Trimaran to the main hull. This allows them to be trailerable and/or to fit in a normal monohull space in a marina. At least six technologies are in use: Although it is possible for a trimaran to capsize, this is less frequent than with monohull boats because of the greater resistance to rolling that the amas offer. Most trimaran designs are considered nearly unsinkable because even when filled with water, the buoyancy of one ama is enough to keep the entire vessel afloat. Because of their stability and safety, special trimarans such as the Challenger have become popular with sailors who
Pontoon bridge a pontoon bridge to cross the Bosphorus and Emperor Caligula built a bridge at Baiae in 37 AD. For Emperor Darius I The Great of Persia (522–485 BC), the Greek Mandrocles of Samos once engineered a pontoon bridge that stretched across the Bosporus, linking Asia to Europe, so that Darius could pursue the fleeing Scythians as well as move his army into position in the Balkans to overwhelm Macedon. Other spectacular pontoon bridges were Xerxes' Pontoon Bridges across the Hellespont by Xerxes I in 480 BC to transport his huge army into Europe: According to John Hale's "Lords of the