hi Dale,

I had a crack once, in a corner, but it's not exatly the corners
you are talking about.

after completing my hatch covers, I sat on the hull to do some work
& I heard a big crack noise.

when I looked I found the crack - it was on the under side of the deck ridge
(it's a coho - s&g) & the spacers on the underside separated from each other, but not from the underside of the deck. they had to allow the flexibility
the deck needed due to my weight (155 lb).

I put some epoxy in the crack & layed 3 layers of fg on that seam, just on
the underside of the spacers, & in all other places where hatch spacers
meet the underside of the deck ridge.

I then jumped on the hull - no problemo.

I think it is easier to understand what I'm talking about if you
look at my webpage under hatches:

http://homepages.go.com/~fl_pelican/home.htm

I didn't had any problems on the corners of the hatch cover, on the cover
or on the deck.

Erez