I replaced my inspection hatch with a Bomar hinged inspection hatch, same size and color as the original. Go to
www.pompanette.com look for the Bomar heading, they come in white,offwhite, and black. Part # G8711
I have a 1985 23' cc in mint shape and wanted to keep the original hardware. the hatch is hinged so you can inspect your bilge pump etc. It will never leak if installed properly. they give you instructions with the hatch.