Loud Engine Blower on Jeanneau SO 43 DS

[a64pilot]

I would not put it on a switch as you can forget to turn on a switch. I'd put it on the ignition side of the engine key switch so that when the key switch is on, the fan runs, that way you can't forget to turn it on, and you listen to hear if it runs before you start the engine.
I'd put a squirrel cage blower in to eliminate the noise as the noise is objectionable. A squirrel cage blower is what is in the AC of your car for instance, look at how much air that moves for very little noise.

[a64pilot]

I've been tempted to duct the fan exhaust to blow on me on cold days

[Prairie Chicken]

Originally Posted by a64pilot

I've been tempted to duct the fan exhaust to blow on me on cold days

LOL, that's not a problem for us.

I understand putting the switch on the ignition side of the engine start key, but if we can install a squirrel cage blower I'm not sure how the switch would be any better than letting the thermostat bring on the blower automatically when required. The question is whether there is room for a squirrel cage blower as we're no where near the boat at the moment.

[Nicholson58]

Originally Posted by dbostrom

A little late to the party here but if you change to a squirrelcage blower you'll get more efficient and quieter performance.

See this:

http://www.xylemflowcontrol.com/file...43000-0405.pdf

A bit bulkier but will fit and is vastly better than the cost-reduced part supplied with the boat. Note the datasheet points on life expectancy; there's an identical blower available with better lifespan but higher cost, if you prefer.

I had one of these. It was surprisingly made of steel with crappy paint. It corroded so badly that the wheel could not be budged with tools. I agree that this is probably the quietest form for a blower. Note that this type is used in home furnaces for reasons of noise & efficiency. I see that it is now made with a plastic housing Now all we have to do is get it stocked at We$t.

[Cheechako]

One nice thing about an independent switch is if you are in southern latitudes... after hours of motoring the engine puts out a lot of heat in the aft portion of the boat, if your berth is back there or a guests is... you can leave the fan on for an hour or two after you shut the engine off to extract the heat. I've done that a lot....

[Phoenician]

Unfortunately, most of the cheap fans (whether axial or centrifugal) that are commercially available in chandleries are poorly built, and will invariably become noisy after a while or will have a limited lifespan.

If you choose the route of changing fans, I'd recommend going for a reputable brand (Xpelair or similar comes to mind), they will be more likely to deliver on their published db ratings and should last a lot longer than the cheaper alternatives

[alcheringa]

We sailed a 2005 43 DS in the Med for two years and had no noise issues with our engine blower at all so I suggest you may have a damaged unit that needs replacing. The standard unit seemed to work fine for us.

Cheers

[HappyMdRSailor]

Originally Posted by a64pilot

A squirrel cage blower you will not hear with the engine running, even at idle.
If it annoys him it's not worth putting up with, fix it.
Wire it so it comes on when the switch is on, before engine start, that way you hear it run every time before you start the engine and know it's still working. You can't over cool the engine compt.

Oh man... I beg to differ in my instance... I have two fairly large squirrel fans like the picture posted... We're talking 5"? ducting.... They are wired to come on with the ignition, and off with a time delay relay... About 3 minutes..

My engine happens to be unbelievably quiet at low rpm, the fans are at least 2x as loud... but again, not annoying... more of a "whoooshing" sound...

Originally Posted by Prairie Chicken

No Phoenician, not the same. The blower is located under the aft bunks & large ducting leads to the vents in the cockpit. There is significant hot air being blown out of the exhaust vent. Putting a switch on the fan as A64pilot suggests makes good sense but does nothing to eliminate the sound. We do believe the fan is necessary so don't want to eliminate it or put the fan on a reostat (another suggestion we got). The squirrel cage fan sounds like the best alternative though if we need to go that way.

Prairie... As advised below, they don't have noise problem... So maybe a new unit is in order... Other thoughts are moving the fan upstream into the engine compartment... Or simply building a cheap sound enclosure around the fan...

Originally Posted by alcheringa

We sailed a 2005 43 DS in the Med for two years and had no noise issues with our engine blower at all so I suggest you may have a damaged unit that needs replacing. The standard unit seemed to work fine for us.

Cheers

[a64pilot]

Happy,
Why would you have so much fan? Dual 5" blowers should pull thousands of CFM combined, that would evacuate the entire engine compt every few seconds.
How many amps do such big blowers pull?
But yes if you are really trying to max out a centrifugal blower, they get loud. Electric leaf blower for instance, but most are spec'd for low noise.
I'm thinking they most likely have the normal axial flow bilge blower, and it has worn bearings, on gas motored inboards we would run the blowers before starting the engines and they weren't that loud, once the engines were started you had to listen to hear them.
I think they need to replace their blower, and since your replacing it anyway, go with a squirrel cage one as most are quiter.

[HappyMdRSailor]

Originally Posted by a64pilot

Happy,
Why would you have so much fan? Dual 5" blowers should pull thousands of CFM combined, that would evacuate the entire engine compt every few seconds.
I dunnae know caapn'!
My engine room although extreeeeemely well insulated is directly below the table... Maybe they just decided to overdo it???

How many amps do such big blowers pull?
NIiiiiiiiIIIINe!!! =9A at 24V!!!

But yes if you are really trying to max out a centrifugal blower, they get loud. Electric leaf blower for instance, but most are spec'd for low noise.
I'm thinking they most likely have the normal axial flow bilge blower, and it has worn bearings, on gas motored inboards we would run the blowers before starting the engines and they weren't that loud, once the engines were started you had to listen to hear them.
I think they need to replace their blower, and since your replacing it anyway, go with a squirrel cage one as most are quiter.

Again... more like a low "whoosh" really low frequency...