Ted wrote:


Hmmm, the math is pretty simple. We measure the output power of motors or
engines in Hp. 1 Hp = 746 watts. 5 Hp = 3730 watts. To produce 5 Hp at 12
volts would require 310.8 amps. (Assuming no IR, friction, and windage
losses) That requires some pretty heavy duty wiring. I doubt that I could
lift a true 5 Hp 12 volt motor.

Ted,

See http://www.electricmotorsport.com/PA...pecs.htm#Page5

This motor (ETEK) is capable of 9HP continuous, and only weighs 21
lbs. Of course, it only puts out about 2HP max at 12V, but you can
get over 9HP at 48V. You are right about the amp draw at 12V of course.

I remember reading in a recent "cruising world" about a new
production day sailer in the 36-40ft range that relies on electric
propulsion and a genset to charge the rather large battery bank.

For a day sailer that is typically connected to dock power every
night, electric seems like an interesting way to go. A genset and
a large house battery bank are pretty nice things to have on a sailboat
anyway, and you have eliminated a bulky and heavy diesel inboard that is
only good for propulsion and charging batteries.

If you start google searching you'll find that there is a lot of interest
in hybrid/electric conversions for autos and boats. There is a lot of
info available and quite a few people experimenting.

Now if we could only get someone to produce a 2,400 lb keel which was
also a huge battery bank (sigh). Either that, or a really affordable
large fuel cell (sigh again).

YMMV

Don W. (Who is toying with the idea of converting a Catalina 27 to electric
and getting rid of the 9.9HP Yamaha 4-stroke)