T&T: Propane Question from Heaters thread

[bob Austin]

I need to clarifly something which I posted about Propane and evacuation of
bilge fumes.  In gasoline powered boats the Bilge blower is to be installed so
that the intake ducting of the blower is just below the engine stringers, but
not to a point where the bilge water can get into the duct.  The blower is
made to suck fumes out of the bilge at low speeds.  It must be ignition
protected.  It is not the intent to push external air into the engine
compartment of a gas powered boat or in the normal circumstances of any vessel
for ventillation.  The intakes should be sized to adequate air intake for the
engine.

The only reason I posted about using a blower into the engine room was in the
assumption that the blower was not ignition protected.  I have seen diesel
boat blowers which were not ignition protected.  Normally blowers should suck
fumes out of diesel boats also--and it is best if they are ignition
protected.

However, one has to remember that as an engine gains speed, it will take in
far more air than a blower can push in or out.  Consider the displacement of
an engine and the revolutions of exchange of air vs what a blower can move.
For the most part diesel enging room blowers remove diesel fumes, and heat
from the engine room at low speeds.

Bob Austin