only. Because the lateral wind forces are highest on a sailing vessel, close-hauled and beating to windward, the resisting water forces around the vessel's keel, centerboard, rudder and other foils is also highest to mitigate leeway—the vessel sliding to leeward of its course. Ice boats and land yachts minimize lateral motion with sidewise resistance from their blades or wheels. Changing tack by tacking Tacking or coming about is a maneuver by which a sailing craft turns its bow into and through the wind (referred to as "the eye of the wind") so that the apparent wind changes from one side to the other, allowing progress on the opposite tack. The type of sailing rig dictates the procedures and constraints on achieving a tacking maneuver. Fore-and-aft rigs allow their sails to hang limp as they tack; square rigs must present the full frontal area of the sail to the wind, when changing from side to side; and windsurfers have flexibly pivoting and fully rotating masts that get flipped from side to side. Downwind A sailing craft can travel directly downwind only at a speed that is less than the wind speed. However, a variety of sailing craft can achieve a higher downwind velocity made good by traveling on a series of broad reaches, punctuated by jibes in between. This is true of ice boats and sand yachts. On the water it was explored by sailing vessels, starting in 1975, and now extends to high-performance skiffs, catamarans and foiling sailboats. Navigating a channel or a downwind course among obstructions may necessitate changes in direction that require a change of tack, accomplished with a jibe. Changing tack by jibing Jibing or gybing is a sailing maneuver by which a sailing craft turns its stern past the eye of the wind so that the apparent wind changes from one side to the other, allowing progress on the opposite tack. This maneuver can be done on smaller boats by pulling the tiller towards yourself (the opposite side of the sail). As with tacking, the type of sailing rig dictates the procedures and constraints for jibing. Fore-and-aft sails with booms, gaffs or sprits are unstable when the free end points into the eye of the wind and must be controlled to avoid a violent change to the other side; square rigs as they present the full area of the sail to the wind from the rear