Convert from shackle to smoot

Unit Definition (shackle)
The shackle is a traditional unit of length used for measuring the lengths of nautical cables and chains, especially anchor chains. Anchor chains are formed by using shackles to join short lengths of chain. When the anchor is dropped and the chain runs out, a seaman counting the number of shackles can report the total length of chain deployed. The size of the unit therefore varied somewhat, depending on the length of the short chains used. In Britain, the unit became standardized in the 16th century at 12.5 fathoms (75 feet or 22.86 meters). In 1949, the Royal Navy adopted a length of 15 fathoms, which is 90 feet or 27.432 meters; this brought the British shackle in line with the U.S. unit, which is usually called the shot.

Unit Definition (smoot)
A smoot is a unit of distance (or "length", as physical scientists say) used for measuring the Harvard Bridge. It is named after an MIT fraternity pledge at Lambda Chi Alpha fraternity, Oliver R. Smoot (class of 1962), who in October, 1958 was rolled head over heels by his fraternity brothers to measure the length of the bridge. The smoot is equal to his height (five feet and seven inches -- 1.70 m), and the bridge's length was measured to be "364.4 smoots plus one ear".