Quote:
|
Originally Posted by Captain Zipper
I agree with the other poster to sniff the blower exit line (but then you run the chance of the blower start up igniting the fumes).
CZ
|
Unless there's a stiff breeze, lifting the engine cover or hatch will not let gas fumes escape. They are heavier than air and need to be pumped out so the blower is a necessity either way. The blower is spark shielded and mounted quite high in the engine compartment, or even outside of it, so it's not likely to cause any combustion, even if it did cause a spark.
Theoretically speaking: Running the blower with the hatch or cover shut is more efficient for getting rid of dangerous concentrations of fumes. Boat ventilation requirments call for a fresh air duct to be plumbed all the way to bottom of the bilge, opposite the blower inlet. This brings turbulent fresh air in to replace the gas fumes, right where they can be dilluted as efficiently as possible. Opening the hatch with the blower running allows air to come in gently from all directions and could, in theory, leave a pocket of gas fumes undisturbed. Running the blower fotr 4 minutes is a great idea, but I'd bet the blower is perfectly effective at preventing bilge gas fumes from being combustible in the first 10 seconds.
Many boats have automatic fire suppression system in the engine compartment. Mine does. That hatch is stying shut until the fire department or insurance company decides to open it, if it ever catches fire...