Engine Cover/ Noise Abatement

[sundown]

I have to do something about the engine noise in my Notrh Sea Pilothouse. The engine sits directly under the floorboards (it actually just about touches them) and has little noise abatement. I lined the sole with sheet lead and that had a wee bit of an improvement but it is still too loud to be comfortable.
I can raise the cabin floor a couple of inches by rebuilding the furniture and there is ample room on both sides and the back of the engine to construct a cowling.
Are there any new sound absorbers on the market such as high density foam? Any materials suggestions would be appreciated.

[unbusted67]

Do you mean Nor'sea?

[sundown]

No it actually is North Sea: It was a small boat yard in British Columbia that made them in the 80's- I don't know how many were actually produced but I have heard somewhere around 40 to 50. They have the same profile as a sloop rigged Colvic Victor. It is a nice sailing, comfortable boat with the exception of the damn engine noise.

[speciald@ocens.]

Remember that your diesel needs alot of air to run. How about lining the engine compartment with noise abating foam/lead panels. I bough some from Westa long time ago. Guess they still sell it.

[sundown]

Yeah that is sort of along the lines of what I am planning on doing: I am unfamiliar with pleasure boats so I am looking for ideas on how other sailboat owners' engines are sound damped. In the past I have used lead sheathing and high-density foam to line the deck and bulkheads of engine rooms but that was 20 years ago. Surely technology has advanced since then?

[boden36]

A while ago I employed a top acoustic engineer in my hotel. Apart from false walls and sound deadening materials, he was fanatical about air gaps. None were allowable. You would have to put sound baffling in any of your engine room vents, as well as any other measure. Regards, Richard.

[sundown]

Boden:
Is what you are suggesting that engine air intakes etc should also be insulated and ducted from outside? Did the engineer make any suggestions as to insulating/sound absorbant material? In the past I have used high density fiberglass mat as exhaust stack insulation and that cut noise considerably (as well as engine room heat).
I am contemplating using a combination of the fiberglass and lead to make a cowling that will fit over my engine and let it draw its needed air from the shaft tunnel and bildge. I am concerned that the alternator will get too hot with this idea though.

[Stevens 47]

I have justed finished lining my engine box and my genset box with this product. I saw it demonstrated at Strictly Sail in Oakland and was impressed. Glacier Bay the manufacture designed it for their Genset Box's. From my research it looks like it has the best noise abatement for a off the shelf product...very pricey though. Scroll down the info is on the second half of the page. Vacuum Insulation Panels (VIPs)

[boden36]

What I am suggesting, is that there be a series of sound abatement baffles in any opening. Imagine a tube, with one baffle coming up a little mote than halfway, then a little further along another baffle coming down the other way, all lined with absorbent material. This is fairly common so there should be diagrams readily available.
In the hotel we used high density glass mat. In a boat I would be using the purpose made stuff which is silver on one side and sticky on the back for easy mounting. If you need more air an in line fan in some ducting will help. The crucial thing is no straight air gaps. This guy went around everything with the edge of a credit card, and if there was any gap it had to be sealed. His name is Louis Challis, and he has an Order of Australia for his work in sound engineering and he really knew his work. Cost more than going to the dentist, though!!. Regards, Richard.

[sundown]

Richard & Stevens: I will chase down the VIP material and will incorp your suggestions to the project.
Thank you very much for your input
Bob

[sundown]

actually I meant I was going to chase the acoustic panels: