La Crosse Mississippi River barge and mooring dolphins-4

Split hopper dredge Currituck at Virginia Beach 3

A hopper barge is a type of

barge A barge is typically a flat-bottomed boat, flat-bottomed vessel which does not have its own means of mechanical propulsion. Original use was on inland waterways, while modern use is on both inland and ocean, marine water environments. The firs ...

commonly designed to transport commodities like coal, steel, rocks,

sand Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but is usually defined by its grain size. Sand grains are smaller than gravel and coarser than silt. Sand can also refer to a textural ...

soil Soil, also commonly referred to as earth, is a mixture of organic matter, minerals, gases, water, and organisms that together support the life of plants and soil organisms. Some scientific definitions distinguish dirt from ''soil'' by re ...

and

waste Waste are unwanted or unusable materials. Waste is any substance discarded after primary use, or is worthless, defective and of no use. A by-product, by contrast is a joint product of relatively minor Value (economics), economic value. A wast ...

. '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. The word 'hopper' has multiple meanings. The

hopper car A hopper car () or hopper wagon () is a type of railroad freight car that has opening doors or gates on the underside or on the sides to discharge its cargo. They are used to transport loose solid bulk commodities such as coal, ore, grain, a ...

is a well known use, but hopper can also mean: "any of various other receptacles for the temporary storage of material". By the 1890s, iron hopper barges used in dredging had doors in the hull for quickly dumping their load on the sea floor. 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. In the 1950s hopper barges ranged from 800 to 3,500 tons.

Characteristics

A hopper barge differs from other

s by having a hopper. This is the area of the open cargo hold. 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. 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. 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.

Hopper barge variants

Open hopper barge

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

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. Another type of cover is the lift-off (stacking) type cover. Covered hopper barges transport grains and other agricultural products, salt, steel products, paper products, minerals, and sometimes packaged products.

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. The hull of the split hopper barge splits longitudinally between the end bulkheads. The vessel consists of two major moving parts (

port A port is a maritime facility comprising one or more wharves or loading areas, where ships load and discharge cargo and passengers. Although usually situated on a sea coast or estuary, ports can also be found far inland, such as Hamburg, Manch ...

and

starboard Port and starboard are Glossary of nautical terms (M-Z), nautical terms for watercraft and spacecraft, referring respectively to the left and right sides of the vessel, when aboard and facing the Bow (watercraft), bow (front). Vessels with bil ...

halves), both are mostly

symmetrical Symmetry () in everyday life refers to a sense of harmonious and beautiful proportion and balance. In mathematics, the term has a more precise definition and is usually used to refer to an object that is invariant under some transformations ...

in design. Both parts of the vessel are hinged at the deck and operated by

hydraulic Hydraulics () is a technology and applied science using engineering, chemistry, and other sciences involving the mechanical properties and use of liquids. At a very basic level, hydraulics is the liquid counterpart of pneumatics, which concer ...

cylinders A cylinder () has traditionally been a three-dimensional solid, one of the most basic of curvilinear geometric shapes. In elementary geometry, it is considered a prism with a circle as its base. A cylinder may also be defined as an infinite ...

. 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.

References

Sources

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