No, but if you told us what submarine, what scale you were using, (what prop
diameter), then max torque could be figured. It is torque and prop shaft
length that determines shaft diameter, not HP. I would hazard a guess at
..625 to .750 inches.
Steve

"Michael" q.quqkq wrote
in message .uk...
Hi,

I'm making a large scale (13ft) model submarine and am currently designing
the propulsion unit for it.

If I told you I have a 2hp driving a 3 bladed prop would someone here be
able to tell me a suitable prop shaft size?

Cheers,

Michael