Windsurfing is a surface water sport that combines surfing and sailing. Like paddle surfing, it originally emerged from surfing. Once the idea of a kite-powered surfboard was first developed, other improved designs were soon available. Nowadays, it consists of a board and a sail powered by wind: a rig is connected to the board by a free-rotating universal joint and consists of a mast, 2-sided boom and a sail. Notions of winds are required. We have windsurfing single and double boards as well as 2.5-sq-m and 5.5-sq-m sails.