I have a 1974 fabuglas boat as my first. There are two holes in the transom and one at the bottom. I know the one on the bottom needs a plug but the other two i am not sure. Between the motor and the back seat is an open area for the fuel tank, battery. It fills up with water and has no way out if the plugs are in. Should those two holes be left open or do i plug them and get a bilge pump back there.