[Kenny]

I used a 3/8" high density foam window gasket between the tank and the hatch but attached to the tank...I also secured the tank with 2 brass 1/4" threaded inserts that screw into the hatch frame and than I drilled 2 holes in the tank to secure the tank to the frame with 1/4" Stainless machine screws...You can get these things at Lowes where they have all the little drawers with screws and nuts...Works great and not a drop of water in the inside when I rolled it in the surf one day....Kenny