Pontoon bridge in 638. The army of the Umayyad Caliphate built a pontoon bridge over the Bosporus in 717 during the Siege of Constantinople (717–718). The Carolingian army of Charlemagne constructed a portable pontoon bridge of anchored boats bound together and used it to cross the Danube during campaigns against the Avar Khaganate in the 790s. Charlemagne's army built two fortified pontoon bridges across the Elbe in 789 during a campaign against the Slavic Veleti. The German army of Otto the Great employed three pontoon bridges, made from pre-fabricated materials, to rapidly cross the Recknitz river at the Battle on the Raxa
Trimaran the current US terminology is derived from the Polynesian terminology. 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 24 feet (7 metres) 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