Tacking is a sailing maneuver by which a sailing vessel, whose desired course is into the wind, turns its bow toward and through the wind so that the direction from which the wind blows changes from one side of the boat to the other, allowing progress in the desired direction. The opposite maneuver to tacking is called 'jibe', or 'wearing' on square-rigged ships, that is, turning the stern through the wind. No sailing vessel can move directly upwind, though that may be the desired direction, making this an essential maneuver of a sailing ship. A series of tacking moves, in a zig-zag fashion, is called beating, and allows sailing in the desired direction.