Hopper barge

File:La Crosse Mississippi River barge and mooring dolphins-4.jpg

Hopper barge going through La Crosse County harbor

File:Split hopper dredge Currituck at Virginia Beach 3.jpg

Split hopper dredge Currituck at Virginia Beach.

A hopper barge is a type of barge commonly designed to transport commodities like coal, steel, rocks, sand, soil and waste.Template:Sfn 'Hopper barge' can also refer to a barge that dumps cargo at sea. These are now commonly called 'split hopper barge', because they split along the length of the hull. Split hopper barges can be non-propelled or self-propelled .

History

The term 'hopper barge' surfaces in the second half of 19th century England, especially in relation to dredging.Template:Sfn The word 'hopper' has multiple meanings. The hopper car is a well known use, but hopper can also mean: "any of various other receptacles for the temporary storage of material".Template:Sfn By the 1890s, iron hopper barges used in dredging had doors in the hull for quickly dumping their load on the sea floor.Template:Sfn

The 1950s American hopper barge descended from the welded steel barge, which replaced wooden cargo carriers. The steel barge offered better protection for the cargo, and required little maintenance.Template:Sfn

In the 1950s hopper barges ranged from 800 to 3,500 tons.Template:Sfn

Characteristics

A hopper barge differs from other barges by having a hopper. This is the area of the open cargo hold.Template:Sfn It may be unloaded either by bulk-handling cranes, or by being constructed with some mechanism to dump the contents through the bottom of the hull.

Hopper barges are usually of double-hull construction. This means that the sides and bottom of the cargo hold are separated from the hull by void spaces.Template:Sfn This is done because the hopper barge has to resist heavy external impacts, as well as the heavy blows of unloading buckets into it. Internal bracing in the internal space transmmits the impact of loading to a larger area, and so ensures that the side shell of the hopper barge is not deformed.Template:Sfn

Non self-propelled hopper barges are seen in two distinctive types; raked hopper and boxed hopper barges. Single raked barges are raked (tapered in depth) at the bow only. Double raked barges are tapered at both bow and stern.Template:Sfn

Hopper barge variants

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Slipway with split barge

Open hopper barge

The open hopper barge is generally used to carry ores and steel on inland waterways.Template:Sfn

Dump hopper barge

A barge where the hopper is closed at the bottom by doors, which can be opened to dump the contents. This is done at sea, to dispose of unwanted wastes, rather than to unload a useful cargo.

Covered hopper barge

In the United States, covered hopper barges generally have steel hatch coverings operating on roller bearings. These quickly open and close over a wide section of the hold and are watertight. As the covers can generally expose about half of the hold, these enable vertical loading.Template:Sfn Another type of cover is the lift-off (stacking) type cover.Template:Sfn

Covered hopper barges transport grains and other agricultural products, salt, steel products, paper products, minerals, and sometimes packaged products.Template:Sfn

Split hopper barge

Split hopper barges are used to dump cargo at sea. This comes mostly from dredging. The split hopper barge is the successor to the hopper barge with doors in the hull, which dumped its cargo by opening these doors.Template:Sfn

The hull of the split hopper barge splits longitudinally between the end bulkheads. The vessel consists of two major moving parts (port and starboard halves), both are mostly symmetrical in design. Both parts of the vessel are hinged at the deck and operated by hydraulic cylinders. When the vessel splits the load is dumped rapidly, which means the barge has to be very stable in order not to capsize or otherwise get damaged.

See also

• Grain bin