ABSTRACT
The ancient Greeks had no windmills, and while they used sails on their ships to harness the power of the wind, their knowledge of wind power generally was weak. The Greeks, the Romans and the Vikings used square sails, and steered using oars instead of rudders, which made it hard to keep a straight course when the wind came from the side and avoid drifting away in the direction of the wind. Therefore their ships had large crews – they needed many strong oarsmen and galley slaves to reach a destination within a reasonable time. When winds increased to storm force, the sails were taken down, a simple method of power control. In other words they had respect for the unpredictable and unreliable wind that could turn even the best of ships into disabled wrecks.
