One of my ongoing research areas is what to cover a skin on frame boat with other than industrial fabrics sealed with modern sealants. Yes, there are animal skins, and I know that people have covered their boats with cow hides, but you see, we live in an industrial society and the imaginary scenario I am creating for myself is that the factories have shut down and one has to operate as boat builders of old did, that is, to find boat building materials in their immediate surroundings.
Perhaps we have to broaden our definition of skin on frame a bit and allow a boat where the skin is the main structural material and the frame is of secondary importance. Enter the plywood boat.
In my case, not a boat exactly but a plywood pool punt. The main idea was to not spend a lot of money. The secondary idea was to provide a stable lounging platform for a pool in an environment that is too cold for swimming for most of the year.
The same day we launched the new improved punt we also ran into a small futon and some quilts that a neighbor was discarding. These are now lining the bottom of the punt. Very comfortable and stable to boot for someone used to sitting in narrow kayaks. Sometimes it is OK to trade speed for comfort.