Boating How-To’s - Boat mufflers/ sound suppression
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08-12-2011, 09:46 AM
I have a 1988 Blackfin express 29' with twin 454 Crusaders. It is a great boat and in like new condition, with rebuilt engines, but it is quite noisy.
I am interested in any tips on how to substantially reduce the noise level. I have already installed 2" foam noise insulation throughout but this only helped a little bit, maybe 25-33% of the problem. I tried to look on the Internet for marine mufflers but just got confused.
Any help will be greatly appreciated, thanks in advance. Ed Michael
08-13-2011, 02:42 AM
I will try to help you as I am thinking of possibly doing this as well, just need a little time to get back to you..
08-13-2011, 02:50 AM
Ok not much time needed I guess, knowing the "no-room" we have outboard our stringers a quick search led me to these
08-13-2011, 03:20 AM
Has anyone tried Dynamat? I have a Optimax.. its pretty loud too, I lined the inside of my cowling with two layers of it. I'd say it reduced the noise by 50%.
08-13-2011, 05:56 AM
Foam will reduce reflected sound..what you need is MASS to ABSORB sound transmitted through the engine boxes. Also, noise escapes through openings under the gunnel and around hatches.
High frequency sound is easier to attenuate that low frequency sound.
My 24' blackfin w/302's is kinda noisy, even with mufflers. It isn't the exhaust, but just general noise transmission through the hull and cockpit floor, even though these things are built like tanks.
Black Magic 32
08-15-2011, 11:06 AM
Ed, I might have the solution for you with regard to exhaust noise (for engine compartment noise that's a different story). I have a pair of wet exhaust mufflers that came off of my 32' Blackfin Flybridge when I converted the boat from gas to diesel. The mufflers fit nicely between the outboard stringers and hullside. The gas engines I took out were Crusader 454's with 4" exhaust - so the same as your engines. I also have the fiberglass "Y" that connects the 4" hose coming from each of the manifolds to the single 4" hose going to the muffler. I also have all of the 4" hose and the SS hose clamps (although the hose is not all in good shape). I am looking to sell it all for a reasonable price plus whatever it costs to ship it. I'm in VA. I'm assuming based on your post that you don't have mufflers - no? You can call me if you like at: 757-617-8422. Vr, Bob