: Pedro: I understand that drilling a hole in the bulkhead near the top,
: filling it with epoxy and then drilling a smaller hole in the epoxy might
: aleviate the hatch sticking down problem.
: Charles Robinson

Charles,
This year I did that to my boat and now the hatches do not expand or contract and easily lift off. I put my holes (1/16") in the center of each bulkhead rather than the top. This way when upside down while rolling or whatever the hole is still in the center.

I have attached my site address so you can see how I built my hatch lips using strips. I use internal bungees and my hatches are completely dry after a day of paddling & some rolling. I use Frost King, Rubber Foam Weatherseal, Self Stick Tape, 3/8" wide 7/16" thick for the gasket. The secret to getting this to work is to have the hatch lip where the tape sticks to really smooth and the underside of the hatch where contact is made smooth also. Since the hatch lips on my boat were built from strips it required some sanding and leveling with epoxy to get a nice smooth surface for the tape to stick to.

The pieces on the underside of each hatch that the bungees attach to were formed prior to the hatches being cut so that they fit the curve of the deck and therefore maintain that curve when the bungees are pulling on them. This keeps them from possibly flattening out. they were also positioned so that the bungee pressure was evenly distributed across the surface of each hatch.

Pictures 81 thru 96 on my site should helop you to see what I did.

Bob