I have a 1978 Chris Craft Catalina with an interior floor I will be replacing. It is not secured and just rests on a ledge under all edges. It is approx. 7ft by 24 in with a hinge in the middle to allow access to the bilge pump under it. The last time I replaced it I used plywood and applied several coats of varnish on both sides and all edges. It lasted several years before moisture got to it. I am open to alternate ideas but I'm also fine with just getting plywood again and using varnish. The varnish looks good but doesn't last forever. I could go with fiberglass resin but I don't want it too slippery either. Any ideas?