COOLING SYSTEM
Page COOLING SYSTEM-4
Z001007/0_4_September 2007
INSTALLATION INSTRUCTION
6. 4. RAW WATER PICK UP AND BOTTOM VALVE
The raw water pick up is to be provided within appropriate distance to the raw water pump of the engine, to avoid
a suction of air when the boat rolls.
Max. suction height of the raw water pump is approx. 9 ft (3 m) for standard installation. If required, the suction
height may be increased by loop-laying of the suction pipe so that the pump can start filled up with water. On top
of the loop an air cock is to be provided which is to be closed when the engine is stopped, to avoid a rising effect.
Before starting, the cock is to be opened.
On wooden boats the raw water inlet should preferably be made of red metal (brass unsuited: corrosion due to
high zinc content). On steel boats red metal is recommended too. If the materials used for the hull and the raw
water inlet are very different with regard to their galvanic characteristics, the inlet is to be electrically insulated
from the hull. Flow area of raw water inlet and screen should be large enough to avoid a throttling and thus a
smaller water supply to the pump.
The pipe should be laid in smooth curves to avoid unnecessary throttling, and preferably be made of copper-
nickel tube. To eliminate tensions, lay it in a curve and terminate it with a reinforced rubber hose at the raw water
pump. The hose should be designed with steel spiral, otherwise the underpressure in the suction pipe may cause
a collapse of the hose, thus no more guaranteeing a sufficient natural water supply.
ill. 6/3
1
raw water pick up
2
stop cock
3
hose
Raw Water Pipes
Dimensions in mm and inches
suction pipe, inside diameter
suction pipe, outside diameter
hose, bottom valve - sea water pump,
inside diameter
connection for bottom valve, thread
pressure pipe, inside diameter
pressure pipe, outside diameter
hose for pressure pipe, inside diameter
connection for outgoing water and
exhaust connection / sprinkler
min. rate of flow of raw water in l/min and gal./min
32
42
32
32
42
32
90
> 140
1 1/4"
1 5/8"
1 1/4"
R 1 1/2"
1 1/4"
1 5/8"
1 1/4"
3,5"
> 30
6. 3. RAW WATER PIPES
Inside diameter of the floor cock should at least be equal
to the suction pipe diameter, see "dimensions raw water
pipe". Make sure that the cock does not cause a reduction
in flow. On wooden boats, connect the bottom valve to the
ship bottom through a board lead-in with through screws.
Provide a proper sealing between valve and ship bottom.
NOTE:
On motor boat installation the grid of the water pick
up must be aligned to the front (driving direction), therewith
on increasing boat speed the water will be pressed into the
external cooling system.
On sailing boat installation the grid of the ater pick up must
be aligned to the rear (aft), therewith water can´t be
pressed into the external cooling system, when the boat is
undersailing conditions with stopped engine.
The bottom valve must be closed if the boat rides at
anchor.
4 + 6 Cyl.
Engine