More than 1300 years ago, Polynesian explorers set out from Havai’I (now Raiatea, in the Society islands) in great double-hulled canoes across the vast unknown expanse of the North Pacific Ocean. By chance, they discovered and subsequently colonized, the Hawaiian Islands. A long canoe voyage across the uncharted ocean must have required an exceptional degree of navigational skill.
Like competent modern sailors, the Polynesian navigators became familiar with the winds and currents systems that affected their vessels. In sailing from Havai’I to Hawaii, a canoe crossed three wind systems and the surface ocean currents related to them. Havai’I lay in the southeast trade-winds belt, where prevailing winds blow from the southeast, and also in the region of a great westward-flowing ocean current that lies just south of the equator. The initial part of the voyage therefore involved sailing somewhat east of north across this belt until, just north of the equator, a belt of light variable winds and an eastward-flowing current
Text from “The Blue Planet, An Introduction to Earth System Science”, B. Skinner, S. Porter, D. Botkin