Monday, 22 October 2012

Figure of 9?

What makes a good knot? it must be easy to tie, easy to untie and not damage the line, finally it must reduce the breaking strain of the rope by an absolute minimum. Remember, when a rope breaks it invariably breaks at the knot! Widely recognised as one of the strongest knots, the figure of 8 is first choice amongst rescue professionals. Unfortunately only 1 out of 10 who claim to be able to tie the knot can do so correctly. Have you ever tied this most basic knot, had it fully loaded and noticed that one or more turns in the knot have been left loose?

The most common of all the knots used in rope rescue. Tied on a single rope it makes an excellent stop knot, more commonly tied on the bight, it forms a secure attachment point. When tied "re-rove" it secures the rope directly to an anchorage point.

The sequence to tieing a good knot is easy, just follow the following order:
  • Choose the right knot for task
  • Tie the knot correctly leaving sufficient tail for a stopper if required
  • Dress the knot, ensuring the lay of the rope is not twisted or crossing over each other
  • Tension the knot, easing all parts snugly together
  • Check the knot visually

The figure of 9 knot, it's just the figure of 8 with an extra turn (8+1=9) hence the origin of its name. The knot is perhaps 1% or 2% stronger than the figure 8. Such a small margin it's not worth worrying about.

Figure of 9 (top view)

We do have figure 9 knots on our rapid deployment kits. The knot is pre-tied and tensioned. It takes a little longer to dress this knot and ensure that none of the lays are twisted.

Figure of 9 Bottom view

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