DS-ZF 7646

Marine Propulsion Systems
ZF 7646
Vertical offset, direct or remote mount marine
transmission.
Description
3 shaft, reverse reduction transmission with hydraulic clutch mounted on the input shaft and another one
mounted on the reverse shaft. Input drive on opposite side to output drive.
Non-reversing NR version also available .
Fully works tested, reliable and simple to install .
Suitable for commercial vessels in all applications as well as for motoryachts etc .
Design, manufacture and quality control standards comply with ISO 9001 and AQAP .
Compatible with all types of engines and propulsion systems, including waterjets and surface-piercing
propellers and cpps .
Features
Grey cast iron casing .
Case hardened and precisely ground gear teeth for long life and smooth running .
Output shaft thrust bearing designed to take maximum propeller thrust astern and ahead .
Smooth and reliable hydraulic shifting with control lever for attachment of push-pull cable or other operating
system .
Compact, space-saving design, complete with oil cooler, pump and full flow filter .
Suitable for multi engine installation (same ratio and torque capacity enginewise or counter enginewise .
Options
Engine-matched torsional coupling .
Mounting brackets for rigid connection to foundation or elastic mounting brackets .
Trolling valve for slow-speed drive .
Propeller shaft flange and coupling bolt sets .
SAE 00 bell housing for centering only .
Monitoring kit .
Trailing pump .
PTO (live) .
Electric clutch control (24 VDC) .
Classification by all major Classification Societies on request .
"AUTOTROLL" .
Last Updated:12:09 PM GMT - 15-Dec-11

ZF 7646
Ratings
Light Duty
MAX.
POWER/RPM INPUT POWER CAPACITY MAX.
RATIOS TORQUE
RPM
Nm ftlb kW hp kW hp kW hp kW hp
1800 rpm 2000 rpm 2100 rpm
3.308*, 3.440, 3.625*, 3.826*, 13400 9883 1.4031 1.8816 2526 3387 2806 3763 2947 3951 2300
4.000, 4.238*, 4.500
* Special Order Ratio.

ZF 7646
Ratings
Medium Duty
MAX.
RATIOS TORQUE
RPM
1600 rpm 1800 rpm 2000 rpm
3.308*, 3.440, 3.625*, 3.826*, 12540 9249 1.3131 1.7609 2101 2817 2364 3170 2626 3522 2300
4.000, 4.238*
4.500 11880 8762 1.2440 1.6682 1990 2669 2239 3003 2488 3336 2300

ZF 7646
Ratings
Continuous Duty
MAX.
RATIOS TORQUE
RPM
1200 rpm 1600 rpm 1800 rpm
3.308*, 3.440, 3.625*, 3.826*, 11000 8113 1.1518 1.5446 1382 1854 1843 2471 2073 2780 1800
4.000, 4.238*
4.500 10300 7597 1.0785 1.4463 1294 1736 1726 2314 1941 2603 1800

ZF 7646
Dimensions
mm (inches)
A B1 B2 H1 H2 L L1 L2 L3 Bell Hsg.
450 (17.7) 500 (19.7) 500 (19.7) 430 (16.9) 806 (31.7) 761 (30.0) 657 (25.9) 146 (5.75) -
Weight kg (lb) Oil Capacity Litre (US qt)
1,750 ( 3,850) 80.0 (84.8)
Output Coupling Dimensions

Bolt Holes
A B C D
Diameter (E)
No.
mm in mm in mm in mm in mm in
435 17.1 385 15.2 330 13.0 35.0 1.38 20 30.4 1.20
Last Updated:12:09 PM GMT - 15-Dec-11 Refer to the Installation Drawing for detail.
ZF 7646
Technical Notes
Duty Definitions
LIGHT DUTY DEFINITION Intermittent operation with large variations in engine speed and power
Average engine operating 2500 hours/year
hours limit: (for hydraulic gearboxes smaller than the ZF 650 series, 2000 hours/year).
Typical hull forms: Planing and semi-displacement.
Typical applications: Private and charter, sport/leisure activities, naval and police activities.
MEDIUM DUTY DEFINITION Intermittent operation with some variations in engine speed and power
Average engine operating 4000 hours/year.
hours limit: 3500 hours/year for gearboxes smaller than ZF 2000 series and workboat ZF W2700 series.
Typical hull forms: Semi-displacement and displacement
Typical applications: Charter and commercial craft (example: crew boats and fast ferries), and naval and police activities.
CONTINUOUS DUTY DEFINITION Continuous operation with little or no variations in engine speed and power
Average engine operating Unlimited
hours limit:
Typical hull forms: Displacement.
Typical applications: Heavy duty commercial vessels, tugs, fishing boats.
Duty Ratings
Ratings apply to marine diesel engines at the indicated speeds. At other engine speeds, the respective power capacity (kW) of the transmission can
be obtained by multiplying the Power/Speed ratio by the speed.
Approximate conversion factors:
1 kW = 1.36 metric hp
1 kW = 1.34 U.S. hp (SAE)
1 U.S. hp = 1.014 metric hp
1 Nm = 0.74 lb.ft.
Ratings apply to right hand turning engines, i.e. engines having counterclockwise rotating flywheels when viewing the flywheel end of the engine.
These ratings allow full power through forward and reverse gear trains, unless otherwise stated.
Contact your nearest ZF Sales and Service office for ratings applicable to gas turbines, gasoline (petrol) engines, as well as left hand turning engines,
and marine transmissions for large horsepower capacity engines.
Ratings apply to marine transmissions currently in production or in development and are subject to change without prior notice.
NOTE: THE MAXIMUM RATED INPUT POWER MUST NOT BE EXCEEDED (SEE RESPECTIVE RATINGS IN THE TECHNICAL DATA SHEETS)
Safe Operating Notice

The safe operation of ZF products depends upon adherence to technical data presented in our brochures. Safe operation also depends upon proper
installation, operation and routine maintenance and inspection under prevailing conditions and recommendations set forth by ZF. Damage to
transmission caused by repeated or continuous emergency manoeuvres or abnormal operation is not covered under warranty. It is the responsibility
of users and not ZF to provide and install guards and safety devices, which may be required by recognized safety standards of the respective country
(e.g. for U.S.A. the Occupational Safety Act of 1970 and its subsequent provisions).
Monitoring Notice
The safe operation of ZF products depends upon adherence to ZF monitoring recommendations presented in our operating manuals, etc. It is the
responsibility of users and not ZF to provide and install monitoring devices and safety interlock systems as may be deemed prudent by ZF. Consult
ZF for details and recommendations.
Torsional Responsibility and Torsional Couplings

The responsibility for ensuring torsional compatibility rests with the assembler of the drive and driven equipment. ZF can accept no liability for gearbox
noise caused by vibrations or for damage to the gearbox, the flexible coupling or to other parts of the drive unit caused by this kind of vibration.
Contact ZF for further information and assistance. ZF recommends the use of a torsional limit stop for single engine powered boats, wherein loss of
propulsion power can result in loss of control. It is the buyer's responsibility to specify this option, which can result in additional cost and a possible
increase in installation length.
ZF can accept no liability for personal injury, loss of life, or damage or loss of property due to the failure of the buyer to specify a torsional limit stop.
ZF selects torsional couplings on the basis of nominal input torque ratings and commonly accepted rated engine governed speeds. Consult ZF for
details concerning speed limits of standard offering torsional couplings, which can be less than the transmission limit. Special torsional couplings may
be required for Survey Society Ice Classification requirements.
12:09 PM GMT - 15-Dec-11 Driveline and Chasis Technology

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Marine Propulsion Systems

Last Updated:12:09 PM GMT - 15-Dec-11

Last Updated:12:09 PM GMT - 15-Dec-11

Last Updated:12:09 PM GMT - 15-Dec-11

Last Updated:12:09 PM GMT - 15-Dec-11

Output Coupling Dimensions

1 kW = 1.34 U.S. hp (SAE)

1 U.S. hp = 1.014 metric hp

Safe Operating Notice

Torsional Responsibility and Torsional Couplings

12:09 PM GMT - 15-Dec-11 Driveline and Chasis Technology

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