User:ThoughtIdRetired/Sandbox/Square rig

Square rig is a type of sailing rig that has square sails as the main type of sail. A square rigged ship or boat may have just one square sail on a single mast, or there may be several masts – some or all of which carry square sails. Square rig usually involves some use of fore and aft sails, both intermixed with square sails on one mast or sometimes on masts that are solely fore and aft rigged.

Square sails, when at rest and viewed in plan view, are positioned at right angles ("square") to the centre line of the hull. This is different from fore and aft rig, where the at-rest sails lie roughly in the same vertical plane as the hull's centre line. As a result, a square sail has a front and a back surface, with only one surface facing the wind when the ship is moving ahead in a normal fashion. Similarly, the edges of a square sail are left and right (port and starboard). In contrast, a fore and aft sail has front and back edges and left and right surfaces.

Generally, square rig is controlled with more lines than fore and aft rig, so it usually needs a larger crew. It is a common misconception that square rigged vessels are less manoeuvrable than comparable fore and aft rigged vessels; generally square rig gives better manoeuvrability, not least because of the ability to back a sail to alter speed. Square rig has been greatly preferred to fore and aft rig for long downwind passages, largely due to the risk of an accidental gybe with fore and aft.

Different forms of square rig have existed at different times. The modern form relies on steel wire rigging and, often, metal pole masts. This enables higher loads in the rig and so bigger ships (which probably also have iron or steel hulls). The use of iron or steel standing rigging and masts became common from the middle of the 19th century onwards. Before then, natural fibre ropes required a lot more maintenance, with the tension of the rigging needing constant monitoring and, when necessary, adjustment.

The operation of older versions of square rig was different from the 19th and early 20th century forms. For example, in the 16th century, all the yards were hoisted and lowered in the normal operation of setting and handing sail. The 19th century ship would have the larger yards semi-permanently fixed in position. Instead of using reefing to reduces sail area, the 16th century ship usually used bonnets – extra pieces which laced onto the bottom of the sail to increase the area. Instead of reefing, the bonnet can be removed. This practice had disappeared by the 19th century. In the classical antiquity period the Mediterranean square rig had some distinctive characteristics

Turn this last paragraph about and put oldest first. Mention the transitional 15th century in which the full rigged ship originated.