KR101608031B1 - A method of providing a ship with a large diameter screw propeller and a ship having a large diameter screw propeller - Google Patents

Abstract

The use of a large diameter propeller 20 extending below the ship's baseline 11 is achieved by providing a distance behind the middle frame 13 where a stern wave floor 40 is formed with a screw propeller 20 A screw propeller (20) is included in a thruster unit or pod unit (6) forming a containerized propulsion unit (6, 60) mounted on a hull (10), and the intermediate frame (13) Wherein the containerized unit 6 comprises one or more generally vertical vertical recesses 13'for attaching the unit 6 so that the containerized unit 6 is rotated from the general navigation position to the bottom of the base line 11 of the hull 10, Allowing a small portion of the screw propeller 20 to be positioned so that it is preferably tilted to a position such that no portion of the rotary screw propeller 20 is located.

Description

METHOD OF PROVIDING A SHIP WITH A LARGE DIAMETER SCREW PROPELLER AND A SHIP HAVING A LARGE DIAMETER SCREW PROPELLER FIELD OF THE INVENTION [0001] This invention relates to a method of providing a large diameter screw propeller to a ship,

The present invention relates to a method for increasing propulsion efficiency and onboard ship comfort performance.

The present invention also relates to a ship having a propeller arrangement which increases propulsion efficiency and ship boarding performance.

The term "ship" as used herein generally refers to a marine vessel of sufficient size to carry its own motes, such as lifeboats, dinghies, or runabouts. The rule of thumb used is that a boat can fit on a boat, but a boat can not fit on a boat.

Further, as used herein, the term "intermediate frame" refers to the surface that forms the stern of a ship. Intermediate frames may be flat or bent and may be vertical or forward inclined (known as "retrousse") or backward (aft). The bottom edge of the intermediate frame can be approximately horizontal (in this case the ship's stern is referred to as the "mid-frame stern"), or the hull can be extended so long as the centerline is well above the midline, (In this case, referred to as "counter stern").

One problem faced by ship designers is keeping the hull vibrations at acceptable levels. Excessive vibration not only generates unpleasant noise in the ship, but also creates dangerous stressing of the ship structure. Also, forces that cause hull vibration can have other negative effects.

There are more problems with hull vibration than in the past, because ships are getting bigger and more power is needed. The increase in power causes an increase in the excitation force and an increase in the size of the hull, causing the hull to become more sensitive to vibrations due to these forces.

The main cause of hull vibration is the pressure fluctuations of the water produced by the propeller acting on the hull on the propeller. In other words, the wings undergo a substantial change in load as the propeller rotates due to the variation across the propeller disk, that is to say the wake, which is swept by the propeller blades. According to a typical single-screw stern structure, the maximum trajectory on the propeller disk can be as large as eight times its minimum trajectory. One effect of the rapid load variation of the propeller blades due to the rotation of the propeller blades is that they generate strong pressure pulses in the water which can excite the hull vibrations and cause severe cavitation erosion of the propeller blades.

In a conventional ship, the stern profile bends rearwardly in the form of an arc over the propeller and bends upward to form the aft extremity of the ship. This bent shape is used to provide a clearance between the propeller in the water and the propeller on the part of the hull which is necessary to moderate the effect of excited pressure fluctuations on the hull, In order to adapt to the trajectory pattern. This bent shape is generally formed as a single piece as a stern frame casting. For 400,000 dwt times, the stern frame can have a height of 50 ft (15 m) and a weight of 600 tonnes. It is extremely expensive to manufacture and it is often found that additional pieces have to be welded in order to twist and modify its shape upon arrival at the shipyard.

US 3,983,829 proposes to solve this problem by creating a complicated profile adjacent to the stern, thereby improving the trajectory pattern, thereby enabling the provision of large diameter propellers. As is well known, improved propulsion efficiency can be obtained by reducing the shaft RPM and increasing the propeller diameter. However, as already mentioned, the design proposed by US 3,983,829 is very complex and therefore very costly, and this seems to be one of the reasons why this design has not been successful in the market since 1974.

It is an object of the present invention to allow the use of large diameter screw propellers to increase propulsion efficiency and onboard boarding performance, which is achieved according to the invention as defined in the appended claims.

The previous solution to the above problem would increase the possibility of increasing the propeller diameter without increasing the induced pressure pulse on the hull, thus making it possible to obtain the propulsion efficiency and increase the boarding performance.

Other advantages and other aspects of the invention will become apparent from the following detailed description when taken in conjunction with the dependent claims.

In the following, the present invention will be described in more detail with reference to preferred embodiments and the accompanying drawings.
1 is a schematic side view of a preferred embodiment of a ship having a rotary large-diameter screw propeller included in a containerized propulsion unit according to the present invention.
Figure 2 is a simplified schematic side view of the stern of the ship of Figure 1 with a tiltable unit containerized in a normal operating position.
FIG. 3 is a simplified schematic side view similar to FIG. 2 except that the containerized unit is in a tilted position where the tip of the propeller blade is swing up to the level of the baseline of the ship's hull.
4 is a principle sketch showing movement of a containerized unit on tilting.
FIG. 5 is a rear view of a twin-screw boat based on the design according to FIG. 1, in which one screw propeller is in a normal operating position and the other is lifted by tilting the containerized unit.
FIG. 6 is a diagrammatic view of the twin-screw ship shown in FIG. 5 from above, showing a plurality of hydraulically controlled stud bolts.
Figure 7 is a partially enlarged cross-sectional view of one of the hydraulic control stud bolts shown in Figure 6 for locking a container of a containerized tiltable unit at a recess in the midplane of the ship.

1, a schematic side view of the ship 1 is shown. The ship 1 comprises a hull 10 having a base line 11, a stem 12, a stern 14 and a transom 13. At the stern 14, a propulsion unit 2 comprising a propeller 20 is arranged. An engine or motor (24) is arranged to drive the propeller (20). Figure 1 also shows a waterline 16 (i.e., a "design waterline", corresponding to the waterline for ship 1 when it carries a "standard load" for its use). And further shows that the boat 1 is floating on the water 4. [ The surface 40 of the water 4 also has a crest of rising waves formed at a distance behind the middle frame 13 of the hull 10 when the boat 1 is propelled at a cruising speed, Lt; RTI ID = 0.0 > 41 < / RTI >

Preferably the propulsion units 6 are "loaded into a container ", that is to say they contain" containers "which are modular housings 60 surrounding the equipment for proper operation of the propulsion unit 6 do. The hull design shown in Figures 1 and 5 includes a structure in the intermediate frame 13 that includes generally vertical recesses / pockets 13 'for the containers 60 of the propulsion units. Each container or housing 60 has its associated thruster unit or pod unit 6 (a streamlined container beneath a pod, fuel, engine, etc.) adjacent its lower end, It is inserted into a recess / pocket 13 'which extends vertically across the intermediate frame 13 and which has a sloping fore wall 13 "(see Figures 2 and 3) The housing / container 60 in the sheath / pocket 13 'is positioned such that the tip of the propeller 20 extends below the base line 11 (Figure 2) and any tip of the propeller 20 extends to the base line 11, The housing / container 60 can be tilted between an up tilted position (FIG. 3) that does not extend below the base line 11 of the hull 10, Or a position where a portion of the rotary screw propeller 20 is not positioned, The arrangement according to the invention allows the use of a large propeller 20 which provides considerable advantages. Furthermore, the arrangement allows the propeller 20 to be located at a distance from the intermediate frame 13, which provides additional advantages Thereby facilitating positioning of the thruster unit or pod unit 6 at a location where the thruster unit or pod unit 6 is located.

As shown in FIGS. 1 to 3, the propeller 20 is mounted with a distance behind the middle frame 13 of the hull 10. Wherein the distance aft of the intermediate frame is shown to be chosen such that the propeller 20 is positioned substantially centrally to the floor of the riser stern wave 41 and this may provide other advantages in some situations, Positioning does not imply any limitation with respect to the basic principles of the present invention.

In the design according to the prior art the diameter of the propeller is at most about 80% of the distance H between the baseline 11 and the baseline 11 and the baseline 11, There must be sufficient clearance between the tip of the propeller and the hull so that no propeller is extended down and no vibration is generated. Third, there is a gap between the tip of the propeller and the surface 40 so that air is not sucked in. Because a certain distance must exist.

By virtue of the arrangement according to the invention, as shown in Figures 1 to 3, the distance H between the baseline 11 and the deadweight contour line 16, which is far greater than in the usual case, It is possible to use the propeller 20 having an outer diameter that can be much larger. In this regard, for example, the present invention may be applied to ships of all kinds of ships of 10 dwt (preferably at least 100 dwt) to 500,000 dwt, i.e. those which use relatively large propellers of, for example, 0.5-15 m diameter You will understand that it is possible. Indeed, the main focus is the seagoing commercial vessel, where the present invention can have a significant positive impact on both cost and environment. Thus, a much larger power output can be achieved only due to the large propeller diameter. According to the present invention, in fact, some 7-15% increased output efficiency can only be achieved by the parameters. Further, the preferred positioning of the propeller 20 will eliminate any major impact on the vibration on the hull 10, which in turn provides improved boarding comfort and in fact eliminates some conventional design constraints . Moreover, it will have a positive effect on the load on the propeller 20, for example the hull 10 to produce a smaller pulsation at this position compared to when it is located before the intermediate frame 13 It can be acquired. In embodiments utilizing the fact that the floor 41 is at a much higher level than the surrounding surface 40, typically about 1-1.5 m higher than the median size at the cruising speed, 20) may be used.

In the design shown in Figure 1, the propulsion unit is a rotatable thruster, for example a pod unit 6. The concept of the present invention is first intended for pushing pod propellers and rotatable thrusters, but is also useful for pulling units and non-rotatable thrusters. As a result, a very large propeller 20 can be used, which has its upper end near dead weight convolution line 16, but is safely submerged at cruising speed due to stern wave 41. As is typical for port units 6, the vertical extension 30 'may be formed to act as a rubber. Here, in some applications, the diameter Dl of the propeller 20 may be selected within a range of about 85-100% of the height H between the horizontal line 16 and the baseline 11. However, in the embodiment shown in FIG. 3, the propeller 20 may even be designed much larger, i.e. having a Dl of about 130% greater than 100% of H, for example. If desired, this can be accomplished in combination with a control system comprising a brake pin 18 projecting deeper than the tip of the propeller and located in / near the stem 12 of the ship 1. Such a system will be described in more detail with reference to FIG.

Fig. 2 is a simplified schematic side view of the stern 14 of the ship of Fig. 1 in more detail with respect to the containerized tiltable unit 6 in its normal operating position. The container or housing 60 is mounted in a substantially vertical and recessed pocket or pocket 13 ', which has a forwardly inclined front wall 13''to allow the containerized propeller to be tilted. Is designed to have sufficient buoyancy for the unit 6 to float and this has several advantages, for example a small vessel up to the desired location for exchange / mounting in connection with the exchange / mounting of the unit 6 The tilting mechanism 62, for example the hydraulic piston (s), is arranged in the pocket 63 of the front wall 13 "to enable movement / tilting. Due to the ability of the tilting, a large propeller can be used compared to conventional arrangements, as it is allowed to extend the propeller beneath the baseline during propulsion on deep water. The housing 60 on the shallow water can be tilted to such an extent that the tip of the lowermost propeller blade 20 does not extend beyond the ship's baseline 11 as shown in Fig. The inclination of the forward inclined front wall 13 "is determined by the desired tilt of the containerized propeller and is determined during the planning and design of the ship. The propeller is preferably located below the corresponding stern wave floor 41 at the back of the ship And the tip of the lowermost propeller blade 20 extends downwardly beyond the baseline 11 of the hull 10.

4 is a principle diagram showing the movement of the unitized container 6 at the time of tilting. The containerized unit 6 includes a propeller 20 having a diameter D and a rotational axis 20 'and a container or housing 60 stands on the support plane 15. [ A slewing bearing 61 is provided at the bottom of the container or housing 60 to allow rotation of the propelling unit 6 around a generally vertical axis 62 and is provided on the rear wall of the container or housing 60. [ . A pivot axis which allows tilting of the containerized unit 6 in the recess or pocket 13 'is located at the corner indicated by 63 and formed by the bottom and front wall of the container or housing 60. 4,

A represents the distance between the rotation axis 20 'of the propeller 20 and the support surface 15,

B represents the distance between the central plane of the propeller 20 and the vertical rotation axis 62 of the propulsion unit 6,

C represents the distance between the tilting axis 63 and the vertical rotation axis 62 of the propulsion unit 6,

D represents the diameter of the propeller 20,

E is the distance between the support plane 15 and the tilting axis 63,

F represents the vertical distance at which the tip of the propeller blade is lifted when tilting the containerized unit 6,

and a represents a tilt angle.

According to the tilt angle on the order of 10 °, the tip of the propeller blade will be lifted by a vertical distance (F) of about 0.15 x D. 4 clearly shows how the vertical distance F at which the tip of the propeller blade is tilted at its bottom position depends on the relationships and sizes of A, B, C, D and E and the tilt angle a. Of course, the increased propeller diameter is achieved by mounting the propeller shaft 20 'at the lower level so that the tip of the propeller blade is prevented from cutting into the air through the floor of the stern wave, in its normal top position, i.e. before tilting In order to achieve the desired results.

In Fig. 5, a rear view is shown showing a ship 10 according to the present invention with a pair of propellers, but it is also within the scope of the present invention to use one propeller.

Figure 5 also shows an embodiment of the invention in combination with a specific control system that allows automatic upward tilting of the housing 6 if the vessel is to enter a shallow region. On a forward part of the ship bottom 11 such as on a bulbous bow so that any tip of the propeller projects deeper than the distance below the base line 11, A downwardly protruding one / several actuating pins / 18, having a length L that positions the end of the pin 18 at a sufficient distance below the actuating pins 11, is mounted. Preferably, the fins 18 are arranged. The pins 18 are arranged in a telescopic or pivotable or retractable manner, for example, when necessary to allow for a " dip down "in the port or shallow water. If the actuation pin 18 is pivoted, a signal will be sent to the control system (not shown) which will engage the tilting system and tilt the housing 6 to move in line with the forward ramp 13 " And thereby securely position the propeller 20 on the baseline 20. For 100 m times the time frame for the control sequence will be about 7 seconds to about 28 seconds and this will cause the tilting operation to take place Which can be easily performed within the time frame by a sufficiently powerful tilt-mechanism 62. It will be about 39 seconds at 5 knots, The use of a unit and the use of a swing-down / up thrower (not shown), and the possibility of the wings stopping the propeller, The combination of tilting of the con- tainer propeller allows still the use of large propellers, which will make it possible to increase the propeller diameter by some 30-40% For a four-wing propeller with a diameter of 5.3 m, this means that the diameter of the propeller can be increased up to 7 m or more by a half load of the original load, and the propeller can have its tip at about 40% This will give roughly an improved propulsion efficiency of more than 15%.

FIG. 6 is a diagrammatic view of the twin-screw ship shown in FIG. 5, looking from above, and particularly showing at least two positions in the pocket, i. E. Containers or housings 60 in the normal operating position and tilted position A plurality of retractable and controlled stud bolts 70 are arranged in the side walls 13a, 13b of each pocket 13 ', which are used to fasten the pockets 13'. An enlarged area 66 representing the stud bolt 70 schematically shown in Fig. 7, with a piston rod 71, which can be displaced in an axial direction by a conventional actuator (for example a hydraulic or screw mechanism (not shown) Is shown in Fig. The piston rod 71 has a free end that carries a head 72 having a tapered front portion. The matching chamber 73 is provided with a side wall 12b of the pocket 13'in which the high recess 73 is provided to provide a snug fit of the head 72 in the recess 73 The entire head 72 can be received. (Alternatively, the chamber 73 may also be tapered, and they may be mated to one another, such that only a portion of the tapered head 72 may push out of the chamber 73) Has a side wall provided in a recess (64) having a taper that mates with that of the top portion of the tapered head (72). The taper guarantees positive locking of the propeller containerized in the desired position in the recess or pocket 13 '. Channels 74 for injecting oil or grease between the tapered surfaces to facilitate relaxing the tapered recesses 64 and the tapered head 72 to the tapered chamber 73. [ And 65, respectively.

In summary, the following advantages can be achieved by the present invention;

By increasing the propeller diameter in a given engine power supply, the load distributed over the propeller disk area is reduced. In practice this means that the efficiency loss due to friction is reduced when accelerating the water and the risk of propeller sucking air from the atmosphere is reduced.

- In addition, the allowance for air suction will be further improved, for example, by allowing positioning in the floor of the stern wave, further behind the propeller.

In addition, by placing the propeller away from the hull, the on-board uction (so-called thrust reduction factor) from the propeller will be reduced, which will also be used to increase hull efficiency with reduced water velocities .

- reduced linear vibration and improved boarding sensation,

- In addition, the entire wave system of the hull can be used in a synergistic manner, for example, while reducing the overall resistance of the hull.

Improved flexibility in the use of propulsion arrangements.

An additional advantage in the use of "Containerized Propulsion Units" is the fact that they can be exchanged easily / quickly, which obviously brings a number of advantages, for example, When one needs maintenance, it can be swapped quickly by another unit. This also means that when a modular concept is used to provide a range of different propulsion units to optimize propulsion efficiency, such as the demand for power and / or speed requirements associated with the load, Thereby making it possible to use different propulsion units.

The present invention is not limited by the examples described above, but may be varied within the scope of the appended claims of the invention. For example, those skilled in the art will appreciate from the foregoing description that the basic principle of the present invention is not to locate the propeller in the case of a wave, but rather to place it at a position behind the intermediate frame, Lt; RTI ID = 0.0 > a < / RTI > tiltable propeller. It will also be appreciated that in some cases it may be advantageous to position the rubber in front of the containerized propeller 6.

Claims (16)

(1) according to claim 1, characterized in that the propulsion unit (6, 60) comprises a screw propeller (20), one or more recesses (13 ') are provided in the hull (10) , ≪ / RTI >
A method of providing a boat having a rotating large-diameter screw propeller (20) at the stern of a ship hull (10)
- providing said recess (13 ') in the form of vertical vertical pocket (13') in the intermediate frame (13) of said hull (10)
- arranging said propulsion unit (6, 60) to include a thruster unit or pod unit (6) attached to a modular housing (60)
- fitting the modular housing (60) into the vertical vertical pocket (13 ') in the intermediate frame (13)
The propulsion unit (6, 60) is arranged to have sufficient buoyancy to bounce,
Said buoyancy being provided in said modular housing (60)
A method of providing a large diameter screw propeller to a ship.
The method according to claim 1,
Characterized in that the propeller (20) is mounted with a distance behind the intermediate frame (13)
A method of providing a large diameter screw propeller to a ship.
3. The method according to claim 1 or 2,
Mechanically locking the modular housing (60) to the recess (13 ') in the intermediate frame (13) at two or more different locations.
A method of providing a large diameter screw propeller to a ship.
3. The method according to claim 1 or 2,
The modular housing (60) is pivotally mounted on the recess (13 ') in the intermediate frame (13)
A portion of the rotary screw propeller 20 may be located below the baseline 11 of the hull 10 from a general cruising position of the modular housing 60, And allowing a portion to be tilted to a position such that no portion is located.
A method of providing a large diameter screw propeller to a ship.
3. The method according to claim 1 or 2,
Wherein the propulsion unit (6) can be tilted by an angle of 5 - 20 degrees,
A method of providing a large diameter screw propeller to a ship.
delete 3. The method according to claim 1 or 2,
The screw propeller 20 has a diameter which is 50-200% of the vertical distance H between the ship's waterline 16 and the baseline 11 of the hull 10,
A method of providing a large diameter screw propeller to a ship.
(13), a screw propeller (20) attached to the propulsion unit (6, 60), at least one recess (13 ') in the hull (10) , And a stern (14) comprising a propulsion unit (6, 60) mounted in said recess (13 '),
The recess 13 'is in the form of a vertical pocket 13' perpendicular to the middle frame 13 of the hull 10,
The propulsion unit (6, 60) comprises a thruster unit or pod unit (6) attached to the modular housing (60), and
The modular housing 60 is fitted into the vertical vertical pocket 13 'in the intermediate frame 13,
The propulsion unit (6, 60) is arranged to have sufficient buoyancy to bounce,
Said buoyancy being provided in said modular housing (60)
A ship containing a large diameter screw propeller.
9. The method of claim 8,
Comprising a fixed arrangement (70) arranged to secure the modular housing (60) to a recess (13 ') in the intermediate frame (13) at two or more different points.
A ship containing a large diameter screw propeller.
10. The method of claim 9,
The first position is a general navigation position
The second position is a position where a portion of the rotary large-diameter screw propeller (20) is located below the baseline (11) of the hull (10)
A ship containing a large diameter screw propeller.
11. The method according to any one of claims 8 to 10,
And a tilting mechanism (62) capable of tilting the modular housing (60) by an angle of 5 - 20 degrees.
A ship containing a large diameter screw propeller.
11. The method according to any one of claims 8 to 10,
The propeller 20 is located at a distance behind the intermediate frame 13 and is positioned so as to be submerged under the ridge 41 of the wavy when the propeller 20 propels the boat at cruising speed.
A ship containing a large diameter screw propeller.
11. The method according to any one of claims 8 to 10,
The screw propeller 20 has a diameter which is 50-200% of the vertical distance H between the horizontal line 16 of the ship 1 and the base line 11 of the ship 10,
A ship containing a large diameter screw propeller.
11. The method according to any one of claims 8 to 10,
Said ship comprising a single screw propeller (20)
A ship containing a large diameter screw propeller.
11. The method according to any one of claims 8 to 10,
The boat was a twin screw boat,
A ship containing a large diameter screw propeller.
11. The method according to any one of claims 8 to 10,
The boat is a multi-propelling boat,
A ship containing a large diameter screw propeller.

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