The Lewmar hatches WITH flange will not fit without grinding out gelcoat.

The Lewmar hatches WITHOUT flange simply surface mount on the deck. No gelcoat mods are required. It's a fairly easy installation - all you need is a drill, some polysulfide caulk, and a screw driver and cresent wrench.

I bought my Lewmar's from West Marine - they were in stock at West's wharehouse.