I am getting the bits together to build my first airboat. i had an old os max-s 30 engine that is going to run this thing i have been reading alot of posts on here and bought an 10/6 prop but it is to thick to allow the prop nut on? Now the questions, have i bought the wrong type of prop? it is plastic do i sand it down? do the letters face away from the engine? just wanted to bench test it before i go any further.

Thanks