Generator noise

[callistov42]

Is there anyway to make a gen set quieter? Power yachts and many big cats run gen sets at night but they just don’t seem as noisy and mine. I am more concerned about noise in the anchorage than on board the boat.
Does anyone have any experience with gas water separator units and or mufflers after the water lift muffler. I am also looking at stepping down from a Westerbeke 7.6kW to a Northern Lights 6.0kW which I am told is quieter. Are most people happy with Northern Lights gen sets dependability? How many people have their gen sets in a sound enclosure? Are they a huge PITA?

[Sailmonkey]

My largest gripe about gen sets in an anchorage is the exhaust. The splash splash splash drives me nuts, along with the AC discharge 3' above the water and adding to the splashing.

The best installations I've ever been around had gas water separators fitted to the exhaust, sound enclosures on the generator, and all seawater discharges low in the boot stripe.

[Lepke]

I have a Onan 3 cylinder and Perkins 4108, both 14kw in enclosures. Perkins is quieter. I can only hear the water splash (but have poor hearing). I don't find the enclosures an issue for usual maintenance. Both can be removed in a few minutes. The muffler and rpm have the biggest effect on exhaust noise. An 1800 rpm engine makes less noise than a 3600 and a 1200 less than a 1800. The smaller the engine, usually the higher the rpm.

[a64pilot]

Myself, I wouldn't want a generator not in an enclosure. Doesn't make any difference to people outside though, but does make it quieter inside of the boat.
My generator is noisier than most exhaust wise, I think it's because I have extremely short exhaust hose runs. 6" or so to the muffler, and the muffler is 6" or so to the exhaust thru hull. I do have about a 2' inverted U from muffler to the thru hull though to prevent backflow of water.
I believe if I had 8' or so exhaust hose, it would be much quieter.

[J Clark H356]

I have a 5KW Northern Lights in a soft custom enclosure with 3217.5 hours. It runs at 1800 RPM and has 3 cylinders. I have a water muffler. I get 65 decibels in my cockpit and my saloon and my genset is in my port cockpit lazarette. We hardly hear the genset after a few minutes as it is background noise. Our airflow from the HVAC makes as much or more noise inside. We run it 24/7 when not at the dock. We have never had any complaints from those anchored nearby and we don't get too close when we get to an anchorage. We have been on the hook 304 days out of 1049 days on board - all with 24/7 generator and HVAC.

My cooling water exits below the boot stripe. I can go 10-15 feet away from the boat and hear nothing but an occasional splash from the cooling water. Any further and I hear nothing.

[Captsteve53]

You cant go wrong with a Northern lights generator, every one has there opinion but I'm basing mine of 40 years of commercial call outs for generator issues, Northern Lights call outs basically very rare compared to others!!, Later models all have servicing points on one side(easy servicing) many have stainless steel drip pans as standard, etc etc,

Installing an actual muffler in the exhaust line(after the water trap) will make a huge difference and even installing the generator on a softer/suitable type mounting material under the sound shield helps as well

[Catmandu]

Another generator to consider is Phasor in FL. Great unit, simple bullet proof and about 1/2 the price of a Northern lights (gunboat put them on their boats).

Water separator is key. Also you could give the folks at Sounddown in Ft Lauderdale a call. The specialize in sound proof mounts, insulation etc.

[TMT2]

We have a Phasor 16KW in a soft enclosure...4" exhaust run is 12 feet exiting at the waterline below the swim platform. We know it's running from the exhaust splash outside and a soft hum inside. Our AC is louder inside than the genny.