Fascinating. A passable route was discovered in 1434 by the Portuguese.
> Examining the Pilot Charts for this area, however, it becomes clear that the main concern lies in the changes in winds that occur at about the point at which Cape Bojador is passed in sailing down the coast. It is here that the winds start to blow strongly from the northeast at all seasons. Together with the half-knot set of current down the coast, these conditions would naturally alarm a medieval mariner used to sailing close to the land and having no knowledge of what lay ahead. In the end it was discovered that by sailing well out to sea—far out of sight of land—a more favorable wind could be picked up.
> Examining the Pilot Charts for this area, however, it becomes clear that the main concern lies in the changes in winds that occur at about the point at which Cape Bojador is passed in sailing down the coast. It is here that the winds start to blow strongly from the northeast at all seasons. Together with the half-knot set of current down the coast, these conditions would naturally alarm a medieval mariner used to sailing close to the land and having no knowledge of what lay ahead. In the end it was discovered that by sailing well out to sea—far out of sight of land—a more favorable wind could be picked up.