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 by Austal. The DARPA is experimenting with the trimaran design, and in 2012 awarded SAIC a contract to perform Phases 2 through 4 of the ACTUV Program. The contract is expected to be completed by August 2015. According to American usage, there are three terms that describe the main components of catamarans and trimarans, namely: “vaka”, “aka” and “ama”. These terms come from the Malay and Polynesian language group terms for parts of the outrigger canoe (The above terminologies reflects only American usage. In the UK the main hull of a trimaran is called simply the "main hull" or "centre