Windsurfing is a surface water sport that combines elements of surfing and sailing. It consists of a board usually 2 to 2.5 metres (6 ft 7 in to 8 ft 2 in) long, with displacements typically between 45 and 150 litres (9.9 and 33.0 imp gal; 12 and 40 US gal), powered by wind on a sail. The rig is connected to the board by a free-rotating universal joint and consists of a mast, boom and sail. On “short” boards The sail area generally ranges from 1.5 to 12 square metres (16 to 129 sq ft) depending on the conditions, the skill of the sailor, the type of windsurfing being undertaken and the weight of the person windsurfing. On long boards, upon which the sport was first popularized -sail areas and board lengths are typically larger and the athleticism required is much less.