"QUITE HOW the Pacific Ocean's early long-distance mariners found their way so impressively will never be precisely known. Islanders had no written language, and by the time Europeans arrived in the Pacific, the colonisation of the last habitable islands of Oceania had all but ended. Widespread open-ocean voyaging between archipelagoes using traditional wayfinding techniques still persisted—European mariners were greatly impressed by Polynesian seafarers' knowledge of the night sky and of their maritime environment. But the voyaging soon came to an end—due to, among other things, catastrophic population crashes in Polynesia caused by introduced diseases.
Only in parts of Micronesia did an active body of navigation knowledge persist just long enough into the modern age to be systematically recorded and learned. Thanks to that luck, and to parsing oral narratives of migration, Western ethnological records, archaeological evidence and, in recent years, trial-and-error efforts on the water, an understanding of how Pacific voyagers accomplished their navigational feats has deepened.
Pacific navigators had none of the essentials of Western navigation: no compass for following a course, no sextant for estimating latitude [1], no chronometer for longitude [2]. That fact has led observers to notice the dissimilarities between Western and Pacific seafaring. In reality, the key stages of making a traditional Pacific voyage are recognisably the same as those of a Western one. Nicholas Thomas sums them up in "Voyagers: the Settlement of the Pacific" as: orientation or course-setting; maintaining a course once it has been determined; and making landfall. Any modern sailor, even one reliant on GPS, would recognise them.
Still, the potential for mutual confusion starts at the beginning. For course-setting, a modern sailor will use the abstraction of laying a course on her paper chart or, more likely these days, her laptop. But Pacific navigators had no charts. Mr Thomas reports how in 1821 an English missionary, John Williams, called at Atiu in the Cook Islands. A local chief, Rongomatane, offered to direct the Europeans to Rarotonga. The largest of the Cook Islands lay a day-and-a-half's sail away on a course of south-west by west, yet Rongomatane was pointing in all sorts of directions, to the Europeans' bafflement.
What they failed to understand was the importance of jumping-off points, with specific landmarks essential for orientation. For instance, the summit of a hill would have to be in line with a spit of land on the shore or even with a rock that had been moved to a particular spot. Rongomatane took Williams's schooner down the coast to the starting-point, where he had the vessel manoeuvred into place. "When his marks on the shore ranged with each other," Williams wrote, "he cried out, 'That's it! That is it!' I looked immediately at the compass, and found the course to be S.W. by W." Today a rising Hawaiian navigator, Kala Baybayan Tanaka, explains how prominent rocks long known to be essential to course-setting have sacred value to her island communities.
Using a back-transit (ie, lining up two features behind you and keeping them in line as you sail away) serves for as long as landmarks are visible astern. After that, stars take over. Because of Earth's rotation, stars rise in the east and set in the west, each one meeting pretty much the same point on the horizon at any given latitude. And so at night ocean navigators orient themselves using rising or setting stars and constellations. When a star rises too high in the night sky to be of use, another one on the horizon is pressed into service.
Star courses are laid down for different destinations. A big part of a navigator's training is in learning the night sky and star courses. On land, a "star-compass" is laid out rather like a compass rose to aid memorisation of stars and their positions when they rise and set. Where there is a cross-wind or known cross-current, the star course makes allowance for leeway (the sideways component of a sailing boat's movement) or set. Peia Patai, a Cook Islands navigator, has a star-compass motif tattooed impressively around his belly button. He knows to recognise and steer by many dozens of stars, many of whose traditional names have been forgotten. Earlier navigators knew and used perhaps 120 stars.
Dead reckoning is a means of tracking a vessel's progress that is well-known to Western sailors—using bearing and speed to estimate position. In the Caroline Islands a remarkable variant exists, known as the etak system, as Ben Finney in "Vaka Moana", a compendium on Pacific voyaging and settlement, explains. When travelling to a distant island a "reference" island is chosen roughly mid-way between starting-point and target, but well off to one side—indeed, it is usually invisible. With the vessel heading to his destination, the bearing of the reference island changes, as do the chosen stars that rise or set beyond it. The exercise usefully divides the voyage into segments, or etak. In a further, impressively abstract, evolution, Peia explains, if no physical reference island exists, you simply invent one, to serve the same purpose.
During the day, or when the night-sky is clouded over, wayfinders must steer in relation to a swell. These are travelling waves, a form of energy imparted by distant wind and weather systems. Disparate swells may overlap with each other, as well as with the waves being generated by the present wind driving the craft. Few Western-style sailors are even remotely as attuned to the complex interplay of swells as are Pacific navigators. Pacific teachers these days often make their students drift on the ocean for hours on their backs, to gain a more visceral feel of swell movements.
Waves are also important for landfinding. A sea that flattens might suggest that an out-of-sight island is blocking the long ocean swell (atolls are rarely visible more than ten miles out, but their dampening effect on upwind swells reaches farther). What is more, swells can refract around invisible land or bounce back to criss-cross with the incoming swell—an effect you can observe in miniature by watching how waves bounce off a harbour wall. Other signs of land include cloud formations and even the green of coconut stands reflected on the underside of distant clouds. Seabirds, too, give vital clues about the presence of land: fairy terns and noddies rarely fly further than 30 nautical miles (55.6km) from land, frigate birds and boobies considerably more. Evening flights of nesting birds can point the way to land.
Like aiming for a bigger target, finding a cluster of atolls is always easier than making for a single speck. But that Pacific navigators routinely did both, over great expanses of ocean, remains staggering. No wonder great status accrued to them on finding new land. A modern-style navigator at the end of a voyage is lucky if she is stood the first round at the Bar du Port.” [3]
· · · 3. "Oceania's wayfinding skills." The Economist, 20 Dec. 2023, p. NA.
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