SounDown acoustic insulation installation

[Troy Scott]

Folks,
I have two kits of West Marine acoustic insulation, 1" thick. This is the stuff:
http://www.westmarine.com/webapp/wcs/st ... yErrorView

I intend to use this stuff to reinsulate the engine compartment of my CD36. This stuff came with aggressive Peel and Stick Adhesive (PSA). It also came with some disagreeable galvanized steel installation hardware, which I'd rather not use. The question is: Is the aggressive Peel and Stick Adhesive (PSA) good enough, even on overhead surfaces, that I could eliminate the steel fasteners? I do know that the original insulation was installed with something like contact cement, and it was really stuck! In fact, I questioned why I was bothering to remove it. However, what's done is done. If there is any doubt about the aggressive Peel and Stick Adhesive (PSA) bonding, I wonder if it would be compatible with a good brush-on contact cement. Thoughts?

[Russell]

I installed the same material about 6 years ago. When I bought it I had to buy the fasteners seperately, they were aluminium though. The material I bought was also by SounDown but it was not a peel and stick backing.

The fasterners I used were these: http://www.jamestowndistributors.com/us ... lation+Kit

They worked fine, no complaints.

Since my 1" soundown was not sticky back, I used a 3M spray adhesive. I would assume this would work better then the stuff that came on your sticky back version. I have had no problems with it.

I would definately consider getting the aluminium fasteners and using them if I was you. Worst case, if the adhesive does fail, your insulation isnt going to start flopping around in the engine room.

[Steve Laume]

I found that lots of the shiny tape on edges and seems helped to hold things together as well as make things look neat.

I buy the tape at my local hardware, rather than marine store, Steve.

[WaywardWind]

There are maybe three gazillion "sound reduction" products sold in all kinds of places for all kinds of situations. Most are pretty much useless.

First off, "sound" IS energy. AND **because energy can not be destroyed** sound to be attenuated MUST be converted from "sound" energy to another form of energy. Most usually that "other form of energy" is heat.

Meaning sound is converted to heat.

In the world of serious sounding proofing of rooms in buildings means floors and ceilings massively heavy and thick. It means walls with an outside of cinder block and an inside also of cinder block, separated by a foot or more of space, which is filled with sand.

HOWEVER, in such walls even a tiny, little, itzy, bitzy "hole" down in one corner will let lots and lots and lots of "noise" through (think a sealed container of water with a hole in one corner).

That massive weight absorbs the sound energy and turns it into heat (not a lot of heat, but nevertheless, heat).

Foam is added as just a way to reduce the amount of sound waves reflected by the wall, reflected waves needing to be bounced off another wall (so many times) until they too are absorbed by something massive to turn the wave into heat.

THAT means HEAVY mass (often lead) must be included in any potential sound attenuation system for a engine compartment. Lack of HEAVY mass in any system leaves the system pretty much a limited effort. Often a very large engine room will help attenuate sound simply by its volume (similar to an exhaust muffler).

Far and away THE best sound attenuation system on a boat is the main and jib sails. Raise 'em.

Most other "sound proofing" systems of recreational boats are a lot of time, money and effort for a tiny reduction in sound. Most of the perceived sound reduction is cognitive dissonance.

[Steve Laume]

Wayward, while your theory is excellent and is based upon science I would beg to differ with your conclusion.

I have installed the sound dampening in phases and each one was an improvement in noise reduction. We are not looking for sound proofing, only noise reduction. If you believe these modern sound reduction materials are of no use I would ask you to run your engine with the cover off and then close it up again. Even a barrier of 3/4" plywood makes a huge difference.

New engine mounts have not gone un noticed either. Noise and vibration can both add to the annoyance of running the engine.

While it would be nice to just sail all the time the realities of cruising tend to dictate the use of and engine at times. If I were only day sailing it might be another matter.

We were motoring home yesterday from our first venture of the season. The water was glossy at sunset with the only disturbance being our own wake and a few Loons. We actually noted how nice it was that Raven had quieted down significantly, over years past.

There is no waste of money in increased tranquility, Steve.

[Russell]

I can attest the 1" soundown I installed on my boat did make a BIG difference. Granted, there is still a LOT of noise, it was most certainly decreased. Its not a terribly expensive upgrade, and certainly worthwhile.

[John Danicic]

Troy:

As you start the process of sound reduction, do you have plans to add insulation aft of the engine? In a sense, to make a totally enclosed engine room? I insulated Mariah's engine compartment's top and three sides and it does make a huge difference. But I didn't make a wall to keep the sound from traveling aft under the cockpit floor and through the quarter berth hatch. A removable wall is what is needed so that you can still get access to the tranny dip stick and the stuffing box.

Any consideration on doing that? By the way, I used an excellent, sticky back product from Sailor's Solutions.
Easy to install and uses no hangers. Hard enough to mount screw-in cable ties and hose holders.
http://www.sailorssolutions.com/index.a ... Item=SPM01

Happy New Year to you and all of the Cape Dory board denizens out there.


Sail on

John Danicic

CD36 - Mariah- #124
Lake Superior- The Apostle Islands (on the hard, under feet of snow)
CDSOA #655

[Ron M.]

If you are attaching the material to plywood I used 'roofer's buttons', 1-1/2" plastic discs designed to hold asphalt paper to a roof or sidewall before shingles are applied. A # 6 ss screw the proper length will hold well. Also readily available are ss fender washers or plastic plaster buttons. Yeah, I know, Rube Goldberg, but hey, they do the job and look fine.
________
Vapor Genie Review

[WaywardWind]

Wayward, while your theory is excellent and is based upon science I would beg to differ with your conclusion.

...... If you believe these modern sound reduction materials are of no use I would ask you to run your engine with the cover off and then close it up again. Even a barrier of 3/4" plywood makes a huge difference.

.....

There is no waste of money in increased tranquility, Steve.

Limited, not useless. It's like putting on a nylon windbreaker over your t-shirt when the tempature is below 50 and the winds are over 30. BTW, an engine cover is pretty massive compared to foam "soundproofing". So is 3/4" plywood.

In high school, I had a buddy who said the EASIEST way to quiet a noisy car engine (in those days we drove cars with noisy engines with well-used parts rattling all around inside) was to turn the radio up louder. -grin-

Diesel engines in recreational boats can be loud enough to far exceed OSHA workplace standards for noise. Even with plenty of currently marketed "soundproofing" added, they still don't meet OSHA standards.

Cognitive dissonance -- sold wherever marine engine compartment soundproofing is sold, and other places -- is probably the most effective product sold.

[mike ritenour]

Troy,

I looked at the 1" stuff and decided I didn't want to lose that much interior space, so I went with a 1/4" lead impregnated rubber sound barrier. It is a better sound deading product than the stuff West Marine sells. I've forgotten the name but could find it for you.

I then mounted the leaded rubber, (marking all the penetrations for equipment), with ss screws and washers and 3M spray glue on all the interior surfaces, including the engine hatch cover, being careful to cover up any cracks or small openings.

Once attached, I then covered it with a shiny aluminum bubble insulation product (from Home Depot) that had a high burn resistance ( tested it with a torch before installing it). Once cut and fit, I used the aluminum tape to finish off the edges.

The completed project took up less room than the factory product I removed, gave the "engine room" a highly reflective surface and really lowered the sound level in the boat.

Best of luck on the project!

Rit

P.S. Sue sends her regards

[Troy Scott]

SounDown has two different 1" thick acoustic insulation products. As sold by Jamestown, their SDN-IVF1010MNSFT12 is 32 x 54 inches by 1 inch and is a multi-layer, mass loaded product apparently more sophisticated than their cheaper foam product. It's priced at about $80. The only difference I can find in this and the ones I have already (from West Marine) is the sticky back. I have this stuff because we bought it for our previous boat, which Katrina destroyed before we had time to install it. Now, six years later, WM is offering this same thing for about $160. I'm considering just buying the better Soundown stuff and some 3M adhesive, which will admittedly eat up some of the price difference.

[Troy Scott]

Guys, If it's an upgrade it won't really LOOK like one. The previously installed acoustic insulation that I pulled out looked very similar; it was just a lot lighter. This stuff is HEAVY. I suspect the original stuff was like the cheaper acoustic foam that Soundown sells. I guess I will use some fasteners in addition to the stickum because it is so heavy.

John, I'm not planning to add a bulkhead behind the engine. I briefly considered it because it's such an obvious possibility. However, there are so many other places for the sound to leak out, like the completely open space under the sole and above the holding tank. The bulkhead separating the icebox from the engine room doesn't go all the way to the hull. There is a large round hole behind the electrical panel that is absolutely open to engine noise. I'm going to add some acoustical material to the panel and to the access door between the foot of the quarter berth and the engine area. I will also close up most of that opening behind the electrical panel. I've chosen to be content with these few additional improvements.

Mike, Say HI to SUE!

[Boyd]

Hi All:

I believe that Soundown is just a renamed version of one of the many readily available acoustic foams. The heavier the better it works. I bought mine locally from one of the marine engine compartment insulators and used SS fender washers with long screws to attach it to the engine compartment. They worked great and the foam is easily removable anytime. No messy glue to fail.

I wont belabor the physics, but the confusion arises from the difference between sound absorbtion in a space and sound transmission to other spaces. Sound absorbers work by converting sound energy to heat internally in the material. They are generally soft and relatively dense materials. Bottom line is they reduce the sound pressure level inside the engine compartment and there by reduce the sound transmitted to other areas. They do work. Yes a small hole (and engine compartments have lots) will let out considerable sound by transmission, but the point is to absorb as much sound as possible inside the space.

I replaced the ageing and oil soaked foam in my engine compartment and the difference in engine noise is quite dramatic. Well worth the effort.

I have yet to figure out how to sail for an hour down a winding river against the current and wind traversing under 4 drawbridges to get to the ocean as some would suggest.

Boyd
s/v Tern
CD30 MkII
Fort Lauderdale, Fla.

[WaywardWind]

I wont belabor the physics...

I have a B.Sc. in physics and mathematics from the institute of technology of a large, well-known, land grant university, a set of schools which has produced a number of Nobel Prize winners, Pulitzer Prize winners, numerous NFL players, a handful of WWF entertainers, some well-known poets, and one or two Roller Derby Ladies. I have discussed the subject at length with an architect with extensive experience with soundingproofing structures, plus a builder of soundproof recording studios.

The only thing that beats cubic mass is cubic feet. Foam don't count for much.

[CD-Sailor]

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