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Outrigger

technology Maturity 11-13 Next article →

An outrigger is a structure that projects from the side of a vessel.

This component serves many different purposes depending on the type of boat being used. In many cases, the primary goal is to increase stability. This prevents the main body of the boat from tipping over. Beyond boats, outriggers can also refer to legs on wheeled vehicles. For example, a crane uses folded-out legs to stay stable when lifting heavy loads.

In sailing canoes and proas, the outrigger acts as a stabilizer. It is a thin, long, and solid hull. This secondary hull is positioned rigidly and parallel to the main hull. By doing this, it makes the main hull less likely to capsize. Capsizing is when a boat flips over in the water. If a vessel uses only one outrigger, it works in two ways. The weight of the outrigger reduces the tendency to tip in one direction. Meanwhile, its buoyancy reduces the tendency to tip in the other direction.

COLLECTIE TROPENMUSEUM Reliëf op de Borobudur TMnr 20025669
COLLECTIE TROPENMUSEUM Reliëf op de Borobudur TMnr 20025669

There are two main types of outrigger boats used in maritime history. The first type uses double outriggers. This design was prevalent in maritime Southeast Asia. The second type uses a single outrigger. This single-outrigger design was common in Madagascar, Melanesia, Micronesia, and Polynesia. These outrigger boats are also the ancestors of modern multihull ships. The technology was originally developed by the Austronesian people.

COLLECTIE TROPENMUSEUM Reliëf op de Borobudur TMnr 20025669
COLLECTIE TROPENMUSEUM Reliëf op de Borobudur TMnr 20025669

Outriggers are also used as specialized tools in the fishing industry. On fishing vessels, an outrigger is a pole or a series of adjustable poles. These are attached to the sides of the boat in front of the hull. They are typically constructed from metal or plastic. These poles allow boats to trawl more lines in the water at once. This setup helps the lines stay spread out so they do not tangle. The arrangement also simulates a school of fish. Additionally, these structures provide stability for the fishing boat and its platform.

In the sport of rowing, an outrigger is called a rigger. It is a triangular frame that holds the rowlock. The rowlock is the part where the oar is slotted. The rigger holds this piece away from the gunwale, or the edge of the boat. This distance is used to optimize leverage for the rower. Wooden outriggers appeared on the new trireme around the 7th or 6th centuries BC. Later, they appeared on Italian galleys around AD 1300.

Scullers with outriggers 1851
Scullers with outriggers 1851

A British professional rower named Harry Clasper changed rowing history. Clasper lived from 1812 to 1870. He popularized the use of the modern tubular-metal version of the rigger. This change provided physiological and ergonomic advantages for the rowers. Because of these benefits, top rowing events eventually accepted its use in competitions.

Scullers with outriggers 1851
Scullers with outriggers 1851

In recent decades, manufacturers have even created wing-riggers. These are reinforced arcs or flattened tubular projections. They are designed to look like the wings found on an aircraft.

Finally, the term outrigger has specific meanings in other sailing contexts. On a keelboat, an outrigger refers to structures used to attach running rigging. This includes items like a sheet, which is a rope used to control a sail. These structures allow the rigging to be attached outboard of the hull. The Racing Rules of Sailing generally prohibit these types of outriggers. However, they are explicitly permitted on certain classes of boats. One example is the IMOCA Open 60, which is used in several major offshore races.

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File:COLLECTIE TROPENMUSEUM Reliëf op de Borobudur TMnr 20025669.jpg
COLLECTIE TROPENMUSEUM Reliëf op de...
File:Outrigger on Hawaiian sailing canoe.png
Outrigger on Hawaiian sailing canoe.png
File:Scullers_with_outriggers_1851.jpg
Scullers_with_outriggers_1851.jpg
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