1. Windsurfer: the original
windsurfing board built in 1968 by
Jim Drake and
Hoyle Schweitzer.
The concept was patented by the inventors, and in 1973 Drake sold his rights to Schweitzer, but prior art has been discovered later. It appeared that S. Newman Darby had conceived and idea of connecting a hand-held sail rig fastened with a universal joint to a floating platform for recreational use. He called it sail boarding in 1965, when he published his designs in the Popular Science magazine. It is incredible that Schweitzer and Darby never heard of one another until 1976.
Schweitzer licensed patents to the windsurfing equipment manufacturers and sued those who didn't buy it. In 1983 a Swiss windsurfing board maker Mistral used the Darby's prior art to prove Schweitzer's patent void. Schweitzer had to re-apply for patent with severely limited terms, and the patent finally expired in 1987.
2. Any person practicing windsurfing.