> If you were going to just screw into the beam through the plywood, maybe
> you should consider using studs and wing nuts? Any decent hardware store
> has studs with wood threads on one half, and machine threads on the other
> half. This way there is no screwdriver rusting and rattling around. Spare
> wingnuts could be mounted on an extra stud in the cockpit.

> Good luck

Why not use a bolt with a wingnut type head?

I saw a plastic day hatch that used a twistlock with a small tee handle that when folded down flush drew down the lid tight based on a cam action.

Greg