400DB Diesel Generator Exhaust Noise

[Michael and Jeanne V2]

Gang... I am looking for some advice. My wife and I are the proud owners of a '98 400 DB with CAT 3116(s) and a Westerbeke 8K Gen. Our engineroom is very well insulated and manages engine and vibration pretty well. Yes we still know we have CATs under the deck!

My question is about the generator and its high pitched exhaust. It seems to me to be excessive and with the exhaust right adjacent to the after deck a bit annoying. Do any of you have the same problem and have you come up with an effective way to quiet the exhaust? I'd love to hear back. Thanks in advance:huh:

 

[my3sons]

I can't speak first hand, but we just purchased a 400Db and during our search, we looked at one particular boat that the owner had actually added a log style muffler after the lift muffler that was on the boat originally, and that gen set was very quiet. I don't know the particulars about the set up because we only looked at that boat once and most of my questions were fairly general. He told me that he uses his gen a lot (it did have quite a lot of hours on it), and he was very happy with the set up he has. So yes, it is annoying to others (I think bekes are noisy in that application also) and that owner did quiet it down. Good luck

 

[Pietro]

I found my quiet happiness with a Centek gas-water separator! It really works!

http://www.centekindustries.com/gen-sep.html

 

[Alex F]

I had the same issue for 3 seasons and finally I decided to address it. I wanted to play safe and instead of picking new or additional muffler I talked to my Cummins/Onan tech. He told me that the mufflers SR installs is a tiny can. He suggested a replacement muffler for $220, which he uses very widely. Basically, the old one is 6"x9" and the new muffler is 10"x10". It looks and feels like it's double in size and "filters" twice the amount of water. I've installed it past weekend and the noise reduction is about 50%.

I wouldn't feel comfortable just adding additional muffler as I'm cautious about the genny performance. I don't want to create too much of exhaust blockage. The swap to a larger unit made a lot more sense to me, especially that it was suggested by my Cummins Tech. I'm pretty happy with the $220 investment. A word of caution, the installation is a huge PITA since to get to the muffler you have to go behind the generator (between genny and the swim platform). I did it all by myself, but it's clearly a two men job.

 

[fwebster]

I've got an 8-BTD as well.......not an Onan. ON the 450DA, the generator sits right under the aft cockpit seating. It is loud, but the actual exhaust noise is very quiet, as long as your impeller is in good shape and there is enough water flow. the BTD generates far more noise from the fuel knock and valve clearances than from the exhaust. So an added muffler probably won't help as much as some type of a sound shield for the engine itself,however, I would first check for adequate water flow.