Re: acrylic dome over the companionway hatch
I had one on my first boat. The shape makes for a huge amount of glare, they are easily scratched, and make it hard to seal a sliding hatch.
If I were to make another , I'd weld up a metal frame, to take four flat panels of laminated glass, so they wouldn't scratch up, and could be easily and cheaply replaced. The metal frame would also make it harder for a thief to break in.
Brent Swain, Boat designer, Builder, and author of "Origami Metal Boatbuilding"