there is a company that makes the screws in ss and brnz. I don't see them in any part of a boat below the water line but the clamping type of use they provide is pretty hard to ignore, IF the hole or plugged hole is not visable.
I'm going to use them to set up the forms for my next building project. a 11 or 12 rowing dingy. Cabinetry seems to be the best way to use pocket screws.
I thought this would be a fun and thought provoking thread!