On Dec 16, 1:07 pm, HK wrote:
Richard van den Berg wrote:



On Sun, 16 Dec 2007 04:35:35 +0100 Heikki
) wrote:
Richard van den Berg wrote:

Regular outboards do have a fair weight/hp compared to e-motor and
batteries. The only thin you have to worry about is fuel. Or how did you
plan to fill your batteries?

Oh, I was planning to have a diesel engine (and a generator) running most of
the time to provide the electricity. The idea was to be able to place the
generator engine where I wanted it, and the propelller(s) and the driving
engine where they would be most useful. Instead of a solid shaft, I would
have flexible cables in between. I could run it on the batteries for a
minutes, if I needed extra manouvering, but in most cases, the power would
come from the generator. Also, I was hoping that the electric propulsion
would be smaller and lighter, so it would be easier to lift out of the
water when going by sail...

For 1 kW (1,34 hp) you can count on about 10 kg motor weight for
standard 3 fase 2900 rpm motors. For a lighter motor you might use one
with a permanent magnet, no idea what it will cost.

Well, it certainly makes no sense to hook up a small diesel engine to a
prop shaft and prop. After all, it's never been tried before.

West (Waste) Marine in their latest catalogue has a 6 hp electric
outboard, kinda expensive though. You could run a generator from a
small diesel like these Listers and have it charge a bank of batteries
that were your sailboat ballast and hav the batteries run your
electric outboard. Why carry around a couple thousand lbs of lead
ballast unless its going to do something like store electricity.