Sound isolation engine compartment

[Frankklose]

My sound insulation material has deteriorate over the years and most came down as dust. Now I need to refurbish the sound absorption material. Since some time some similar material is used in car bonnets I wonder how good it is in comparison to the mats which are available at the chandlers at horrific prices. Has anybody experience with the soundproof mattes of the car industry in boats.

 

[Guest]

Re: Guess what

Just before xmas while driving along the track by my moorings .I saw some large sections of metal by the waters edge.
On closer inspection it was the remains of a large site generator !! obviously been nicked and cut up there .
Guess what they used to sound proof the unit ,plain old loft insulation ,the inner faces had perforated aluminium sheeting .The fibreglass was compressed to about one and a half inches or so .I will be using the same style of sound proofing on my tug .
Mick

 

[georgeb]

Re: Guess again

Doesn't mean it was particularly effective, just cheap.

 

[colin_jones]

The Halyard materials are not cheap, but they really are very effective in cutting dwn sound and reducing the boat's (apparent) vibration. We did our boat about three years ago and were very pleased with the resultant extra comfort. It is also fireproof.

Most of the other gear we looked at was either not suitable for sea use, or not very effective, or very messy to install.

At LIBS where they are giving it away ( or by post) Halyard have a super little video ion sound proofing

 

[vyv_cox]

I agree. We replaced the original foam stuff on our Sadler with Halyard sound proofing. Made a remarkable difference to sound levels in the accommodation and in the cockpit. I doubt whether using rock wool or glass fibre would make any appreciable difference. The stuff used on car bonnets is selected more for its damping properties, to prevent panel vibration, than its sound-proofing properties.

 

[tristan]

It is my guess that the materials used on car bonnets will be too expensive if you were to buy it from the manufacturers, as well as being totally unsuitable (it will absorb water and not provide much sound insulation as it has the wrong properties.
My advice is to buy the dedicated marine insulation, it is fireproof, does not absorb water, and has excellent sound insulating properties. It will also last many years (the product that is on your boat at the moment has now been discontinued).
As for the price, there are a number of suppliers offering reasanoble prices (for a marine product!!) if you consider the lifespan of the insulation.
As for the fiberglass in the aluminium mesh, i would strongly advise against this, as the fiberglass can break down and be drawn through the air filter into the engine (i have had to rebuild engines that have been wrecked as a result of this, so this is not heresay).

Hope this helps.

P.s. If your insulation is breaking down, then remove it, as there is a chance it may block your air filter as it becomes powder form.
Hope this helps

 

[Avocet]

I used Halyard's stuff on my engine bay. Density seems to be the only thing that really stops noise. Years ago, decent sound proofing was a "foam-lead-foam" sandwich. Nowadays, lead gets a bad press just 'cause it's a bit poisonous but some of the synthetic sandwich "fillings" are supposed to be as good. Basically, if it's heavy, it will work. Unfortunately, it's expensive and not especially easy to work (it won't follow any kind of curve!)

If I was doing my engine bay again:

1. I'd try to build the smallest "box" possible round my engine and insulate that rather than the inside of the boat round the engine - a sort of box in a box as it were.

2. I was worried about engine bay temperatures and getting enough air to the engine so I left too many too large gaps. ANY gap seems to break the chain and a disproportionate amount of noise seems to get out of the hole you've left. The answer seems to be to have a baffled (and fairly tortuous) route for the air to get in and sound-deaden its full length.

3. The nice reflective aluminised surface on the Halyard stuff looses its shine pretty quickly.

4. The stuff they use on cars is usually to dampen panel resonances rather than to reduce overall sound. It just changes the mass of the panel so it vibrates at a different frequency to whatever they were trying to stop from vibrating it (like the engine).

 

[Guest]

Re: Guess what

Have successfully used loft insulation on my boat above two loud Ford engines. I boxed the underneath of the removable floor panels with 1" square dowel and then compresssed 6" loft insulation into this box and covered it with varnished hardboard... it works a treat!

 

[Guest]

I used a product available in most builders merchants under the trade name Kingspan. It is a laminate of plywood, 4" of rigid high density fire resistant foam and an aluminiumised inner surface. It worked remarkably well was easy to use and cost only £38 for an 8' x 4' sheet. Cheaper versions without plywood laminate sell for £19 where appearance is less important.