A catamaran is a boat consisting of two hulls connected in the center by a flat section called a wing. Although there are both power and sailing catamarans, the sailing boats, especially small racing and day sailers, are more popular. Catamarans range in length from about 12 feet up to 150 feet (3-45 meters), for cruising boats. The outstanding characteristics of catamarans are speed and stability. Speeds up to 30 knots (55 km/h) have been reached.
Powered catamarans are useful for operations requiring a stable platform in shallow waters, such as survey work. In the US Navy catamaran ships are used for submarine rescue and diver support.
The noted boat designer Nathanael Herreshoff was probably the first American to build catamaran sailing boats. Starting in the 1870's, he imitated the ideas of the Polynesians, who had built double-hulled boats hundreds of years before.
These were formed of three logs lashed together, and with outrigger. The central log is longest, with a curved surface at the fore-end which terminates in a point. It is about 7 m long, and is managed by two men, who squat upon it and work paddles.
The trimaran, built on the same principles as the catamaran, has three hulls.