: cut out my hatches. made lip with short stripsleft over from cockpit.what i
: was wondering is should there be a spacer between the deck and the lip to
: compensate for the gasket? i have some 4mm. ply. and was thinking of
: useing that.

A big yeas on the spacer. as for the size of it, though, that depends on the material you use for the seal, the compressability of it, the uncompressed thickness of it, and how tight you can cinch down the hatch cover so that it can be compressed to seal the hatch opening.

For example, if you have a 4 mm thick piece for a spacer, you would certainly want your sealing material to be thicker than that. probably want 6mm to 8mm stiff foam, or even up to 12 mm thick foam if it is very soft and easily compresed.

A simple trial with a few scraps should give you the info you need.

hoe this helps

PGJ