: Here is another option to consider. The beveled edge is easier to install and
: eliminates concentrated stress. Can be as light as 3 oz. This is what
: Sterling Donalson is putting in the Ice Kaps and Illusions.

I take it what you're making here is fiberglass bulkheads with curved edges, much like what you see in many commercial boats? That creates the same effect as the undersize flat bulkheads attached with glass tape I mentioned, but with the advantage of having a one-piece bulkhead that's easier to install. They're a bit more effort to fabricate, but probably worth the effort.

: On the pressure build up question, someone on this board came up with the
: brilliant solution of a miniscule tube that is low on one side of the
: bulkhead and high on the other. The more common solution is to drill a
: hole less than .040" (#60 drill) at the center of the bulkhead or any
: small hole plugged with a cord will let pressure equalize. If only hatch
: covers were good enough to make this a more common problem.

There's no need to make any effort to angle the holes or partially plug them. Unless the boat is swamped, there will never be any leakage between compartments and even then, it will be only a few drops.