All of the cat drivers I know have mounted the motor directly to the frame, some in the rear, some of them have mounted the motor to the front of their frame instead and the motor pulls the cat rather than pushes it. The challenge in mounting a motor to a round raft is the fact that the frame usually peters out before you get to the rear of the raft, that's why I have an auxilliary frame that I have the motor mounted on behind my main frame. Yours is a cat, IIRC.