A trimaran (or double-outrigger) is a multihull boat that comprises a main hull and two smaller outrigger hulls (or "floats") which are attached to the main hull with lateral beams. Most modern trimarans are sailing yachts designed for recreation or racing; others are ferries or warships. They originated from the traditional double-outrigger hulls of the Austronesian cultures of Maritime Southeast Asia; particularly in the Philippines and Eastern Indonesia, where it remains the dominant hull design of traditional fishing boats. Double-outriggers are derived from the older catamaran and single-outrigger boat designs.
Terminology
The word "trimaran" is a portmanteau of "tri" and "(cata)maran", a term that is thought to have been coined by Victor Tchetchet, a pioneering, Ukrainian-born modern multihull designer. Trimarans consist of a main hull connected to outrigger floats on either side by a crossbeam, wing, or other form of superstructure—the traditional Polynesian terms for the hull, each float and connector are vaka, ama and aka, respectively (although trimarans are not traditionally Polynesian, since they instead use single-outrigger and catamaran configurations).
Sailing trimarans
History
The first double-outrigger boats were developed by the Austronesian people and are still widely used today by traditional fishermen in maritime Southeast Asia. It developed from the more ancient single-outrigger boats as a way to deal with the problem of the instability of the latter when tacking leeward. Double-outrigger boats, however, did not develop among Austronesians in Micronesia and Polynesia (although it exists in western Melanesia), where single-outrigger boats and catamarans are used instead.
Warships with double-outriggers were used widely in Maritime Southeast Asia since ancient times up until the early modern period, with examples like the karakoa, lanong kora kora, knabat bogolu, and the Borobudur ships . These were often referred to by Europeans during the colonial era as "proas", a general term which can also refer to single-outriggers and even to native ships without outriggers.
20th century
Recreational sailing catamarans and trimarans gained popularity during the 1960s and 1970s. Amateur development of the modern sailing trimaran started in 1945 with the efforts of Victor Tchetchet, a Ukrainian émigré to the US, who built two trimarans made of marine plywood, which were about long. He is credited with coining the term, "trimaran." In the 1950s and 60s, Arthur Piver designed and built plywood kit trimarans, which were adopted by other homebuilders, but were heavy and not sea-kindly by modern standards. Some of these achieved ocean crossings, nonetheless. Other designers followed, including Jim Brown, Ed Horstman, John Marples, Jay Kantola, Chris White, Norman Cross, Derek Kelsall and Richard Newick, thus bringing the trimaran cruiser to new levels of performance and safety.
Following the homebuilt movement, production models became available. Some trimarans in the are designed as "day-sailers" which can be transported on a road trailer. These include the original Farrier – Corsair folding trimarans, such as the F-27 Sport Cruiser – and original John Westell swing-wing folding trimaran (using the same folding system later adopted also on Quorning Dragonfly) and like trimarans.
Modern western-built trimarans typically do not use Austronesian rigging like tanja or crab claw sails. Instead they use a standard Bermuda rig. Trimarans are also typically significantly wider. In addition, trimaran floats are much more buoyant than those of outrigger canoes to support a large sailplan. They contribute to drag when heavily immersed, and their level of immersion indicates when to reef. In terms of performance, an objective comparison by Doran (1972) in terms of maximum progress against the wind, maximum speed, and speed downwind concluded that both the traditional double-outrigger vinta of the Philippines and the single-outrigger wa of the Caroline Islands, respectively, are still superior to the modern trimaran.
Folding trimarans
Several manufacturers build trimarans in which the floats can be removed, repositioned, or folded near to the main hull. This allows them to be trailerable and/or to fit in a normal monohull space in a marina. Several mechanisms allow the amas or outriggers to be stored compactly: