Coracles (from the Welsh "cwrwgl") have a history dating back thousands of years. The coracle was originally covered with animal skins and in some countries they are still made this way. In Wales they are now skinned with calico which is waterproofed using a bitumastic paint.
http://www.data-wales.co.uk/coracle1.htm
http://en.wikipedia.org/wiki/Coracle
