Hamilton Jet HJ212, Installation And Service Manual, Page: 30 / 198

Design Basics
Installation and Service Manual
Engine Location and Mounting
Engines should be positioned to give the craft the most suitable fore and aft trim for the proposed boat
speed.
For semi-planing and moderate planing speed craft, the engine(s) should be positioned well forward towards
amidships for best trim and speed.
For very high speed vessels the engine(s) should be positioned aft, close to the jet unit, to obtain best trim
and speed.
Follow the boat designer's recommendations or consult C.W.F. Hamilton & Co Ltd.
Engine mounting
Mount the engine via mounting feet fixed to the engine bearers.
The feet and bearers do not have to withstand the propulsion thrust load as this is transmitted from the jet
unit directly to the hull.
Flexible engine mounts will reduce vibration and noise but must be used in conjunction with a driveshaft
system which does not cause radial or side loads at the jet unit coupling as the engine moves.
H-bar drive lines
In vessels designed for higher operational hours and severe use e.g. tourist boats operating in
narrow, shallow rivers, the H-bar type drive shaft or companion flange plus Cardan shaft must
be used.
This is to isolate the jet unit from possible high engine inertia forces associated with extreme
manoeuvres or groundings.
For steel hulls
Make sure the driveline is electrically isolated from the jet unit.
Engine systems
Follow the manufacturer's recommendations for engine wiring, instrumentation and throttle systems.
For steel hulls
With steel hull vessels, make sure that the controls do not electrically connect the jet unit to the vessel hull.
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