Westerbeke 9.0 BCG Technical Manual page 24

Exhaust System Failures
When engine sea water is fed into an exhaust system so that the full stream strikes a surface, erosion may
cause premature failures.
Proper design of either a water jacketed or water injected ''Wet'' exhaust system to prevent this problem re-
quires that the sea water inlet be positioned so that the entering stream of sea water does not directly strike
a surface. In addition, the velocity of the entering sea water stream should be as low as possible which is
achieved by having inlet fittings as big in diameter as possible.
In addition to the above design considerations, dividing the sea water flow at the point of entry to the ex-
haust system so only a portion of this water enters the exhaust system is usually advantageous. The
remainder of this sea water is usually piped over the side. The proper proportion of sea water flow to pass
through the exhaust system can only be determined by trial and error. The goal is to prevent excessive ex-
haust temperatures with the least volume of sea water. This dividing of the raw water, some into the exhaust
and some directly overboard, can be a means of reducing exhaust system back pressure.
Westerbeke Generators
18