I am not familar with duct board. However, it sounds like a form of spun fiberglass insulation with a very light weight (paper?) face on both sides, maybe in "boards" form that makes it slightly stiff. Will it survive soaking and greasing? As was mentioned, if meticulously sealed almost any material will stop high frequency sound; the heavier the material, the more sound it will stop. I would guess if you used "duct board" you would experience some sound reduction; and if you sealed _both_ sides of the seams you would get better results. However, as mentioned, engine noise at lower frequency would probably go through it as well as traveling through the structural members.
Usually on a job that requires a lot of painstaking work, as this does, the labor and the hoped for long term benefits so far out weigh the materials cost that it's well worth researching and going with the best most appropriate material you can get - maybe on a "Phase I, Phase II... schedule. The thought of re-doing a job like this is daunting and while you might be disappointed no matter what material you use, if you have installed specific sound proofing material properly you can probably build on that base, improving various problem areas one at a time, WITHOUT having to worry and 2nd guess your original installation and start over. If it were me, I'd start with the really hard part that requires almost no material - the total sealing off of the engine room space vis-vis the living space. This means caulking every hole and gasketing every hatch, door, or drawer that communicates with the engine room. This will be necessary to realize much benefit no matter what materials you use and it _may_ be sufficient for you by itself. You probably then need to ensure combustion and cooling air for the engine from outside the boat - hopefully at a distance from the cockpit because those penetrations for air-in and air-out will spray engine noise. As mentioned, the bilge is a major problem because it's hard to reach but also because you need to deal with bilge water on both sides of your sound barrier. Maybe limber holes deep in the bilge will be an adequet compromise, but limber holes of any size always tend to clog up and they _will_ transmit sound. This is a wonderful QoL improvement but I think to get any worthwhile results involves a huge amount of detailed exacting labor. In light of your commitment of time and blood it makes sense to give yourself the best chance possible in materials. Rufus > ----- Original Message ----- > From: Peter Kafer > Sent: 08/02/11 09:44 AM > To: [email protected] > Subject: Re: [Liveaboard] Engine soundproofing > > I would like to thank everyone for their input. However, few of the comments > pertains directly to my question, "How is duct board different from similar > products sold in the marine market as "soundproofing" material. The products > I have seen generally have a textured foil face and a relatively dense spun > fiberglass interior. The look, in fact, just like duct board. since I have > a fairly good supply of duct board, I thought I might try it. > > thanks again for all the input. > > Peter > s/v Now or Never! > > > > ________________________________ > From: "[email protected]" <[email protected]> > To: [email protected] > Sent: Tuesday, August 2, 2011 9:15 AM > Subject: Re: [Liveaboard] Engine soundproofing > > On Tue, 02 Aug 2011 05:03:51 +0000, you wrote: > > Soundproofing is something that I know a little bit about - just > enough to be dangerous. > > A smooth surface reflects sound and a rough surface doesn't reflect > all the sound and doesn't reflect it in the same way. So a rough > cinderblock wall will make things quieter, and a painted cinderblock > wall even though it looks nicer will be noisier because all the little > holes in the cinderblock are plugged up. Ceiling tiles use this > concept with all their little holes. I don't know what ductboard is > but I suspect the problems in an engine compartment will be grease and > heat resistance. > > Vibration isolation is important. We've got a 1932 Plymouth where > they had something called 'Floating Power' to isolate the vibration of > the 4 cylinder engine from the car. The engine was suspended on > rubber mounts. When the motor is running, you can open the hood and > see the engine just bouncing around, but the rubber mounts keep the > vibration from being transmitted to the car body. > > If you have a sheet of metal that is vibrating you can reduce the > noise by putting holes in it. > > High frequency noise is easy to block. You can even do it with paper > in some cases - you just need some kind of box with no holes. Low > frequency noise (most engine noise and things like jackhammers) is > almost impossible to block because it travels through solids. That's > where increased mass comes in. I once did an inspection in a sawmill > and to block the low frequency noise the engineer had figured out that > they needed a wall 12 feet thick. > > If you can't afford an expensive engineering survey, I'd say just try > things out and see if they work. You might want to borrow a Sound > Level Meter from somewhere to check to see if what you are doing is > effective. > > >My understanding is > >- Weight (density) wins when stopping sound > >- Surface configuration does have an affect on the high frequencies > >- You don't want: > > 1) Physical contact between the surface receiving the sound and the > >surface on on your side of the wall > > 2) Any arerobic connection _at all_ between the noise space and your > >space. High freqs go through tiny holes, just like mice. > > > >You need to fill, plug, gasket and caulk the H*** out of your bulwarks. > >Electrical wires and plumbing are serious problems; the bilge connection is > >a MAJOR problem. Lead/foam work well when meticulously installed; cement > >board can work but is harder to install so it is isolated from the quite > >space. > > > >Lots on this topic. Google. > > > >Cheers, Rufus > > > >> ----- Original Message ----- > >> From: Peter Kafer > >> Sent: 07/20/11 07:08 PM > >> To: [email protected] > >> Subject: [Liveaboard] Engine soundproofing > >> > >> I would like to add insulation and soundproofing to the engine compartment > >> on Now or Never!, a Pearson 323. I have access to quite a bit of duct > >> board (1 inch thick, foil faced fiberglass insulation). Is there any > >> reason I should not use that? How is it different from similar products > >> specifically aimed at the marine market? > >> > >> thanks > >> Peter > >> s/v Now or Never! > >> > > > >_______________________________________________ > >Liveaboard mailing list > >[email protected] > >To adjust your membership settings over the web > >http://liveaboardonline.com/mailman/listinfo/liveaboard > >To subscribe send an email to [email protected] > > > >To unsubscribe send an email to [email protected] > >The archives are at http://www.liveaboardonline.com/pipermail/liveaboard/ > > > >To search the archives > >http://www.mail-archive.com/[email protected] > > > >The Mailman Users Guide can be found here > >http://www.gnu.org/software/mailman/mailman-member/index.html > > _______________________________________________ > Liveaboard mailing list > [email protected] > To adjust your membership settings over the web > http://liveaboardonline.com/mailman/listinfo/liveaboard > To subscribe send an email to [email protected] > > To unsubscribe send an email to [email protected] > The archives are at http://www.liveaboardonline.com/pipermail/liveaboard/ > > To search the archives > http://www.mail-archive.com/[email protected] > > The Mailman Users Guide can be found here > http://www.gnu.org/software/mailman/mailman-member/index.html _______________________________________________ Liveaboard mailing list [email protected] To adjust your membership settings over the web http://liveaboardonline.com/mailman/listinfo/liveaboard To subscribe send an email to [email protected] To unsubscribe send an email to [email protected] The archives are at http://www.liveaboardonline.com/pipermail/liveaboard/ To search the archives http://www.mail-archive.com/[email protected] The Mailman Users Guide can be found here http://www.gnu.org/software/mailman/mailman-member/index.html
