Combustible gasses have two limits, the lower limit of combustion and the
upper limit of combustion, too much air and not enough fuel - it will not
burn, too much fuel and not enough air and it will not burn. These limits
are expressed in percentages.
A proper blower located up high with an intake in the lowest areas should
safely remove the vapors.
If there is any question ventilate, as long as the source of the fumes is
shut off ventilation should remove the hazard (just make sure the method of
venting does not introduce an ignition source).

Eric

"rmcinnis" wrote in message
...

"Mick Davies" wrote in message
om...
I understand there are sniffers to detect propane build-up but if such a
pocket of collected gas is found how do you clean it out and make the
boat
safe again?

Open the hatches and circulate air.

Propane isn't any worse than gasoline. Both are heavier than air and will
settle to the lowest spot. In most cases there will be a path to the
lowest
part of the boat, which is generally the engine compartment where there
should be a bilge blower. Run the blower to get the fumes out.

IF yo have a propane locker it should have a drain leading directly
overboard so that any leaks there will take care of themselves.

Rod