Sharp corners on hatches something to be aware of. Snagging/damaging lines, sails, and flesh. Think smooth rounded corners. Also, the idea of aft deck hatches would need to be well executed as far as strength, and sealing out the sea. At sea, it seems everything that can go wrong, will go wrong.....usually at the worst time. (I like the lattice and light idea. Nice creativity.) It's good you get the satisfaction of working with your hands, and putting that fine little ship back in shape. Wishing you joy and success in your project.