Running rigging refers to the lines on a boat or ship, usually made of rope, which are used to adjust the sails. While the standard rigging of a boat is typically checked and adjusted before setting sail and then left in that position, running rigging is frequently adjusted while under sail to change the positions of and tensions in the sails to change direction or speed. These lines may control the sails directly, as do those which are attached to the sails themselves, or indirectly, as do lines attached to the boom.
The complexity of running rigging spans a wide range and depends on the size and type of vessel on which it is used. It may be relatively simple for a single-mast sloop used for recreational cruising as compared to the more complex rigging of a racing boat or larger vessel with multiple masts and several sails. Custom equipment may supplement standard equipment on racing boats to optimize sail positions and tensions and to help speed the process of raising and lowering running rigging.
Some lines, such as halyards and sheets, are used to control the sails directly. Attached to the top corner, or head, of each sail is a halyard that is used to raise and lower it. A sheet is used to position the movable corner, or clew, at the foot of a sail. An outhaul is attached to the clew of the mainsail and can be tightened to flatten the lower portion of the mainsail. In inclement weather, a reefing line is used to reduce the area of the mainsail to better control the boat.
Other lines control the sails indirectly. For example, the boom vang, also called the kicking strap, is a line and pulley system that runs from the bottom of the mast to the boom. It is used to flatten the mainsail, to prevent it from twisting, and to prevent the boom from lifting in an uncontrolled manner, particularly in the event of an accidental jibe in which the boom swings unexpectedly to the other side of the vessel.
Factors that a sailor might take into account in selecting sailboat running rigging include cost, quality and reliability, performance, and how it will be used. For example, a well-funded racing vessel might be outfitted with custom, high-performance equipment of significant cost. A small, recreational boat for day sailing might have simple and inexpensive running rigging. Reliability and quality might be high priorities for distance cruisers traveling to remote areas where repair or replacement of equipment would be difficult or impossible.
Failures of running rigging are often related to the conditions under which it is used. Lines may be degraded because of prolonged exposure to the harsh environment of salt water and ultraviolet light from the sun. They are also vulnerable to wear from abrasion, both between the line and the hardware with which it makes contact on the boat and between the fibers of the line and salt or dirt particles that may have worked their way into the line. When a line is knotted or bent around a piece of hardware, uneven load distribution among the fibers is also a concern. Such uneven loading may significantly reduce the strength of a line.
