RDG603A73 - Issue 3
Page 34 of 96
overall design of the system, and choice of components, will have a result on the back
pressure in the exhaust which is vital to the performance and life of the engine.
Barrus
recommend that Halyard (M&I) Limited are used for the Lift Silencer, Siphon Break
and other components. Contact Halyard (M&I) Limited for further information.
The
silencer must be drained before the boat is craned or transported and during the winter.
There must be at least 450mm distance between the water injection point and the position
of the silencer to allow adequate cooling of the exhaust gases. Maximum temperature
during continuous operation of the silencer is limited to 85 degrees centigrade. Normally in
a well-designed system, the temperature of the silencer should be between 50-70 degrees
centigrade. Such operation will result in longer exhaust life.
Connections to the silencer should be made using suitable exhaust hose, which is type
approved by Lloyds and DNV. Do not use oil or grease to lubricate hoses when installing,
wetting the inside of the hoses with water will help them slip more easily over the silencer
spigots. A minimum of 2 hose clips must be used. Securely tighten all hose clamps, but be
careful not to overtighten.
The silencer should be positioned within 300mm of the centre line of the vessel, or to the
engine on which it is installed. This is particularly important on sailing vessels where a
substantial angle of heel can be encountered. On systems where the exhaust manifold is
near or below the water line, a siphon break should be used to prevent the water flow
continuing after the engine shut down.
In all installations the silencer should be at the lowest point of the entire exhaust system.
The top of the silencer should be at least below the exhaust manifold outlet for the best
performance. If a distance less than is allowed, the margin of safety for preventing reverse
flow of water towards the manifold will decrease.
•
Siphon Breaker Fitting Instructions
1. The unit must be positioned upright, well above waterline. The height above
waterline will vary from vessel to vessel but will be between 150mm and 2
metres. Please seek guidance on this if you are unsure, or if you are not familiar
with the correct way to incorporate a siphon breaker into your particular exhaust
system.
2.
The inverted “U” bend at the top must be connected to a hose draining into the
bilge, or over the side of the vessel. In no circumstances must this drain into a
