Damper Drive Plate - Linear - 450 lb ft Max. Torque

The drive plate, or damper as it is often called, bolts to the engine flywheel and connects the engine to the transmission/gearbox splined shaft.
It provides a flexible, shock absorbing connection between the engine and transmission.

Damper Drive Plates are designed to prevent gearbox rattle (aka gear chatter/gear clatter) at low engine speeds.* This is typically caused by naturally occuring fuel ignition and combustion irregularities, as well as the lightweight flywheels found in modern diesels which don't create the vibration-smoothing inertia of older, heavy flywheels.
The damper allows an engine to operate through its entire RPM range without shock loading the drive train and causing extra transmission gear wear and damage.

R & D drive plates feature a flexible polyurethane element, designed to be stiff enough to transmit the engine power yet flexible enough to isolate vibration and shock. They are also designed to fail in safe mode, so the boat can continue to function.

Damper plate type is chosen according to vessel use, and actual selection is based on transmission splines, flywheel diameter and engine torque.

Three types of damper plates are available for different applications:
• Linear Elements - designed for general applications, provides a linear dampening of the torque applied to the system with up to a 3 degree deflection of the element
• Hammer Head Elements - designed for general use where motoring at low RPMs is common, provides a two stage dampening of the torque with up to a 9 degree deflection of the element
• High Deflection Elements - has a softer element designed for use in vessels where low RPM engine use is the norm as in work boats, many pleasure boats, or where gear noise is being experienced; gives three distinct stages of dampening with up to a 30 degree deflection of the element

• Models available for engines up to 800 hp, with 60 to 1400 lb ft of torque
• Reduces gear noise
• Allows engine to run at lower RPM
• Fail-safe design
• Machined and ready to bolt to the flywheel
• No springs to rust or fret

Details required for Damper Selection –
1. Manufacturer of engine, maximum horsepower, maximum engine rpm, number of cylinders.
2. Manufacturer of gearbox, model number, gear reduction, and input spline details.
3. Back plate outside diameter, number of fastener holes, diameter of holes, pitch circle diameter of holes. Are the holes equally spaced? Does the plate fit on the face of the flywheel or in a register?
4. Will the element of the Drive Plate fit on the outside of the flywheel or be reversed and fit inside a flywheel recess?
5. Boat use - pleasure powerboat, sailboat, work boat? Does the boat spend long periods running at low engine speeds?
Damper Plate selection is a complex process which almost always requires professional knowledge; please call your Fisheries representative for assistance at 800-426-6930.

All styles of these damper plates use a flexible, molded polyurethane element to absorb engine torque. The fail safe design of the plate ensures that even in the unlikely event that the flexible element fails (from severe shock load), the drivetrain system would remain functional.
(If the flexible element fails, the rivets attached to the spline plate will rotate into contact with the rivets attached to the backing plate to maintain serviceable torque transmission to the shaft until the plate can be replaced.)
The back plates of the damper plates are punched and ready to install. They can be installed within the existing space of a metal damper.

* Note that the causes of gear clatter can be varied and complex, and that low engine RPM is not the only possible cause. Installation of a Damper Drive Plate, while often successful, may not prevent all vibrations and rattles - particularly those occuring at high engine RPM. To solve difficult engine vibration issues, a detailed assessment of torsion vibrations, performed by the engine installer, may be required.