Fron what I understand, the higher frequency noise of the 3600
RPM gensets is easier to dampen than the lower frequency of the
1800 RPM units. My 3600 RPM unit makes about as much
noise as a window air conditioner.

Doug
s/v Callista

"Me" wrote in message
...
In article ,
"Skip Gundlach"
skipgundlach.sez.remove.this.and.the.dots.to.mail
wrote:

In several of the mailing lists of which I partake, there's been
discussion
of generators of late, originally about using AC, but migrating to
charging,
noise, space and cost considerations and other issues.

As we prepare to cut the cord for the rest of our lives, we're actively
considering an arch to carry solar and wind gear, as we'll be spending
the
rest of our lives in the Caribbean, where there's ample of both.
However,
the boat currently (pardon the expression) has a working generator of
recent
vintage (under 600 hours). It's got a (Diesel) Kubota engine driving an
Onan 6.5KW 3600 RPM electrical end (along with an alternator on a belt).

Unfortunately, despite its large motor mounts, hush box and muffler, and
located inside an engine room, other than from a fair distance off,
outside
the boat, it's enough to drive you (well, me, for sure!) mad with the
noise,
and, to a much lesser extent, the vibration. As a result, I refuse to
run
it except in emergency conditions, and wouldn't consider running it for
more
than a few minutes in an anchorage. FWIW, the exhaust noise outside the
boat is pretty minimal - but the engine noise from inside is fierce.

Has anyone successfully tamed the 3600RPM noise monster? If so, what
did
you do? Alternatively (again, please excuse the expression), is anyone
interested in a low-hours 6.5KW generator? It would free up a great
deal of
battery space! We're inclined toward wind and solar, but have this
otherwise perfectly good, expensive, piece of gear already installed
which,
if we don't have someone buy it for some significant amount of money, is
likely to stay put.

Thanks for any input on how to kill the noise monster...

L8R

Skip and Lydia

Morgan 461 #2
SV Flying Pig
http://tinyurl.com/384p2

"And then again, when you sit at the helm of your little ship on a
clear night, and gaze at the countless stars overhead, and realize
that you are quite alone on a great, wide sea, it is apt to occur to
you that in the general scheme of things you are merely an
insignificant speck on the surface of the ocean; and are not nearly
so important or as self-sufficient as you thought you were. Which is
an exceedingly wholesome thought, and one that may effect a
permanent change in your deportment that will be greatly appreciated
by your friends." - James S. Pitkin



News Flash,
What you need is to trash that 3600 Rpm Genend, and get an 1800 Rpm
Genend to replace it. Then reset the Injector pump for 1800 Rpm and
enjoy the quiet that results. diesels that turn 3600 Rpm are near the
limit of their mechanical operational range, anbd are NOISY as Hell.
I have a single cyl Fairbanks/Morse that turns at 1200 rpm and is as
quiet as a mouse in winter.

me

On Fri, 11 Jun 2004 10:53:28 -0400, "Doug Dotson"
wrote:
Fron what I understand, the higher frequency noise of the 3600
RPM gensets is easier to dampen than the lower frequency of the
1800 RPM units.

===========================================

That has not been my experience for what its worth. My last boat had
a 3600 RPM gas Kohler with a decent sound shield and water lift
muffler, shock mounted under the rear deck. Inside the cabin with the
A/C on, the noise level was barely noticeable. Outside in the cockpit
however I found it objectionable. Not really ear splitting or
anything, just annoying. It had kind of a frantic over reving quality
to it that I have not noticed in 1800 RPM units.

Not sure what you mean by a "frantic over reving quality"? Sounds
like it wasn;t working properly, perhaps a govenor problem.

Doug
s/v Callista

"Wayne.B" wrote in message
...
On Fri, 11 Jun 2004 10:53:28 -0400, "Doug Dotson"
wrote:
Fron what I understand, the higher frequency noise of the 3600
RPM gensets is easier to dampen than the lower frequency of the
1800 RPM units.

===========================================

That has not been my experience for what its worth. My last boat had
a 3600 RPM gas Kohler with a decent sound shield and water lift
muffler, shock mounted under the rear deck. Inside the cabin with the
A/C on, the noise level was barely noticeable. Outside in the cockpit
however I found it objectionable. Not really ear splitting or
anything, just annoying. It had kind of a frantic over reving quality
to it that I have not noticed in 1800 RPM units.

On Sat, 12 Jun 2004 00:52:25 -0400, "Doug Dotson"
wrote:

Not sure what you mean by a "frantic over reving quality"? Sounds
like it wasn;t working properly, perhaps a govenor problem.

=========================================

It was working fine. That's just my attempt to describe what I found
objectionable about the sound quality. 3600 to my ears sounds overly
busy, not yet chainsaw or weed whacker busy, but too busy. It's very
subjective and may not sound the same to everyone but I will probably
not buy another.

Ah, the PLEASURE of owning a Honda INVERTER genset.....

Runs 1200 RPM inside the fiberglass and steel enclosure until the load gets
to around 1800 watts, then GRADUALLY increases to its full-load-speed of
2200 RPM.............all the while feeding high frequency AC to its 3KW,
solid state inverter which puts out a rock-solid 60 Hz synthesized sinewave
to the loads, no matter what the engine is doing.....

Too bad someone doesn't use this technology in a YACHT GENSET of reasonable
price.....instead of the old 60 Hz alternator-on-a-driveshaft.

Larry

58 dB @ rated load
49 dB @ 1/4 load

http://www.hayesequipment.com/eu3000is.htm

It makes no more noise than someone talking at a normal level......