Bilge Blower - "Intermittent Use Only"?

[Cadence]

Originally Posted by HopCar

Valhalla is correct. Once you start the engine, it is going to be moving far more air than the blower. No need to run the blower once the engine is running. That is why so many bilge blowers are rated for intermittent use.

If you want to spend the money, there are continuous duty blowers available.

He does not have a blown diesel.

With his gas engine a weep in a fuel line may cause explosive vapors.

[CarinaPDX]

I currently have this fan for my diesel in a small compartment: Lil' Champ Four Inch Ignition Protected DC Blower. I have a PWM motor controller to reduce the prodigious air flow.

Small engine compartments require forced air cooling for diesels. (My Volvo installation manual has a section for working out the flow rate needed IIRC.) I tried to make do with the old Sabb with the usual bilge blowers but they just don't last long.

Greg

[30West]

Originally Posted by Cadence

With his gas engine a weep in a fuel line may cause explosive vapors.

True, but gas vapor fires are rare in modern gas boats, despite huge numbers of them out there. Electrical fires are far, far more common. Most of us have multiple gasoline-powered cars enclosed in garages attached to our homes, and don't consider that a danger.

That said, I still check my bilge and run my blowers when below cruise speed. And I have fume sensors in my bilge.

[30West]

Originally Posted by CarinaPDX

I currently have this fan for my diesel in a small compartment: Lil' Champ Four Inch Ignition Protected DC Blower. I have a PWM motor controller to reduce the prodigious air flow.

Small engine compartments require forced air cooling for diesels. (My Volvo installation manual has a section for working out the flow rate needed IIRC.) I tried to make do with the old Sabb with the usual bilge blowers but they just don't last long.

Greg

Impressive.

[hamburking]

I've owned 3 sailboats with inboard gas engines, 2 of those were atomic 4. Before starting the engine I would go below and sniff for gas fumes. Then, blower ON for about 5 minutes. Then engine on.

I leave the blower ON all the time while the engine is running. Always ON.

After shutting off the engine, last thing is to shut off the blower.

FWIW, I could tell the state of battery charge by the sound(speed) of the blower.

Another boat I owned had a volvo diesel, but was originally an A4. Since it had blowers, I ran the blowers. Why not?

[Cadence]

Originally Posted by hamburking

I've owned 3 sailboats with inboard gas engines, 2 of those were atomic 4. Before starting the engine I would go below and sniff for gas fumes. Then, blower ON for about 5 minutes. Then engine on.

I leave the blower ON all the time while the engine is running. Always ON.

After shutting off the engine, last thing is to shut off the blower.

FWIW, I could tell the state of battery charge by the sound(speed) of the blower.

Another boat I owned had a volvo diesel, but was originally an A4. Since it had blowers, I ran the blowers. Why not?

Smart in my book.

With a gas boat I believe in opening the engine hatchs for 5 min. or more prior to starting. Gas fumes are volatile as hell. On a diesel I've kept a bucket of fuel oil in the engine room for a butt bucket to extinguish the butts . Diesel and gas/petrol are two entirely different animals.

[FionaJC]

Can I get this clear, Gas engines need a bilge blower prior to staring. We virtually all use diesel for sailing boats in the UK and no one has bilge blowers as far as I am aware. I have a thermostatically controlled centrifugal fan that sucks the air out the top of the engine compartment. Fresh air is fed from a vent in the cockpit side down to near the engine air intake. So am I right diesel doesn't need it before starting but some have it to take out the extra heat?

[CarinaPDX]

Originally Posted by FionaJC

So am I right diesel doesn't need it before starting but some have it to take out the extra heat?

Yes

Greg

[a64pilot]

Originally Posted by FionaJC

Can I get this clear, Gas engines need a bilge blower prior to staring. We virtually all use diesel for sailing boats in the UK and no one has bilge blowers as far as I am aware. I have a thermostatically controlled centrifugal fan that sucks the air out the top of the engine compartment. Fresh air is fed from a vent in the cockpit side down to near the engine air intake. So am I right diesel doesn't need it before starting but some have it to take out the extra heat?

That is my understanding.
I need to do the thermostat thing on my engine room blower, not to keep the engine from getting hot, but to try to keep the heat out of the boat, that much heat, some has to escape into the salon after shutdown.

[CarinaPDX]

Originally Posted by a64pilot

That is my understanding.
I need to do the thermostat thing on my engine room blower, not to keep the engine from getting hot, but to try to keep the heat out of the boat, that much heat, some has to escape into the salon after shutdown.

Another approach is to simply use a delayed-off relay, triggered by the engine power. That way the fan comes on when the engine is switched on, and continues to run for a programmed time after shut down. That would help the engine to cool sooner but would require some thought in setting the delay for the climate.

Greg

[HopCar]

Originally Posted by CarinaPDX

Another approach is to simply use a delayed-off relay, triggered by the engine power. That way the fan comes on when the engine is switched on, and continues to run for a programmed time after shut down. That would help the engine to cool sooner but would require some thought in setting the delay for the climate.

Greg

Blue Sea Systems just came out with a timer that should do the job nicely.

https://www.bluesea.com/products/7615

[CarinaPDX]

Originally Posted by HopCar

Blue Sea Systems just came out with a timer that should do the job nicely.

https://www.bluesea.com/products/7615

Yes, but at $135 MSRP that is a pretty spendy solution.

For the digerati, at $5, this would work for me: DC 12v 24v LED Display Cycle Delay Timing Timer Relay Switch Turn ON/OFF Module | eBay

For the analog crowd, for $10: Qianson DC 5V 12V 24V Infinite Cycle Delay Timing Timer Relay ON OFF Switch Loop

Greg

[valhalla360]

Originally Posted by Cadence

He does not have a blown diesel.

With his gas engine a weep in a fuel line may cause explosive vapors.

No one said he had a blown diesel, so not sure what that is about?

Yep, and the engine will suck those vapors in as they are generated and expel them (burnt) with the exhaust.

Again, it doesn't hurt to run the blower but even a small engine is just a big air pump constantly evacuating air (including vapors) from the engine room.

If there was a safety benefit, it would be standard practice to tie the blower in with the ignition so it's always on with the engine.

Gas needs to be treated with care and respect, not blind unreasoning fear.

[AKA-None]

Originally Posted by 30West

True, but gas vapor fires are rare in modern gas boats, despite huge numbers of them out there. Electrical fires are far, far more common. Most of us have multiple gasoline-powered cars enclosed in garages attached to our homes, and don't consider that a danger.



That said, I still check my bilge and run my blowers when below cruise speed. And I have fume sensors in my bilge.

Gas fumes ina car fall out the big hole under the engine. In a boat it falls into the bilge.

[NV US]

morning all from the canal du midi,

when I changed my antique mercedes 636 fir a nanni 43 hp engine I wired the blower to run anytime the engine is running... I mosly cruise for 8 houra a day and it appears it does my blower no harm at all... the merc636 used to overheat all the time and it left an indelible & incurable urge to constantly check the temp gauge... I'm still doing it 3 yrs after changing engines...