Sound Proofing

Alternative approach is the Thinsulate thermal and acoustic insulation. PBO did an article on it in the last year or so.

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Go for the thinulate to reduce the level of the noise however to actually reduce noise you need the sound deadening pads first. The combo is actually about the same as Halyard but much much lighter easier to fit, ie you glue it on and better and reducing noise polution.

<hr width=100% size=1>Dom

<A target="_blank" HREF=http://www.soltron.co.uk>the website</A>
MMS - Discount Chandlery
 
I went for Halyard as they were the only ones to put attenuation figures on at the time. I can definitely say it works but it isn't the easiest to fit - especially on curves! Also, my engine bay wasn't a good shape to enclose and I think it's fairly true to say that if you leave any gaps, you might almost as well not bother! It made a big difference (and was easiest to fit) on the underside of the companionway steps but if I was doing the job again, I'd seriously re-think the whole project. Whatever you use, if you can't completely "box-in" the problem, don't expect miracles! Obviously, you have to let the engine get air so the way it sucks intake air needs a bit of careful thought. Most people seem to set up a series of baffles so the noise has to take a fairly tortuous path to get to the engine. Also, if your boat has the odd small leak, this stuff is pretty good atabsorbing and holding water - and its pretty heavy to start with!

In retrospect, I probably wouldn't do it again. It costs a great deal and make the boat a fair bit heavier. If you have a more modern boat with an engine bay designed to have insulation in it, I wouldn't hesitate recommending the Halyard stuff. If not, think really carefully about the possibility of creating a complete enclosure.

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Thanks all.

My engine compartment is boxy and built with a view to sealing. I always believed you needed a mixture of mass and porosity to cope with both ends of the noise spectrum.

Insofar as engine breathing is concerned, if the engine inlet is ducted with the opening in the coaming or similar, that makes the sealing that much easier. It also has another considerable benefit in that a semi-airtight engine room means that in the event of an engine room fire CO2 would probably be effective. At an RNLI safety meeting, the lecturer stated that any other fire fighting chemical would be likely to ruin the engine if ingested. Whether the engine room ambient would then be unacceptable, I don't know. If it becomes necessary to ventilate for that reason, you needn't have bothered in the first instance!

I note that Vetus and ECS market sound deadening materials. After the adverse comments about Vetus, maybe they should be avoided but I would welcome information on any other suppliers.


<hr width=100% size=1>GBW
 
Intake air...

My engine draws intake air through a duct behind the coaming. I built a baffled box arrangement for the intake, lined with sound-deadening material (OK, it was actually foam-back carpet) and this gave a significant reduction in the engine noise heard in the cockpit.

Another thought on intake air: if you duct it in to the engine space, arrange the end of the duct so that the cool incoming air blows over the alternator.

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Re: DepSol

Hi DepSol, could you expand a little on your answer please, or perhaps I am having a blonde moment.
Are you suggesting that to be effective, Thinsulate has to be applied over a layer of conventional sound deadening?, or are the sound deadening 'pads' that you refer to, something other than full sound deadening sheets?
As re-lining the engine box is on this winter's to-do list - all info gratefully received.



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Have just received some thinsulate (2" ish) to hopefully reduce further the sound of a 6 cyl ford just under the wheelhouse floor.

Existing efforts are approx. 1.5" of eggbox foam inside inspection hatches that cover much of the space, with perforated hardboard covering this & 19mm ply with a sound deadening(?) rubbery layer in the middle. (all factory fit).

Needed something light since hatches heavy enough, so will likely be adding thinsulate to above setup + tackling a few areas where no original foam was used.


I'll let you know the results.

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Re: DepSol

No Thinsulate is effective in itself at reducing noise levels howver, sound is vibration therefore if you reduce the vibration you reduce the amount of sound being amplified down the boat. Once you have reduced the amplification you can then reduce the residual noise by using thinsulate on top.

If you do not have much vibration then Thinsulate on its own is fine however, for the costs of the pads then its worth just sticking them in. Further evidence of this should appear in various magazines shortly as its popularity with boat manufacturers is growing.

The new Seline T61 (i think its the 61) has Thinsulate and sound deadening pads all over it to make it the quitest boat in its class. Thinsulate comes in 2 forms one with metallic covering for the engine bay and another with for the other areas of the boat with a black backing (ie for making sleeping areas quiter to reduce the wave slapping noise on the hull) and both materials are hydroscopic so won absorb water.

In some instances I have used thinsulate to lag fuel tanks (especially on yachts) which are constantly being kept warm by residual heat in the engine bay and forming the correct temperatures for bugs to breed. This allows them to get an advantage over the bugs breeding habits and clear the tank with continuos use of Soltron. No doubt some body is going to expand this thread out of proportion dis agreeing with this but dont knock it unless you have tried it.

Any body wants to talk to me more about it then PM me and I will pass on my phone number to save me typing out more long posts.

<hr width=100% size=1>Dom

<A target="_blank" HREF=http://www.soltron.co.uk>the website</A>
MMS - Discount Chandlery
 
Just as in a friend of mine firing a high velocity round into so called bullet proof plastic......Who among us has lit the thinsulate?
Sytrofoiam makesd phosgende...polyurethene makes cyanide so the question is thinsulate makes ?
Ian

<hr width=100% size=1>Building a steel sailboat in Comox, B.C. Canada.
 
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