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Do you Run Your Bilge Blower When Underway?

Posted: February 21st, 2020, 5:53 pm
by Marty
Just looking for feedback as to if you tend to run your blower when underway? We have had issues with our CO2 alarms going off when underway and I was wondering if running the bilge blower had anything to do with the airflow and part of the cause? We always keep our windows and cabin door shut and have a 326 Aft cabin.

Any feedback is appreciated.

Thanks all!

Re: Do you Run Your Bilge Blower When Underway?

Posted: February 21st, 2020, 7:46 pm
by throwback2
Usually cruising with windows and front hatch open and blowers off. 28 Voyager

Re: Do you Run Your Bilge Blower When Underway?

Posted: February 21st, 2020, 7:56 pm
by denpooch
I cruise with the blowers turned on. I leave them on when I return to the dock for little bit of time to get rid of some of heat in the engine compartment.

Re: Do you Run Your Bilge Blower When Underway?

Posted: February 22nd, 2020, 11:00 am
by Cooler
Blowers always on under 1500 RPM. Off after that because the air flow is moving due to engines spinning. I never have windows or salon door open when cruising. Station wagon effect sucks exhaust in to the point I don't need detectors other than my nose. My exhaust exits straight out the stern. Always instruct passengers to make sure to close doors during cruise. Conservative approach would be to leave blowers on all the time. Don't think it would be negative in any way other than blowers wear out faster. 8-) er

Re: Do you Run Your Bilge Blower When Underway?

Posted: February 22nd, 2020, 11:32 am
by Midnightsun
Just an FYI.

Explosive fumes are easily detected with the nose however CO has no smell whatsoever so the nose is useless. I have diesels yet have CO detectors just in case the wind is blowing in the wrong direction and the gas boat/generator CO close by is getting into my boat. Food for thought. ;-)

Re: Do you Run Your Bilge Blower When Underway?

Posted: February 22nd, 2020, 11:51 am
by bud37
Marty wrote:Source of the post Just looking for feedback as to if you tend to run your blower when underway? We have had issues with our CO2 alarms going off when underway and I was wondering if running the bilge blower had anything to do with the airflow and part of the cause? We always keep our windows and cabin door shut and have a 326 Aft cabin.

Any feedback is appreciated.

Thanks all!


Once the boat is underway I shut the blowers off, at this point, imo, the engines will change lots of air in that compartment. We try to have a forward vent or hatch open, in nice weather, to create a higher pressure in the cabin. There has been lots of innovations over the years in the boat world to deal with the station wagon effect , which is a very real and dangerous problem, well worth reading about.

A question ,to be sure, Marty, you are referring to the CO monitors in the cabin alarming , not the fume detector at the helm?

If it is the CO monitors in the cabin area, did you smell any exhaust gas/fumes outside when the alarms are sounding. There is not always a smell associated with Carbon Monoxide which is odorless and also would require you to enter a space with an alarm sounding not knowing the gas concentration......that is not a good idea, always ventilate first with known fresh air BEFORE entering. Overcharging batteries ( off gas hydrogen ) can set them off as well.

Re: Do you Run Your Bilge Blower When Underway?

Posted: February 22nd, 2020, 12:33 pm
by Marty
Yes cabin CO2 alarms are the ones I am referring to. Also when they go off there is a very strong exhaust smell. We never cruise with our doors or windows open but at times the kids like to be in the cabin when underway, but we always have to keep an eye on them and the alarms

Re: Do you Run Your Bilge Blower When Underway?

Posted: February 22nd, 2020, 8:25 pm
by bud37
Marty wrote:Source of the post Yes cabin CO2 alarms are the ones I am referring to. Also when they go off there is a very strong exhaust smell. We never cruise with our doors or windows open but at times the kids like to be in the cabin when underway, but we always have to keep an eye on them and the alarms


If this frequently happening, you might want to check your exhaust system in the engine room, check for cracks, any kind of leakage there, when and if the ice melts.... :-D

Be aware that even if the alarms have not sounded, you could still be experiencing low levels of CO , enough so to be toxic for the kids over a time period. Maybe consider some digital readout CO monitors to set out so you can monitor the situation more closely.....that may allow you to move canvas around, openings, etc to help the situation.......Good luck, I am glad you are addressing this.... :down:

Re: Do you Run Your Bilge Blower When Underway?

Posted: February 23rd, 2020, 5:41 am
by RGrew176
I generally run with the blower off. At cruising speeds there is plenty of air intake into the engine compartment.

Re: Do you Run Your Bilge Blower When Underway?

Posted: February 23rd, 2020, 7:35 am
by pepmyster
My vessels is wired that the moment I turn on the ignition, the blowers start. Only way the turn them off is with the breaker. Was told this is normal, I personally find it strange. I've always had the habit of on before you start, then when under way, off, when arriving to dock and secured, leave running for another 5 minutes. I find the way it is set up, on my boat, it just puts an unnecessary load on my alternators while under way. My thoughts only.