"Rod McInnis" wrote in message

"Matt Lang" wrote in message

Is it necessary to install a fan to blow air in BEFORE starting?

Is this an outboard, or an I/O?

The legal requirements state that any boat with an engine in an enclosed
compartment must have proper forced air ventilation, which means an
electric
blower.

Be careful here. It is important to note that the blower should be set up
to exhaust air --to suck air out of the compartment rather than blow it in.
More efficient removal of fumes that way. This requires that there be other
vent openings of a certain size to allow replacement air into the
compartment.


If you have an outboard, and there is no machinery in the compartment
where
the gas tank is located, then you do not need to have a blower.

Generally, yes. But if the tank is alone in the compartment, and the tank
vents into that compartment, then the compartment must be ventilated.


Regards,

John Gaquin
Brefnie Queen
1974 Luhrs 32

"John Gaquin" wrote in message
...


Be careful here. It is important to note that the blower should be set up
to exhaust air --to suck air out of the compartment rather than blow it
in.
More efficient removal of fumes that way. This requires that there be
other
vent openings of a certain size to allow replacement air into the
compartment.


True. In fact, there are additional requirements for the blower/ventilation
system. I am not exactly sure what they are, but I know that there are
requirements that state how low in the bilge the air must be drawn from. It
doesn't do any good to suck air off the top, you need to get the heavy fumes
off the bottom. If I recall, the requirement is not higher than a certain
distance but above the expected level of bilge water (you don't want the
blower hose blocked by water).

There should also be natural ventilation that will keep the bilge ventilated
without the aid of the blower once the vessel is underway. This usually
means forward facing vents towards the front and rear facing vents towards
the rear. I believe these requirements have changed over the years so new
boats will have a different setup than older boats.

Rod