I finally got around to doing this little project & here's what I found -
The hatch is a Bomar G927. It is still available. It comes in black or white. My rough opening was 13" x 18". The deck is about 2" thick in that area. The lens (window sheet) on the hatch is 16-3/4" x 11-3/4" x 0.225" thick. My lens had the Bomar logo on it, so I believe it to be original. A small sticker from Pompanette was still visible on the underside of the frame. It instructed to only use 5200 for bedding.
Fortunately, the good people who originally installed this hatch ignored the instructions to use 5200 & instead used what appears to be white silicone. That made removal MUCH easier. The silicone stuck to the deck pretty well but released from the hatch frame with only moderate effort. The custom molded gasket that was left behind was clean 90% of the way around, with only one corner being a little dirty. I didn't look like this was the source of my rampant water intrusion.
When I took the hatch assembly back to the house, I tested the window with tap water. The water ran through the lens to frame joint like a waterfall. The black bedding compound that was between the lens & the frame had gotten crusty & failed. I popped out the lens, cleaned off the old black crud, sanded the edges of the lens, replaced it back in the frame with fast 5200 & put the assembly aside to cure overnight. Results looked good this morning. I cleaned up the deck flange & brought the hatch back to the boat. My only complaint with the original installation was that the silicone did not encapsulate most of the screw holes. I made sure to put down a wider band of sealant this time. I used 3M Marine Grade Silicone, which 3M recommends for mounting hatches. The hatch went back in with no trouble. I was able to reuse the original screw holes. I tightened the screw down just enough to get the goo to squeeze out the edges of the flange. When it is dry, I will trim the excess with a razor. At this time, all looks good. I'll plan to put the boat outside in the rain tomorrow to test for leaks.
