The story of the ocean

How humans have explored the world by boat

A. What is the ocean? Today we refer to live individual oceans - the Atlantic, Pacific, Indian, Arctic, and Southern. But in the distant past, people saw the 'ocean' as the whole mysterious mass of water surrounding the places where they lived. In fact, nothing separates the oceans from each other. There is no moment when one passes from the Atlantic to the Indian Ocean, or from the Indian Ocean to the Pacific and in total they cover the greater part of the surface of the Earth.

B. Ocean voyages were made as long ago as 1000BCE, when Polynesians began migrating across the Pacific, setting off into the unknown. They reached small inhabited islands using only knowledge passed from navigator to apprentice, often using songs to memorize important facts, such as where specific stars would rise and set on the horizon. From Europe, Viking sailors crossed the North Atlantic and reached North America by 1000CE. In the Middle Ages, sea trade routes linked China to Egypt and Venice to London. Most seafarers kept close to the coastline whenever possible, however, and for many scholars, the ocean remained the subject of terror or denial. Arab geographer Al-Masudi in 957CE recorded a common sailors' tale that at the exit from the Mediterranean Sea into the Atlantic there were giant statues, indicating that there was 'no way beyond'. The German storyteller Adam of Bremen wrote in 1076: 'Beyond Norway, which is the farthermost northern country, you will find no human habitation, nothing but ocean, terrible to look at and limitless.' Around 1290 a map was presented to Hereford Cathedral. In medieval fashion, it showed the world as consisting of the continents of Europe, Africa and Asia, which was all that was known about at the time. Even the Mediterranean was not accurately drawn. The band of oceans surrounding the great landmass was not much wider than the rivers - the oceans were simply not considered important.

C. This narrow view of the world was soon to change during the 13th - 15th centuries. Venetian Marco Polo's 1298 account of his travels in the east, including a sea journey from China to the Persian Gulf, broadened the scope of knowledge. The works of the ancient Greek geographer Ptolemy, in which he had plotted the Indian Ocean, had been forgotten for many centuries, but by 1400 they were again influential in Europe. Between 1405 and 1433, the Chinese admiral Zheng He led a series of voyages into the Indian Ocean, travelling as far as the east coast of Africa. The expanding view of the world is represented in a great map made by the monk Fra Mauro in Venice around 1450. It was one of the first maps to recognize the Atlantic as an ocean. The European experience soon spread to the rest of the world. Adventurers and sailors, now sometimes backed by acquisitive kings, queens and emperors, set out in search of trade, territory and treasure. Setting out in 1498, Vasco da Gama led a Portuguese fleet around the southern tip of Africa to India. In 1519, Ferdinand Magellan, a Portuguese in the service of Spain, set off on a voyage around South America, his crew completing a circumnavigation of the globe. The age of ocean denial was over.

D. Once humans could travel over vast areas of sea, it was perhaps justifiable to use the term 'conquering the ocean'. Yet for centuries, ocean voyagers confronted discomfort and danger. Without prior knowledge or charts, sailors could never be sure what was under the surface of the sea. If bad weather came, it was often not possible to find shelter. Sicknesses, such as scurvy, killed thousands of people at sea, and accidents were commonplace. Sea travelers might run out of food or water, and it was not possible for a sailor in trouble to call for help beyond the horizon. The first ocean-going sailing ships were central to world trade and warfare and conflict, yet remained entirely at the mercy of the currents and the winds.

E. The other problem of ocean travel was the lack of navigational techniques. Observing heavenly bodies, continually measuring the ship's speed, and using the magnetic compass could at best achieve a fair degree of precision in calculating a ship's position. Sailors far out to sea often had only a vague notion of where they were, but years of technological progress, better navigational instruments and maritime experience gradually improved ocean travel. By the 19th century, scurvy was almost eliminated once it was realized it could be prevented and treated with citrus fruit, and navigation was greatly improved. As ocean-going steamships replaced sail in the second half of the century, the time spent at sea was reduced. By the 20th century, ocean travel had become reasonably safe, at least in times of peace.

F. In a sense, the ocean has not been 'conquered'. We cannot control the currents and weather, and human impact has mostly been negative. But we have at least developed the means to travel over vast areas, and this achievement has been the product of many centuries of adventures. Seafarers from ancient times down to the present day have faced a hard struggle against the elements, demanding endurance, skill, and ingenuity. The record of their lives includes barely credible stories of voyages into uncharted waters and survival at sea. Their experience deserves to be remembered and honored, as does the essential contribution of modern sailors to our ever-evolving history.