Which of these is a boat with three hulls in parallel?
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.
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.
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