I'd like some advice on building a stitch and glue version of my fabric covered kayak. It's an old Folbot Glider, 14.5' long, 37" beam, with a 112" by 28" cockpit (it's worked great for 1 or 2 with gear, in comfort, in protected waters, for the past 27 years). With frame and stringer construction, it weighs about 60 pounds. I'm interested in building a replacement that would be tougher (less likely to be cut on rocks or shell bars), and significantly lighter, say 40 to 45 pounds.

I've not found a pattern - or commercially available boat - that fits the bill, so I'm looking at using the "facets" between stringers on my old boat as patterns for plywood panels. The very large cockpit means that the decking would not give great structural support, so perhaps I need some frames or open "bulkheads", to also serve as seat backs.

Questions: Do I need frames in a stitch and glue boat; how do I figure out where and how many?

How thick must the plywood be; does 3 or 4 mm make sense?

Do I glass both inside and out; what weight cloth?

Do builders use just epoxy and glass, or is polyester resin used with glass for some purposes?

I'll appreciate any advice with this project.

AB