Float (nautical) marine salvage, often deployed uninflated then pressurized to raise a sunken object. In popular usage, the term "pontoon" can refer to any of several of the following objects that make use of nautical floats. A pontoon boat is a flattish boat that relies on nautical floats for buoyancy. Common boat designs are a catamaran with two pontoons, or a trimaran with three. In many parts of the world, pontoon boats are used as small vehicle ferries to cross rivers and lakes. In Australia and New Zealand, the term "pontoon" often refers to an anchored raft-like platform used for diving from.
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