General arrangement and planning
24
Plan the engine room so that maintenance can be
easily carried out. Compare with the instruction book
and make sure that all filter replacesments, oil chang-
es and other servicing measures can be carried out
normally. Also ensure that it is possible to install and
remove the engine.
Before starting any installation work, make sure
that up-to-date dimensional drawings for the en-
gine and its equipment are used. Dimensional
drawings provide all the necessary measurements for
installation, such as the distance from the centre of
the crankshaft to the engine brackets (reverse gear
brackets) and to the centre line of the propeller shaft.
Note that the small silhouette drawings on leaflets
and brochures should not be used for this purpose.
The engine and drive line should be installed in such
a way as to minimise noise and vibrations, i.e. air
noise and body noise (vibrations).
Vibrations from the engine and propeller are transmit-
ted via the suspension and engine bed out in the hull.
Other channels are via the exhaust pipe, coolant
pipes, fuel pipes, cabling, and control cables.
Pressure shocks from the propeller are transmitted
through the water into the hull. Pulsating force on the
propeller goes into the hull via the support brackets,
bearings and seals.
If the propeller is at a large angle this pulsating pres-
sure and force can be considerable. Use of an incor-
rect propeller can result in cavitation, which also
causes noise and vibrations.
Torsional vibrations from correctly selected compo-
nents in the drive package are often negligible.
NOTE! Always consider international and local re-
quirements.
1. Engine room layout
Only use updated and approved dimensional drawings.
Study the drawings carefully. Consider soundproofing
material, the engine’s movements when running and
accessibility for servicing and repairs.
For twin installations, the distance between the en-
gines should be sufficient to allow easy performance of
inspection and service work.
2. Weight distribution
Consider the weight distribution of the boat so that it is
evenly distributed even with different levels of fuel and
water in the tanks. Place heavy units so that the boat
is balanced around the centre of gravity according to
the designer’s recommendations.
NOTE! Pay special attention to obtain the best centre
of gravity possible. This has a major influence on
performance in planing boats.
3. Fuel system
Determine the type of fuel system. Choose to use fuel
hoses or fuel pipes. Consider classification rules.
Decide where to place extra water separating fuel fil-
ters and plan for the routing of fuel hoses and pipes,
fuel filler and venting hoses, shut off devices etc. Fuel
feed and return hoses or pipes should be placed low in
the engine room so as not to transmit extra heat to the
fuel.
4. Cooling system
Chose where to place seawater intakes and seawater
filters. Plan the routing of hoses.
In boats where the engine is located low in relation to
the water line an anti-siphone valve should be consid-
ered.
5. Exhaust system
Determine the type of exhaust system, wet or dry.
Plan the installation of the exhaust line components,
such as silencer and hoses.
6. Electrical system
Plan the routing of cabling and check the length of in-
strument cable harnesses. Decide where to place fuse
boxes and main switches.
Avoid joints and cable connections where there is risk
of moisture or water. Do not make any joints or con-
nections behind fixed bulkheads or similar which are
difficult to reach after finishing the boat.
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