Friday, December 9, 2011

Knots: Figure-of-Eight

The figure-eight knot is a type of knot. It is very important in both sailing and rock climbing as a method of stopping ropes from running out of retaining devices. Unlike the overhand knot, which will bind iron-hard under strain, often requiring the rope to be cut, the figure of eight can be easily untied after even the greatest strain.
Different types of figure-eight knots


Double figure-eight knot



Double figure-eight knot (figure-eight loop) is used like an overhand loop knot. This type of knot can be used in prusik climbing when used in conjunction with a climbing harness, a climbing rope, and locking carabiner designed for climbing, to ascend or descend with minimal equipment and effort.





Figure-eight splice knot


Figure-eight splice knot is used to quickly and effectively "splice" together two ropes, not necessarily of equal diameter. This knot is tied starting with a loose figure eight knot on one rope (the larger-diameter one if unequal), and threading of the other rope's running end through the first figure eight, starting at the first figure-eight's running end and paralleling the path of the first rope through the figure eight until the second's ropes running end lies parallel against first's standing end. The result is two figure-eight knots, each partly inside the other and tightening its hold on the other when they are pulled in opposite directions. This can be a permanent or temporary splice. While it precludes the ropes' slipping relative to each other, it is a typical knot in having less strength than the straight ropes.


Tying


  • When used as a stopper knot, the figure eight takes a more compact tightened form.
  • Make a bight in a rope
  • Twist it around half a turn away from the working end
  • Bring the working end around from below, then through the loop from above
  • Pull


or like how we remember;


  • Make an alien (create a loop).
  • Choke it (wrap one end around the alien's "neck").
  • Poke it in the eye (push the end through the "alien" loop).

 Among other uses, it's very popular as a "tie in" for attaching the climbing rope to your harness. 

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