that doesnt look like my '81 G-Cat 5.0 It had a lip, but no "insert" in the top of the hull like this one appears to have.
Jeep, I can get those measurements, but it will be later this month when I see that boat again.
I think I will make a website devoted strictly to the G-Cat line, including the rigging manual I sent you, and the line lengths, shroud lengths and other important info. I also thin you need to see the way we run our jib sheets and barber haulers. Makes handling the sails much easier. Look for it soon at www.seacats.org

David Mosley
F18 on the way(supposedly in truch headed east