Windsurfing, also known as boardsailing, is a water sport which involves travel over water on a windsurf board or sailboard two to five meters long, powered by wind which acts on a single sail. The sail is connected to the board by a free-rotating flexible joint. A hybrid between sailing and surfing, steering is accomplished by tilting and rotating the mast and sail or by planing and carving the board as opposed to a sailboat where steering is done through a rudder.
Although windsurfing can be done in winds near 0 knots, the ideal wind speed for planing are between 15 to 25 knots. Displacement mode sailing is done with lighter winds. Windsurfing also combines specific athletic aspects of skateboarding, snowboarding, waterskiing, and wakeboarding. Distinct windsurfing disciplines include speed sailing, slalom, course racing and freestyle. Historically speaking, windsurfing as a sport and recreational activity did not gain popularity until the 1970s.