Acoustics

hardee · Posted: Wed Nov 10, 2021 1:48 am Post subject:

Well, That was back in my "Awesome" daze Shocked

Didn't want to scare the patients away.

Harvey
SleepyC Moon

Smitty.io · Posted: Thu Nov 11, 2021 3:14 am Post subject:

Foam won’t do much to deaden the sound, let alone a single piece of sheet rock or coatings. I have had a recording studio for 20 years and the way I insulated my control room from the “live” room with drums and amps etc. was to install two walls with three pieces of varying thickness sheet rock on each with a 3 foot dead space that was airtight.

I think the on ear would be a cheaper, lighter way to go. The acoustic foam only provides a little high end frequency absorption, usually for reducing reverb on microphones.

thataway · Posted: Thu Nov 11, 2021 12:01 pm Post subject:

Smitty.io · Posted: Thu Nov 11, 2021 10:55 pm Post subject:

I think the max you get putting any effort in to deadening the sound, you might get a 10 decibel reduction with the engine being so close to the cabin.

hardee · Posted: Fri Nov 12, 2021 12:26 am Post subject:

On the 22, the forward wall of the splash well is pretty low. I noticed a reduction in engine noise when I ran with my cooler hanging from the cross bar at the front of the splash well. At the time (and still am) running the Yamaha 40's (twins) that were rated as the quietest 409 on the market at the time. Between the cooler and the cabin door being closed, the OM sound was barely perceptible. (But then, my cruising speed is barely perceptible to some Laughing

Harvey
SleepyC Moon

travhale · Joined: 12 Nov 2021 Posts: 7

Has anyone tried applying sound dampening material inside the engine cowling to reduce noise? I've also seen some commercial boats with an outboard motor shroud built onto the transom that provides a barrier between the engine and cockpit. Mounting a large cooler on transom like was mentioned previously likely does something similar albeit less effectively.

zuunami · Posted: Mon Dec 13, 2021 3:40 pm Post subject:

C-Wolfe · Posted: Mon Dec 13, 2021 6:00 pm Post subject:

ssobol · Posted: Mon Dec 13, 2021 6:33 pm Post subject:

zuunami · Posted: Mon Dec 13, 2021 8:11 pm Post subject:

Even here the cost of shipping from Amazon costs almost as much as the product, and the product doesn't weigh very much. I can't really find any definitive information on the benefits of ceramic vs glass balloons, or I would try glass. Today I asked a question on Amazon about the Hy-Tech product and it's use for condensation under a metal carport, and a rep responded within about 30 minutes, so that was impressive nowadays Smile

Anyway, still thinking about it, I just hate paying so much in postage, but I should just do it and do some experiments Smile

T.R. Bauer · Posted: Tue Dec 14, 2021 9:49 am Post subject:

Lots of ideas here, but I don't think there is really a solution that will make a big difference.

Hunkydory · Posted: Tue Dec 14, 2021 12:19 pm Post subject:

TR, overall I agree with you, however I did come up with a noise lowering solution for the motors, that works, just very expensive. Going from 80 hp to 120 hp with the Honda 60’s allowed for a much lower motor rpm, which does equal substantially less noise.

Jay

stevej · Posted: Fri Jan 28, 2022 5:29 pm Post subject:

Surprised no one brought up the old Mascoat thread BC started way back when.
I put 5 gallons on the interior of Shearwater prior to the first Alaska trip. 3 coats, top, sides and under the V-berth. 2 coats full length the hull sides to 12" below the gunnel. 3 coats of latex.
Made a difference, takes the sharp edge off the noise and changed the acoustics enough that running at speed with the door shut is not bad at all.
Some insulating value also, it's not huge but it is noticeable from a condensation perspective.

Might be tough to do with the newer boats that have the interior liners. Had to remove 80% my interior to get uninterrupted coating the full length of the cabin on the uncored surfaces (roof is cored on shearwater).

stevej