I may surprise you to know that I'm interested in how I'm going to do that as wellVT_Jeff wrote: ↑Thu Nov 05, 2020 10:50 am Great work per usual Alan, slow and steady wins the race!
I'll be very interested to see how you get the hatch covers flush once glass/epoxy has been applied to the rails and to the underside of the hatches. I'm trying to puzzle this out myself as I think through the hatch design and it seems like the only way is to leave an oversized gap and then shim them up to flush once all glass/epoxy has been applied.

Right now I'm not planning to glass the inside of the hatch covers. I made it all out of Meranti off-cuts so its pretty stable and shouldn't move or check too much. I am able to trim the rails a little with a block plane or router if I need to. I did originally contemplate a neoprene seal on top of the rails but after thinking about it I decided that even though these lockers will technically be dry, they wont be that dry and really only splash proof from spray, waves and loads or rain in New England. I may go with a rub-strip of some sort later on.