I had a terrible time with the Cape Charles, for the same problem. Even bending them to beams didnt cure it, but it hepled. I finally got them pretty good using silicone caulk and threaded T-nuts. Now I dont like the looks of it, and I think I have a cool hatch idea for the re-do. I'm not gonna tell until I post pix though :)

: Steve,

: Is it possible to glue some braces to the underside of the hatch cover to
: force it to match the curvature of the deck at that point? If the
: side-to-side curvatures don't match, you'll have trouble getting a good
: seal regardless of the type of hold-downs you use.

: Ross