The Oxford English Dictionary has the first reference to a sheepshank knot in 1627, used to shorten the fall of a tackle. It was also called a dogshank. An animal's shank has two bones plus a long tendon--three long parts.
The knot had another use that a lot of people don't know about. Here, shortening the rope was incidental. You know that the knot holds under tension; shake it a few times and it falls apart. But when it's under tension, you can cut any one of the three component lengths of rope and the knot will still hold--as long as it's under tension.
So, someone working on a high place and needing a safety line--a church steeple, say, or someone who had to lower himself off a cliff, or ford a river, and who didn't have enough rope to double it over a high block/limb/beam/whatever, could tie off the rope at the top and still recover all but a couple feet. He would make a sheepshank just below where the top end was fixed, cut any one of the three strands, lower himself when the work was done and shake the knot loose from below.
Then maybe go home and have a nice leg of mutton.
John V.
|