Ok. I'll be the first to admit I don't use mine. I did when I had a boat with a gas engine, but not with diesels. First, I do check for any kind of fumes. Second, I have no drips of any engine fluids anywhere.

Gary,
Out of habit, I use my blower each time I start the engine. It might only be for 30 seconds or so, but I usually put it on. I also use it when motoring for long periods in hot weather. I haven't done a quantitative analysis, but I'm sure it lowers the engine compartment temperature somewhat.

While the blower may not be necessary with diesel fuel as it would be with gasoline, using it certainly cannot hurt.

One thing to check however, is the integrity of the flexible hose. I found mine was crushed as it passed aft under the bulkhead and not able to move any air.

When I do vessel safety checks as a Coast Guard Auxiliarist, I make sure the blower actually passes a good volume of air, and caution the owner to make sure the bilge pumps actually pump water. It is very easy to hear the blower or bilge pump motor come on and assume it will work.

I have found several boats with the blower hose disconnected from the blower and I found one boat with a stuck bilge hose check valve (not recommended in any case); it ran a lot but could not pump a drop of water.

Something else to consider as I read it some other place. Is to make sure that the blower is rated for continuous running if your going to run it all the time. It was a fire factor as I never gave it a thought either.
Randy

I have an air supply blower in addition to the standard air exhaust blower. When it is really hot on the TX coastal waters, I'll run both to keep the compartment cooler, supply enough fresh air to the engine and to keep the alternator cooler. My supply blower line is directed towards the alternator. The engine also seems to run better with ample fresh air forced into the compartment.

Hans Treu
C36-849 "Dutch Boy"

That is a good idea in my book, is it on the same switch so both come on at the same time?

They are on a single pull switch on the engine panel. The switch is either off, powers the supply when pulled out half way and powers the supply and exhaust when pulled out fully. When both are running they use quite a bit of power, but my new 70Amp alternator is keeping up without problems. I installed the supply blower in 2001, after I measured temperatures of 140-150 degrees in the compartment on a very hot and windless summer day on the Galveston Bay. I made estimates of the combustion air required by the engine at 2500-2800rpm, which turned out to be abt. 80 CFM, and I was not convinced at all that much air would make it to the engine w/o forcing it into this tight and closed compartment. The air supply blower takes air from an aft facing scoop on the outside of the port cockpit coaming and is instaled in a small cabinet in the back of the galley with a supply duct going into the compartment.

Hans Treu
Hull 849 - "Dutch Boy"