A jackline is a rope, wire or webbing strung from a

ship A ship is a large watercraft that travels the world's oceans and other sufficiently deep waterways, carrying cargo or passengers, or in support of specialized missions, such as defense, research, and fishing. Ships are generally distinguished ...

's bow to stern to which a safety harness can be tethered, allowing a crewmember to move about the deck safely when there is risk of falling or being swept overboard. At sea, falling overboard is one of the leading causes of death in boating; fastening oneself to the ship with a safety harness tethered to a jackline reduces this risk. Generally, the jacklines are run from the bow to the stern on both the

port A port is a maritime facility comprising one or more wharves or loading areas, where ships load and discharge cargo and passengers. Although usually situated on a sea coast or estuary, ports can also be found far inland, such as H ...

and starboard side of a ship. Jack lines are used in heavy weather and in periods of reduced

visibility The visibility is the measure of the distance at which an object or light can be clearly discerned. In meteorology it depends on the transparency of the surrounding air and as such, it is unchanging no matter the ambient light level or time o ...

, i.e. fog or at night. Jacklines may be rigged temporarily when bad weather is expected, or, especially on

sailboat A sailboat or sailing boat is a boat propelled partly or entirely by sails and is smaller than a sailing ship. Distinctions in what constitutes a sailing boat and ship vary by region and maritime culture. Types Although sailboat terminolo ...

s heading offshore, they may be left in place all the time and used as necessary. They are usually attached to strong padeye or cleat fittings at both ends of the boat, allowing the crewmember to move fore and aft by sliding their harness' clip along the line. Jacklines may be made of

wire Overhead power cabling. The conductor consists of seven strands of steel (centre, high tensile strength), surrounded by four outer layers of aluminium (high conductivity). Sample diameter 40 mm A wire is a flexible strand of metal. Wire is c ...

or low-stretch

rope A rope is a group of yarns, plies, fibres, or strands that are twisted or braided together into a larger and stronger form. Ropes have tensile strength and so can be used for dragging and lifting. Rope is thicker and stronger than similar ...

. More recently, sailors are using high strength nylon webbing. The reason is that flat webbing does not roll under foot while working on deck and there is less chance to confuse it with other lines in difficult conditions. This reduces the hazard that can be created by using rope. A jackline is also a rope installed in the luff of a

mainsail A mainsail is a sail rigged on the main mast of a sailing vessel. * On a square rigged vessel, it is the lowest and largest sail on the main mast. * On a fore-and-aft rigged vessel, it is the sail rigged aft of the main mast. The sail's foot i ...

to allow the luff slides to migrate horizontally away from the mast when the sail is reefed. By allowing the slides to migrate, more space is left in the mast track for the upper luff slides to descend, making the operation easier.

References

{{Reflist Sailing rigs and rigging Sailboat components Sailing ship components

See also

References