replacement of hatch gasket

[newboatowner]

Greeting to all on the beginning of a new season.
I recently purchased a 1978 Gulfstar 43 that needs a bit of work. It is basically very sound but there are problems that need attention and the more I look, the more I find.
All of the systems on the boat are original. The PO changed very little and did minimal upgrades and maintenance.

I have found the following condition that requires immediate attention. The hatches all leak from poor gaskets. I confirmed this by opening them in a rain and put butyl tape on the rim and closed them tight. The leaking virtually stopped. The question is what gasket will I need? I see many different configeration and the boat is 100 miles from me at the present.
Does anyone know what the shape should be and where I can get them?

[rourkeh]

Gasket replacement for your hatches is not something you want to guess about.
You need to remove one of the old gaskets and inspect to make sure they were correct in case the previous owner replaced with whatever he could find.
There are a lot of hatch gaskets out there Series 0631 Gaskets. Freeman Marine Equipment, Inc. provides the finest marine and specialty closures available. Custom fabricated doors, hatches, portlights and windows.
and you need to make sure the new ones fit the track properly and are the right height. Gaskets need to compress properly or they will leak.