The hangman's knot
or hangman's noose
(also known as a collar
during Elizabethan times) is a well-known knot
most often associated with its use in hanging
. For a hanging, the knot of the rope is typically placed under or just behind the left ear. As the blow when the condemned drops to the end of the rope is supposed to break the neck (for modern "long-drop" hangings), this knot can add additional striking force against the head and neck. The knot is non-jamming but tends to resist attempts to loosen it. The knot works because the part of the rope passing straight through it is not entangled in the knot.
The hangman's knot was used on ropes in Colonial America as well as England during the 16th and 18th centuries. It is still used in those US states that employ hanging as a method of capital punishment
Number of coils
Each additional coil adds friction to the knot, which makes the noose harder to pull closed or open. The number of coils should therefore be adjusted depending on the intended use, the type and thickness of rope, and environmental conditions such as wet or greasy rope. Six to eight loops are normal when using natural ropes; more may be used on nylon ropes. One coil makes it equivalent to the simple slip knot
According to popular belief, the hangman's noose must have 13 coils; however, this would make the knot sloppy and almost impossible to handle. Most such nooses only have 6 or 8 coils.
Use in language
The phrase "tightening the noose" refers to knots of this sort; it is used metaphorically to describe encircling military maneuvers, by law enforcement to describe either a physical attempt at surrounding a criminal or the ongoing success of an investigation generally, etc.
A variation of this knot is used in fishing and is called the Uni-knot
. It is used to tie fishing line to terminal tackle, join two pieces of line, or for snelling hooks. It is especially useful when used with slick braided line as more coils can be added to increase the friction of the knot and will not let the knot pull out. It is also useful in that the knot can be pulled down tight to the lure or it can be left with a larger loop that gives the lure more freedom of movement. The hangman's noose can also be used in boating to secure an eyelet
on a rope or sheet without splicing it.