I have an 8 inch screw-out in the deck behind my seat. Sand jams it a little, although what I've found jams it worse is when the O-ring slips down in the threads.

I've put a drawer-pull type handle on the hatch to give me a better grip. The finger-indentations are really not adequate when reaching behind my back in waves.

If I were doing it over (and I may), I'd probably go with the press-in type. They seem to seal pretty well.

I've got my hatch cover on a lanyard, and also have a chunk of closed-cell foam attached so if the lanyard breaks the cover will still float to be recovered. Of course, I tend to overbuild & have multiple backups for most everything.