Finding the Way Across the Pacific

Long before Europeans learned to cross the open ocean, the peoples of the Pacific were settling islands scattered across a third of the globe. From South East Asia they spread eastwards across thousands of kilometres of empty water, reaching Hawaii, Easter Island and New Zealand at the far corners of a vast triangle. They did all of this without a magnetic compass, without printed charts and without any of the instruments that European sailors came to depend upon. To later observers it seemed almost impossible, and for a long time some scholars insisted that these islands must have been reached by accident, by canoes blown off course and carried helplessly downwind. The distances involved were staggering. From one island group to the next might lie a thousand kilometres of open sea with nothing at all to steer by, and to find a small island in that immensity, and then to find the way home again, demanded a mastery of the ocean that outsiders could scarcely imagine.

In truth the voyagers relied on an intricate body of knowledge, memorised and passed on by word of mouth from one generation of navigators to the next. The most important guide was the night sky. Navigators learned the points on the horizon where particular stars rise and set, and by holding a course towards a known rising star, and then the next star to rise behind it, they could keep a steady bearing through the hours of darkness. This mental framework of star positions is often called a star compass, though it exists only in the navigator's trained memory. Learning it took many years. A pupil would sit with an experienced teacher, sometimes arranging pieces of coral on a mat to stand for the stars, memorising which star rose over which island and in what order, until the whole sky and the whole ocean were fixed firmly in the mind.

The sea itself offered further signs. Long ocean swells, generated by distant and dependable winds, travel in steady directions, and an experienced navigator lying in the hull of a canoe could feel the way these swells lifted and rocked the vessel, using them like the lines of an invisible grid. When such a swell struck an island it bent around the obstacle and was thrown back, and this disturbance in the familiar rhythm could betray the presence of land that was still far below the horizon and quite out of sight. The most skilled navigators were said to be able to pick out several different swells crossing the ocean at once, each running in its own direction, and to read from the way they met and combined the presence of islands lying days of sailing away.

Living things were read as carefully as the waves. Certain seabirds, such as terns and frigatebirds, feed at sea during the day but return to land each evening to roost; a navigator who spotted them flying purposefully at dusk knew that an island lay in the direction of their flight, and roughly how far. The green tint that land can cast on the underside of clouds, floating vegetation, and even the behaviour of the water were all folded into the same rich picture. No single sign was ever trusted on its own; instead the navigator wove dozens of small clues together, weighing the stars against the swells and the birds against the clouds, constantly correcting and refining a running estimate of where the canoe had reached.

By the twentieth century this art was close to being lost, surviving in only a few communities. Its dramatic revival owed much to a master navigator named Mau Piailug, from the small island of Satawal in Micronesia, one of the last people fully trained in the traditional way. In 1976 he guided a double-hulled voyaging canoe named Hokulea from Hawaii to Tahiti using no instruments at all, steering by stars, swells and birds across more than four thousand kilometres of ocean. The voyage was a triumph. It demonstrated beyond reasonable doubt that such journeys could be made deliberately rather than by chance, and it inspired a wider renaissance of traditional navigation across the Pacific that continues today. Piailug went on to teach a new generation of navigators, passing on knowledge he had feared might die with him, and voyaging canoes built in the old style now sail once more between the islands, keeping alive a science that was very nearly lost forever.