Outrigger boats can also vary in their configuration, from the ancestral double-hull configuration (catamarans), to single-outrigger vessels prevalent in the Pacific Islands and Madagascar, to the double-outrigger vessels (trimarans) prevalent in Island Southeast Asia.
As such, the hulls of outrigger or double-hull boats are typically longer, narrower and more hydrodynamically efficient than those of single-hull vessels.
They were the vessels that enabled the Austronesian expansion from Taiwan into the islands of both the Indian and Pacific Ocean from around 3000 BC.
They have spread to other cultures Austronesians came into contact with, notably in Sri Lanka and southern India as well as in the coast of East Africa.
Outrigger boats were originally developed by the Austronesian-speaking peoples of the islands of Southeast Asia for sea travel.
It is believed that the use of outriggers may have been initially caused by the need for stability on small watercraft after the invention of crab claw sails some time around 1500 BCE.
The ancestral rig was the mastless triangular crab claw sail which had two booms that could be tilted to the wind.
In Island Southeast Asia, these developed into double outriggers on each side that provided greater stability.
To deal with the problem of the instability of the boat when the outrigger faces leeward when tacking, they instead developed the shunting technique in sailing, in conjunction with reversible single-outriggers.
Similarly, the Spanish priest Francisco Combés, describing the large karakoa outrigger warships of the Visayan Islands in the Philippines, remarked:[9] "That care and attention, which govern their boat-building, cause their ships to sail like birds, while ours are like lead in this regard.
The acquisition of the catamaran and outrigger boat technology by the non-Austronesian peoples in Sri Lanka and southern India is the result of very early Austronesian contact with the region, including the Maldives and Laccadive Islands.
For example, Tamil paṭavu, Telugu paḍava, and Kannada paḍahu, all meaning "ship", are all derived from Proto-Hesperonesian *padaw, "sailboat", with Austronesian cognates like Javanese perahu, Kadazan padau, Maranao padaw, Cebuano paráw, Samoan folau, Hawaiian halau, and Māori wharau.
The links between seafaring and outrigger boats in the Philippines extend through to political life, in which the smallest political unit in the country is still called "barangay" after the historical balangay outrigger boats used in the original migrations of the first Austronesian peoples across the archipelago and beyond.
The German linguist Otto Dempwolff (1871-1938) originally reconstructed the Proto-Austronesian word for "boat" as *waŋkaŋ, and included the reflexes for both *baŋkaʔ and *waŋkaʔ as its descendants.
[13][14] Mahdi (2016) instead reconstructs four words for "boat" in the Austronesian languages, all ultimately derived from the monosyllabic protoforms *Cu and *baŋ.
The protoforms *qabaŋ and *baŋkaʔ are composites with a common precursor, with the *qa- and -*ka positioned differently.
'[18] The outrigger boom—spars connecting the ama to the main hull (or the two hulls in a double-hull canoe)—are called ʻiako in Hawaiian and kiato in Māori (with similar words in other Polynesian languages), ultimately from Proto-Oceanic *kiajo or its doublet *kayajo both meaning 'outrigger boom' (compare Loniu kiec, Kiribati kiaro, and Tongan kiato, as well as Seimat ayas and Gedaged ayad, all meaning 'outrigger boom').
An unusual type of double-outrigger boat design, preserved in scale models in the Pitt Rivers Museum, forms a triangle shape.
It is connected to the main hull by spars called ʻiako (Hawaiian), ʻiato (Tahitian), or kiato (Māori).
The paddlers need to be careful to avoid leaning too far on the opposite side of the ama, as that may cause the canoe to capsize (huli or lumaʻi).
The single outrigger is used to provide lateral stability, while still allowing fishermen to work with fishing nets.
OC1 commonly use ʻiako made of aluminium or carbon fiber, with a mechanism for quickly assembling and disassembling the canoe (snap buttons, large wing nuts, etc.).
The stroker should have a high level of endurance to keep the rate (the number of strokes taken in a given amount of time) manageable for whatever the situation may be.
A good steersman is able to maintain the straight attitude of the canoe throughout the course of a race, and also keep the boat and the crew safe in rough sea conditions.
From a water safety perspective the steersman should also be among the most experienced crew members, and be knowledgeable with the waterways and weather conditions, relevant maritime rules and other safety considerations such as the use of personal flotation devices, rigging of the canoe, placement of paddlers in the various seating positions, and recovery from a huli by righting the canoe and bailing out the water.
A seat 5 paddler with steering skill can also assist in preventing a huli by staying on the ama side during a particularly rough stretch of water.
Typically, nine paddlers form a crew, with six paddling the OC6 and the other three resting, drinking, and/or eating on an escort boat.
Replacement typically occurs at 20 to 30 minute intervals; the escort boat drops the relief paddlers into the water ahead of the OC6, which is steered toward them.
The Molokaʻi Hoe in Hawaii, The Hamilton Cup in Australia,[26] The Vaka Eiva in Rarotonga (Cook Islands),[27] The Motu2Motu in Aitutaki (Cook Islands)[28] and the Catalina Channel crossing in California[29] are four examples of races involving water changes.
Gender classification is typically straightforward, with male, female, and coed classifications, with the latter being a crew with equal numbers of male and female paddlers (different rules may apply to nine-person coed crews doing a race with paddler replacements).