soundproofing

[CAPTAIN FANTASTIC]

I need to soundproof my engine compartment. There are a few types of soundproofing panels available on the market of various thickness and texture. I wonder how effective the egg-box type in comparison to the flat panels; what is your experience with soundproofing?

 

[MoodySabre]

Comparison test in YM this month.

My experience - eggbox type is rubbish, Halyard is much better.

 

[CAPTAIN FANTASTIC]

Comparison test in YM this month.

My experience - eggbox type is rubbish, Halyard is much better.

Thanks, I will have a look at the YM report.

 

[Avocet]

I tried that - with only limited success.

First of all, the halyard "sandwich" panels are very good - and relatively easy to cut. They're heavy though!

Secondly, you might find (as I did) that a lot of your "noise" is structure-borne. In my case, through the engine mounts and propshaft into the stern tube and then the structure of the boat. A set of hydraulic engine mountings and a flexible coupling made a very big improvement, whereas the sound deadening made less of an improvement.

Thirdly, unless the shape of your engine bay really lends itself to being completely lined (including under the engine), your soundproof enclosure won't really be an "enclosure" - and sound is really good at finding tiny gaps! Getting the engine intake air through is one of the biggest challenges. Some people build a sort of "labyrinth" passageway for the air to flow down, lined with sound deadening and containing baffles so that it's harder for the sound to "bounce" straight out.

Lastly, if you have ANY potential leaks, this stuff holds water beautifully!

 

[johnalison]

It is probably well worth soundproofing with the proper stuff. My current boat is OK but our previous Sadler 29 came with the egg box type which I changed to decent stuff with a layer of lead. The difference was quite marked, though it can be a messy job. The use of indented labour in the form of a flexible teenage daughter is recommended.

 

[TonyBuckley]

I would guess that soundproofing is also akin to heatproofing. I'd like to understand that better as the foam in my engine box is disintegrating and I am looking to replace but not with something that keeps more of the heat in.

 

[PetiteFleur]

When I re-engined I replaced the eggbox type with the flat shhets from asap supplies. Although I used the best insulation, all carefully installed, I was dissapointed that the new engine, Beta 25hp, was noisier than the original BMC 1500 and I put this down to a higher idling speed and much less cast iron in the new engine. The old engine was inaudable at idling.
However the Beta is considerably more reliable, always starts and no smoke out the back - I used to leave the marina in a smoke screen!