A skiff is any of a variety of essentially unrelated styles of small boats, usually propelled by sails or oars. Traditionally, these are coastal craft or river craft used for work, leisure, as a utility craft, and for fishing, and have a one-person or small crew. Sailing skiffs have developed into high performance competitive classes. Many of today's skiff classes are based in Australia and New Zealand in the form of 12 ft (3.66 m), 13 ft (3.96 m), 16 ft (4.88 m) and 18 ft (5.49 m) skiffs. The 29er, 49er, SKUD and Musto Skiff are all considered to have developed from the skiff concept, all of which are sailed internationally.