On Wed, 1 Oct 2008 11:31:27 +0200, "Edgar"
wrote:


"Richard Casady" wrote in message
.. .
On Tue, 30 Sep 2008 20:05:12 +0000, Larry wrote:

Brian Whatcott wrote in
:

Still, a useful tip...



It's time the boats went diesel-electric. Sure works great for the
trains...(c;

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.

'Multi-million gearbox'?
Have you ever looked at an engine that will turn a big ships propeller at
80-100 rpm with direct drive?
They do not come cheap.


It seems to be more a matter of size as the BIG engines are all low
RPM engines that at lower RPM while lower power engines are usually
higher speed engines. for example, the Emma Mursk uses a 108,920 H.P.
@ 102 RPM engine and probably doesn't require a reduction gear, while
a smaller ship might use a 5,800 Hp @ 600 RPM engine with reduction
gear.

Bruce-in-Bangkok
(correct Address is bpaige125atgmaildotcom)