Trimaran Trimaran 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 trimarans are sailing yachts designed for recreation or racing; others are ferries or warships. The word "trimaran" is a portmanteau of "Tri" and "(Cata)maran". It is thought to have been invented by Victor Tchetchet, a pioneering, Ukrainian-born modern multihull designer. The first trimarans were developed by the Austronesian people and are still widely used today by traditional fishermen in maritime Southeast Asia, Madagascar, Micronesia, and Polynesia. Some of
Pontoon bridge remain in place much longer. Hobart Bridge, a long pontoon bridge built 1943 in Hobart, was only replaced after 21 years. The fourth Galata Bridge that spans the Golden Horn in Istanbul, Turkey was built in 1912 and operated for 80 years. Provisional and lightweight pontoon bridge are easily damaged. The bridge can be dislodged or inundated when the load limit of the bridge is exceeded. The bridge can be induced to sway or oscillate in a hazardous manner from the swell, from a storm, a flood or a fast moving load. Ice or floating objects (flotsam) can accumulate on