Floor Hatch - gasket material for water proof/resi

[abl1111]

Has anyone ever figured out how to keep the weather out of the hinged floor hatches ?

I'm putting a useable hatch in the floor where it used to be screwed down permanantly ( to cover a fuel tank ). It will be a much used storage area - and unfortunately, a wet storage area unless I can devise a way to keep rain water from getting in. I'm resolved to the Rubbermaid w/ a cover idea unless one of you has addressed this ?

Thx