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one of a number of floats used chiefly to support a bridge, to raise a sunken ship, or to float a hydroplane or a floating dock. Pontoons have been built of wood, of hides stretched over wicker frames, of copper or tin sheet metal sheathed over wooden frames, of aluminum, and of steel. The original and widespread use was to support temporary military bridges. Cyrus the Great built (536 B.C.) the earliest pontoon bridge in history, using skin-covered pontoons. However, Homer mentions pontoon bridges as early as c.800 B.C. The U.S. army began experimenting with rubber pontoons in 1846 and in 1941 adopted collapsible floats of rubber fabric with steel-tread roadways. At the same time the navy developed box pontoons of light, welded steel for ship-to-shore bridges during landing operations. These box pontoons could be assembled into bridges, docks, causeways and, by adding a motor, into self-propelling barges. Permanent civilian pontoon bridges have been built where the water is deep and the water level fairly constant or controllable, often also where the crossing is narrow or where the bottom makes it difficult to sink piers. The modern permanent pontoon is composed of many compartments, so that if a leak occurs in one compartment, the pontoon will not sink. Permanent pontoons are fastened together and several anchors are dropped from each. Often a section of a bridge built on them can swing aside to let a ship pass. Several pontoon bridges have been built across the Mississippi River. Pontoons for raising sunken ships are watertight cylinders that are filled with water, sunk, and fastened to the submerged ship; when emptied by compressed air, they float the ship to the surface. A pontoon lifeboat consists of a raft supported by watertight cylinders.
The Columbia Electronic Encyclopedia™ Copyright © 2013, Columbia University Press. Licensed from Columbia University Press. All rights reserved. www.cc.columbia.edu/cu/cup/
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



a very simple vessel without its own means of propulsion, usually with perpendicular sides and a flat bottom, with or without a deck. The pontoon may have a contoured bow and stern lines to decrease resistance to a current.

By connecting pontoons by means of special coupling devices, pack bridges and the floating supports of raft bridges and ferries are formed. Pontoons are the basic elements of the ferrybridge equipment of bridge trains. Floating docks on which cranes are mounted are also assembled with pontoons. They are used to hoist sunken vessels and to guide deep-draft ships along shallow channels. Pontoons were first used by the Dutch Army in the early 17th century. Other armies adopted them later. Modern pontoons may be made of metal (steel or light alloys), inflated rubberized materials, or reinforced concrete.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.


(aerospace engineering)
A float on an airplane.
(naval architecture)
A low, flat-bottomed ship, similar to a barge, carrying cranes, capstans, and other machinery used to lift weights, to lean ships on their sides for repairs, and to perform other such operation.
A wooden flat-bottomed boat or other float, used particularly to make temporary bridges.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.


Nautical a float, often inflatable, for raising a vessel in the water


1. a gambling game in which players try to obtain card combinations worth 21 points
2. (in this game) the combination of an ace with a ten or court card when dealt to a player as his first two cards
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005
References in periodicals archive ?
To offer even better comfort for such activities, Pontoon boats are available in two-tube and three-tube styles.
"Because of the versatility and modular capacity of the Pontoon, we will get full use of it by changing its capabilities.
Accordingly, the pontoon is both functional and visually appealing, providing largely unobstructed views of the river," he said.
After the pontoons were assembled, the bottom and lower halves of their sides were covered with fiberglass fabric and resin to protect against ice.
The dredge material and quarry-fill material was used to construct the east reclamation area so that work could begin to install the concrete pontoons, gangways, boat ramp and 150m quay wall that will link to it.
Stockton Council's Cabinet member for arts, leisure and culture, Councillor Ken Dixon, said: "I'm delighted to see the floating pontoon being used by the Wheelyboats, Upstream Sailing Association and other river users, making it easier for people to travel by water between Tees Barrage, Stockton town centre, Preston Park and Yarm.
He added when the pontoon arrives at Humberside vessels would moor either side of the Finger Pier at Grimsby River Terminal.
Additionally, Damen Pontoons & Barges has started building a second new design: the Damen Crane Barge (CBa) 6324, a transshipment barge for handling dry bulk and container operations.
A pontoon boat provides a base of operations--much like an RV--with gear storage, sleeping spaces and the option of mobility.
A RECOVERY operation swung into action yesterday after a pontoon capsized in a river.
We may have jumped the gun in talking about the Highway 520 pontoon construction project Tuesday in a story about the Port of Grays Harbor's new business activity.
The boat owners have traditionally paid just pounds 1 per year to anchor their vessels within the sheltering walls of the inner harbour, but now claim to have been forced to berth at a visitors' 24-hour pontoon and not allowed access to their yachts.