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 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. The trimaran concept has