Modern ship routing is a matter for specialist forecasters using a mass of meteorological observations processed by large, high-speed electronic computers, as will appear below.

Historically, some form of routing has been practised for centuries as the result of observations made by navigators and explorers as they gradually laid bare the geography of the earth's oceans and continents.

It cannot be known whether the very early navigators followed routes based on weather considerations, but they may have done so in limited areas of the globe. There is some reason to suppose that the Atlantic islands and even perhaps the West Indies were known to the Phoenicians. Legends which suggest this are supported by the finding of a stock of fourth century b.c. Phoenician coins at Corvo in the Azores. It has been reasonably supposed in some quarters that these coins were from a Phoenician trader wrecked on the island whilst on passage westwards, but how far west we cannot be sure.

It has never been seriously doubted that the north-east coast of America was discovered and temporarily colonised by Vikings from Greenland during the latter part of the first century A.D. Certain archaeological finds have been held by some to support this view. An account of some early pioneering voyages has been given by Villiers (1956).

These early voyages can hardly have been consciously weather routed, though some knowledge of the prevailing wind conditions may well have been acquired. Perhaps it was as late as the end of the fifteenth century that the first known weather-routed voyage was made. Henry the Navigator (Prince Henry of Portugal) was intent on finding a way round the Cape into the Indian Ocean in order to oust the Venetians and Arabs from their lucrative trading in that area. He fitted out expedition after expedition, but they all turned back as they hugged the African coast and were caught in the doldrums. Eventually they learned to stand well out to sea and so get the benefit of the N.E. trades and in 1434 they reached the equator. However, it was another half-century before the Cape was reached and this could conceivably be regarded as the first weather-routed voyage.