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Posted: Wed Oct 12, 2016 7:14 pm
by jimlong
Curious if anyone has used a sound deadener in the engine bays on the outboard models to kill off that monotonous drone noise or if it would even work?

Re: Dynamat

Posted: Thu Oct 13, 2016 5:04 pm
by amytom
I'm interested as well. My boat has marks as if something was glued on at one time but nothing there now.

Re: Dynamat

Posted: Fri Oct 14, 2016 9:05 pm
by thinwater
I thought about that, but...

a. I'm not sure I want anything that holds dampness.

b. I REALLY don't want to loose any space in the engine well.

c. I'm pretty sure that most the drone is vibration originating from the engine mounts and transmitted into the core. Foam wouldn't help. For example, pile about 4 quilts over the engine an notice that there is some damping of high frequencies, but no effect lower. I tried this with a dB meter, since I was also considering just doing the cover (wouldn't be in the way).

The cure would be some really cushy mounts (not just a rubber pad--that will NOT decouple the motion, because there is too much area), like you have for an AC compressor or automobile engine. A real design challenge, and not enough room under the clamps to fit it.

But I would love to look into if someone has tried it or something different. I like projects!

Re: Dynamat

Posted: Sat Oct 15, 2016 3:38 pm
by doubledutch
I added 1 inch thick sound deadener to the access lid on my 32 but it did not make any significant difference.

Re: Dynamat

Posted: Sun Oct 16, 2016 8:55 am
by jimlong
I can deal with the vibration, its the combustion noise from the exhaust that I would like to minimize. From what I understand Dynamat is like tar with a thin aluminum covering so don't think any foam is involved and can't imagine it would take up that much room. This stuff isn't cheap and thought I'd put feelers out to see if anyone has insulated the entire area. Oh well, I suppose it will just give me more incentive to hoist the sails.