Sound Deadening

[Jug]

I needed to do some repair to the engine box that surrounds my auxilliary so I removed all of the old sound deadening material from the inside of it and now need to replace it with some new material. I'd love to hear from anyone out there with some real life experience with what works and doesn't work so well. The easiest to apply would be the paint but I've read other places that it doesn't work well at all.

What do you say? Any good experiences.

Thanks

Jug
SV Panacea
37' Flying Dutchman

[Faster]

Marine outlets sell a foil backed foam sheet about 1" thick that can be glued to the engine box walls with contact cement. It comes in sheets about 36"x60" IIRC, depending on sales, at between $60-$90 per. Leaving the foil exposed makes for a clean bright engine space.

We used to have our air compressors surrounded by lead-lined rubber curtains.. haven't seen these commercially but they worked great The material is quite heavy, about 1/8" thick and probably as effective as the 1" foam. It's also very good to use as curtains to block off some areas that do not have a solid surface available.

Another trick we used in a previous boat was to drape an old dentist's Xray blanket over the engine. This was extremely effective noise control, and made no difference to the operation of the diesel other than you have to make sure the blanket doesn't/can't block the air intake. We had to remove it for routine service, but that was a minor inconvenience.

[jr438234606]

I went looking for something at Lowes. I found a foam board with an aluminum-like backing from Owens-Corning, but I didn't buy it because it was not flame retarded. Whatever you put in there, make sure it can't catch flame.

[sandsailor]

and apply it wet like a giant spit wad excellent for sound, thermal,fire and mildew

[xort]

Controlling sound is more than just insulation. This website has a very good tutorial on the total picture.

Soundown (Sound Down, sound down, sounddown) - The Woldwide Leader in Noise Control Engineering

[JohnRPollard]

Originally Posted by xort

Controlling sound is more than just insulation. This website has a very good tutorial on the total picture.

Soundown (Sound Down, sound down, sounddown) - The Woldwide Leader in Noise Control Engineering

XORT,

Great link, thanks!

Anybody tried this product yet? Reports on effectiveness, ease of application/installation? Etc?

[Jug]

Originally Posted by Faster

Marine outlets sell a foil backed foam sheet about 1" thick that can be glued to the engine box walls with contact cement. It comes in sheets about 36"x60" IIRC, depending on sales, at between $60-$90 per. Leaving the foil exposed makes for a clean bright engine space.

We used to have our air compressors surrounded by lead-lined rubber curtains.. haven't seen these commercially but they worked great The material is quite heavy, about 1/8" thick and probably as effective as the 1" foam. It's also very good to use as curtains to block off some areas that do not have a solid surface available.

Another trick we used in a previous boat was to drape an old dentist's Xray blanket over the engine. This was extremely effective noise control, and made no difference to the operation of the diesel other than you have to make sure the blanket doesn't/can't block the air intake. We had to remove it for routine service, but that was a minor inconvenience.

Thanks, the X-ray blanket is a unique idea. Overall I think that leaded rubber is a good material, especially if it's backed with a foam material as an isolator.

I'd really rather have some sort of rigid material for ease of installation. My boat is rather unique in that the engine sits just below the companion way and is covered with a wooden box that is removable to expose the entire engine. It makes for super accessability but adds to the overall noise level. Fortunately when I repowered two years with a new Beta it was supplied with rubber isolated engine mounts and the four cylinder just naturally ran quieter than the old three cylinder Volvo.

[JohnRPollard]

Originally Posted by Jug

My boat is rather unique in that the engine sits just below the companion way and is covered with a wooden box that is removable to expose the entire engine. It makes for super accessability but adds to the overall noise level.

Agreed, it does make for easy access, and increases the need for good sound-proofing.

But it's actually not such an unusual arrangement. Quite a few boats are configured in a similar manner, including ours. On ours, the cover hinges up for quick access, but can be removed entirely for bigger projects.

PSC31, sistership:

[camaraderie]

Try here:
Soundown - The Woldwide Leader in Noise Control Engineering

[chucklesR]

My engine (weterbeake 30b) is rather unique in that it is actually in the cockpit on the Gemini (rear center lazerette). PCI did rather good with the insulation (soundown) and while running full rpm I can still have a conversation easily. You can't beat the access.

Practical Sailor did a review of the paint, and gave it a thumbs up as having made a difference. Since it's thin, light and easy I intend to put it on this spring as yet another layer of sound proofing - paint also doesn't close off air flow which is a serious plus.