Generator Noise

[Paul]

Hello fellow Trojan owners,

I'm planning ahead for a few spring projects, one of which is fabricating an enclosure for my generator. I'll explain what I plan on doing and hope to get some feedback from those of you who have enclosures as to whether my efforts will be worth it or not.

The boat is a '78 F-26 in which I rebuilt and installed a '70-'71 2.5kW Kohler marine generator a few years ago. As part of the installation, I added flame arrestors to the generator itself, the motor already has this, and updated the controls and exhaust system. This unit provides us with 120VAC @ 60Hz and enough amperage to run the AC, hot water tank, microwave, etc. My only complaint is the amount of noise. The exhaust isn't the problem, it consists of a Vernalift muffler and a Gensep water seperator. Most of the noise is from the motor itself.

Here's the plan. Using 1/8" 6061 aluminum sheet, I will build an enclosure with four sides and a lid. The front and right sides will be formed from one piece and will be held on to the left and rear sides with latches. The left and rear sides will be screwed to the stringers. The lid will be held on with lathces as well so thet the whole thing can be quickly opened up without tools. The bottom will be left open for ventilation. The right and left sides will have louvers stamped into them also for ventilation. All panels will be powdercoated and have sound insulation glued on the inside.

Well that pretty much covers it. Any suggestions that would help this idea work would be greatly appreciated.

Thanks,

[ready123]

Only comment I would make is to consider marine ply for the cabinet as that will have better sound absorption properties. What material are you using for sound proofing the box?
Is the underside of the engine/generator compartment roof/floor sound insulated?
With the need to leave the bottom of your genny box open for ventilation the whole compartment should also be sound insulated from the living space above... as sufficient sound will still leak out into the engine room.
In my experience sound proofing the underside floor of my salon made a big difference to the noise levels and I have yet to replace the ply box around my genny nor to insulate it as per initial plan. I can carry on a conversation in the salon quite comfortably while the genny is running.... also while underway too.
Here is what I used as insulation, foil towards sound, easy to install, spray glue and press cut sections in place, must tape the seams with the ally tape:
FTMM200
http://www.wilrep.com/WilrepDataSheets/ ... M/FTMM.htm
I was going to use this but decided that the increased sound protection was minimal at freq: of concern and also saved the extra weight.
http://www.wilrep.com/WilrepDataSheets/ ... TMM14C.htm

They are conveniently located on Dixie Rd just south of 401.
I had planned to do all walls of the engine room but have found that just doing the underside of salon floor more than satisfactory (hull side to hull side and forward bulkhead to aft bulkhead).
I did use F200 on the underside of the aft deck which has made things quieter while underway and while at anchor with genny running and sitting out on the aft deck.... did not need the foil as that area was not exposed to potential oil/liquid spray. That might have been overkill but it was pretty cheap and easy to do.

Hope this gives you some alternative ideas....

[Paul]

The underside of my cockpit floor and hatches are insulated with a foil covered fablic pad for heat & noise reduction but it's only about 5/8" thick. I think I'll try the thicker stuff that you've shown me inside the enclosure. Even though the bottom of the enclosure is open, it is about 60% blocked by the drip pan under the generator.

Thanks for the reply.