Vertical caving terminology and methods > Knots > Common knots
Avoid
A knot tied on a bight. Used to create a loop that can be clipped into a carabiner. Designed to be loaded on only one of its tails, directly away from the anchor, and is considered fairly strong when loaded that way. Can alternatively be loaded in three different directions at once, with two of those directions almost opposite each other, one pointing away from the anchor. Can be used where a traverse line changes direction. Sometimes used as one arm of a Y-hang, because it can be easily adjusted; this variation has the traverse line coming in to one side of the Y. However, this knot has some very serious shortcomings. Cross loading with a fairly low load, such as when someone clips a cows tail into the loop, causes the knot to capsize into a noose based on the figure of 8 knot, so that the loop rapidly enlarges, taking rope from the tail that comes sideways out of the knot. If the wrong tail of the knot is loaded, it can very easily capsize into a noose based on the figure of 8 knot, that tightens around whatever it is tied to, but then releases when the other tail is loaded (which it normally will be). For this reason, although it may be seen as part of a traverse line, it can only be used there if that tail will never be loaded. It must never be used at the start of a rope, to ensure that if it capsizes, it cannot fall off the end of the rope. When used as part of a Y-hang, it is less likely to capsize, since both arms would normally be under load at the same time, which forces the knot to keep its structure. However it can suddenly capsize if someone clips a cows tail into the wrong arm of the Y-hang, unbalancing the Y-hang, and removing the redundancy aspect of it. This might also happen when clipping cows tails into the loop, depending on how much load is applied to it, so neither side is safe. When used for a Y-hang, if the knot has capsized and the anchor that the knot is connected to fails, the knot immediately slips, causing a significant shock load, which competely defeats the safety aspect of a Y-hang. While this knot is sometimes used for rigging, it is a liability, and should absolutely be avoided. There are many better knots to use instead, such as an alpine butterfly knot, but the locked directional figure of 8 might also be a viable alternative. Made from a figure of 8 on a bight with one of the tails performing half a turn less than the other. Just like the figure of 8 on a bight, there is a version that is easier to intentionally untie after loading, and a version that is difficult to untie. The loaded rope should go around the shoulder of the knot (as shown in the illustration), not where the collar of the knot would have been. The rope that comes sideways out of the knot should be the one that would have formed the collar of the knot if it had been a figure of 8 on a bight.
<< Figure of 8 on a bight bend, figure of 8 on a bight rethreaded bend | Locked directional figure of 8, locked incomplete figure of 8 >>
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