring equipment
Section are complied with. (Resolution A478)
• echo sounding equipment (Resolution A224)
1.1.3 The composition and the qualification of the
• radio direction finder (Resolution A223)
personnel on watch remain the responsibility of the Owner
and the Administration. The authorisation to operate the • electronic navigational aids – general requirements
ship in such condition remains the responsibility of the (Resolution A574)
Administration. • VHF Radio installation (Resolution A609)
• automatic pilots (Resolution A342)
1.2 Operational Assumptions • rate-of-turn indicators (Resolution A526).
1.3.2 (1/7/2024)
1.2.1 The requirements are framed on the following
The requirements and guidelines of the following
assumptions:
international standards are applicable:
• Plans for emergencies are specified and the conditions • ISO 8468 “Ships bridge layout and associated
under which a one man watch is permitted are clearly equipment – Requirements and guidelines”
defined in an operations manual which is acceptable to
• IEC 872: ARPA – Operational and performance
the Administration with which the ship is registered.
requirements – Methods of testing and required test
• The manning of the bridge watch is in accordance with results
the national regulations in the country of registration • IEC 62388936: Marine navigation and
and for the waters in which the ship is operating. radiocommunication equipment and systems -
• The requirements of the International Convention on Shipborne radar – Operational and pPerformance
Standards of Training Certification and Watchkeeping requirements – M, methods of testing and required test
for seafarers (STCW) and other applicable statutory results
regulations are complied with. • IEC 61023: Marine speed and distance measuring
equipment (SDME) – Operational and performance
1.3 Regulations, guidelines, standards requirements – Methods of testing and required test
results
1.3.1 The requirements are based on the understanding • IEC 60092-504Document 18 (Central Office) 534:
that the applicable regulations and guidelines issued by the Special features – Control and instrumentation.
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Part F
Additional Class Notations
Chapter 9
ICE CLASS (ICE)
SECTION 1 GENERAL

SECTION 3 MACHINERY
RINA Rules 2024 67

Pt F, Ch 9, Sec 3
SECTION 3 MACHINERY
1 Propulsion c0,7 : chord length of blade section at 0,7R propeller

radius, in m
1.1 Propulsion machinery performance CP : controllable pitch
1.1.1 (1/7/2020) D : propeller diameter, in m
The engine output P is the total maximum output that the d : external diameter of propeller hub (at propeller
propulsion machinery can continuously deliver to the pro- plane), in m
peller. If the output of the machinery is restricted by techni- Dlimit : limit value for propeller diameter, in m
cal means or by any regulations applicable to the ship, P is EAR : expanded blade area ratio;
to be taken as the restricted output. In no case may P be less Fb : maximum backward blade force for the ship's
than the values calculated in accordance with Sec 1, [3.1.2] service life, in kN;
or Sec 1, [3.1.4], as applicable. If additional power sources
Fex : ultimate blade load resulting from blade loss
are available for propulsion power (e.g. shaft motors), in
through plastic bending, in kN
addition to the power of the main engine(s), they are also to
be included in the total engine output. Ff : maximum forward blade force for the ship's ser-
vice life, in kN
2 Class notations IAS, IA, IB and IC Fice : ice load, in kN
(Fice)max : maximum ice load for the ship's service life, in
2.1 Propulsion machinery kN
FP : fixed pitch
2.1.1 Scope (1/7/2020) h0 : depth of the propeller centreline from lower ice
These requirements apply to propulsion machinery cover- waterline, in m
ing open- and ducted-type propellers with controllable hice : thickness of maximum design ice block entering
pitch or fixed pitch design for the ice classes IAS, IA, IB and
propeller, in m
IC. The given loads are the expected ice loads throughout
the ship's service life under normal operational conditions, I : equivalent mass moment of inertia of all parts
including loads resulting from the changing rotational on engine side of component under considera-
direction of FP propellers. However, these loads do not tion, in kgm2
cover off-design operational conditions, for example when It : equivalent mass moment of inertia of the whole
a stopped propeller is dragged through ice. The regulations propulsion system, in kgm2
also apply to azimuthing and fixed thrusters for main pro- k : shape parameter for Weibull distribution
pulsion, considering loads resulting from propeller-ice inter- LIWL : lower ice waterline, in m
action; the given azimuthing thruster body loads are the
expected ice loads for the ship’s service life under normal m : slope for S-N curve in log/log scale, in kNm
operational conditions. The local strength of the thruster MBL : blade bending moment
body is to be sufficient to withstand local ice pressure when MCR : maximum continuous rating
the thruster body is designed for extreme loads. However, n : propeller rotational speed, in rev./s
the load models of the regulations do not include propel- nn : nominal propeller rotational speed at MCR in
ler/ice interaction loads when ice enters the propeller of a
free running condition, in rev./s
turned azimuthing thruster from the side (radially) or the
load case when an ice block hits the propeller hub of a pull- Nclass : reference number of impacts per propeller rota-
ing propeller. Ice loads resulting from ice impacts on the tional speed per ice class
body of thrusters are to be estimated, but ice load formulae Nice : total number of ice loads on propeller blade for
are not available. the ship's service life
The thruster global vibrations caused by blade order excita- NR : reference number of load for equivalent fatigue
tion on the propeller may cause significant vibratory loads. stress (108 cycles)
NQ : number of propeller revolutions during a mill-
2.2 Symbols ing sequence
2.2.1 (1/7/2020) P0,7 : propeller pitch at 0,7R radius, in m
The symbols used in the formulae of this Section have the P0,7n : propeller pitch at 0,7R radius at MCR in free
meaning indicated hereinafter. The loads considered are running condition, in m
defined in Tab 1. P0,7b : propeller pitch at 0,7R radius at MCR in bollard
c : chord length of blade section, in m; condition, in m

Pt F, Ch 9, Sec 3
0,2 minimum yield or 0.2% proof strength to be specified

on the drawing 4  EAR 3
C spex = C sp  C fex = 0 7   1 –  ------------------- 
  Z  
c, t, and r are, respectively, the length, thickness, and radius
of the cylindrical root section of the blade at the weakest
section outside the root filet.
Csp is a non-dimensional parameter taking account of the
2.5.6 Spindle Torque, Qsex (1/7/2020) spindle arm

Cfex is a non-dimensional parameter taking account of the
The maximum spindle torque due to a blade failure load
reduction of the blade failure force at the location of the
acting at 0.8R is to be determined. The force that causes
maximum spindle torque.
blade failure typically reduces when moving from the pro-
peller centre towards the leading and trailing edges. At a If Cspex is below 0,3, a value of 0,3 is to be used for Cspex
certain distance from the blade centre of rotation, the maxi- CLE0.8 is the leading edge portion of the chord length at
mum spindle torque will occur. This maximum spindle
0.8R
torque is to be defined by an appropriate stress analysis or
using the equation given below. CTE0.8 is the trailing edge portion of the chord length at
0.8R
Qsex = max(CLE0,8;0,8·CTE0,8)·Cspex· Fex [kNm]
Fig 6 illustrates the spindle torque values due to blade fail-
where ure loads across the entire chord length.
Figure 6 : Schematic figure showing a blade failure load and the related spindle torque when the force acts at a dif-
ferent location on the chord line at radius 0.8R. (1/7/2020)
2.6 Design fied formulae can be used in estimating the blade

stresses for all propellers at the root area (r/R < 0,5). The
2.6.1 Design principle (1/1/2010) root area dimensions based on the following formula
The strength of the propulsion line is to be designed accord- can be accepted even if the FEM analysis would show
ing to the pyramid strength principle. greater stresses at the root area.
This means that the loss of the propeller blade is not to
cause any significant damage to other propeller shaft line M BL
components.  st = C 1 --------------------- [MPa]
100  ct
2
2.6.2 Propeller blade (1/4/2021) where

a) Calculation of blade stresses
The blade stresses are to be calculated for the design acutal stress
loads given in [2.5.2]. Finite element analysis is to be constant C 1 is the ---------------------------------------------------------------------------------------------
stress obtained with beam equation
used for stress analysis for final approval for all propel-
lers. When this analysis is carried out by the Designer, it If the actual value is not available, C1 is to be taken as
is to be submitted to the Society. The following simpli- 1,6.
RINA Rules 2024 95

Pt F, Ch 9, Sec 3
MBL = (0,75 - r/R) · R · F , for relative radius r/R < 0,5 Figure 7 : Two-slope S-N curve (1/1/2010)
F is the maximum of Fb and Ff, whichever is greater.

Slope 4,5
b) Acceptability criterion
amplitude
The following criterion for calculated blade stresses is to
be fulfilled. Slope 10
(ref2 / st ) > 1,53
Stress
s exp
where:
st is the calculated stress for the design loads. If FEM

analysis is used in estimating the stresses, von Mises
stresses are to be used. 1,E+0,4 1,E+0,6 1,E+0,8 1,E+10
Numbers of loads
ref2 is the reference stress, defined as:
Figure 8 : Constant-slope S-N curve (1/1/2010)
ref2 = 0,7 · u or
ref2 = 0,6 · 0,2 + 0,4 · u , whichever is the lesser.
c) Fatigue design of propeller blade

amplitude
Slope m=8
The fatigue design of the propeller blade is based on an
Slope m=10
estimated load distribution for the service life of the ship
and the S-N curve for the blade material. An equivalent
Stress
stress that produces the same fatigue damage as the

expected load distribution is to be calculated and the
s exp
acceptability criterion for fatigue is to be fulfilled as
given in this section. The equivalent stress is normalised
for 100 million cycles.
For material with a two-slope F-N curve if the following 1,E+0,4 1,E+0,6 1,E+0,8 1,E+10
criterion is fulfilled, fatigue calculations according to Numbers of loads
this chapter are not required.
d) Equivalent fatigue stress:
exp > B1 · ref2B · log (Nice)B
2 3
the equivalent fatigue stress for 100 million stress cycles
which produces the same fatigue damage as the load
where B1, B2 and B3 coefficients for open and ducted distribution is:
propellers are given in Tab 15.
fat =  · (ice)max
An alternative approach may be accepted by the Society where:
on a case-by-case basis, if deemed equivalent based on
(ice)max = 0,5 ((ice)f max - (ice)b max)
the information provided by the manufacturer.
(ice)max is the mean value of the principal stress ampli-
tudes resulting from design forward and backward blade
Table 15 (1/4/2021) forces at the location being studied
(ice)f max is the principal stress resulting from forward
Open propeller Ducted propeller load
B1 0,00328 0,00223 (ice)b max is the principal stress resulting from backward
load.
B2 1,0076 1,0071
In calculation of (ice)max, case 1 and case 3 (or case 2
B3 2,101 2,471 and case 4) are considered as a pair for (ice)f max, and
(ice)b max calculations. Case 5 is excluded from the
fatigue analysis.
For calculation of equivalent stress, two types of S-N
curves are available. e) Calculation of  parameter for two-slope S-N curve:
The parameter  relates the maximum ice load to the
1) Two-slope S-N curve (slopes 4.5 and 10) (see Fig 7). distribution of ice loads according to the regression for-
mulae.
2) One-slope S-N curve( the slope can be chosen) (see
Fig 8).  = C1 · (ice)max c · fl c · log(Nice)c
2 3 4
where:
The type of the S-N curve is to be selected to correspond
to the material properties of the blade. If the S-N curve fl =  · v · m · exp
is not known, the two-slope S-N curve is to be used. fl =  ·  · v · m · exp

Part F
Additional Class Notations
Chapter 10
POLAR CLASS (POLAR)
SECTION 1 GENERAL
SECTION 2 HULL
SECTION 3 MACHINERY
107
RINA Rules 2024
...OMISSIS...
Pt F, Ch 10, Sec 3
SECTION 3 MACHINERY
1 General the case of propeller damage including the Controllable

Pitch (CP)- mechanism. Sufficient ship operation means that
the ship should be able to reach safe haven (safe location)
1.1 Application
where repairs can be undertaken. This may be achieved
1.1.1 (1/7/2024) either by a temporary repair at sea, or by towing, assuming
This Section applies to main propulsion, steering gear, assistance is available. This would lead however to a condi-
emergency and essential auxiliary systems essentialrequired tion of approval.
for the safety of the ship and the survivability of the crew.
1.3.3 (1/7/2024)
The ship operating conditions are defined in Sec 2. Means are to be provided to free a stuck propeller by
The requirements herein are additional to those applicable turning it in reverse direction. This is also to be possible for
for the basic open water class of the ship. a propulsion plant intended for unidirectional rotation.
1.3.4 (1/7/2024)
1.2 Drawings and particulars to be The propeller is to be fully submerged at the ships LIWL.
submitted
1.2.1 (1/7/2024) 2 Materials
The following drawings and particulars are to be submitted.
1.2.12 (1/7/2024) 2.1 General
Details of the intended environmental operational 2.1.1 (1/7/2024)
conditions and therequired ice strengtheningpolar class Materials are to be of an approved ductile material. Ferritic
for the machinery, if different from the ship's polarice nodular cast iron may be used for parts other than bolts. For
class. nodular cast iron an averaged impact energy value of 10 J at
1.2.23 (1/7/2024) testing temperature is regarded as equivalent to the Charpy
Detailed drawings and descriptions of the main propulsion, V test requirements defined below.
steering, emergency and auxiliary machinery. Description
of the main propulsion, steering, and emergency and 2.12 Materials exposed to sea water
essential auxiliaries is to include operational limitations.
2.12.1 (1/7/2024)
Iinformation on the essential main propulsion load control
functions. The descriptions are to include operational Materials exposed to sea water, such as propeller blades,
limitations. propeller hubs and cast thruster bodiesblade bolts, are to
have an elongation not less than 15% on a test specimen
1.2.34 (1/7/2024)
according to Pt D, Ch 1, Sec 2piece the length of which
Description detailing howwhere main, emergency and isfive times the diameter.
auxiliary systems are located and how they are protected to
prevent problems from freezing, ice and snow, Charpy V-notch impact testsing areis to be carried out for
accumulation and evidence of their capability to operate in materials other than bronze and austenitic steel materials.
the intended environmental conditions. The Ttests are to be carried out on three specimens at
minus 10 ºC and thepieces taken from the propeller
1.2.45 (1/3/2008) castings are to be representative of the thickest
Calculations and documentation indicating compliance section of the blade.An average impact energy value
with the requirements of this Section. ofis to be not less than 20 J taken from three Charpy V
tests is to be obtained at minus 10 ºC.
1.3 System Design However, Charpy V impact test requirements of Pt D, Ch 2,
1.3.1 (1/3/2008) Sec 3 or Pt D, Ch 4, Sec 2 as applicable for ships with ice
Machinery and supporting auxiliary systems are to be class notation, are also to be applied to ships covered by
designed, constructed and maintained to comply with the this Section.
requirements of "periodically unmanned machinery spaces"
with respect to fire safety. Any automation plant (i.e. 2.23 Materials exposed to sea water
control, alarm, safety and indication systems) for essential temperature
systems installed is to be maintained to the same standard.
2.23.1 (1/7/2024)
1.3.21 (1/3/2008)
Materials exposed to sea water temperature are to be of
Systems subject to damage by freezing are to be drainable.
steel or other approved ductile material.
1.3.32 (1/7/2024)
Charpy V-notch impact testing is to be carried out for
Single screw ships classed PC1 to PC5 inclusive are to have
materials other than bronze and austenitic steel. The tests
means provided to ensure sufficient vesselship operation in are to be carried out on three specimens at minus 10 ºC,
RINA Rules 2024

127
Pt F, Ch 10, Sec 3
and Anthe average impact energy value ofis to be not less h0 : depth of the propeller centreline from lower ice
than 20 J taken from three tests is to be obtained at minus waterline (LIWL), in m
10 ºC. However, the Charpy V impact test requirements of (Hice) : Ice block dimension for propeller load
Pt D, Ch 2, Sec 3 as applicable for ships with ice class definition, in m
notation, are also to be applied to ships covered by this
I : equivalent mass moment of inertia of all parts
Section.
on engine side of component under
This requirement applies to components such as but not consideration, in kgm2
limited to blade bolts, CP-mechanisms, shaft bolts, It : equivalent mass moment of inertia of the whole
propeller shaft, strut-pod connecting bolts, etc. This
propulsion system, in kgm2
requirement does not apply to surface hardened
components, such as bearings and gear teeth or sea water k : shape parameter for Weibull distribution
cooling lines (heat exchangers, pipes, valves, fittings etc.). LIWL : lower ice waterline, in m
For a definition of structural boundaries exposed to sea m : slope for S-N curve in log/log scale
water temperature see Sec 2, Fig 2. MBL : blade bending moment, in kNm
MCR : maximum continuous rating
2.34 Material exposed to low air temperature N : number of ice load cycles
2.34.1 (1/7/2024) n : propeller rotational speed, in rev./s
Materials of essential components exposed machinery and nn : nominal propeller rotational speed at MCR in
foundationsto low air temperature are to be manufactured free running condition, in rev./s
offrom steel or other approved ductile material.
Nclass : reference number of ice impacts per propeller
An average impact energy value of 20 J taken from three revolution per ice class
Charpy V tests is to be obtained at 10 ºC below the lowest Nice : total number of ice load cycles on propeller
design temperature. Charpy V impact tests are not required blade for the ship's service life
for bronze and austenitic steel.
NR : reference number of load cycles for equivalent
This requirement does not apply to surface hardened fatigue stress (108 cycles)
components, such as bearings and gear teeth. For a
NQ : number of propeller revolutions during a
definition of structural boundaries exposed to air
milling sequence
temperature see Sec 2, Fig 2.
P0,7 : propeller pitch at 0,7R radius, in m
3 Definitions P0,7n : propeller pitch at 0,7R radius at MCR in free
running condition, in m
P0,7b : propeller pitch at 0,7R radius at MCR in bollard
3.1 Definition of Symbols
condition, in m
3.1.1 (1/7/2024) PCD : pitch circle diameter, in m
The symbols used in the formulae of this Section have the
Q() : torque, in kNm
meaning indicated hereinafter. The loads considered are
defined in Tab 1. QAmax : maximum response torque amplitude as a
simulation result, in kNm
c : chord length of blade section, in m;
Qemax : maximum engine torque, in kNm
c0,7 : chord length of blade section at 0,7R propeller
QF() : Ice torque excitation for frequency domain
radius, in m
calculations, in kNm
CP : controllable pitch
Qfr : friction torque in pitching mechanism;
D : propeller diameter, in m
reduction of spindle torque, in kNm
d : external diameter of propeller hub (at propeller Qmax : maximum torque on the propeller resulting
plane), in m
from propeller/ice interaction, in kNm
dpin : diameter of shear pin, in mm Qmotor : electric motor peak torque, in kNm
Dlimit : limit value for propeller diameter, in m Qn : nominal torque at MCR in free running
EAR : expanded blade area ratio; condition, in kNm
Fb : maximum backward blade force for the ship's Qr(t) : response torque along the propeller shaft line,
service life (negative sign), in kN; in kNm
Fex : ultimate blade load resulting from blade failure Qpeak : maximum of the response torque Qr(t), in kNm
through plastic bending, in kN Qsmax : maximum spindle torque of the blade for the
Ff : maximum forward blade force for the ship's ship's service life, in kNm
service life (positive sign), in kN Qsex : extreme spindle torque corresponding to the
Fice : ice load, in kN blade failure load Fex, in kNm
(Fice)max : maximum ice load for the ship's service life, in Qvib : vibratory torque at considered component,
kN taken from frequency domain open water TVC,
FP : fixed pitch in kNm
128 RINA Rules 2024

Pt F, Ch 10, Sec 3
R : propeller radius, in m v : the reduction factor for fatigue; variable

S : Safety factor amplitude loading effect
Sfat : Safety factor for fatigue m : the reduction factor for fatigue; mean stress
Sice : Ice strength index for blade ice force effect
r : blade section radius, in m  : a reduction factor for fatigue correlating the
T : Hydrodynamic propeller thrust in bollard maximum stress amplitude to the equivalent
condition, in kN fatigue stress for 108 stress cycles
Tb : maximum backward propeller ice thrust for the 0,2 : proof yield strength of (at 0.2% plastic strain)
ship's service life, in kN material, in MPa
Tf : maximum forward propeller ice thrust for the exp : mean fatigue strength of blade material at 108
ship's service life, in kN cycles to failure in sea water, in MPa
Tn : propeller thrust at MCR in free running fat : equivalent fatigue ice load stress amplitude for
condition, in kN; 108 stress cycles, in MPa
Tr : maximum response thrust along the shaft line, fl : characteristic fatigue strength for blade material,
in kN in MPa
Tkmax : maximum torque capacity of flexible coupling, ref1 : reference stress ref1 = 0,6 · 0,2 + 0,4 · u, in
in kNm MPa
Tkmax2 : Tkmax at N=1 load cycle, in kNm ref2 : reference stress, in MPa ref2 = 0,7 · u or
Tmax1 : Tkmax at N=5.104 load cycle, in kNm ref2 = 0,6 · 0,2 + 0,4 · u whichever is the lesser
Tkv : vibratory torque amplitude at N=106 load st : maximum stress resulting from Fb or Ff, in MPa
cycles, in kNm u : ultimate tensile strength of blade material, in
Tkmax : maximum range of Tkmax at N=5.104 load MPa
cycles, in kN icebmax : principal stress caused by the maximum
mt : maximum blade section thickness, in m backward propeller ice load, in MPa
Z : number of propeller blades icefmax : principal stress caused by the maximum
Zpin : number of shear pins forward propeller ice load, in MPa
i : duration of propeller blade/ice interaction iceAmax : maximum ice load stress amplitude at the
expressed in rotation angle, in [deg] considered location on the blade, in MPa
 : the reduction factor for fatigue; scatter and test mean : mean stress, in MPa
specimen size effect iceA(N) : blade stress amplitude distribution, in MPa
Table 1 : Definitions of loads (1/7/2024)
Definition Use of the load in design process

Fb The maximum lifetime backward force on a propeller blade Design force for strength calculation of the propeller blade.
resulting from propeller/ice interaction, including hydrody-
namic loads on that blade. The direction of the force is per-
pendicular to 0,7R chord line. See Fig 1.
Ff The maximum lifetime forward force on a propeller blade Design force for calculation of strength of the propeller
resulting from propeller/ice interaction, including hydrody- blade.
namic loads on that blade. The direction of the force is per-
pendicular to 0,7R chord line.
Qsmax The maximum lifetime spindle torque on a propeller blade In designing the propeller strength, the spindle torque is auto-
resulting from propeller/ice interaction, including hydrody- matically taken into account because the propeller load is
namic loads on that blade. acting on the blade as distributed pressure on the leading
edge or tip area.
Tb The maximum lifetime thrust on propeller (all blades) result- Is used for estimation of the response thrust Tr. Tb can be used
ing from propeller/ice interaction. The direction of the thrust as an estimate of excitation for axial vibration calculations.
is the propeller shaft direction and the force is opposite to the However, axial vibration calculations are not required in the
hydrodynamic thrust. Rules.
Tf The maximum lifetime thrust on propeller (all blades) result- Is used for estimation of the response thrust Tr. Tf can be used
ing from propeller/ice interaction. The direction of the thrust as an estimate of excitation for axial vibration calculations.
is the propeller shaft direction acting in the direction of hydro- However, axial vibration calculations are not required in the
dynamic thrust. Rules.
RINA Rules 2024 129

Pt F, Ch 10, Sec 3
Definition Use of the load in design process

Qmax The maximum ice-induced torque resulting from propeller/ice Is used for estimation of the response torque (Qr) along the
interaction on one propeller blade, including hydrodynamic propulsion shaft line and as excitation for torsional vibration
loads on that blade. calculations.
Fex Ultimate blade load resulting from blade loss through plastic Blade failure load is used to dimension the blade bolts, pitch
bending. The force that is needed to cause total failure of the control mechanism, propeller shaft, propeller shaft bearing
blade so that plastic hinge is caused to the root area. The and thrust bearing. The objective is to guarantee that total
force is acting on 0,8R. propeller blade failure should not cause damage to other
components.
Qsex Maximum spindle torque resulting from blade failure load Is used to ensure pyramid strength principle for the pitching
mechanism.
Qr Maximum response torque along the propeller shaft line, tak- Design torque for propeller shaft line components.
ing into account the dynamic behaviour of the shaft line for
ice excitation (torsional vibration) and hydrodynamic mean
torque on the propeller.
Tr Maximum response thrust along shaft line, taking into Design thrust for propeller shaft line components.
account the dynamic behaviour of the shaft line for ice excita-
tion (axial vibration) and hydrodynamic mean thrust on the
propeller.
Figure 1 : Direction of the backward blade force resultant taken perpendicular to the chord line at radius 0,7R. Ice
contact pressure at leading edge is shown with small arrows (1/7/2024)
Shaft direction
Back side
Fb
Direction of
rotation
34 Design Ice interaction lLoads fixed(geared and podded) thrusters with geared
transmission or an integrated electric motor (“geared and
podded propulsors”), considering loads due to propeller ice
34.1 Propeller ice interactionGeneral interaction. However, the load models of the regulations do
not include propeller/ice interaction loads when ice enters
34.1.1 (1/7/2024)
the propeller of a turnedice loads due to ice impacts on the
This Section covers open and ducted type propellers body of azimuthing thrusters are not covered by this
situated at the stern of a ship having controllable pitch or Sectionfrom the side (radially) or loads when ice blocks hit
fixed pitch blades. Ice loads on bow-mounted propellers on the propeller hub of a pulling propeller. Ice loads
and pulling type propellers are to receive special resulting from ice impacts on the body of thrusters are to be
consideration. The given loads are expected, single estimated on a case by case basis, however are not
occurrence, maximum values for the whole ship's service included within this Section.
life for normal operational conditions, including loads
resulting from directional change of rotation where The loads given in this item [4.3] are total loads
applicable. These loads do not cover off-design operational including(unless otherwise stated) during ice-induced
conditions, for example when a stopped propeller is loads and hydrodynamic loads (unless otherwise stated)
dragged through ice. This Section also applies tocover loads during ice interaction, and are to be applied separately
due to propeller ice interaction for azimuthing and (unless other-wise stated) and are intended for component
strength calculations only. The different loads given here are
to be applied separately.
130 RINA Rules 2024
Pt F, Ch 10, Sec 3
Fb is the maximum force experienced during the lifetime of 34.2 Ice Class fFactors
the ship that bends a propeller blade backwards when the
34.2.1 (1/7/2024)
propeller mills an ice block while rotating ahead. Ff is the
The dimensions of the considered design ice block are Hice
maximum force experienced during the lifetime of the ship
x 2Hice x 3Hice. The design ice block and ice strength index
that bends a propeller blade forwards when the propeller
mills an ice block while rotating ahead. Fb and Ff originate (Sice) are used for the estimation of propeller ice loads. Both
from different propeller/ice interaction phenomena, which Hice and Sice are defined for each Ice class in Tab 12.
do not act simultaneously. Hence they are to be applied lists the design ice thickness and ice strength index to be
separately. used for estimation of the propeller ice loads.
• Fb is a force bending a propeller blade backwards when
the propeller mills an ice block while rotating ahead.
• Ff is a force bending a propeller blade forwards when
the propeller interacts with an ice block while rotating
ahead.
Table 12 Design Ice Class Factors (1/7/2024)
IIcePolar Class Hice [m] Sice [-] Sgice [-]
PC1 4,0 1,2 1,15

PC2 3,5 1,1 1,15
PC3 3,0 1,1 1,15
PC4 2,5 1,1 1,15
PC5 2,0 1,1 1,15
PC6 1,75 1 1
PC7 1,5 1 1
Hice : Ice thickness for machinery strength design where:

Sice : Ice strength index for blade ice force • Dlimit = 0,85 ( Hice)1.4, in m
Sgice : Ice strength index for blade ice torque. • n is the nominal rotational speed (at MCR in the free
running open water condition) for a CP -propellers and
34.3 DesignPropeller ice interaction loads for 85% of the nominal rotational speed (at MCR free
running condition) for a FP -propeller (regardless of
open propeller
driving engine type)[rps].
34.3.1 Maximum backward blade force, Fb for open For ships with the additional notation Icebreaker, the
propellers (1/7/2024) above stated backward blade force Fb is to be multiplied by
The maximum backward blade force Fb, in KN, is equal to: a factor of 1,1.
• when D < Dlimit Fb is to be applied as a uniform pressure distribution to an
area on the back (suction) side of the blade for the following
ꞏ
0 3 load cases:
F b = – 27 S ice  nD 
0 7  EAR
----------- D2
 Z  a) Load case 1: from 0,6R to the tip and from the blade
leading edge to a value of 0,2 chord length,
ꞏ
0 3
b) Load case 2: a load equal to 50 % of the Fb is to be
F b = 27S ice  nD 
0 7  EAR
-----------  D 2 applied on the propeller tip area outside of 0,9R
 Z 
c) Load case 5: for reversible propellers a load equal to
• when D >Dlimit 60% of the Fb, is to be applied from 0,6R to the tip and
from the blade trailing edge to a value of 0,2 chord
ꞏ
0 3
length.
F b = – 23 S ice  nD 
0 7  EAR
-----------  H ice  1 4  D 
 Z  See load cases 1, 2 and 5 in Tab 3.
34.3.2 Maximum forward blade force, Ff for open

propellers (1/7/2024)
ꞏ
0 3
F b = 23S ice  nD 
0 7  EAR
-----------  H ice  1 4  D 
The maximum forward blade force, Ff , in KN, is equal to:
 Z 
• when D < Dlimit
RINA Rules 2024 131

Pt F, Ch 10, Sec 3
Ff is to be applied as a uniform pressure distribution to an

area on the face (pressure) side of the blade for the
F f = 250  -----------  D  2
EAR
 Z  following load cases:
• when D >Dlimit a) Load case 3: from 0,6R to the tip and from the blade
leading edge to a value of 0,2 chord length
  b) Load case 4: a load equal to 50 % of the Ff is to be
F f = 500  -------------- H ice  -----------  D 
1 EAR
 d  Z  applied on the propeller tip area outside of 0,9R
 1 – ----
D
c) Load case 5: for reversible propellers a load equal to
where: 60% Ff is to be applied from 0,6R to the tip and from the
blade trailing edge to a value of 0,2 chord length,
  See load cases 3, 4, and 5 in Tab 4.

D limit =  -------------- H ice
2
 d
 1 – ---- 4.3.3 Loaded area on the blade for open
D propellers (1/7/2024)
• d = propeller hub diameter, in m
Load cases 1-4 are to be covered, as given in Tab 3, for CP
• D = propeller diameter, in m and FP propellers. In order to obtain blade ice loads for a
• EAR = expanded blade area ratio reversing propeller, load case 5 is also to be covered for
• Z = number of propeller blades. propellers where reversing is possible.
132 RINA Rules 2024

Pt F, Ch 10, Sec 3
Table 3 : Loaded areas and load case definition for open propellers (1/l7/2024)
Right-handed propeller
Force Loaded area
blade seen from behind
Load case 1 Fb Uniform pressure applied on the back of the blade (suc-
tion side) to an area from 0,6R to the tip and from the
leading edge to 0,2 times the chord length.
0,2
c
0,6
R
Load case 2 50% of Fb Uniform pressure applied on the back of the blade (suc-
tion side) on the propeller tip area outside of 0,9R radius.
0,9
R
Load case 3 Ff Uniform pressure applied on the blade face (pressure

side) to an area from 0,6R to the tip and from the leading
edge to 0,2 times the chord length.
0,2
c
0,6
R
Load case 4 50% of Ff Uniform pressure applied on propeller face (pressure

side) on the propeller tip area outside of 0,9R radius.
0,9
R
Load case 5 60 % of Ff or Fb, Uniform pressure applied on propeller face (pressure

whichever is the side) to an area from 0,6R to the tip and from the trailing
greater edge to 0,2 times the chord length.
2c
0,
R
0,6
4.3.4 Maximum backward blade ice force, Fb for

ducted propellers (1/7/2024)
The maximum backward blade force Fb, in kN, is equal to: n is to be taken as in [4.3.1].
• when D < Dlimit For ships with the additional notation Icebreaker, the
above stated backward blade force Fb is to be multiplied
0 3 by a factor 1.1.
F b = 9 5 S ice  -----------
EAR
 nD  0 7 D 2
 Z 
4.3.5 Maximum forward blade ice force, Ff for
• when D Dlimit ducted propellers (1/7/2024)
0 3
F b = 66S ice  -----------
EAR
 nD  0 7 D 0 6  H ice  1 4 The maximum forward blade force Ff, in kN, is equal to:
 Z 
• when D  Dlimit
where:
Dlimit = 4 Hice, in m
RINA Rules 2024 133

Pt F, Ch 10, Sec 3
2
F f = 250  ----------- D 2
EAR D limit = -------------------  H ice , in m
 Z   1 – --- d
-
 D
• when D >Dlimit
4.3.6 Loaded area on the blade for ducted
propellers (1/7/2024)
F f = 500  ----------- D ------------------- H ice
EAR 1
 Z 
Load cases 1 and 3 are to be covered, as given in Tab 4, for
 1 – --- d- all propellers. In order to obtain blade ice loads for a
 D
reversing propeller, load case 5 is also to be covered for
where: propellers, where reversing is possible.
134 RINA Rules 2024

Pt F, Ch 10, Sec 3
Table 4 : Loaded areas and load case definition for ducted propellers (1/7/2024)
Right handed propeller

Force Loaded area
blade seen from behind
tion side) to an area from 0,6R to the tip and from the 0,2
c
leading edge to 0,2 times the chord length.
0,
6R

0,5
edge to 0,5 times the chord length. c
0,
6R
Load case 5 60 % of Ff or Uniform pressure applied on propeller face (pressure

60 % of Fb, side) to an area from 0,6R to the tip and from the trailing
whichever is the edge to 0,2 times the chord length.
2c
0,
greater
6R
0,
4.3.7 Maximum blade spindle torque Qsmax for open

and ducted propellers (1/7/2024)
The spindle torque Qsmax around the axis of the blade where:
fitting shall be determined both for the maximum backward
blade force Fb and forward blade force Ff which are applied k : shape parameter of the spectrum
as per Tab 3 and Tab 4. If the above method gives a value Nice : number of load cycles in the spectrum, see
which is less than the default value given by the formula [4.3.9]
below, the default value is to be used. Fice : random variable for ice loads on the blade, 0 
Default value Qsmax = 0,25.F.c0.7 in KNm Fice  (Fice)max
This results in a blade stress amplitude distribution
where:
F is taken as either Fb or Ff whichever has the greater
1
---
absolute value. log  N  k
  ice  A  N  =   ice  Amax   1 – -----------------------
The blade failure spindle torque Qsex is defined in [4.4].  log  N ice 
4.3.8 Load distributions (spectra) for blade where:

loads (1/7/2024)
The Weibull-type distribution (probability that Fice exceeds
(Fice)max ), as given in Fig 2 is used for the fatigue design of   ice  fmax –   ice  bmax
  ice  Amax = --------------------------------------------------
-
the blade. 2
 –  ----------------------- k The shape parameter k = 0,75 is to be used for the ice force
-  ln  N ice 
F
F ice    F ice   
P   -------------------
-  -------------------- = e
F max distribution of an open propeller and the shape parameter k
  F ice  max  F ice  max = 1,0 for that of a ducted propeller blade.
RINA Rules 2024 135

Pt F, Ch 10, Sec 3
Figure 2 : The Weibull-type distribution (probability that Fice exceeds (Fice)max) that is used for fatigue design
(1/7/2024)
4.3.9 Number of ice loads (1/7/2024) where:

Number of load cycles Nice in the load spectrum per blade Nclass is the reference number of impacts per propeller
is to be determined according to the formula: revolution for each ice class (see Tab 5)
Nice = k1.k2.Nclass.n
Table 5 Reference number of impacts (1/7/2024)
Ice Class PC1 PC2 PC3 PC4 PC5 PC6 PC7

Nclass 21x106 17x106 15x106 13x106 11x106 9x106 6x106
k1 = 1 for centre propeller values are less than the default value, in kNm, given below,
the default minimum value is to be used.
= 2 for wing propeller
Default value Qsmax = 0,25 F c0,7
= 3 for pulling propeller (wing and centre)
where:
k2 = 0,8 - f when f < 0
c0,7 = length, in m, of the blade chord at 0,7R radius
= 0,8 - 0.4.f when 0  f  1 F is either Fb or Ff, whichever has the greater absolute value.
= 0,6 - 0.2.f when 1< f  2,5
3.3.4 Maximum propeller ice torque applied to the
= 0,1 when f > 2,5 propeller (1/3/2008)
where the immersion function f is: The maximum propeller ice torque Qmax, in kNm, is equal
f = (h0 - Hice) /(D/2)-1 to:
• when D < Dlimit
If h0 is not known, h0 = D/2.
For ships with the additional notation Icebreaker, the
above stated number of load cycles Nice is to be multiplied Q max = 105  1 – d  D S qice  P 0 7  D  0 16  t 0 7  D  0 6  nD  0 17 D 3
by a factor of 3.
• when D >Dlimit
For components that are subject to loads resulting from
propeller/ice interaction with all the propeller blades, the
1 1  P
Q max = 202  1 – d  D S qice H ice 0 16  t 0 6  nD  0 17 D 1 9
number of load cycles (Nice) is to be multiplied by the 0 7  D  0 7  D 
number of propeller blades (Z).

where:
3.3.3 Maximum blade spindle torque, Dlimit = 1,81 Hice, in m
Qsmax (1/3/2008)
Sqice = Ice strength index for blade ice torque
Spindle torque Qsmax around the spindle axis of the blade
fitting is to be calculated for the load cases described both P0,7 = propeller pitch at 0,7R
in [3.3.1] for Fb and in [3.3.2] for Ff. If these spindle torque t0,7 = max thickness at 0,7 radius
136 RINA Rules 2024

Pt F, Ch 10, Sec 3
n is the rotational propeller speed, in rpm, at bollard

condition. If not known, n is to be taken as follows:
• nn, for CP propellers
F f = 500  ----------- D ------------------- H ice

• nn, for FP propellers driven by turbine or electric motor EAR 1
 Z 
• 0,85 nn, for FP propellers driven by diesel engine,  1 – --- d
-
 D
where nn is the nominal rotational speed at MCR free
running condition. For CP propellers, propeller pitch P0,7 is
to correspond to MCR in bollard condition. If not known,
P0,7 is to be taken as 0,7P0,7n , where P0,7n is propeller pitch where:
at MCR free running condition.
3.3.5 Maximum propeller ice thrust applied to the

shaft (1/3/2008)
The maximum propeller ice thrust Tf and Tb, in kN, are
2
equal to: D limit = -------------------  H ice , in m
 1 – --- d
-
Forward:  D
Tf = 1,1 Ff
Backwards:
Tb = 1,1 Fb
Ff is to be applied as a uniform pressure distribution to
3.4 Design ice loads for ducted propeller an area on the face (pressure) side for the following load
cases (see Tab 3):
3.4.1 Maximum backward blade force, Fb (1/7/2024)
a) Load case 3: on the blade face from 0,6R to the tip
The maximum backward blade force Fb, in kN, is equal to: and from the blade leading edge to a value of 0,5
• when D < Dlimit chord length
b) Load case 5: a load equal to 60% Ff is to be applied
EAR 0 3 from 0,6R to the tip and from the blade leading edge
F b = – 9 5 S ice  -----------  nD  0 7 D 2
 Z  to a value of 0,2 chord length.
• when D >Dlimit 3.4.3 Maximum propeller ice torque applied to the
propeller (1/3/2008)
0 3 Qmax is the maximum torque, in kNm, on a propeller due to
F b = – 66S ice  -----------
EAR
 nD  0 7 D 0 6  H ice  1 4
 Z  ice propeller interaction:
where:
Dlimit = 4 Hice, in m
0 16 0 6
d P 0 7  t------
Q max = 74  1 – ----  -------- 0 7 0 17
n is to be taken as in [3.3.1]. - -  nD  S qice D 3
 D  D   D
Fb is to be applied as a uniform pressure distribution to
an area on the back side for the following load cases • when D  Dlimit
(see Tab 2):
0 16 0 6
d P 0 7  t------
Q max = 141  1 – ----  -------- 0 7 0 17
a) Load case 1: on the back of the blade from 0,6R to - -  nD  S qice D 1 9 H 1 1 ice
 D  D   D
the tip and from the blade leading edge to a value of
0,2 chord length where Dlimit = 1,8 Hice, in m
b) Load case 5: for reversible rotation propellers a load n is the rotational propeller speed, in rps, at bollard
equal to 60% of Fb is applied on the blade face from condition. If not known, n is to be taken as follows:
0,6R to the tip and from the blade trailing edge to a • nn, for CP propellers
value of 0,2 chord length.
• nn, for FP propellers driven by turbine or electric
3.4.2 Maximum forward blade force, Ff (1/3/2008) motor
The maximum forward blade force Ff, in kN, is equal to: • 0,85 nn, for FP propellers driven by diesel engine,
where nn is the nominal rotational speed at MCR free
running condition.
F f = 250  ----------- D 2
EAR
 Z  For CP propellers, propeller pitch P0,7 is to correspond to
MCR in bollard condition. If not known, P0,7 is to be taken
• when D >Dlimit as 0,7P0,7n , where P0,7n is propeller pitch at MCR free
running condition.
RINA Rules 2024 137

Pt F, Ch 10, Sec 3
3.4.4 Maximum blade spindle torque for CP- Tf = 1,1 Ff

mechanism design, Qsmax (1/3/2008) Tb = 1,1 Fb
Spindle torque Qsmax, in kNm, around the spindle axis of the
blade fitting is to be calculated for the load case described 34.54 Blade Failure Load for both Open and
in [3.1.1]. If these spindle torque values are less than the Ducted PropellersDesign loads on
default value given below, the latter value, in kNm, is to be
propulsion line
used:
Default value Qsmax = 0,25 F c0,7 3.5.1 Torque (1/3/2008)
The propeller ice torque excitation for shaft line dynamic
where: analysis is to be described by a sequence of blade impacts
• c0,7 is the length of the blade section at 0,7R radius which are of half sine shape and occur at the blade
frequency or at twice tb blade frequency (see Fig 1). The
• F is is either Fb or Ff, whichever has the greater absolute torque due to a single blade ice impact as a function of the
value. propeller rotation angle is then:
• when i
3.4.5 Maximum propeller ice thrust (applied to the
shaft at the location of the propeller) Q () = Cq Qmax sin [(180 / i)]
(1/3/2008) • when i...360
The maximum propeller ice thrust Tf and Tb, in kN, are Q () = 0
equal to: where Cq and i parameters are given in Tab 2.
Table 2 : Parameters Cq and αi
Torque excitation Propeller ice interaction Cq i
Case 1 Single ice block 0,5 45

Case 4 Two ice blocks with 45 degree phase 0,5 45
in rotation angle
The total ice torque is obtained by summing the torque of vibration. Alternatively, the propeller thrust magnification
single blades taking into account the phase shift 360°/Z. factor may be calculated by dynamic analysis.
The number of propeller revolutions during a milling • Maximum shaft thrust forwards Tr = Tn + 2,2Tf
sequence is to be obtained with the formula:
• Maximum shaft thrust backwards Tr = 1,5 Tb
NQ = 2 Hice
where:
The number of impacts is Z NQ. Tn = propeller bollard thrust, in kN
See Fig 1. Tf and Tb = maximum forward and backward propeller ice
thrust, in kN
Milling torque sequence duration is not valid for pulling
bow propellers, which are subject to special consideration. If hydrodynamic bollard thrust, Tn, is not known, Tn is to be
taken as follows:
The response torque at any shaft component is to be
• 1,25 T, for CP propellers (open)
analysed considering excitation torque Q() at the propeller,
• 1,1 T, for CP propellers (ducted)
actual engine torque Qe and mass elastic system.
• T for FP propellers driven by turbine or electric motor
Qe = actual maximum engine torque at considered speed • 0,85 T, for FP propellers driven by diesel engine (open)
The design torque (Qr) of the shaft component is to be • 0,75 T, for FP propellers driven by diesel engine (ducted)
determined by means of torsional vibration analysis of the
T = nominal propeller thrust at MCR at free running open
propulsion line. Calculations are to be carried out for all
water condition.
excitation cases given above and the response is to be
applied on top of the mean hydrodynamic torque in bollard 34.54.31 Bending Force, FexBlade failure load for
condition at the considered propeller rotational speed. both open and ducted propeller (1/7/2024)
The minimum load required resulting in blade failure
3.5.2 Maximum response thrust (1/3/2008) through plastic bending. This is to be calculated iteratively
Maximum thrust along the propeller shaft line is to be along the radius of the blade from blade root to 0,5R using
calculated with the formulae below. The factors 2,2 and 1,5 the below equation with the ultimate load assumed to be
take into account the dynamic magnification due to axial acting at 0,8R in the weakest direction.The force is acting at
138 RINA Rules 2024

Pt F, Ch 10, Sec 3
0,8R in the weakest direction of the blade and at a spindle 4.4.2 Spindle Torque, Qsex (1/7/2024)
arm of 2/3 of the distance of the axis of blade rotation of The maximum spindle torque due to a blade failure load
leading and trailing edge, whichever is the greater. acting at 0,8R is to be determined. The force that causes
blade failure typically reduces when moving from the
The blade failure load, in kN, is equal to:
propeller centre towards the leading and trailing edges. At a
certain distance from the blade centre of rotation, the
maximum spindle torque will occur. This maximum spindle
0 3  c  t   ref
2
-  10 3
F ex = ------------------------------------ torque is to be defined by an appropriate stress analysis or
08  D – 2  r
using the equation given below.
Qsex = max(CLE0,8;0,8·CTE0,8)·Cspex· Fex [kNm]
0 3  c  t   ref1
2
where:
-  10 3
F ex = --------------------------------------
08  D – 2  r
4  EAR 3
where σref1 = 0,6 σ0,2 + 0,4 σu C spex = C sp  C fex = 0 7   1 –  ------------------- 
  Z  
and where σu (minimum ultimate tensile strength to be
specified on the drawing) and σ0,2 (minimum yield or 0,2%
Csp is a non-dimensional parameter taking account of the
proof strength to be specified on the drawing) are
spindle arm
representative values for the blade material, in N/mm2.
Cfex is a non-dimensional parameter taking account of the
c, t and r are, in mm, respectively the actual chord length, reduction of the blade failure force at the location of the
maximum thickness and radius of the cylindrical root maximum spindle torque.
section of the blade, atwhich is the weakest section outside
If Cspex is below 0,3, a value of 0,3 is to be used for Cspex
the root fillet and willlocated typically be at the termination
of the fillet into the blade profile. CLE0.8 is the leading edge portion of the chord length at
0.8R
The Society may approve alternative means of failure load
CTE0.8 is the trailing edge portion of the chord length at
calculation by means of an appropriate stress analysis
reflecting the non-linear plastic material behaviour of the 0.8R
actual blade. A blade is regarded as having failed, if the tip Fig 3 illustrates the spindle torque values due to blade
is bent by more than 10% of the propeller diameter. failure loads across the whole chord length.
Figure 3 : Schematic figure showing blade failure load and related spindle torque when the force acts at different
location on the chord line at radius 0.8R. (1/7/2024)
RINA Rules 2024 139

Pt F, Ch 10, Sec 3
4.5 Axial design loads acting on open and where :

ducted propellers kopen = 14,7 for PC1 - PC5; and
kopen = 10,9 for PC6 - PC5
4.5.1 Maximum ice thrust on propeller Tf and Tb
acting on open and ducted when D ≥ Dlimit :
propellers (1/7/2024) 0 16
d P 0 7
The maximum forward and backward ice thrusts are: Q max = 1 9  k open  1 – ---- --------
-  nD  0 17 D 1 9 H 1 1 ice  kNm 
D D
Tf = 1,1 · Ff [kN]
Tb = 1,1 · Fb [kN] where
However, the load models within this Section do not Dlimit = 1,8 · Hice [m]
include propeller/ice interaction loads where an ice block n is the rotational propeller speed in rev/s in bollard
hits the propeller hub of a pulling propeller. condition. If not known, n is to be taken as indicated in
Tab 7.
4.5.2 Design thrust along the propulsion shaft line
for open and ducted propellers (1/7/2024)
Table 7 Guidance for rotational speeds to calculate
The design thrust along the propeller shaft line is to be
torsional loads (1/7/2024)
calculated with the formulae below. The greater value of the
forward and backward direction load is to be taken as the
Rotational
design load for both directions. The factors 2,2 and 1,5 take Propeller type
speed n
into account the dynamic magnification resulting from axial
vibration. CP propellers nn
In a forward direction: FP propellers driven by turbine or elec- nn
Tr = T + 2,2 · Tf [kN] tric motor
In a backward direction: FP propellers driven by diesel engine 0,85 nn
Tr = 1,5 · Tb [kN]
If the hydrodynamic bollard thrust, T, is not known, T is to For CP propellers, the propeller pitch P0,7 is to correspond to
be taken as indicated in Tab 6. MCR in bollard condition. If not known, P0,7 is to be taken
as 0,7 · P0,7n, where P0,7n is the propeller pitch at MCR in
Table 6 Guidance for bollard thrust values (1/7/2024) free running condition.
Propeller type T 4.6.2 Design ice torque on propeller Qmax for

ducted propellers (1/7/2024)
CP propellers (open) 1,25 Tn
when D < Dlimit :
CP propellers (ducted) 1,1 Tn
FP propellers driven by turbine or electric Tn 0 16

d P 0 7
motor Q max = k ducted  1 – ---- ---------  nD  0 17 D 3  kNm 
D D
FP propellers driven by diesel engine (open) 0,85 Tn
where :
FP propellers driven by diesel engine (ducted) 0,75 Tn
kducted = 10,4 for PC1 - PC5; and
Here, Tn is the nominal propeller thrust at MCR in free run- kducted = 7,7 for PC6 - PC7
ning open water condition. when D ≥ Dlimit :
For pulling type propellers ice interaction loads on propeller
hub are to be considered in addition to the above. These 0 16
will be considered by the Society on case by case basis. d P 0 7
Q max = 1 9  k ducted 1 – ---- ---------  nD  0 17 D 1 9 H 1 1 ice  kNm 
D D
4.6 Torsional design loads acting on open

and ducted propellers where:
4.6.1 Design ice torque on propeller Qmax for open Dlimit = 1,8 · Hice [m]
propellers (1/7/2024) n is to be taken as in [4.6.1].
Qmax is the maximum torque on a propeller resulting from
For CP propellers, the propeller pitch P0,7 is to correspond to
ice/propeller interaction. MCR in bollard condition. If not known, P0,7 is to be taken
when D < Dlimit : as 0,7 · P0,7n, where P0,7n is the propeller pitch at MCR in
free running condition.
0 16
d P 0 7
Q max = k open  1 – ---- ---------  nD  0 17 D 3  kNm 
D D
140 RINA Rules 2024

Pt F, Ch 10, Sec 3
4.6.3 Ice torque excitation for open and ducted propeller revolution and vice versa to decrease it to zero
propellers (1/7/2024) (see the examples of different Z numbers in Fig 12 and
The given excitations are used to estimate the maximum Fig 13).
torque likely to be experienced once during the service life The number of propeller revolutions during a milling
of the ship. The following load cases are intended to reflect sequence are to be obtained from the formula:
the operational loads on the propulsion system when the NQ = 2·Hice
propeller interacts with ice and the corresponding reaction
of the complete system. The ice impact and system The number of impacts is Z·NQ for blade order
response cause loads in the individual shaft line excitation.
components. The ice torque Qmax may be taken as a An illustration of all excitation cases for different blade
constant value in the complete speed range. When numbers is given in Fig 12 and Fig 13.
considerations at specific shaft speeds are performed a
A dynamic simulation is to be performed for all
relevant Qmax may be calculated using the relevant speed.
excitation cases starting at MCR nominal, MCR bollard
Diesel engine plants without an elastic coupling are to be condition and just above all resonance speeds (1st
calculated at the least favourable phase angle for ice versus
engine and 1st blade harmonic), so that the resonant
engine excitation, when calculated in time domain. The
vibration responses can be obtained. For a fixed pitch
engine firing pulses are to be included in the calculations
propeller propulsion plant the dynamic simulation is to
and their standard steady state harmonics can be used. A
also cover bollard pull condition with a corresponding
phase angle between ice and gas force excitation does not
speed assuming the maximum possible output of the
need to be regarded in frequency domain analysis. Misfiring
engine.
does not need to be considered.
If a speed drop occurs down to stand still, it indicates
If there is a blade order resonance just above MCR speed,
that the engine may not be sufficiently powered for the
calculations are to cover the rotational speeds up to 105%
intended service task. For the consideration of loads, the
of MCR speed.
maximum occurring torque during the speed drop
See also Guidelines for calculations given in [4.7] process is to be applied. On these cases, the excitation
a) Excitation for the time domain calculation is to follow the shaft speed.
The propeller ice torque excitation for shaft line b) Frequency domain excitation
transient dynamic analysis (time domain) is defined as a For frequency domain calculations the following torque
sequence of blade impacts which are of half sine shape excitation may be used. The excitation has been derived
and occur at the blade. The torque due to a single blade so that the time domain half sine impact sequences
ice impact as a function of the propeller rotation angle have been assumed to be continuous and the Fourier
is then defined using the formula: series components for blade order and twice the blade
when  rotates from 0 to i plus integer revolutions: order components have been derived. The frequency
Q() = Cq · Qmax · sin ((180/i)) domain analysis is generally considered as conservative
when  rotates from i to 360 plus integer revolutions: compared to the time domain simulation provided there
is a first blade order resonance in the considered speed
Q() = 0
range.
Where:
QF() = Qmax · (Cq0 + Cq1 · sin (Z · E0 ·  + 1) + Cq2 ·
 is the rotation angle starting when the first impact
sin(2 · Z · E0 ·  + 2)) [kNm]
occurs
Cq and i are given in Tab 8. Where:
i is the duration of propeller blade/ice interaction Cq0 is mean torque component
expressed in propeller rotation angle. Cq1 is the first blade order excitation amplitude
The total ice torque is obtained by summing the torque Cq2 is the second blade order excitation amplitude
of single blades, taking account the phase shift 360
1, 2 are phase angle of the excitation component
deg./Z.
At the beginning and end of the milling sequence Z is the number of blades
(within the calculated duration) linear ramp functions E0 is the number of ice blocks in contact
are to be used to increase Cq to its maximum within one The values of the coefficients are given in Tab 9
Table 8 Ice impact magnification and duration factors for different blade numbers (1/7/2024)
i [deg] i [deg] i [deg] i [deg]

Torque excitation Propelled/ice interaction Cq
Z=3 Z=4 Z=5 Z=6
Excitation case 1 Single ice block 0,75 90 90 72 60
RINA Rules 2024 141

Pt F, Ch 10, Sec 3
i [deg] i [deg] i [deg] i [deg]

Torque excitation Propelled/ice interaction Cq
Z=3 Z=4 Z=5 Z=6
Excitation case 3 Two ice block (phase shift 360/(2.Z) 0,5 45 45 36 30
deg.)
Table 9 Coefficients for simplified excitation torque estimation (1/7/2024)
Torque excitation Cq0 Cq1 1 Cq2 2 E0
Torque Excitation: Z = 3
Excitation case 1 0,375 0,375 -90 0 0 1
Excitation case 2 0,7 0,33 -90 0,05 -45 1
Excitation case 3 0,25 0,25 -90 0 0 2
Excitation case 4 0,2 0,25 0 0,05 -90 1
Excitation case 1 0,45 0,36 -90 0,06 -90 1
Excitation case 2 0,9375 0 -90 0,0625 -90 1
Excitation case 3 0,25 0,251 -90 0 0 2
Excitation case 4 0,2 0,25 0 0,05 -90 1
Excitation case 1 0,45 0,36 -90 0,06 -90 1
Excitation case 2 1,19 0,17 -90 0,02 -90 1
Excitation case 3 0,3 0,25 -90 0,048 -90 2
Excitation case 4 0,2 0,25 0 0,05 -90 1
Excitation case 1 0,45 0,375 -90 0,05 -90 1
Excitation case 2 1,435 0,1 -90 0 0 1
Excitation case 3 0,3 0,25 -90 0,048 -90 2
Excitation case 4 0,2 0,25 0 0,05 -90 1
Torsional vibration responses are to be calculated for all The highest torque amplitude during a sequence of impacts
excitation cases. is to be determined as half of the range from max to min
torque and is referred to as QAmax.
The results of the relevant excitation cases at the most
critical rotational speeds are to be used in the following An illustration of QAmax is given in Fig 4. It can be
way: determined by:
The highest response torque (between the various lumped

max  Q r  time   – min  Q r  time  
masses in the system) is in the following referred to as peak Q Amax =  ---------------------------------------------------------------------------------------
-  kNm 
torque Qpeak  2 
142 RINA Rules 2024

Pt F, Ch 10, Sec 3
Figure 4 : Interpretation of different torques in a measured curve, as example (1/7/2024)
4.6.4 Design torque along shaft line (1/7/2024) Table 10 Guideline for the determination of maximum
motor torque (1/7/2024)
a) If there is no relevant first order propeller torsional
resonance in the range 20% (of nn ) above and 20%
below the maximum operating speed in bollard Propeller type Qemax
condition (see Tab 7), the following estimation of the Propellers driven by electric motor Qmotor
maximum response torque can be used to calculate the
design torque along the propeller shaft line. CP propellers not driven by electric motor Qn
For directly coupled two stroke Diesel engines without FP propellers driven by turbine Qn
flexible coupling:
FP propellers driven by diesel engine 0,75Qn
Qr = Qemax + Qvib + Qmax . I/It
For all other plants:

4.7 Guideline for torsional vibration
calculation
Qr = Qemax + Qmax . I/It 4.7.1 (1/7/2024)
where: The aim of torsional vibration calculations is to estimate the
torsional loads for individual shaft line components over the
I : equivalent mass moment of inertia of all parts life time in order to determine scantlings for safe operation.
on engine side of component under The model can be taken from the normal lumped mass
consideration and elastic torsional vibration model (frequency domain)
including the damping. Standard harmonics may be used to
It : equivalent mass moment of inertia of the whole
consider the gas forces. The engine torque - speed curve of
propulsion system. the actual plant is to be applied.
All the torques and the inertia moments are to be For time domain analysis the model should include the ice
reduced to the rotation speed of the component being excitation at propeller, the mean torques provided by the
examined. prime mover and the hydrodynamic mean torque produced
by the propeller as well as any other relevant excitations.
If the maximum torque, Qemax, is not known, it is to be
The calculations should cover the variation of phase
taken as in Tab 10 where Qmotor is the electric motor between the ice excitation and prime mover excitation. This
peak torque. is extremely relevant for propulsion lines with direct driven
combustion engines.
b) If there is a first blade order torsional resonance in the
range 20% (of nn ) above and 20% below the maximum For frequency domain calculations the load should be
operating speed (bollard condition), the design torque estimated as a Fourier component analysis of the
(Qr) of the shaft component is to be determined by continuous sequence of half sine load peaks. The first and
second order blade components should be used for
means of a dynamic torsional vibration analysis of the
excitation. The calculation should cover the whole relevant
entire propulsion line in the time domain or
shaft speed range. The analysis of the responses at the
alternatively in the frequency domain. It is then
relevant torsional vibration resonances may be performed
assumed that the plant is sufficiently designed to avoid
for open water (without ice excitation) and ice excitation
harmful operation in barred speed range.
separately. The resulting maximum torque can be obtained
for directly coupled plants by the following superposition:
RINA Rules 2024 143

Pt F, Ch 10, Sec 3
Qpeak = Qemax + Qopw + Qice D : Miners damage sum

where:
Guidance:
Qemax : is the maximum engine torque at considered
rotational speed The stress distribution should be divided into a frequency
Qopw : is the maximum open water response of engine load spectrum having minimum 10 stress blocks (every 10
excitation at considered shaft speed and % of the load). Calculation with 5 stress blocks has been
determined by frequency domain analysis found to be too conservative. The maximum allowable load
is limited by ref2 for propeller blades and yield strength for
Qice : is the calculated torque using frequency domain
all other components. The load distribution (spectrum)
analysis for the relevant shaft speeds, ice should be in accordance with the Weibull distribution.
excitation cases 1-4, resulting in the maximum
response torque due to ice excitation
5.3 Propeller blades
45 Design
5.3.1 Calculation of blade stresses due to static
loads (1/7/2024)
45.1 Design principle
The blade stresses (equivalent and principal stresses) are to
45.1.1 (1/7/2024) be calculated for the design loads given in [4.3]. Finite
The propulsion line is to be designed according to the element analysis (FEA) is to be used for stress analysis as
pyramid strength principle in terms of its strength. This part of the final approval for all propeller blades. The von
means that the loss of the propeller blade is not to cause Mises stresses, taken as st, is to comply with the formula in
any significant damage to other propeller shaft line [5.3.2].
components.
Alternatively the following simplified formulae can be used
The propulsion line components are to withstand maximum in estimating the blade stresses for all propellers in the root
and fatigue operational loads with the relevant safety area (r/R < 0,5) for final approval.
margin. The loads do not need to be considered for shaft
alignment or other calculations of normal operational
M BL
conditions.The strength of the propulsion line is to be  st = C 1 --------------------- [MPa]
100  ct
2
designed:
a) for maximum loads in [3] where
b) such that the plastic bending of a propeller blade will
acutal stress
not cause damage to other propulsion line components constant C 1 is the ---------------------------------------------------------------------------------------------
stress obtained with beam equation
c) with sufficient fatigue strength.
If the actual value is not available, C1 is to be taken as 1,6.
5.2 Fatigue design in general MBL = (0,75 - r/R) · R · F , for relative radius r/R < 0,5
5.2.1 (1/7/2024) F is the maximum of Fb and Ff, whichever is greater.
The design loads are to be based on the ice excitation and
5.3.2 Acceptability criterion for static
where necessary (shafting) dynamic analysis, described as a loads (1/7/2024)
sequence of blade impacts [4.6.3], a). The shaft response
The following criterion for calculated blade stresses is to be
torque is to be determined according [4.6.4].
fulfilled.
The propulsion line components are to be designed so as to
(ref2 / st )  1,3
prevent accumulated fatigue failure when considering the
relevant loads using the linear elastic Miner’s rule as where:
defined below. st is the calculated stress for the design loads. If FE analysis
is used in estimating the stresses, von Mises stresses are to
be used.
n n n
D = ------1 + ------2 + + -----k-  1
N1 N2 Nk 5.3.3 Fatigue design of propeller blade (1/7/2024)
or a) General
For material with a two-slope F-N curve (see Fig 5) the
fatigue calculations defined in this Article are not
j=k
nj required if the following criterion is fulfilled.
D =  -----
N
1
j exp  B1 · ref2B · log (Nice)B 2 3
j=1
where B1, B2 and B3 are coefficients for open and ducted
where: propellers, given in Tab 11.
k : is the number of stress levels Where the above criterion is not fulfilled the fatigue
N1...k : is the number of load cycles to failure of the requirements defined below are to be applied:
individual stress level class The fatigue design of the propeller blade is based on an
n1...k : is the accumulated number of load cycles of the estimated load distribution for the service life of the ship
and the S-N curve for the blade material. An equivalent
case under consideration, per class
144 RINA Rules 2024

Pt F, Ch 10, Sec 3
stress fat that produces the same fatigue damage as the Figure 6 : Constant-slope S-N curve (1/7/2024)
expected load distribution is to be calculated according
to Miner’s rule and the acceptability criterion for fatigue
should be fulfilled as given in this article. The equivalent
stress is normalised for 100 million cycles.
amplitude
Slope m=8
The blade stresses at various selected load levels for
fatigue analysis are to be taken proportional to the Slope m=10
stresses calculated for maximum loads given in [4.3].
The peak principal stresses f and b are determined
Stress
from Ff and Fb using FEA. The peak stress range max
s exp
and the maximum stress amplitude Amax are
determined on the basis of load cases 1 and 3, 2 and 4.
max = 2.Amax = |(ice)fmax| + |(ice)bmax|
1,E+0,4 1,E+0,6 1,E+0,8 1,E+10
The load spectrum for backward loads is normally
Numbers of loads
expected to have a lower number of cycles than the
load spectrum for forward loads. Taking this into b) Equivalent fatigue stress
account in a fatigue analysis introduces complications
that are not justified considering all uncertainties The equivalent fatigue stress for 108 cycles which
involved. produces the same fatigue damage as the load
distribution is:
For the calculation of equivalent stress two types of S-N
curves are available. fat =  · (ice)max
1) Two-slope S-N curve (slopes 4. 5 and 10) (see Fig 5). where:
2) One-slope S-N curve (the slope can be chosen) (see (ice)max = 0,5 ((ice)fmax - (ice)bmax)
Fig 6). (ice)max is the mean value of the principal stress
The type of the S-N curve is to be selected to correspond amplitudes resulting from design forward and backward
with the material properties of the blade. If the S-N blade forces at the location being studied
curve is not known, the two-slope S-N curve is to be (ice)fmax is the principal stress resulting from forward
used. load
(ice)bmax is the principal stress resulting from backward
Figure 5 : Two-slope S-N curve (1/7/2024)
load.
In calculation of (ice)max, case 1 and case 3 or case 2
Slope 4,5 and case 4 are considered as a pairs for (ice)fmax, and
amplitude
(ice)bmax calculations. Case 5 is excluded from the

fatigue analysis.
Slope 10
Note 1: A more general method of determining the equivalent
fatigue stress of propeller blades is described in [5.5], where
Stress
the principal stresses are considered according to [4.3] using

s exp the Miner’s rule. For a total number of load blocks nbl > 100,
both methods deliver the same result. Therefore, they are
regarded as equivalent.
• Calculation of parameter ρ for two-slope S-N curve:
1,E+0,4 1,E+0,6 1,E+0,8 1,E+10 The error of the following method to determine the
Numbers of loads
parameter ρ is sufficiently small, if the number of
load cycles Nice is in the range
5.106 ≤ Nice ≤ 108
The parameter ρ relates the maximum ice load to the
distribution of ice loads according to the regression
formulae.
ρ = C1 · (σice)max c · σfl c · log(Nice)c
2 3 4
where:
σfl = γε1 · γε2 · γv · γm · σexp is the blade material fatigue
strength at 108 load cycles, see [5.3.3], c).
The coefficients C1, C2 , C3 , and C4 are given in
Tab 12.
RINA Rules 2024 145

Pt F, Ch 10, Sec 3
• Calculation of parameter ρ for constant-slope S-N curve: are determined under conditions approved by the
Society.
For materials with a constant-slope S-N curve - see
Fig 6 - the  factor is to be calculated with the The S-N curve characteristics are based on two slopes,
following formula: the first slope 4,5 is from 1000 to 108 load cycles; the
second slope 10 is above 108 load cycles.
1/m The maximum allowable stress for one or low number
N ice
 =  G ---------
–l  k
 ln  N ice   of cycles is limited to ref2 /S, with S=1,3 for static loads.
 NR 
The fatigue strength fat is the fatigue limit at 100 mil-
where: lion load cycles.
k is the shape parameter of the Weibull distribution The geometrical size factor () is:
k = 1,0 for ducted propellers and
 = 1 - a.ln(t/0,025)
k = 0,75 for open propellers
where:
NR is the reference number of load cycles (=108).
“a” is as given in Tab 14 below and “t” is the maximum
Values for the parameter G are given in Tab 13. blade thickness at the considered point
Linear interpolation may be used to calculate the The mean stress effect (m) is:
value of G for other m/k ratios other than those given
in Tab 13. m = 1,0 - (1,4.mean / u )0,75
c) Acceptability criterion for fatigue The following values should be used for the reduction
factors if actual values are not available:
The equivalent fatigue stress fat at all locations on the
γε1 = 0,85, γv = 0,75 and γm = 0,75.
blade is to fulfil the following acceptability criterion:
Table 11 Coefficients to check a dispense from fatigue

 fl calculation (1/7/2024)
-  1 5
-------
 fat
Open propeller Ducted propeller
where
B1 0,00328 0,00223
fl =  ·  · v · m · exp
B2 1,0076 1,0071
 is the reduction factor due to scatter (equal to one
standard deviation) B3 2,101 2,471
 is the reduction factor for test specimen size effect

v is the reduction factor for variable amplitude loading Table 12 Coefficients to evaluate material fatigue
m is the reduction factor for mean stress strength (1/7/2024)
exp is the mean fatigue strength of the blade material at Open propeller Ducted propeller
108 cycles to failure in sea water.
C1 0,000747 0,000534
exp in Tab 14 has been defined from the results of con-
C2 0,0645 0,0533
stant amplitude loading fatigue tests at 107 load cycles
and 50% survival probability and has been extended to C3 -0,0565 -0,0459
108 load cycles. C4 2,22 2,584
Fatigue strength values and correction factors other than
those given in Tab 14 may be used, provided the values
Table 13 : Value for the parameter G for different m/k ratios (1/7/2024)
m/k G m/k G m/k G

3 6 5,5 287,9 8 40320
3,5 11,6 6 720 8,5 119292
4 24 6,5 1871 9 362880
4,5 52,3 7 5040 9,5 1,133.106
5 120 7,5 14034 10 3,623.106
146 RINA Rules 2024

Pt F, Ch 10, Sec 3
Table 14 : Mean fatigue strength σexp for different material types at 108 load cycles and stress ratio R = -1 with a
survival probability of 50% (1/7/2024)
Mean fatigue strength exp for different material types at 108 load cycles
Bronze and brass (a=0.10) Stainless steel (a=0.05)

Mn-Bronze, CU1 (high tensile brass) 84 MPa Ferritic (12Cr 1Ni) 144 MPa (1)
Mn-Ni-Bronze, CU2 (high tensile brass) 84 MPa Martensitic (13Cr 4Ni/13Cr 6Ni) 156 MPa
Ni-Al-Bronze, CU3 120 MPa Martensitic (16Cr 5Ni) 168 MPa
Mn-Al-Bronze, CU4 113 MPa Austenitic (19Cr 10Ni) 132 MPa
(1) This value may be used, provided a perfect galvanic protection is active. Otherwise a reduction of about 30 MPa is to be
applied.
5.4 Blade bolts, propeller hub and CP

mechanism F ex   0 8  D – d   S  
d bb = 41  -----------------------------------------------------------
- [mm]
 0ꞏ 2  Z bb  PCD
5.4.1 General (1/7/2024)
where:
The blade bolts, the CP mechanism, propeller boss and the  = 1,6 torque guided tightening
fitting of the propeller to the propeller shaft are to be = 1,3 elongation guided
designed to withstand the maximum static and fatigue
= 1,2 angle guided
design loads (as applicable), as defined in [4.3] and [5.3].
= 1,1 elongated by other additional means
The safety factor S against yielding due to static loads and
against fatigue is to be greater than 1,5, if not stated other- other factors may be used, if evidence is demonstrated
wise. The safety factor S for loads, resulting from propeller dbb is the effective diameter of blade bolt in way of thread
blade failure as defined in [4.4] is to be greater than 1,0 [mm]
against yielding. Zbb is the number of blade bolts
S = 1,0 safety factor
Provided that calculated stresses duly considering local
stress concentrations are less than yield strength, or maxi- 5.4.3 CP mechanism (1/7/2024)
mum of 70% of u of respective materials, detailed fatigue Separate means, e.g. dowel pins, are to be provided in
analysis is not required. In all other cases components are order to withstand the spindle torque resulting from blade
to be analysed for cumulative fatigue. An approach similar failure Qsex (see [4.4.2]) or ice interaction Qsmax (see
to that used for shafting assessment may be applied (see [4.3.7]), whichever is greater. Other components of the CP
[5.5]). mechanism are not to be damaged by the maximum spindle
torques (Qsmax , Qsex). One third of the spindle torque is
5.4.2 Blade bolts (1/7/2024) assumed to be consumed by friction, if not otherwise
documented trough further analysis.
Blade bolts are to withstand the following bending moment
considered around a tangent on bolt pitch circle, or any The diameter of fitted pins dfp between the blade and blade
other relevant axis for non-circular joints, parallel to carrier can be calculated using the formula:
considered root section:
 Q s – Q fr 
d fp = 66  --------------------------------------
- [mm]
PCD  z pin   0.2
M bolt = S  F ex  0 8  ---- – r bolt
D
[KNm]
 2 
where:
where: Qs = max(S.Qsmax ; S.Qsex ) [kNm]
rbolt is the radius to the bolt plane [m] S = 1,3 for Qsex and
= 1,0 for Qsex
Qfr = friction between connected surfaces = 0,33.Qs
Blade bolt pre-tension is to be sufficient to avoid separation
The Society may approve alternative Qfr calculation
between mating surfaces when the maximum forward and
backward ice loads defined in [4.3] (open and ducted according to reaction forces due to Fex or Ff, Fb whichever is
propellers respectively) are applied. For conventional relevant, utilising a friction coefficient = 0,15.
arrangements, the following formula may be applied: The stress in the actuating pin can be estimated by
RINA Rules 2024 147

Pt F, Ch 10, Sec 3
by relief valves on the hydraulic actuator side, reduced by

2 relevant friction losses in bearings caused by the respective
h pin 
  F  --------  2
- ice loads. The design pressure is in any case not to be less
 2   F 
 vMises = - + 3   ----------------
 --------------------- 2 
- [MPa] than relief valve set pressure.
  d pin    d pin
3
 ----------------  ----------------
 32   4 
5.5 Propulsion line components
where:
5.5.1 (1/7/2024)
F = (Qs - Qfr ) /m [kN]
The ultimate load resulting from total blade failure Fex as
m distance pitching centre of blade - axis of pin [m]
defined in [4.4] is to consist of combined axial and bending
hpin height of actuating pin [mm] load components, wherever this is significant. The
minimum safety factor against yielding is to be 1,0 for all
dpin diameter of actuating pin [mm] shaft line components.
Qfr friction torque in blade bearings acting on the blade
The shafts and shafting components, such as bearings,
palm and caused by the reaction forces due to ex or Ff, Fb
couplings and flanges are to be designed to withstand the
whichever is relevant; taken to one third of spindle torque operational propeller/ice interaction loads as given in [4].
Qs
The given loads are not intended to be used for shaft
The blade failure spindle torque Qsex is not to lead to any
alignment calculation.
consequential damage.
Fatigue strength is to be considered for parts transmitting the Cumulative fatigue calculations are to be conducted
spindle torque from the blade to a servo system considering according to the Miner’s rule. A fatigue calculation is not
the ice spindle torque acting on one blade. The maximum necessary, if the maximum stress is below fatigue strength at
amplitude Qsamax is defined as: 108 load cycles.
Qsamax = (Qsb + Qsf ) The torque and thrust amplitude distribution (spectrum) in
the propulsion line is to be taken as (because Weibull
where:
exponent k = 1):
Qsb spindle torque due to |Fb| [kNm]
Qsf spindle torque due to |Ff| [kNm]
log  N 
Q A  N  = Q Amax   1 – -------------------------------
5.4.4 Servo pressure (1/7/2024)  log  Z  N ice 
The design pressure for the servo system is to be taken as
the pressure caused by Qsmax or, Qsex when not protected This is illustrated by the example in the Fig 7.
Figure 7 : Cumulative torque distribution (1/7/2024)
The number of load cycles in the load spectrum is defined the load spectrum should be divided into a minimum of ten
as Z.Nice. load blocks when using the Miner summation method.
The Weibull exponent should be considered as k = 1,0 for The load spectrum used counts the number of cycles for
both open and ducted propeller torque and bending forces. 100% load to be the number of cycles above the next step,
The load distribution is an accumulated load spectrum, and e.g. 90 % load. This ensures that the calculation is on the
conservative side. Consequently, the fewer stress blocks
used the more conservative the calculated safety margin.
148 RINA Rules 2024

Pt F, Ch 10, Sec 3
Figure 8 : Example of ice load distribution (spectrum) for the shafting (k = 1) (1/7/2024)
The load spectrum is divided into nbl-number of load blocks Any additional stress raisers such as recesses for bolt
for the Miner summation method. heads is not to interfere with the flange fillet unless the
flange thickness is increased correspondingly.
The following formula can be used for calculation of the
number of cycles for each load block. The flange fillet radius is to be at least 10% of the
required shaft diameter.
The diameter of shear pins is to be calculated according
i k i
1 –  1 – ------- to the following equation:
 n bl
n i = N ice – n i–1
i=1
where: Q peak  S
d pin = 66  --------------------------------------
- [mm]
i = single load block i and nbl is the number of load blocks. PCD  z pin   0.2
where
5.5.2 Propeller fitting to the shaft (1/7/2024)
Zpin = number of shear pins
a) Keyless cone mounting
The friction capacity (at 0° C) is to be at least S = 2,0
times the highest peak torque Qpeak as determined in The bolts are to be designed so that the blade failure
[4.6] without exceeding the permissible hub stresses. load Fex (see [4.4]) in backward direction does not
cause yielding of the bolts. The following equation
The necessary surface pressure P0°C can be determined
should be applied:
as:
F ex   0 8  ------------ + 1  
D
2  S  Q peak  PCD 
P 0o C = ------------------------------------------
-3 [MPa] d b = 41  -------------------------------------------------------------- [mm]
    D S  L  10
2
z b   0.2
where:
where:
 = 1,6 torque guided tightening
 = 0,15 for steel-steel,
= 1,3 elongation guided
= 0.13 for steel-bronze
= 1,2 angle guided
DS = is the shrinkage diameter at the mid-length of the
= 1,1 elongated by other additional means
taper [m]
other factors may be used, if evidence is
L = is the effective length of taper [m]
demonstrated
Above friction coefficients may be increased by 0,04 if db diameter flange bolt [mm]
glycerine is used in wet mounting.
Zb number of flange bolts
b) Key mounting
Key mounting is not permitted. 5.5.3 Propeller shaft (1/7/2024)
c) Flange mounting The propeller shaft is to be designed to fulfil the following:
The flange thickness is to be at least 25% of the required a) The blade failure load Fex (see [4.4]) applied parallel to
aft end shaft diameter (see Pt C, Ch 1, Sec 7, [2.5.1]). the shaft (forward or backwards) is not to cause yielding.
RINA Rules 2024 149

Pt F, Ch 10, Sec 3
The bending moment need not to be combined with any ABF11 Berechnung von Wohlerlinien fur Bauteile aus
other loads. The diameter dp in way of the aft stern tube Stahl”.
bearing is not to be less than: The high cycle fatigue (HCF) is to be assessed based on
the above fatigue strengths, notch factors (i.e.
geometrical stress concentration factors and notch
F ex  D
d p = 160  ---------------------------------
4
- [mm] sensitivity), size factors, mean stress influence and the
3   1 – ---- di  required safety factor of 1,6 at 3 million cycles
 -
0.2
 d p
4
increasing to 1,8 at 109 cycles.
where: The low cycle fatigue (LCF) representing 104 cycles is to
dp = propeller shaft diameter [mm] be based on the smaller value of yield or 0,7 of tensile
strength/(30,5). The criterion utilises a safety factor of
di = propeller shaft inner diameter [mm] 1,25.
Forward from the aft stern tube bearing the shaft The LCF and HCF as given above represent the upper
diameter may be reduced based on direct calculation of and lower knees in a stress-cycle diagram. Since the
the actual bending moment, or by the assumption that required safety factors are included in these values, a
the bending moment caused by Fex is linearly reduced Miner sum of unity is acceptable.
to 25% at the next bearing and in front of this linearly to
zero at third bearing. 5.5.4 Intermediate shafts (1/7/2024)
Bending due to maximum blade forces Fb and Ff have The intermediate shafts are to be designed to fulfil [5.5.3],
b) to [5.5.3], d).
been disregarded since the resulting stress levels are
much lower than the stresses caused by the blade failure 5.5.5 Shaft connections (1/7/2024)
load.
a) Shrink fit couplings (keyless)
b) The stresses due to the peak torque Qpeak are to have a See [5.5.2], a). A safety factor of S = 1,8 is to be applied.
minimum safety factor of S=1,5 against yielding in plain
b) Key mounting
sections and S=1,0 in way of stress concentrations in
order to avoid bent shafts. Key mounting is not permitted.
Minimum diameter of: c) Flange mounting
The flange thickness is to be at least 20% of the required
plain shaft:
shaft diameter (see Pt C, Ch 1, Sec 7, [2.5.1]).
Any additional stress raisers such as recesses for bolt
Q peak  S heads are not to interfere with the flange fillet unless the
d p = 210  ---------------------------------
- [mm]

4
di  flange thickness is increased correspondingly.
3 
0.2  1 – -----
 d
4 The flange fillet radius is to be at least 8% of the shaft
diameter (see Pt C, Ch 1, Sec 7, [2.5.1]).
notched shaft: The diameter of ream fitted (light press fit) bolts is to be
chosen so that the peak torque is transmitted with a
Q peak  S   t
safety factor of 1,9. This accounts for a prestress. Pins
d p = 210  ---------------------------------
4
- [mm] are to transmit the peak torque with a safety factor of 1,5
3   di 
0.2  1 – ----- against yielding (see equation in [5.5.2], c)).
 d
4
The bolts are to be designed so that the blade failure

where: load (see [4.4]) in backward direction does not cause
t = local stress concentration factor in torsion. yielding.
d) Splined shaft connections
Notched shaft diameter is to in any case not be less than
Splined shaft connections can be applied where no
the required plain shaft diameter.
axial or bending loads occur. A safety factor of S = 1,5
c) The torque amplitudes (see [4.6.4]) with the against allowable contact and shear stress resulting from
corresponding number of load cycles are to be used in Qpeak is to be applied.
an accumulated fatigue evaluation where the safety
factor is Sfat =1,5. If the plant has high engine excited e) Gear transmissions
torsional vibrations (e.g. direct coupled 2-stroke 1) Shafts
engines), this is also to be considered. Shafts in gear transmissions are to meet the same
d) The fatigue strengths σF and τF (3 million cycles) of shaft safety level as intermediate shafts, but where
relevant, bending stresses and torsional stresses are
materials may be assessed on the basis of the material’s
to be combined (e.g. by von Mises for static loads).
yield or 0,2% proof strength as: Maximum permissible deflection in order to
σF = 0,436.σ0,2 + 77 = τF.30,5 [MPa] maintain sufficient tooth contact pattern is to be
This is valid for small polished specimens (no notch) considered for the relevant parts of the gear shafts.
and reversed stresses, see “VDEH 1983 Bericht Nr.
150 RINA Rules 2024

Pt F, Ch 10, Sec 3
2) Gearing f) Bearings
The gearing is to fulfil following three acceptance See [5.5.9].
criteria: g) Gear wheel shaft connections
• Tooth root stresses The torque capacity is to be at least 1,8 times the highest
• Pitting of flanks peak torque Qpeak (at considered rotational speed) as
determined in [5.5] without exceeding the permissible
• Scuffing hub stresses of 80% yield.
In addition to above 3 criteria subsurface fatigue
may need to be considered. 5.5.6 Clutches (1/7/2024)
Clutches are to have a static friction torque of at least 1,3
Common for all criteria is the influence of load
times the peak torque Qpeak and dynamic friction torque
distribution over the face width. All relevant
parameters are to be considered, such as elastic 2/3 of the static.
deflections (of mesh, shafts and gear bodies), Emergency operation of clutch after failure of e.g. operating
accuracy tolerances, helix modifications, and pressure is to be made possible within reasonably short
working positions in bearings (especially for time. If this is arranged by bolts, it is to be on the engine
multiple input single output gears). side of the clutch in order to ensure access to all bolts by
turning the engine.
The load spectrum (see [5.5]) may be applied in
such a way that the numbers of load cycles for the 5.5.7 Elastic couplings (1/7/2024)
output wheel are multiplied by a factor of (number
There are to be a separation margin of at least 20% between
of pinions on the wheel / number of propeller blades
the peak torque and the torque where any twist limitation is
Z). For pinions and wheels operating at higher
reached.
speeds the numbers of load cycles are found by
multiplication with the gear ratios. The peak torque Qpeak <0,8.Tkmax (N=1) [kNm]
(Qpeak) is also to be considered during calculations.
There shall be a separation margin of at least 20% between
Cylindrical gears can be assessed on the basis of the the maximum response torque Qpeak (see Fig 4) and the
international standard ISO 6336 series (i.e. ISO torque where any mechanical twist limitation and/or the
6336-1:2019, ISO 6336-2:2019, ISO 6336-3:2019, permissible maximum torque of the elastic coupling, valid
ISO 6336-4:2019, ISO 6336-5:2016 and ISO 6336- for at least a single load cycle (N=1), is reached.
6:2019), provided that “method B” is used. A sufficient fatigue strength is to be demonstrated at design
Standards within the Society can also be applied torque level Qr(N=x) and QA(N=x). This may be
provided that they are considered equivalent to the
demonstrated by interpolation in a Weibull torque
above mentioned ISO 6336.
distribution (similar to Fig 7):
For Bevel Gears the methods or standards used or
acknowledged by the Society can be applied
Qr  N = x  log  x 
provided that they are properly calibrated. --------------------------
- = 1 – -------------------------------
Qr  N = 1  log  Z  N ice 
Tooth root safety is to be assessed against the peak
torque, torque amplitudes (with the pertinent respectively
average torque) as well as the ordinary loads (open
water free running) by means of accumulated fatigue QA  N = x  log  x 
---------------------------
- = 1 – -------------------------------
analyses. The resulting factor of safety is to be at QA  N = 1  log  Z  N ice 
least 1,5. (Ref ISO 6336 Pt 1, 3 and 6 and Pt C, Ch 1,
Sec 6) Where Qr(N=1) corresponds to Qpeak and QA(N=1) to
QAmax.
The safety against pitting is to be assessed in the
same way as tooth root stresses, but with a minimum Qr(N=5E4).S < TKmax(N=5E4) [kNm]
resulting safety factor of 1,2. (Ref ISO 6336-1:2019,
ISO 6336-2:2019 and ISO 6336-6:2019 as well as Qr(N=1E6).S < TKV [kNm]
Pt C, Ch 1, Sec 6).
QA(N=5E4).S < Tmax [kNm]
The scuffing safety (flash temperature method – ref.
S is the general safety factor for fatigue, equal to 1,5.
ISO/TR 13989-1:2000 and ISO/TR 13989-2:2000)
based on the peak torque is to be at least 1,2 when See illustration in below Fig 9, Fig 10 and Fig 11.
the FZG class of the oil is assumed one stage below The torque amplitude (or range ) is not to lead to fatigue
specification. cracking, i.e. exceeding the permissible vibratory torque.
The permissible torque may be determined by interpolation
The safety against subsurface fatigue of flanks for
in a Weibull torque distribution where TKmax1 respectively
surface hardened gears (oblique fracture from active
flank to opposite root) is to be assessed at the TKmax refer to 50000 cycles and TKV refer to 106 cycles.
discretion of the Society. (It should be noted that See illustration in below Fig 9, Fig 10 and Fig 11.
high overloads can initiate subsurface fatigue cracks
TKmax1 Qr at 5.104 load cycles [kNm]
that may lead to a premature failure. In lieu of
analyses UT inspection intervals may be used.)
RINA Rules 2024 151

Pt F, Ch 10, Sec 3
Figure 9 : (1/7/2024) Figure 10 : (1/7/2024)
Figure 11 : (1/7/2024)
5.5.8 Crankshafts (1/7/2024) 5.5.10 Seals (1/7/2024)

Special considerations apply for plants with large inertia Seals are to prevent egress of pollutants and be suitable for
(e.g. flywheel, tuning wheel or PTO) in the non-driving end the operating temperatures. Contingency plans for
front of the engine (opposite to main power take off). preventing the egress of pollutants under failure conditions
are to be documented.
5.5.9 Bearings (1/7/2024)
Seals installed are to be suitable for the intended
The aft stern tube bearing as well as the next shaft line
application. The manufacturer is to provide service
bearing are to withstand Fex as given in [4.4], in such a way
experience in similar applications and/or testing results for
that the ship can maintain operational capability. Rolling consideration.
bearings are to have an L10a lifetime of at least 40 000 hours
according to ISO 281:2007. Thrust bearings and their
housings are to be designed to withstand with a safety factor
45.26 Azimuthing main propulsors
S = 1,0 the maximum response thrust [4.5] and the axial 45.26.1 (1/7/2024)
force resulting from the blade failure load Fex in [4.4]. For In addition to the above requirements, special consideration
the purpose of calculation, except for Fex, the shafts are is to be given to theose loading cases which are
assumed to rotate at rated speed. For pulling propellers extraordinary for propulsion units when compared with
special consideration is to be given to loads from ice conventional propellers. The Eestimation of the load cases
interaction on the propeller hub. is to reflect the way operational realities of the ship and the
152 RINA Rules 2024

Pt F, Ch 10, Sec 3
thrusters are intended to operate on the specific ship. In this S : safety factor, to be taken equal to:
respect, for example, the loads caused by impacts of ice • trailing edges:
blocks on the propeller hub of a pulling propeller are to be S = 2,5
considered. FurthermoreAlso, loads due toresulting from
the thrusters operating inat an oblique angle to the flow are • leading edges:
to be considered. The steering mechanism, the fitting of the S = 3,5
unit, and the body of the thruster are to be designed to • for tip:
withstand the loss of a blade without damage. The plastic S=5
bendingloss of a blade is to be considered infor the
Sice : according to [3.2]
propeller blade positionorientation which causes the
maximum load on the studied component being studied. pice : ice pressure, to be taken equal to 16 Mpa for
leading edge and tip thickness
Typically, top-down blade orientation places the maximum
ref : according to [4.3.1].
bending loads on the thruster body.
The requirement for edge thickness is to be applied for the
Azimuth thrusters are also to be designed for estimated
leading edge and in the case of reversible rotation open
loads due tocaused by thruster body / ice interaction. The
propellers also for the trailing edge. Tip thickness refers to
thruster body is to withstand the loads obtained when the
the maximum measured thickness in the tip area above
maximum ice blocks, which are given in [4.2], strike the
0,975R radius. The edge thickness in the area between
thruster body when the ship is at a typical ice operating
position of maximum tip thickness and edge thickness at
speed. In addition, the design situation in which an ice
0,975 radius is to be interpolated between edge and tip
sheet glides along the ship’s hull and presses against the
thickness value and smoothly distributed.
thruster body should be considered. The thickness of the
sheet should be taken as the thickness of the maximum ice
block entering the propeller, as defined in [4.2]. 4.4 Prime movers
4.4.1 (1/3/2008)
4.3 Blade design The main engine is to be capable of being started and
running the propeller with the CP in full pitch.
4.3.1 Maximum blade stresses (1/3/2008) 4.4.2 (1/3/2008)
Blade stresses are to be calculated using the backward and Provision is to be made for heating arrangements to ensure
forward loads given in [3.3] and [3.4]. The stresses are to be ready starting of the cold emergency power units at an
calculated with recognised and well documented FE- ambient temperature applicable to the Polar Class of the
analysis or another acceptable alternative method. The ship.
stresses on the blade are not to exceed the allowable
stresses all for the blade material given below. 4.4.3 (1/3/2008)
Emergency power units are to be equipped with starting
Calculated blade stress for maximum ice load is to comply devices with a stored energy capability of at least three
with the following:. consecutive starts at the design temperature in [4.4.2]. The
σcalc < σall source of stored energy is to be protected to preclude
where σall = σref / S critical depletion by the automatic starting system, unless a
second independent means of starting is provided. A
S = 1,5 second source of energy is to be provided for an additional
σref = reference stress, equal to the minimum of: three starts within 30 min, unless manual starting can be
σref = 0,7 σu demonstrated to be effective.
σref = 0,6 σ0,2 + 0,4 σu

6 Prime Movers
where σu and σ0,2 are representative values for the blade
material.
6.1 Propulsion engines
4.3.2 Blade edge thickness (1/3/2008) 6.1.1 (1/7/2024)
The blade edge thickness ted and tip thickness ttip are to be Engines are to be capable of being started and running the
greater than tedge, in mm, given by the following formula: propeller in bollard condition.
Propulsion plants with CP propeller are to be capable being
3p ice operated even when the CP system is at full pitch as limited
t edge  xS  S ice -----------
- by mechanical stoppers.
 ref
x : distance from the blade edge, in mm, measured
along the cylindrical sections from the edge;
6.2 Starting arrangements
this is to be 2,5% of chord length, though need 6.2.1 (1/7/2024)
not be taken greater than 45 mm. In the tip area The capacity of the air receivers is to be sufficient to
(above 0,975R radius) x is to be taken as 2,5% provide, without recharging, not less than 12 consecutive
of 0,975R section length and is to be measured starts of the propulsion engine, if this has to be reversed for
perpendicularly to the edge; however, it is not going astern or 6 consecutive starts if the propulsion engine
to be taken greater than 45 mm. does not have to be reversed for going astern.
RINA Rules 2024 153

Pt F, Ch 10, Sec 3
If the air receivers serve any other purposes than starting the
av = 2,5 (FIB / ∆) Fx
propulsion engine, they are to have additional capacity
sufficient for these purposes. where:
The capacity of the air compressors is to be sufficient for Fx = 1,3 at FP
charging the air receivers from atmospheric to full pressure Fx = 0,2 amidships
in one (1) hour, except for a ship with the ice class PC6 to
Fx = 0,4 at AP
PC1, if its propulsion engine has to be reversed for going
astern, in which case the compressor is to be able to charge Fx = 1,3 at AP for ships conducting ice breaking astern.
the receivers in half an hour. Intermediate values of Fx are to be interpolated linearly.
6.3 Emergency power units 57.2.3 Transverse impact acceleration at (1/3/2008)

6.3.1 (1/7/2024) Combined transverse impact acceleration at any point
along the hull girder, in [m/s2]
Provisions are to be made for heating arrangements to
ensure ready starting from cold of the emergency power at = 3 Fi (Fx / ∆)
units at an ambient temperature applicable to the Polar where:
Class of the ship.
Fx = 1,5 at FP
Emergency power units are to be equipped with starting
devices with a stored energy capability of at least three Fx = 0,25 amidships
consecutive starts at the above mentioned temperature. The Fx = 0,5 at AP
source of stored energy is to be protected to preclude Fx = 1,5 at AP for ships conducting ice breaking astern.
critical depletion by the automatic starting system, unless a
second independent mean of starting is provided. A second Intermediate values of Fx are to be interpolated linearly.
source of energy is to be provided for an additional three Fi = total force normal to shell plating in the bow area due
starts within 30 min, unless manual starting can be to oblique ice impact, defined in Sec 2, [4.3.4], in kN.
demonstrated to be effective.
68 Auxiliary systems
57 EquipmentMachinery fastening
loading accelerations 68.1 General
68.1.1 (1/3/2008)
57.1 General Machinery is to be protected from the harmful effects of
ingestion or accumulation of ice or snow. Where
57.1.1 (1/7/2024) continuous operation is necessary, means are to be
Essential equipment and main propulsion machinery provided to purge the system of accumulated ice or snow.
supports are to be suitable for the accelerations as indicated 68.1.2 (1/7/2024)
below. Accelerations are to be considered acting Means are to be provided to prevent damage to tanks
independently.
containing liquids due to freezing, for tanks containing
liquids.
57.2 Accelerations
68.1.3 (1/3/2008)
57.2.1 Longitudinal Impact Accelerations, al Vent pipes, intake and discharge pipes and associated
(1/7/2024) systems are to be designed to prevent blockage due to
Maximum longitudinal impact acceleration al at any point freezing or ice and snow accumulation.
along the hull girder, in m/s2, is equal to:
al = (FIB / ) { [ 1,1 tan ( + ) ] + (7H/L)}
79 Sea inlets and cooling water
systems
where:
 : maximum friction angle between steel and ice, 79.1 General
in degrees, normally taken as 10° 79.1.1 (1/7/2024)
 : bow stem angle at waterline, in degrees Cooling water systems for machinery that is essential for the
 : displacement, in t propulsion and safety of the ship, including sea chest inlets,
L : length between perpendiculars, in m are to be designed for the environmental conditions
applicable to the ice classfor the additional class notation
H : distance in metres from the waterline to the
POLAR CLASS.
point being considered, in m
79.1.2 (1/7/2024)
FIB : vertical impact force, defined in Sec 2, [5.2.1],
At least two sea chests are to be arranged as ice boxes (sea
in kN.
chests for water intake in severe ice conditions) for
57.2.2 Vertical acceleration av (1/3/2008) classes PC1 to PC5 inclusive. The calculated volume for
each of theice boxes is to be at least 1m3 for every 750
Combined vertical impact acceleration at any point along
kW of the totalinstalled power. For PC6 and PC7 there is
the hull girder, in [m/s2]
to be at least one ice box located preferably near the
centreline.
154 RINA Rules 2024

Pt F, Ch 10, Sec 3
79.1.3 (1/7/2024) where manual de-icing is possible. Anti-icing protection of

Ice boxes are to be designed for thean effective separation the air inlets may be accepted as an equivalent solution to
of ice and venting of air. location on both sides of the ship and manual de-icing at
79.1.4 (1/3/2008) the Society’s discretion. Notwithstanding the above,
multiple air intakes are to be provided for the emergency
Sea inlet valves are to be secured directly to the ice boxes.
generating set and are to be as far apart as possible.
The valve is to be a full bore type.
79.1.5 (1/3/2008) 9.1.2 (1/3/2008)
Ice boxes and sea bays are to have vent pipes and are to Accommodation ventilation air intakes are to be provided
have shut-off valves connected directly to the shell. with means of heating.
79.1.6 (1/3/2008)
Means are to be provided to prevent freezing of sea bays, 911.1.32 (1/7/2024)
ice boxes, ship side valves and fittings above the load The temperature of inlet air provided to machinery from air
waterline. intakes is to be suitable for safe operation of the machinery.:
79.1.7 (1/7/2024)
• the safe operation of the machinery; and
Efficient means are to be provided to recirculate cooling
seawater to the ice box. The total sectional area of the • the thermal comfort in the accommodation.
circulating pipes is not to be less than the area of the
cooling water discharge pipe. Accommodation and ventilation air intakes shall be
79.1.8 (1/3/2008) provided with means of heating, if needed.
Detachable gratings or manholes are to be provided for ice
boxes. Manholes are to be located above the deepest load 12 Steering Systems
line. Access is to be provided to the ice box from above.
79.1.9 (1/7/2024)
Openings in ship sides for ice boxes are to be fitted with
12.1 General
gratings, or holes or slots in shell plates. The net area 12.1.1 (1/7/2024)
through these openings is to be not less than 5 times the
area of the inlet pipe. The diameter of holes or theand width Rudder stops are to be provided. The design ice force on
of slots in shell plating is to be not less than 20 mm. rudder is to be transmitted to the rudder stops without
Gratings of the ice boxes are to be provided with a means of damage to the steering system.
clearing. The means of clearing is to be of a type using low An ice knife is in general to be fitted to protect the rudder in
pressure steam. Clearing pipes are to be provided with centre position. The ice knife is to extend below BWL.
screw-down type non-return valves. Design forces are to be determined according to the Sec 2,
[10].
810 Ballast tanks
12.1.2 (1/7/2024)
810.1 General The rudder actuator is to comply with the following
810.1.1 (1/3/2008) requirements:
Efficient means are to be provided to prevent freezing in a) The rudder actuator is to be designed for a holding
fore and after peak tanks and wing tanks located above the torque obtained by multiplying the open water torque
waterline and where otherwise found necessary. resulting from the application of SOLAS Reg. II-1
/29.3.2 (considering however a maximum speed of 18
911 Ventilation system knots), by the factors in Tab 15:
b) The design pressure for calculations to determine the

911.1 General scantlings of the rudder actuator is to be at least 1,25
911.1.1 (1/7/2024) times the maximum working pressure corresponding to
Air intakes for machinery and accommodation ventilation the holding torque defined in a) (Derived from SOLAS
are to be located on both sides of the ship at locations Reg. II-1 / 29.2.2).
Table 15 : (1/7/2024)
Ice Class PC1 PC2 PC3 PC4 PC5 PC6 PC7
Factor 5 5 3 3 3 1,5 1,5
12.1.3 (1/7/2024) 16 without an undue pressure rise (see Pt C, Ch 1, Sec 11,

The rudder actuator is to be protected by torque relief [[2.2.5]] for undue pressure rise).
arrangements, assuming the turning speeds [deg/s] in Tab
RINA Rules 2024 155

Pt F, Ch 10, Sec 3
If the rudder and actuator design can withstand such rapid conventional one may be used instead (see Pt C, Ch 1, Sec
loads, this special relief arrangement is not necessary and a 11, [[2.2.5]]).
Table 16 : Steering gear turning speeds (1/7/2024)
Ice Class PC1and PC2 PC3 to PC5 PC6 and PC7

Turning speeds [deg/s] 10 7,5 6
12.1.4 (1/7/2024) the oil viscosity at the lowest expected ambient temperature
Additionally for icebreakers, fast-acting torque relief in the steering gear compartment.
arrangements are to be fitted in order to provide effective For alternative steering systems the fast-acting torque relief
protection of the rudder actuator in case of the rudder being arrangement is to demonstrate an equivalent degree of
pushed rapidly hard over against the stops. protection to that required for hydraulically operated
arrangements.
For hydraulically operated steering gear, the fast-acting
torque relief arrangement is to be so designed that the The turning speeds to be assumed for each ice class are
pressure cannot exceed 115% of the set pressure of the shown in Tab 17 .
safety valves when the rudder is being forced to move at the The arrangement is to be designed such that steering
speed indicated in Tab 17, also when taking into account capacity can be speedily regained.
Table 17 : Steering gear turning speeds for icebreakers (1/7/2024)
Ice Class PC1and PC2 PC3 to PC5 PC6 and PC7

Turning speeds [deg/s] 40 20 15
103 Alternative design submitted with a request for validation by an agreed test
program.
103.1 General
103.1.1 (1/3/2008)
As an alternative, a comprehensive design study may be
156 RINA Rules 2024

Pt F, Ch 10, Sec 3
Table 3 : Load cases for open propeller (1/l7/2024)

Force Loaded area
blade seen from back
tion side) to an area from 0,6R to the tip and from the
leading edge to 0,2 times the chord length
0,2
c
0,6
R
Load case 2 50% of Fb Uniform pressure applied on the back of the blade (suc-
tion side) on the propeller tip area outside of 0,9R radius
0,9
R

edge to 0,2 times the chord length
0,2
c
0,6
R
Load case 4 50% of Ff Uniform pressure applied on propeller face (pressure

side) on the propeller tip area outside of 0,9R radius
0,9
R
Load case 5 60 % of Ff or Fb, Uniform pressure applied on propeller face (pressure

whichever is the side) to an area from 0,6R to the tip and from the trailing
greater edge to 0,2 times the chord length
2c
0,
R
0,6
RINA Rules 2024 157

Pt F, Ch 10, Sec 3
Table 4 : Load cases for ducted propeller (1/7/2024)

Force Loaded area
blade seen from back
tion side) to an area from 0,6R to the tip and from the 0,2
c
leading edge to 0,2 times the chord length
0,
6R

0,5
edge to 0,5 times the chord length c
0,
6R
Load case 5 60 % of Ff or Uniform pressure applied on propeller face (pressure

F b, side) to an area from 0,6R to the tip and from the trailing
whichever is the edge to 0,2 times the chord length
2c
0,
greater
6R
0,
Figure 1 : Shape of the propeller ice torque excitation for 45, 90, 135 degrees single blade impact sequences and
45 degrees double blade impact sequence (two ice pieces) on a four-bladed propeller (1/3/2008)
12
12
1
1
0,8
0,8
Q/Qmax
Q/Qmax
0,6
0,6
0,4 0,4
0,2
0,2
0
0
0 90 180 270 360 450 540 630 720
Angle of rotation [deg]
0 90 180 270 360 450 540 630 720
12 12
1 1 ice block 2
ice block 1
0,8 0,8
Q/Qmax
Q/Qmax
0,6 0,6
0,4 0,4
0,2 0,2
0 0
0 90 180 270 360 450 540 630 720 0 90 180 270 360 450 540 630 720
158 RINA Rules 2024

Pt F, Ch 10, Sec 3
Figure 12 : Excitation torque for all torsional load cases for blade numbers Z=3 and Z=4. The plots have been made
using data for PC7 (Hice = 1.5) (1/7/2024)
RINA Rules 2024 159

Pt F, Ch 10, Sec 3
Figure 13 : Excitation torque for all torsional load cases for blade numbers Z=5 and Z=6. The plots have been made
using data for PC7 (Hice = 1.5) (1/7/2024)
160 RINA Rules 2024

Pt F, Ch 13, Sec 18
SECTION 18 CARRIAGE OF SPECIFIC SOLID CARGOES

IN BULK
1 General Rules and in the applicable statutory Regulations, in par-

ticular in the IMSBC Code for the carriage of that cargo.
1.1 Application Cargoes for which each of the above notations is granted
are to be listed in the Certificate of Classification.
1.1.1 (1/8/2011)
This Section provides the criteria for the assignment of the
following additional class notations, in accordance with 1.2 Definitions
Pt A, Ch 1, Sec 2, [6.14.24]: 1.2.1 (1/8/2011)
• IMSBC-A, assigned to ships specially constructed or • Angle of repose: the maximum slope angle of non-cohe-
specially fitted for the carriage of IMSBC Code Group A sive (i.e. free-flowing) granular material. It is measured
cargoes, having actual moisture content in excess of as the angle between a horizontal plane and the cone
their Transportable Moisture Limit (TML), in accordance slope of such material;
with the requirements in [2].
• Group A: cargoes which may liquefy if shipped at a
• IMSBC-nitrate, assigned to ships specially designed for
moisture content in excess of their TML;
the carriage of IMSBC Code Group B nitrate cargoes, in
accordance with the requirements in [3]. • Group B: cargoes which possess a chemical hazard
• IMSBC-non cohesive, assigned to ships specially which could give rise to a dangerous situation on a ship;
designed for the carriage of non cohesive cargoes with • IMSBC Code: International Maritime Solid Bulk Cargoes
an angle of repose less than or equal to 30°, in accord- Code, IMO Resolution MSC.286(85), in the text: the
ance with the requirements in [4]. It is highlighted that Code;
the same cargoes may be carried with an angle of
• Non Cohesive material: dry materials that readily shift
repose greater than 30°, irrespective on the assignment
due to sliding during transport;
of the notation IMSBC-non cohesive.
• Transportable Moisture Limit (TML): the maximum
1.1.2 (1/8/2011) moisture content of the Group A cargoes.
For the purpose of the assignment of the Additional Class
Notations listed in [1.1.1], the relevant requirements of this
1.3 Documents to be submitted
Chapter are to be complied with.
It is intended that the carriage of a specific cargo is subject 1.3.1 (1/8/2011)
to the compliance with all the requirements stated in these The documents listed in Tab 1 are required.
Table 1 : Documentation to be submitted (1/8/2011)
No. I/A (1) Document

1 I List and characteristic of the cargoes
2 A IMSBC-A: Booklet with the information to the Master
3 A IMSBC-A: Structural drawings of newly fitted structures, if any
4 A IMSBC-A: Structural drawings of movable bulkheads, if any
5 A IMSBC-A: Information to the Master for movable bulkheads
6 A IMSBC-nitrate: Lay-out and arrangements of water fire extinguishing additional system
7 I IMSBC-nitrate: Calculation of fire extinguishing additional system water quantity for IMSBC-
nitrate
8 A IMSBC-nitrate: Booklet with the information to the Master
9 A IMSBC-non cohesive: Booklet with the information to the Master
(1) A : to be submitted for approval, in four copies
I : to be submitted for information, in duplicate.
RINA Rules 2024 275

Pt F, Ch 13, Sec 18
2 Class notation IMSBC-A for ships constructed between 1 February 1992 and 31 December
2008.
2.1 General 2.2.2 Information to the Master (1/8/2011)
2.1.1 (1/7/2024) Information regarding the stability is to be provided to the

Master in the form of a separate booklet. As a minimum, the
Ships specially constructed or specially fitted for the car- booklet is to contain the following items:
riage of cargoes Group A having a moisture content in
excess of their TML are to comply with the following • a general description of the ship
requirements. • instructions on the requirements and criteria to be ful-
filled according to [2.2.1]
Ships intended for the carriage of "cargoes which may
undergo dynamic separation" (as defined in ISMBC Code, • instructions on the use of the booklet with a working
as amended by IMO Res. MSC.500(105)) and complying example
with the stability requirements in Pt E, Ch 13, Sec 2, [1.1.2],
are considered in compliance with the requirements in • taking into account the information already provided in
[2.2.1]. the approved Trim and Stability booklet:
- general arrangement plan showing watertight com-
2.2 Specially constructed ships partments, means of closures, vents, downflooding
points, permanent ballast
2.2.1 Stability criteria (1/8/2011) - hydrostatic curves or tables and cross curves of sta-
bility
The following criteria and requirements apply for each
loading condition; with reference to Fig 1: - capacity plan or tables showing capacities and cen-
tres of gravity for each cargo hold
a) the righting lever curve (GZ liquid curve) is to be calcu-
lated considering the cargo in the holds as being liquid - tank sounding tables showing capacities, centres of
gravity, and free surface data for each tank
b) for the purpose of heeling arm curve calculation, the
cargo in the holds is to be considered as a bulk cargo - table of liquid free surface corrections for the cargo
subject to a shift equal to 25° holds
- volumetric heeling moments at 25° for cargo holds
c) the angle of heel EQ is to be not greater than 12° or
at different filling ratio
than the angle at which the deck edge is immersed
• typical loading conditions with the relevant stability cal-
d) the angle F is defined as the lower of the following culations.
angles:
• 40° 2.2.3 Hull strength (1/8/2011)

Boundary structures of cargo holds are to be calculated
• the angle at which the difference between the GZ
considering the cargo as a liquid. In case of cargo holds
liquid curve and the heeling arm reaches its maxi-
partly filled, sloshing loads are also to be taken into
mum value
account.
• the first downflooding angle
At this purpose, the level of liquid inside the holds is to be
e) the minimum residual area AR comprised between the considered at the rated upper surface of the bulk cargo
heeling arm curve and the GZ liquid curve, from EQ to (horizontal ideal plane of the volume filled by the cargo), as
F, is to be greater than 0,075 m rad defined in Pt B, Ch 5, Sec 6, [3.1.2]. The density of the liq-
uid is to be assumed equal to 1,0 t/m3.
f) the initial metacentric height GM, after correction for
The criteria for the strength checks of the boundary struc-
free surface effects according to Pt B, Ch 3, Sec 2, [4.2],
tures are those in Part B, Chapter 7 or Part B, Chapter 8, as
is to be not less than 0,30 m
applicable depending on the ship length, and Part E, for
g) for ships subject to the SOLAS Convention, the initial ships with one of the following service notations:
metacentric height GM (or the vertical distance KG • bulk carrier ESP
between the baseline and the centre of gravity), after
correction for free surface effects according to Pt B, • combination carrier ESP
Ch 3, Sec 2, [4.2], has to fulfill the GM (or KG) limiting
• ore carrier ESP
curve, as applicable (see Note 1). This requirement does
not apply to ships with type B-60 or B-100 freeboard,
For ships with the service notation bulk carrier ESP CSR, the
provided that no cargo on deck is carried.
requirements are those in Part B, Chapter 7 and in the
Note 1: Solas Convention: Ch. II-1 part B-1 Reg. 5-1 for ships con- “Common Structural Rules for Bulk Carriers and Oil Tank-
structed on or after 1 January 2009, or Ch. II-1 part B-1 Reg. 25-8 ers”.
276 RINA Rules 2024

...OMISSIS...
Pt F, Ch 13, Sec 35
SECTION 35 NH3 FUELLED READY (X1, X2, X3…)
1 General having the following characteristics:

• Design (X1); and
1.1 Application • One of the following:
1.1.1 (1/5/2021) - Structure (X2);
The additional class notation NH3 FUELLED READY (X1,
- Tank (X3);
X2, X3…) is assigned, in accordance with Pt A, Ch 1, Sec 2,
[6.14.53], to ships fulfilling the requirements of this section. - Piping (X4);
A Statement of Compliance may be issued to ships not - Users (X5).
classed with the Society, fulfilling the requirements of this The notation characteristics (X1, X2, X3…) are defined in
section. Sec 24, Tab 1.
Irrespective of previous assignment of the NH3 FUELLED
2 Assignment criteria READY notation, when the ship will be converted to use
NH3 as fuel, approval for compliance with RINA require-
2.1 ments in force at the time of conversion, followed by testing
2.1.1 (1/5/2021) and commissioning under survey, will be required.
The additional class notation NH3 FUELLED READY (X1,
X2, X3…) is assigned:
a) to new buildings that are in accordance with the RINA
Rules in force at the date when the contract for con-
struction between the Owner and the shipbuilder is
signed;
b) to existing ships that are in accordance with the RINA
Rules in force at the date of request of notation assign-
ment.
Table 1 : Description of the notation characteristics (1/5/2021)
Xi Characteristic Description
1 Design The complete design of the ship with NH3 fuelled system is found to be in compliance with the rules applica-
ble to new buildings, including those in Pt C, Ch 1, App 13
2 Structure Structural reinforcements to support the fuel containment system (NH3 fuel tank(s)) are installed and materials
to support the relevant temperatures are used.
3 Tank NH3 storage tank, tank master isolation valve, fuel venting arrangements and, where applicable, the fuel stor-
age hold space, structural fire protection and ventilation arrangements for under deck tank locations are built
under survey and installed in accordance with approved drawings and certified fit for NH3 fuel operations.
4 Piping All piping equipment associated with the NH3 fuelled system, e.g. pipes, pumps, valves, etc. including all bun-
kering arrangements and associated access arrangements including structural fire protection as applicable, are
built and installed in accordance with approved drawings and certified fit for NH3 fuel operations
334 RINA Rules 2021

Pt F, Ch 13, Sec 35
Xi Characteristic Description
5 Users Engineering systems are installed in accordance with approved drawings and certified fit for using NH3 as fuel
or ready to be retrofitted:
• MENH3r: Main engine(s) installed can be converted to using NH3 as fuel;
• MENH3: Main engine(s) installed are suitable to use NH3 as fuel;
• AENH3r: Auxiliary engines installed can be converted to using NH3 as fuel (see Note 1);
• AENH3: Auxiliary engines installed are suitable to use NH3 as fuel (see Note 1);
• BNH3r: Boilers installed can be converted to using NH3 as fuel;
• BNH3: Boilers installed can be operated on NH3 as fuel.
Note 1: The capacity of the converted auxiliary engines is to be sufficient for the ship power balance.
Examples:
• NH3 FUELLED READY (Design, Users(MENH3r)) means that the future NH3 fuelled design has been examined and found in com-
pliance with the applicable rules and the ship main engine is of a type that can be converted to use NH3 as fuel;
• NH3 FUELLED READY (Design, Structure, Users(MENH3r, AENH3r)) means that the future NH3 fuelled design has been examined
and found in compliance with the applicable rules, the ship is constructed with the necessary structural reinforcement and suita-
ble materials around the NH3 fuel tank(s), and the main and auxiliary engines are of types that can be converted to dual fuel
engines.
3 Documents to be submitted deemed necessary for the evaluation of the systems and
components.
3.1 Documentation requirements for charac-
teristic "Design" 3.2 Documentation requirements for charac-
3.1.1 (1/5/2021) teristics "Structure", "Tank", "Piping",
The list of plans and documents to be submitted is given in "Users"
Sec 24, Tab 2.
The documentation is to be marked "NH3 FUELLED ready" 3.2.1 (1/5/2021)
in each drawing title. The design, applicable to the assigned characteristic, is to
The Society reserves the right to require additional docu- be submitted and approved for compliance with the appli-
ments in the case of non-conventional design or if it is cable requirements of Pt C, Ch 1, App 13.
Table 2 : Documents to be submitted (1/5/2021)
Item
Documentation Additional description
n°
1 General arrangement Including NH3 tank location with distances from ship side, adjacent spaces, bunkering
station location, pipe routing, engine room arrangement and location of any other
spaces containing NH3 equipment. Location of entrances (air locks as relevant) for
spaces with NH3 equipment are also to be shown.
2 Engine room arrangement Only if not included in the general arrangement.
3 Design philosophy/ Including information on the NH3 storage, machinery configuration, engine room
description arrangements, fuel arrangements, shut down philosophy, redundancy considerations
etc.
4 Hazardous zones drawing General arrangement plan with the indication of the hazardous area classification
according to IEC 60092-502, but including the additional areas to be regarded as haz-
ardous in respect of toxic or oxygen depleted atmosphere.
5 Ventilation system For NH3 equipment spaces, including ventilation capacity, location of inlets and out-
lets, segregation from other ventilation systems.
6 Tank drawings and arrangement Including arrangement of tank connection space and pump rooms/compressor rooms
where relevant. The NH3 tank design drawings are preferably to contain sufficient
detail to allow for structural strength and thermal exposure calculations for surrounding
structure.
7 Structural strength calculation for
the NH3 fuel tank location
RINA Rules 2021 335

...OMISSIS...

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Amendments to the “RINA Rules for the Classification of Ships”

Effective from 1/7/2024

Reasons of the amendments

Part A – Classification and Surveys

Part B - Hull and Stability

Part D – Materials and Welding

Part F – Additional Class Notations

SECTION 2 CLASSIFICATION NOTATIONS

1 General brackets does not form part of the classification notation

e) operating area notations (optional)

RINA Rules 2024 41

42 RINA Rules 2024

4.1.7 (1/7/2009) 4.2 Cargo ships

Reference Reference chapter

RINA Rules 2024 ...OMISSIS... 43

4.2.15 (1/7/2024) - XII/13: "Availability of Pumping Systems".

RINA Rules 2024 49

52 ...OMISSIS... RINA Rules 2024

SECTION 2 MAINTENANCE OF CLASS

Table 1 : List of periodical surveys (1/1/2016)

Type of survey Reference in this Section Reference to scope of survey

94 RINA Rules 2024

1.2.2 (1/7/2020) 1.4.5 (1/7/2006)

1.3.2 The extent of any survey also depends upon the

RINA Rules 2024 95

2.2 Terminology related to hull survey 2.2.4 Overall survey

96 RINA Rules 2024

2.2.6 Transverse section • fair: condition with local breakdown at edges of

RINA Rules 2024 97

• bitumen, tar and their emulsions. 2.2.25 Edge corrosion (1/7/2012)

Figure 1 : Edge corrosion (1/7/2012)

98 RINA Rules 2024

SECTION 2 SURVEY FOR ASSIGNMENT OF CLASS OF A SHIP

222 RINA Rules 2024

SECTION 2 BULK CARRIERS, COMBINATION CARRIERS AND

1 General renewal surveys for purposes of verifying continuing com-

262 ...OMISSIS... RINA Rules 2024

RINA Rules 2024 ...OMISSIS... 267

270 ...OMISSIS... RINA Rules 2024

Age of ship (in years at time of intermediate survey)

272 RINA Rules 2024

SECTION 3 OIL TANKERS AND COMBINATION CARRIERS

1 General 1.2.2 A survey report file is to be a part of the documenta-

288 ...OMISSIS... RINA Rules 2024

292 RINA Rules 2024

TRANSVERSE BULKHEADS AND SWASH BULKHEADS

6.4.5 (1/7/2006) surveyor provided the following conditions are complied

RINA Rules 2024 299

SECTION 4 DOUBLE HULL OIL TANKERS

1 General umentation is to be kept on board for the lifetime of the

• oil tanker ESP CSR. 1.2.2 (1/1/2003)

RINA Rules 2024 307

RINA Rules 2024 311

4.4.3 (1/7/2006) date on which the overall or close up survey is

4.4.5 (1/7/2006) 4.5.3 (1/7/2006)

318 RINA Rules 2024

SECTION 5 CHEMICAL TANKERS

1 General Surveyor. The documentation is to be kept on board for the

326 RINA Rules 2024