Help me identify this portlight, and replace the gasket

[SpaceRnglr]

Hi Cruisers. I am struggling to stop a leak in the portlight shown in the pictures. I believe it is original to my 1994 boat, but there are no manufacturing marks of any kind. I can't find similar hinges / latches to find the manufacturer. The gasket that seals the portlight is cracked at the bottom. Someone tried to fix with silicon, but it didn't work and has been leaking I would guess for years. You can see the repair in the middle of the bottom of the seal. There are 5 other similar portlights, so if I would much rather fix the gasket than replace.

Does anyone know what type of portlight this is, so I can get the correct gasket?

If not, does anyone know how to use generic gaskets to fix? The gasket seems to be sort of "U" shaped with the bottom of the U sealing against the glass.