what kind of wood can you use for making cranks?

Whatever wood you want to use. Balsa is preferred by most as it is very easy to work with and floats very nice. Cedar is another that many use or even basswood. I would stick to the softer woods as they are easier to work with.

awesome thanks

Keith is right.  I'd stick with balsa on the first attempts.  Cedar will have you cussin in no time and basswood likes to split on the grain.

J

I just find a pine tree an cut off a branch ;D is cheap