How did Polynesian wayfinders navigate the Pacific Ocean?

The night before starting work, the canoe builder lodged his axe in the sacred enclosure. A feast of fatted pig dedicated to the gods was followed by sleep before he rose at dawn to begin assembling the word to build the boat.

Over 1,000 years before the Europeans first sailed into the Pacific Ocean in the 16th century, Polynesians had been exploring the 25,000 islands in its waters.

For a long voyage, they would build either a vaka, a boat with two hulls, or an outrigger – a boat with a float fixed to arms extended on one side, which gives extra stability. A crew of six sufficed: two steersmen, a sail man, a bailer, a spare hand so that rests could be taken and, most important of all, a navigator whose years of training enabled him to find his way, without instruments or a fixed star, in the vast ocean.

The travelers took coconuts, vegetables, dried fruit and fish, and a cooked paste made of breadfruit with them, although stowage was limited and the crew must have gone hungry when they could not catch sufficient fish on the journey. To supplement rainfall and coconut milk, some water was carried on board in gourds or hollow bamboo.

Getting the feel of the sea

To keep the vessels on course, navigators could correct a few degrees variation in the wind direction by checking it against that of the long-range swells generated by the trade winds. Some would lie down on the outrigger to “feel” the sea as it rose and fell, and swells were considered significant enough to be recorded on schematic reed maps, some of which survive.

The navigators also built up a prodigious knowledge of the ocean’s currents as they gained experience at sea.

The Polynesians judged the latitude of their boats by the Sun and monitored their exact course by the stars – the movements of 16 groups of guiding stars were committed to memory by means of rhymes. They could associate stars with particular destinations accurately enough, according to a Spanish visitor of 1774, to find the harbor of their choice at night.