Well, for starters most (but not all) hatch
manufacturers use cell-cast acrylic
sheeting for their hatch
lenses. NOT polycarbonate! (except like one, maybe two) (but I think you know that already Sailorman)
"Uh, but polycarbonate is unbreakable!!!" you say?
Well that is really not true. You can break it just fine, thank you. However it is very resilient, much more so than acrylic which is harder, stiffer, and more scratch resistant than polycarbonate. (all qualities that generally make it more suitable for hatches, that get walked on)
The key to understanding the strength of a typical hatch lens lies mainly in the thickness of the lens itself in proportion to the size of the unsupported panel. To streamline production, most will use a single
size thickness of material based on their largest hatch size. Blah blah blah.
Where I am going with all of this is that polycarbonate IS ultimately stronger than acrylic and IF you can identify the original spec as acrylic, you might be able to get away with going down a size in the thickness with new polycarbonate, which would make it a lot easier to cold-form.
That would be ideal. If you could make that work, you would be making life a lot easier for yourself. If the original is polycarbonate, match existing thickness and bend away!
The real down side of poly over acrylic is less scratch resistance and shorter service
life, but this could easily be offset by much cheaper up-front costs for not having to make a mold
and by simply not using a scrub brush and Softscrub to clean your lenses.
I have had experience cold forming thin-ish polycarbonate with metal forming tools, it's kinda interesting actually. Can also be rolled successfully. Acrylic is too brittle and doesn't really lend itself to cold forming. Looks like you have either cylindrical our conic shapes so should be workable.
Might be a good experiment
just to get a strip of material in the thickness you want to use and hold them up to the curve and to see how easy/hard it is to make them conform.
If you can't cold form it then you have to thermoform it which means making a mold
which is expensive, blah, blah.
I am setting up to slump-form a cambered companionway
hatch slide for my boat with a friend who does some really crazy architectural Corian thermoforming. I have the mold made and should post some pictures.
Best of luck with your project!