Most commercial boat designers design decks on offshore boats to carry a 48"
head on weather decks (boat filled with water to 48"). In other words, the
deck must be designed to carry 1.78 psi without fail, and deck hatches must
meet or exceed this capability and do so without leaking.

For noncommercial boats, which typically have 30" or lower deck-to-sheer
freeboard, designing around 30" of head is more typical (1.11 psi, or 160
lbs / sq. ft). Hatches must also meet or exceed this requirement without
leaking. Downflooding is no fun.

These are _design rules_, not actual expected conditions. Design rules are
designed to exceed actual requirements.

That said, does anyone know of quality deck hatches suitable for weather
decks that live up to the noncommercial requirements listed above?
Hopefully without costing an arm and a leg too?

(Yes, I know that I can put a screwed-in hatch that would be a wonderful
solution ...but for commonly inspected locations, screwed-in hatches are
encourage you to NOT inspect very often...)

Thanks in advance,

Brian D