Tethering device used to keep a surfboard from being washed away after rider and board are separated, usually after a wipeout. Today's surf leash is made from a length of pliant and mildly elastic urethane cord. One end is attached to a thin rectangular nylon rail saver (to keep the cord from gouging into the board's rail), which in turn is connected by a looped and knotted piece of nylon rope to a leash plug sunk into the deck of the surfboard near the tail. The other end is attached to a Velcro strap that loops around the surfer's rear ankle. A small metal swivel is added to each end of the urethane cord to prevent it from twisting and kinking.
Surf leashes come in about eight basic sizes and styles, from light, quarter-inch-thick, six-foot-long "string" or "comp" leashes used on most high-performance shortboards, to sturdy 10-foot cords used by longboards, as well as 1/3-inch-thick, 18-foot "monster cords" used by paddle-in big-wave surfers. Because the leash trails in the water behind the board's wake and cause a small amount of drag, most surfers try to use the smallest and lightest leash possible. Bigger waves require a longer, thicker leash, because the surfer needs to put more distance between himself and the breaking wave while still strapped to what in effect is a flotation device. Added thickness increases the leash's strength.
An early version of the leash was invented in the mid-1930s when American surfboard designer Tom Blake attached a 10-foot length of cotton rope from a belt on his waist to his board; he gave the device up as too dangerous. Other homemade rope-constructed surf leashes were occasionally tried in the '50s and '60s. A French surfer named George Hennebutte invented a double-velcro-strapped "footline," with elastic line and a double-velcro ankle strap, in 1958, but it didn't catch on.
Credit for the invention of the surf leash is usually given to Santa Cruz's Pat O'Neill, son of wetsuit kingpin Jack O'Neill, who in 1970 fastened a length of surgical tubing to the nose of his board with a suction cup, and looped the other end to his wrist. Aside from the leash keeping the board nearby after a wipeout, it was initially thought that the surfer could use the new handheld product to leverage turns and cutbacks; by late 1971, however, the leash was much more sensibly connected to the ankle and the board's tail section (as the Frenchman Hennebutte had done years earlier), and was being sold—first by Control Products and Block Enterprises, both from Southern California, then by dozens of companies world- wide—simply as a board saver. Advertised as safe, the prototype rubber versions were in fact dangerous: Jack O'Neill permanently lost the sight in his left eye in 1971, after his leashed board snapped back and hit his face. Surfers by the thousands were meanwhile making their own leashes from lengths of marine surplus bungee cord.
"To Leash or Not to Leash, That is the Question" was the title of a 1972 Surfing magazine article, and for two or three years the question divided the surf world. Purists correctly noted that leashes encouraged less-skilled riders to try spots they would have otherwise avoided (board-damaging rocky breaks in particular), and that by removing the swim time from the surfing experience, lineups were more crowded than ever. Also, by relying on their leashes, surfers in general were becoming less water-savvy. "Leashes are for dogs" was the unofficial motto of the no-leash group. Leash advocates said it was more fun to surf than swim, and that leashes promoted a freer, more progressive brand of surfing. By 1975 the pro-leash group had won the debate (although it was a few more years before leashes would be used in large waves), and by 1980 it was rare to find a surfer not using a leash.
Leash construction and reliability improved steadily through the years, most significantly in 1975 with the introduction of the Control Products Power Cord, which threaded eight feet of nylon cord inside six feet of rubber tubing and thus limited the amount of tensile stretch; and in 1978, when urethane became the primary material.
A small number of surfers have drowned after their leashes became tangled on an underwater rock or reef (including, in all likelihood, big-wave surfer Mark Foo, at Mavericks in 1994), and leash-recoil is estimated to be the cause of over 10 percent of surf-related injuries. Untold thousands of injuries, however, have been avoided as boards no longer fly spearlike toward shore after each wipeout. Many big-wave riders, furthermore, claim to have saved their own lives after a long wipeout when they were able to use their leash to "climb" to the surface.
Australians call the surf leash a "legrope." Dozens of surf leash synonyms, many of them derogatory, have been used over the years, including "ding string," "surf strap," "shot cord," "shock cord," "power cord," "kook connector," "kook cord," "sissy string," "dope rope," and "goon strap."
Most full-time surfers break between two and 10 leashes a year. A six-foot leash costs about $25. In a 2011 Surfer magazine survey, 99% of respondents said they wore a leash.