C-Miner (renamed) is a 1988 cruiser. I do not remember the hatch size - it was a long time ago. I just measured the existing opening and got the hatches that had “close” dimensions. Had to cut an in insert and glass it in anyway, so it can be sized accordingly. The duraglass was purchased at an autobody / paint supply store. It has glass filaments in fiberglass filler to provide strength. Once completed, it never exhibited cracking, etc while I owned it. My current 1993 Angler has raised ridge around the opening and the cover, although not gasketed, has a dipping out perimeter that stops water intrusion.