page_title: Sailing
section_title: Changing tack by tacking
hierarchical_section_title: Sailing / Course under sail / Upwind / Changing tack by tacking
caption_attribution_description: English: The yacht Canada (left), skippered by Aemilius Jarvis, crosses tacks with Vencedor on Lake Erie, near Toledo, Ohio, in the 1896 match-racing series from which Canada emerged the victor.
context_page_description: Sailing
  employs the wind—acting on sails, wingsails or kites—to propel a craft on the surface of the water, on ice or on land over a chosen course, which is often part of a larger plan of navigation.
  A course defined with respect to the true wind direction is called a point of sail.
  Conventional sailing craft cannot derive power from sails on a point of sail that is too close into the wind. On a given point of sail, the sailor adjusts the alignment of each sail with respect to the apparent wind direction to mobilize the power of the wind. The forces transmitted via the sails are resisted by forces from the hull, keel, and rudder of a sailing craft, by forces from skate runners of an iceboat, or by forces from wheels of a land sailing craft to allow steering the course.
  In the 21st century, most sailing represents a form of recreation or sport. Recreational sailing or yachting can be divided into racing and cruising. Cruising can include extended offshore and ocean-crossing trips, coastal sailing within sight of land, and daysailing.
  Until the mid of the 19th century, sailing ships were the primary means for marine commerce; this period is known as the Age of Sail.
context_section_description: Tacking or coming about is a maneuver by which a sailing craft turns its bow into and through the wind (called 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.
caption: Two sailing yachts on opposite tacks
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