A pontoon is a flotation device with buoyancy sufficient to float itself as well as a heavy load. A pontoon boat is a flattish boat that relies on pontoons to float. Pontoons may be used on boats, rafts, barges, docks, floatplanes or seaplanes. Pontoons may support a platform, creating a raft. A raft supporting a house-like structure is a houseboat. A fixed platform can be used as a dock. Common boat designs are a catamaran with two pontoons, or a trimaran with three. Pontoons may be simply constructed from sealed cylinders such as pipes or barrels, or fabricated as boxes from metal or concrete. Pontoon boat drafts may be as shallow as eight inches, which reduces risk of running aground and underwater damage. The pontoon effect is when a large force applied to the side capsizes a pontoon boat without much warning, particularly a top-heavy boat.
Poontoon boats for pleasure boating and fishing can be low cost for their capacity, and cheaper to insure than other boats, even when equipped with substantial engines.
Pontoon boats are used as small vehicle ferries to cross rivers and lakes in many parts of the world, especially in Africa. Pontoon ferries may be motorised, such as the Kazungula Ferry across the Zambezi River, or powered by another boat, or pulled by cables. A type of ferry known as the cable ferry ("punts" in Australia and New Zealand) pull themselves across a river using a motor or human power applied to the cable, which also guides the pontoon.
The 1952 invention of the pontoon motorboat in the USA is credited to a farmer who lived on the Horseshoe Chain of Lakes, near Richmond, Minnesota. Ambrose Weeres put a wooden platform on two columns of steel barrels welded together end-to-end, creating a sturdy deck that would be more stable on a lake than a conventional boat. Living in the "Land of 10,000 Lakes," Weeres thought this idea might be marketed. The first boat was "The Empress". He built a few boats and sold them with the help of dealers. He started Weeres Industries to meet unexpected demand. Weeres, later called "Mr. Pontoon", was elected to the Minnesota Marina Hall of Fame.[1]