Find a used GE engine from a Golf cart. Some provide 11 HP at 48 volts
while the most common provide 3 HP at 36 volts. This is way enough for your
submarine because compare it to a 15 ft aluminum boat with two anglers
aboard - a troller engine can push the boat easily.

Just by curiosity is this remote controlled or wire controlled ? With a
camera or for fun ? do you have a website that shows construction ?

"Michael" wrote in message
...
Hi,

I'm building a model submarine it will have a displacement of around 500kg
and a length of 4m.
Having worked out a rough idea as to the size of the motor required, 3hp.
I'm now looking for suggestions. Sites like technobots don't stock ones
large enough and so I'm struggling to find an answer.
Then there is the matter of how to control the speed. Ideally I'd like
proportional control.

So, does anyone know where I can find a large enough motor, ideally with
the
electronics to control it? The onboard power will be provided for by two
12V
batteries,
of which the AH is still undecided.

Thanks

Michael