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Larry

(Richard Casady) wrote in
:

How about direct drive as used by the WWII German torpedo boats? You
stop the engine and restart it turning the other way. They didn't have
a compressor and only had enough air to start the engines once. Put a
premium on seamanship to say the least. All the biggest ships, tankers
and boxboats both, are that way. They avoid having a multimillion buck
gearbox. As for diesel-electric, all the Holland-America cruise ships
have it. One of the ones I was on had five engines for two shafts.
That way you can overhaul one and run on four easily. I saw them
loading cylinder heads at the start of a trip. All their ships have a
bar directly above the wheelhouse, with floor to ceiling glass on all
three outside walls. Great in a Norwegian or Alaskan fjord, or in a
harbor.

Casady

My concept for diesel-electric stems from the boaters' tremendous need
for electrical power for an ever-increasing array of electrical gadgets
far exceeding low voltage DC's ability to provide it. This need exceeds
the need for propulsion 95% of the time, the propulsion only used to get
in and out of the dock in real sailboats. So, it simply makes sense to
remove the 5%-used, directly coupled propulsion engine that doesn't
provide real electrical power and replace it with a real genset that
does. Now having real electrical power aboard, high voltage AC to match
real loads, it's simply a matter of providing the driveshaft solid-state
speed controlled, high voltage AC traction motors, just like trains have
been using for decades, to drive the boat in and out that other 5% of
use.

It simply makes better sense.....

To make machinery noise much more tolerable to the inhabitants, we must
do away with the high revolution prime movers of this electrical system
and, instead, use very primative, very slow turning diesels, which have
a very long history of amazingly long MTBF (mean time between failures),
very low maintenance (just change the oil a couple of times a month for
24 hour service), with a minimal number of moving parts (Listeroids have
12). Now disconnected from the drive shaft and its constant alignment
problems, engines and alternators can be put on a horizontal, not
slanted, subframe with intensive use of soft rubber mounts between the
engines and the frame and the frame and the boat. This is exactly why
the interior diesel and mechanical noises heard by passengers of a
Mercedes Benz diesel sedan are so low. There are two levels of dampers
between the body and the engine and one layer of dampers between the
body and the suspension system. Add soft mounting to extensive sound
absorbing materials, with tight controls on penetration of the
materials, and you have a very quiet diesel power plant anyone can live
with except, of course, the sailing hermits, who are not a major part of
the customers.

A lot of the propulsion noise you hear in a boat is transmitted by rigid
engine mounts to keep it aligned which are marginal dampers and through
the shaft to hull bearings, themselves. Diesel-electric eliminates
both.