cable

cable.
1. Basically any very large hemp or wire rope, but normally associated with the anchor of a ship, and thus the means by which the ship is attached to the anchor as it lies on the bottom or is stowed in the hawsepipe or inboard. Originally, all such cables were of hemp, and an early definition of a cable, c.1740, was a hemp rope of 20 inches (50.8 cm) in circumference containing 1,943 yarns—a yarn being rope fibres twisted right handed—although the term was rapidly revised downwards to include any rope of 10 inches (25.4 cm) or more in circumference. By 1780 the general rule for the size of an anchor cable was half an inch (1.27 cm) for every foot (30.5 cm) in beam of the ship; thus a ship with a beam of 60 feet (18.3 m) had a cable 30 inches (76.2 cm) in circumference. Such a size of cable was that normally supplied to a first-rate ship of war; it was tested to a breaking strain of 65 tons, and, in the days when fathoms were used as a measurement of length (and depth), 100 fathoms (183 m/600 ft) weighed 12.5 tons. Chain cable first made an appearance in about 1800 (Nelson's attack on the French invasion vessels anchored in Boulogne in 1801 was frustrated by the use of chain cables by the French ships), but was not introduced into the US Navy until after the War of 1812. In its larger sizes the links of chain cable are studded across the middle to prevent them kinking, and its size is measured by the diameter of the links.

2. A measure of length of cable. The length of a rope cable is 100–115 fathoms (600–90 ft/183–218 m), and a hawser-laid cable 130 fathoms (780 ft/238 m). Studded chain anchor cable is made in lengths of 15 and 7.5 fathoms (90–45 ft/27.4–13.7 m), and is known as ‘shackles of cable’ and ‘half-shackles of cable’ respectively, though before 1949 a shackle of cable used in the Royal Navy was 12.5 fathoms (75 ft/22.8 m) long, eight shackles being considered as a cable length.

3. A measure of distance at sea. In Britain this equates to one-tenth of a nautical mile (6,080 ft/1,854 m) or 608 feet (185 m), but sometimes 100 fathoms or 600 feet. In the USA a cable is 720 feet (220 m).