Windsurfing was invented in the mid-sixties by two southern Californian surfers, Hoyle Schweitzer and Jim Drake. Surfers need strong rolling waves, and they hate days of calm sea. Schweitzer noticed that on days when waves were not high enough to surf, there was often a strong wind and he set about finding a way to use it. His first experiments involved standing on his surfboard holding out a piece of sail cloth in his hands. Gradually he and Drake refined this idea into a basic design for a sailboard, similar to a surfboard, but holding a mast and a triangular sail which could be tilted and turned in any direction. The windsurfer operates a boom which controls the amount of wind in the sail, for speed and change of direction. Schweitzer immediately went into business designing and making the new sailboards and taking the idea abroad. By mid-seventies, the sport had spread to Holland, Germany and France.