Polynesian navigation
Polynesian navigation or Polynesian wayfinding was used for thousands of years to enable long voyages across thousands of kilometres of the open Pacific Ocean. Polynesians made contact with nearly every island within the vast Polynesian Triangle, using outrigger canoes or double-hulled canoes. The double-hulled canoes were two large hulls, equal in length, and lashed side by side. The space between the paralleled canoes allowed for storage of food, hunting materials, and nets when embarking on long voyages. Polynesian navigators used wayfinding techniques such as the navigation by the stars, and observations of birds, ocean swells, and wind patterns, and relied on a large body of knowledge from oral tradition. This island hopping was a solution to the scarcity of useful resources, such as food, wood, water, and available land, on the small islands in the Pacific Ocean. When an island’s required resources for human survival began to run low, the island's inhabitants used their maritime navigation skills and set sail for new islands. However, as an increasing number of islands in the South Pacific became occupied, and citizenship and national borders became of international importance, this was no longer possible. People thus became trapped on islands with the inability to support them.
Navigators travelled to small inhabited islands using wayfinding techniques and knowledge passed by oral tradition from master to apprentice, often in the form of song. Generally, each island maintained a guild of navigators who had very high status; in times of famine or difficulty, they could trade for aid or evacuate people to neighbouring islands. As of 2014, these traditional navigation methods are still taught in the Polynesian outlier of Taumako in the Solomons and by voyaging societies throughout the Pacific.
Both wayfinding techniques and outrigger canoe construction methods have been kept as guild secrets, but in the modern revival of these skills, they are being recorded and published.
History
Between about 3000 and 1000 BC speakers of Austronesian languages spread through the islands of Southeast Asia – most likely starting out from Taiwan, as tribes whose natives were thought to have previously arrived from mainland South China about 8000 years ago – into the edges of western Micronesia and on into Melanesia, through the Philippines and Indonesia. In the archeogenetic record, there are well-defined traces of this expansion that allow the path it took to be followed and dated with a degree of certainty. In the mid-2nd millennium BC, a distinctive culture appeared suddenly in north-west Melanesia, in the Bismarck Archipelago, the chain of islands forming a great arch from New Britain to the Admiralty Islands.This culture, known as Lapita, stands out in the Melanesian archeological record, with its large permanent villages on beach terraces along the coasts. Particularly characteristic of the Lapita culture is the making of pottery, including a great many vessels of varied shapes, some distinguished by fine patterns and motifs pressed into the clay. Between about 1300 and 900 BC, the Lapita culture spread farther to the east from the Bismarck Archipelago, until it reached as far as Tonga and Samoa. Lapita pottery persisted in places such as Samoa, Tonga, and Fiji for many years after its introduction to Western Polynesia but eventually died out in most of Polynesia due to the scarcity of clay. Although the production of ceramics did not travel beyond Western Polynesia, some ceramic materials have been recovered through archeological excavations in the Central Polynesia but have been attributed to trade.
In accordance with Polynesian oral tradition, the geography of Polynesian navigation pathways is said to resemble the geometric qualities of an octopus with head centred on Ra'iātea and tentacles spread out across the Pacific. In oral tradition the octopus is known by various names such as Taumata-Fe'e-Fa'atupu-Hau, Tumu-Ra'i-Fenua and Te Wheke-a-Muturangi.
Specific chronology of the discovery and settlement of specific island groups within Eastern and Central Polynesia is hotly debated among archeologists, but a generally accepted timeline puts the initial settlement of the Cook Islands before 1000 AD. From this point, navigation branched out in all directions with Eastern Polynesia settled first followed by more remote regions such as Hawaii, Easter Island, and New Zealand peopled later. The pattern of settlement also extended to the north of Samoa to the Tuvaluan atolls, with Tuvalu providing a stepping stone to the founding of Polynesian Outlier communities in Melanesia and Micronesia. The natives of Easter Island likely originated from Mangareva. They discovered the island by using the flight path of the sooty tern. When the first European to visit the island, Jacob Roggeveen, landed on Easter Island, he found no evidence of navigation. Instead, he noticed that there were not enough trees to build seaworthy canoes and the rafts the natives were using were not seaworthy either.
The archeological record supports oral histories of the first peopling of region including both the timing and geographical origins of Polynesian society.
Navigational techniques
Polynesian navigation relies heavily on constant observation and memorization. Navigators have to memorize where they have sailed from in order to know where they are. The sun was the main guide for navigators because they could follow its exact points as it rose and set. Once the sun had set they would use the rising and setting points of the stars. When there were no stars because of a cloudy night or during daylight, a navigator would use the winds and swells as guides.Through constant observation, navigators were able to detect changes in the speed of their canoes, their heading, and the time of day or night. Polynesian navigators thus employed a wide range of techniques including the use of the stars, the movement of ocean currents and wave patterns, the patterns of bioluminescence that indicated the direction in which islands were located, the air and sea interference patterns caused by islands and atolls, the flight of birds, the winds and the weather.
Bird observation
Certain seabirds such as the white tern and noddy tern fly out to sea in the morning to hunt fish, then return to land at night. Navigators seeking land sail opposite the birds' path in the morning and with them at night, especially relying on large groups of birds, and keeping in mind changes during nesting season.Harold Gatty suggested that long-distance Polynesian voyaging followed the seasonal paths of bird migrations. In The Raft Book, a survival guide he wrote for the U.S. military during World War II, Gatty outlined various Polynesian navigation techniques for shipwrecked sailors or aviators to find land. There are some references in their oral traditions to the flight of birds, and Gatty claimed that departing voyages used onshore range marks pointing to distant islands in line with their flight paths. A voyage from Tahiti, the Tuamotus or the Cook Islands to New Zealand might have followed the migration of the long-tailed cuckoo, just as a voyage from Tahiti to Hawaii would coincide with the track of the Pacific golden plover and the bristle-thighed curlew.
It is also believed that Polynesians, like many seafaring peoples, kept shore-sighting birds. One theory is that voyagers took a frigatebird with them. This bird's feathers become drenched and useless if it lands on water, so voyagers would release it when they thought they were close to land, and would follow it if it did not return to the canoe.
Navigation by the stars
The positions of the stars helped guide Polynesian voyages. Stars, as opposed to planets, hold fixed celestial positions year-round, changing only their rising time with the seasons. Each star has a specific declination, and can give a bearing for navigation as it rises or sets. Polynesian voyagers would set a heading by a star near the horizon, switching to a new one once the first rose too high. A specific sequence of stars would be memorized for each route.The Polynesians also took measurements of stellar elevation to determine their latitude. The latitudes of specific islands were also known, and the technique of "sailing down the latitude" was used. That is, Polynesians navigated by the stars through knowledge of when particular stars, as they rotated through the night sky, would pass over the island to which the voyagers were sailing. Also knowledge that the movement of stars over different islands followed a similar pattern provided the navigators with a sense of latitude, so that they could sail with the prevailing wind, before turning east or west to reach the island that was their destination.
Some star compass systems specify as many as 150 stars with known bearings, though most systems have only a few dozen. The development of sidereal compasses has been studied and hypothesized to have developed from an ancient pelorus instrument.
For navigators near the equator, celestial navigation is simplified, given that the whole celestial sphere is exposed. Any star that passes through the zenith moves along the celestial equator, the basis of the equatorial coordinate system.
Swell
The Polynesians also used wave and swell formations to navigate. Many of the habitable areas of the Pacific Ocean are groups of islands in chains hundreds of kilometres long. Island chains have predictable effects on waves and currents. Navigators who lived within a group of islands would learn the effect various islands had on the swell shape, direction, and motion, and would have been able to correct their path accordingly. Even when they arrived in the vicinity of an unfamiliar chain of islands, they may have been able to detect signs similar to those of their home.Once they had arrived fairly close to a destination island, they would have been able to pinpoint its location by sightings of land-based birds, certain cloud formations, as well as the reflections of shallow water made on the undersides of clouds. It is thought that the Polynesian navigators may have measured sailing time between islands in "canoe-days".
The energy transferred from the wind to the sea produces wind waves. The waves that are created when the energy travels down away from the source area are known as swell. When the winds are strong at the source area, the swell is larger. The longer the wind blows, the longer the swell lasts. Because the swells of the ocean can remain consistent for days, navigators relied on them to carry their canoe in a straight line from one house on the star compass to the opposite house of the same name. Navigators were not always able to see stars; because of this, they relied on the swells of the ocean. Swell patterns are a much more reliable method of navigation than waves, which are determined by the local winds. Swells move in a straight direction which makes it easier for the navigator to determine whether the canoe is heading in the correct direction.