Originally Posted by hellosailor
"basically two sheets of fiberglass, inner and outer one with air in between,"
Without a solid filler panel, you will get leaks again. You might want to checkthe width of that gap and see if you can use some cheap cutting boards from the dollar store (which tend to be HDPE or other good stable plastic) or else order in some similar plastic material instead of teak (expensive! and still can rot) to fill the gap and be the spacer.
It wasn't leaking there, the leak was from the lens, the gasket cracked I think and it started leaking between the glass and the rubber that is around the glass.