page_title: Square rig
section_title: Sail characteristics
hierarchical_section_title: Square rig / Sail characteristics
caption_attribution_description: English: A picture of a square rigged ship I shot at Ostend, Belgium during the "Oostende Voor Anker"-event (28-30 May 2010). The picture clearly shows that the yards of the vessel move with the wind. This allows the yards to direct themselves better to the wind, and thus increase efficiency of the sails. Note that besides yards, there are also other rigging arrangements that allow the sails to move autonomously depending on the winddirection. An example is the rigging used at the Reaper ship.
context_page_description: Square rig is a generic type of sail and rigging arrangement in which the primary driving sails are carried on horizontal spars which are perpendicular, or square, to the keel of the vessel and to the masts. These spars are called yards and their tips, beyond the last stay, are called the yardarms. A ship mainly rigged so is called a square-rigger.
  The square rig is aerodynamically the most efficient running rig, and stayed popular on ocean-going sailing ships until the end of the Age of Sail. The last commercial sailing ships, windjammers, were usually square-rigged four-masted barques.
context_section_description: On multi-sail, multi-mast vessels, a square-rigged sail is not in fact square or rectangular, but more nearly trapezoidal, being symmetrical but longer in the foot than the head. Like all sails it is three-dimensional, and its curve or belly means that its foot (lower edge) is not a straight line at all. It is fixed to a spar (the yard) along its head, and its clews (bottom corners) are controlled by sheets that are often run to blocks on the spar immediately below the sail.
  Square-rigged ships are still used for training, tourism and ceremonial purposes.
caption: The yards are mounted on the mast in such a fashion that they allow free movement by the wind
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