Noisy engine compartment blower

[agaliha]

I to "highjack" a thread in the "Ask All Sailors" category with this question and didn't get any bites.

The factory installed blower in my 2002 B361 went bad last year. I replaced it with a "Yellowtail" brand 3-inch inline blower. It works, but it shreaks like a F18 afterburner! I had to mount an "off" switch so I could talk over it. Does anyone have any experience with a quieter way to remove engine heat from the engine compartment? Would a "squirrel cage" blower be quieter? Another brand of inline?

Thanks,
Agaliha

 

[Ron20324]

I don't know Yellowtail, but did you return it for another one? And get the same problem? Maybe there's a squirrel in it?

 

[Philip_Oceanis 361]

Jabsco makes some blowers that (at least when new) are OK. I have one which does make a lot of noise but it's 10 years old now and probably needs replacement. On the other hand a friend has a newer one and it's much better.

 

[Ralph Johnstone]

I Feel Your Pain ....................

................. as I too have a 3" Yellowtail. Well, had is probably more correct. I was trying to install it last summer primarily to keep my alternator cool as this is the first time it's had to work for a living. Installed a Balmar ARS-5 and it really heats up. The engine compartment sat at about 138 deg. F. at 85% throttle. I now realize I've got to cool that compartment somewhat for better combustion. The noise was unbearable.

The Yellowtail cranks over at 11,000 RPM and delivers more than 100 CFM depending on the back pressure. No wonder it sounds like a banshee. Lots of air for a small fan but at a price.

This summer I intend to tame it by installing a rheostat to reduce the RPM down to a tolerable decibel level and see what it does to the engine compartment temperature.

 

[DougM]

Sounds to me like a lot of velocity and not much volume...I think I would opt for a blower that runs at a lower rpm and higher cfm if at all possible. When mounting the blower try not to bolt it down tight. Try to use some form of an isolating mounting. This would help to avoid transmitting noise and vibration through the boat. I doubt that it is running at 11000 rpm, anyway you are probably only getting around 130 cfm if its a 3 inch blower on 12 volts.

 

[Stu Jackson]

Doug's got the idea, plus in line fans have completely different noise frequency outputs, so it's bound to sound different than the inherently quieter backwards inclined box fans most of us have.

 

[agaliha]

Thanks for feedback

The Yellowtail came with rubber isolation grommets, so the problem isn't soundboard effect. Ralph said it right...the noise is unbearable. I haven't looked to see if Practical Sailor has ever tested blower fans for noise output.

The rheostat is a good idea...might try that before I go in on my head again to replace the blower.

By the way, I have a max recording thermometer in my engine compartment and I was able to prove that the blower (old and new) bring the temperature down about 30 degrees. I helps keep the icebox and rear cabin cooler. During the winter, of course, the added heat is nice so I turn the blower off.

Agaliha