OK, moving along here, the next issue is the conversion of the deck cut-out to the hatch cover itself. Teak Vinson looked at this for a long time, and in the end we decided to peal off all the balsa, all the foam, everything but the teak decking and the layer of fiberglass it was attached to, then build the rest of the hatch with divinicell coring, completely glassed over with two central mahogany reinforcement beams routed and glassed into the coring itself. The beams not only made the cover more rigid, but they also helped the whole assembly resist crowning (bowing) when all that resin soaked coring dried.
The result was an enormously strong component, something you could drive a loaded dump truck over without incident. In the end, it would have been easier and cheaper to simply build a new hatch cover. True, we saved the original teak decking, but spent a lot of time mating the decking and glass attached to the new materials. One other positive element was that with the old decking never being removed, the alignment of the deck boards never changed, and even the caulking was preserved.
"I'd rather be happy than dignified".