Thanks for the link. Those fabric boats are interesting but don't look durable enough. They're probably suitable for calm harbors. I am looking for a hull design to lay up in kevlar, a super tough, light fabric that is commonly used in whitewater boats. These river craft take a real beating. Polyester resin and standard mat/cloth are certainly plenty strong but the thickness required to attain adequate rigidity and strength results in a lot of weight. Kevlar can be laid up thinner because it is much stronger than traditional glass fiber. Marine Composites | DuPont? Kevlar®
If the pram design were more seaworthy, it could probably be built light enough with these kinds of materials but I'm looking for a hull design that rows really well.