hi,

i have a small boat 15X40cm which was originally a toy rc boat.
the electronics don't work anymore,so i'm thinking to convert it to a real rc boat.
i already have everything i need from other projects, the only thing is,i don't know what motor to choose.

here are some motors i have:

a 370 size motor,with 5:1 gearbox,
and a 180 size heli motor,
both brushed

batteries will be 900mah 3S

what would be a good overall motor for it?
it don't has to be a speed monster.

Use the 370 and get rid of the gear box, you have a pic of the hull? For boats this size you can go 3000-3500rpm brushless with about 20 amps and that should put you close to the hulls limit. Or at least generally, especially running on 3s lipo.

thanks for your reply,

here is a pic from the boat ,
it is not the actual one but very similar.

btw,
everything is made of plastic.

if you want a bit more performance, get the graupner 480bb Race.
reasonably priced...great performance!

It depends what speed control you're using - the motors you have are brushed, correct?
going brushless may be a little more expensive, but I'd only go brushless if you want "speed monster".