A cheaper solution
Yes, it is a similar task to the portlights. But the gasket material ain't cheap! However, I have an idea that IS. My hatches leaked since new....I think they may have been slightly warped. In desperation, I got some of that sticky-backed close cell foam tape, the kind that you use to seal a window or mount the camper shell on a pick-up truck. It is probably a quarter of an inch thick, no more. I then stuck it carefully on the lower frame of the hatch, so that the gasket would squeeze it when closed. No leaks, ever! The first time you close the hatch, you have to pressure it down pretty hard, to compress the tape, but it works very well. I probably put new tape on every four to six years. In fact, I have never bothered to replace the Bomar gasket!
