Refit Engine Room Insulation.

[Pelagic]

I hate sound boxes around generators as they hide all kinds of minor problems that can become expensive repairs if not discovered.
So now that we are ashore for a year, I am taking the opportunity to make the whole ER the sound box and to clean up and label the wiring runs.

What I discovered when I removed the original 2 ½” Rockwool behind 3/8 dense fiber pegboard is that the hull shell and frames are in great shape. Corten steel, Dutch built schooner (1984)
The Ceiling just had some cheap stick on rock wool whose silver lining had turned to powder.

Biggest surprise was that the integral Diesel tank tops which forms the forward ER Bulkhead, have about a 4” gap with no barrier insulation, so that would is the biggest noise generator into the accommodation.

Also a few bulkhead penetrations for piping, had no noise baffles, so that is an easy fix.

If you look at my sketch my new Insulation Plan is to :

1. Stay with the Fiberglass Rockwool and original pegboard on hull sides (Orange 0.9m)
2. Ceiling, (Red) ,Side Deck Top and Inboard (Purple) as well as Aft ER Bulkhead, switch to a 2” 2lb composite barrier Vinyl /foam switching to the Quiet Tech Aloy pegboard.

Undecided how to re-do the Fwd ER Bulkhead. It is an Integral tank, built into the hull… I don't know what is needed for noise purposes on the ER tank side, since there is 2,400 liters of fuels behind it?

Should I just replace with loose Fiberglass, to make it easier to remove, or go with the same 2” 2lb composite barrier Vinyl /foam?

I will dam and fill up the void space above tank top with barrier insulation and Rockwool…. But what about the vertical face of the tanks??
Does it need a noise barrier?? ….Or just an absorber like rockwool and pegboard?

Any thoughts or suggestions are appreciated.

[bstreep]

Folks always comment on how quiet our engine and generator are. Last year, we replaced the insulating material on the generator surround with the foam composite from LED lighting, soundproof, Sailor's Solutions Inc.. It works well. Interestingly, the material we pulled off (that was failing) obviously had a lead layer in it.

[lorenzo b]

Steel boats are noisy, the hull itself vibrates. They make all kinds of expensive materials to dampen vibrations, but foam panels and acoustic ceiling tiles work fine. Very cheap and easy to install.

[gjordan]

You might want to do burn/smell test on any foam insulation before you install it. It can have all kinds of safety claims and still be dangerous. I was dismantling a damaged airplane a few years ago and hit some of the FAA approved foam insulation with the cutting torch and almost knocked myself over with the smell. It was self extinguishing like the rule said, but the smell would have been overwhelming in any enclosed space(like a boat). I was outside in the fresh air when I did this and think I would have been incapacitated in a few seconds time if it had been in a small space. I dont know how they ever made that garbage legal to put in an airplane, and there are less rules for boats. Try a small piece first.___My 2 cents worth._____Grant.

[CarlF]

Foam absorbs sound but doesn't stop sound's transmission. Decoupled mass blocks it.

Green-glue is designed to go between two sheets of dense material (like plywood). Might even work between steel and plywood. Very common now in high end housing.

Look at the test results especially at lower frequencies (diesel frequencies)

NOISEPROOF YOUR LIFE® | Green Glue