The navigator also had to add any movement of the ship to the side caused by waves or the wind.
VOA: special.2009.12.23
Cloth sails were used to catch the wind to move a ship through the water.
VOA: special.2009.12.23
But if a big gust of wind pushes the ship too far to the left, the solution is not to figure out a way to generate an equally-sized gust of wind to push the ship back in the other direction.