twin-hulled sailing and powered boat developed for sport and recreation in the second half of the 20th century. Its design is based on a raft of two logs bridged by planks that had earlier been used by peoples in the Indonesian archipelago and throughout Polynesia and Micronesia. Early catamarans were up to 21.3 m (70 ft) long, originally paddled by many men, and used for visiting, in war, and in exploration. Especially after the sail was added, voyages of more than 3,704 km (2,000 mi) were made.

The U.S. designer of America's Cup boats Nathanael Herreshoff (Herreshoff, Nathanael Greene) designed and built catamarans in the 1870s that sailed so successfully against monohulled boats that they were barred from organized racing. Production of the current form of catamaran, which averages about 12.2 m (40 ft) in length, began in the 1950s. The early catamarans tended to have difficulty coming about when sailing to windward, but later designs overcame this. The catamaran remained difficult to right after capsizing, however. Smaller catamarans raced successfully against monohulled boats in 1959, and international competition began in 1961 between the United States and Great Britain, the latter winning through 1968. Thereafter, Danish and Australian boats also competed, the Australians dominating. Catamarans are very fast boats, achieving speeds of 32.19 kph (20 mph). The addition of engines also made the catamaran a popular motor-cruising boat.