Floats (nautical)
Encyclopedia
Floats are airtight hollow structures, similar to pressure vessel
s, whose air-filled interior makes them buoyant in water. They are most often used to make up the multipart hulls
of trimarans, small open catamarans, and floatplane
s (a kind of seaplane
). Their main purpose is to supply buoyancy
, not storage space. The other principal domain of use for pontoons is in marine engineering and construction—shipbuilding
, marine salvage
, dredging, port facilities, and so on. In such applications, pontoons are sunk, positioned under objects needing raising (such as sunken ships being recovered for their scrap metal
value or to clear channels
), and then pumped full of air with air compressor
s, raising the object. Pontoons are also used to build things like pontoon bridge
s and floating pier
s. Such applications make them a useful tool for combat engineers and civilian engineers alike.
from steel plate and sheet. Pontoons as parts of watercraft and aircraft are more typically molded in glass-reinforced plastic
. Before the 1970s, glass-reinforced plastic was rare; older techniques include those of traditional wooden boatbuilding as well as plywood
over wooden ribs or metal sheets over metal ribs (aluminium or steel), reflecting the prevailing practice in aircraft and boats.
Pressure vessel
A pressure vessel is a closed container designed to hold gases or liquids at a pressure substantially different from the ambient pressure.The pressure differential is dangerous and many fatal accidents have occurred in the history of their development and operation. Consequently, their design,...
s, whose air-filled interior makes them buoyant in water. They are most often used to make up the multipart hulls
Hull (watercraft)
A hull is the watertight body of a ship or boat. Above the hull is the superstructure and/or deckhouse, where present. The line where the hull meets the water surface is called the waterline.The structure of the hull varies depending on the vessel type...
of trimarans, small open catamarans, and floatplane
Floatplane
A floatplane is a type of seaplane, with slender pontoons mounted under the fuselage; only the floats of a floatplane normally come into contact with water, with the fuselage remaining above water...
s (a kind of seaplane
Seaplane
A seaplane is a fixed-wing aircraft capable of taking off and landing on water. Seaplanes that can also take off and land on airfields are a subclass called amphibian aircraft...
). Their main purpose is to supply buoyancy
Buoyancy
In physics, buoyancy is a force exerted by a fluid that opposes an object's weight. In a column of fluid, pressure increases with depth as a result of the weight of the overlying fluid. Thus a column of fluid, or an object submerged in the fluid, experiences greater pressure at the bottom of the...
, not storage space. The other principal domain of use for pontoons is in marine engineering and construction—shipbuilding
Shipbuilding
Shipbuilding is the construction of ships and floating vessels. It normally takes place in a specialized facility known as a shipyard. Shipbuilders, also called shipwrights, follow a specialized occupation that traces its roots to before recorded history.Shipbuilding and ship repairs, both...
, marine salvage
Marine salvage
Marine salvage is the process of rescuing a ship, its cargo, or other property from peril. Salvage encompasses rescue towing, refloating a sunken or grounded vessel, or patching or repairing a ship...
, dredging, port facilities, and so on. In such applications, pontoons are sunk, positioned under objects needing raising (such as sunken ships being recovered for their scrap metal
Scrap Metal
Scrap Metal were a band from Broome, Western Australia who played rock music with elements of country and reggae. The members had Aboriginal, Irish, Filipino, French, Chinese, Scottish, Indonesian and Japanese heritage. The band toured nationally as part of the Bran Nue Dae musical and with...
value or to clear channels
Channel (geography)
In physical geography, a channel is the physical confine of a river, slough or ocean strait consisting of a bed and banks.A channel is also the natural or human-made deeper course through a reef, sand bar, bay, or any shallow body of water...
), and then pumped full of air with air compressor
Air compressor
An air compressor is a device that converts power into kinetic energy by compressing and pressurizing air, which, on command, can be released in quick bursts...
s, raising the object. Pontoons are also used to build things like pontoon bridge
Pontoon bridge
A pontoon bridge or floating bridge is a bridge that floats on water and in which barge- or boat-like pontoons support the bridge deck and its dynamic loads. While pontoon bridges are usually temporary structures, some are used for long periods of time...
s and floating pier
Pier
A pier is a raised structure, including bridge and building supports and walkways, over water, typically supported by widely spread piles or pillars...
s. Such applications make them a useful tool for combat engineers and civilian engineers alike.
Construction
Pontoons for marine industrial uses are usually fabricatedFabrication (metal)
Fabrication as an industrial term refers to building metal structures by cutting, bending, and assembling. The cutting part of fabrication is via sawing, shearing, or chiseling ; torching with handheld torches ; and via CNC cutters...
from steel plate and sheet. Pontoons as parts of watercraft and aircraft are more typically molded in glass-reinforced plastic
Glass-reinforced plastic
Fiberglass , is a fiber reinforced polymer made of a plastic matrix reinforced by fine fibers of glass. It is also known as GFK ....
. Before the 1970s, glass-reinforced plastic was rare; older techniques include those of traditional wooden boatbuilding as well as plywood
Plywood
Plywood is a type of manufactured timber made from thin sheets of wood veneer. It is one of the most widely used wood products. It is flexible, inexpensive, workable, re-usable, and can usually be locally manufactured...
over wooden ribs or metal sheets over metal ribs (aluminium or steel), reflecting the prevailing practice in aircraft and boats.
See also
- OutriggerOutriggerAn outrigger is a part of a boat's rigging which is rigid and extends beyond the side or gunwale of a boat.In an outrigger canoe and in sailboats such as the proa, an outrigger is a thin, long, solid, hull used to stabilise an inherently unstable main hull. The outrigger is positioned rigidly and...
- HullHull (watercraft)A hull is the watertight body of a ship or boat. Above the hull is the superstructure and/or deckhouse, where present. The line where the hull meets the water surface is called the waterline.The structure of the hull varies depending on the vessel type...
- Pontoon (disambiguation)
- Semi-submersibleSemi-submersibleA semi-submersible is a specialised marine vessel with good stability and seakeeping characteristics. The semi-submersible vessel design is commonly used in a number of specific offshore roles such as for offshore drilling rigs, safety vessels, oil production platforms and heavy lift cranes.The...