SEXTANT — A YOUNG MAN'S DARING SEA VOYAGE AND THE MEN WHO MAPPED THE WORLD'S OCEANS

Crossing an ocean under sail today is not an especially risky undertaking. Accurate offshore navigation—for so long an impossible dream—has now been reduced to the press of a button, and most modern yachts are strong enough to survive all but the most extreme weather. Even if errors, accidents, or hurricanes should put a boat in danger, radio communications give the crew a good chance of being rescued.

Few sailors now lose their lives on the open ocean: crowded inshore waters where the risk of collision is high are far more hazardous. But it was not always so. When a young man called Alvaro de Mendana set sail from Peru in November 1567 to cross the Pacific with two small ships, accompanied by 150 sailors and soldiers and four Franciscan friars, he faced difficulties so great that his chances of survival, let alone achieving his objectives, were slim. Mendana's orders from his uncle, the Spanish viceroy, were to convert any "infidels" he encountered to Christianity, but the expedition was certainly not motivated entirely by religious zeal.

According to Inca legend, great riches lay on islands somewhere to the west. Were these islands perhaps outliers of the great southern continent that was believed to lie hidden somewhere in the unexplored South Seas? Mendana, who was twenty-five, hoped to find the answer, to set up a new Spanish colony, to make his fortune and win glory. However, any optimism he may have felt as the coast of Peru dipped below the horizon would have been misplaced.

Although Magellan had managed to cross the Pacific from east to west in 1520-21, he had been killed in fighting with local people after reaching the Philippines, and only four out of the forty-four men who sailed with him aboard his small flagship had returned safely to Spain. This first epic circumnavigation was counted as a brilliant success, but other expeditions ended in oblivion.