Winds and storms made the South Atlantic impossible to sail. Iin 1400 no one had ever crossed it accidentally, let alone on purpose. Here are three of the major weather obstacles.Across central Africa and out into the Atlantic (where the clouds show on this August 1992 image) month-long periods of calm are frequent. Until 1434 Europeans never sailed past these clouds.
Sailing southward past these clouds winds blew in the contrary direction, pushing ships backwards, and into the middle of the South Atlantic. (Accompanying these prevailing winds were powerful matching currents.)
Rather than fight these winds, Portuguese sailors would have to sail westward almost all the way across the South Atlantic to Brazil before turning to the east, to the southern tip of Africa.
Finally in order to sail back across the Atlantic from the bulge of South America to the tip of southern Africa (as Bartholomew Dias finally did in 1487) was difficult because of strong winds, powerful intersecting currents, and storms with winds up to 180 kilometers per hour.
All ocean sailors before 1400 relied upon highly predictable seasonal winds and currents that came to be called "trade winds" because when they blew, the traders sailed into or out of harbors. Trade winds and currents were the reason for regular long-distance travel in the Pacific and Indian Oceans.Other sailors (the Northern Europeans and Chinese) had a coastal shelf to follow. Where Leif Ericson could follow an ocean ledge to North America, no such edge connected the tip of Africa with South America's tail, only vicious storms. Crossing the South Atlantic required a different approach to navigation.
Pacific Ocean Weather| Indian Ocean Weather | North Atlantic Coastal Shelf | South China Sea Coastal Shelf | Ocean Currents | |Home page
