Skin on frame
From KayakWiki
Skin on frame kayaks, or SOF's, are kayaks built by stretching a fabric or hide skin over a frame. This is the traditional method of kayak construction used by all the native peoples of the north. Early recreational kayaks followed the native builders examples. Many home builders choose skin on frame for it's easy adaptability and custom fit, minimal use of forms, low tech ease of construction, low costs, and minimal reliance on expensive tools.
The "skin" normally used over the last few years is actually cloth. Many kinds of cloth have been used, including cotton canvas, nylon, and other synthetics. Most home builders use a non-waterproof cloth, finishing the skin with several coats of paint, elastomer coating or varnish. Others have used cloth that already has a waterproof coating applied during manufacture.
Skin on frame boats include several forms of kayaks, most notably the Greenland kayak and the baidarka. Others have built canoes, currachs, bull boats, prams, river boats, and sail boats using SOF construction techniques.
To this day Feathercraft, Klepper, Folbot and others manufacture skin on frame and folding kayaks for the commercial market.
See also:
For more on folding kayaks try this link:

