Hi
A while back, I was given a 1960s frog 349 marine diesel engine. I finally got round to buying a hull on ebay, and am now trying to build a working rc boat with it. The hull came with a propellor, but I have no idea whether it will be the right size for the engine. What size prop would you fit?

The hull is 57cm long, and the prop required is of the submerged type. The propshaft is m4 threaded at the end, so I gather I need one that threads straight on rather than one that requires a dog drive?
Engine specs are .21/3.47cc, peak bhp of .32 at 13500rpm, peak torque of 29 oz-in at 9000 rpm according to the manual.

Im new to the world of RC boating, so have no idea!

Thanks

Hate to do this to you but the best way i can help you is point you in a good direction to get the info your looking for you go to the offshorercracing forum ,
There is alot of knowedgable people on there.