Figure-eight knot

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Figure-eight knot
Figure-eight knot.svg
NamesFigure-eight knot, figure-of-eight knot, Savoy knot, Flemish knot, double stopper
Category Stopper
Efficiency80%
Origin Ancient
Related Stevedore knot, figure-eight loop, figure-eight follow through, directional figure eight
Releasing Jamming
Typical useGeneral-purpose stopper knot. Replaces the common overhand knot in many uses.
ABoK #420 #520 #570
Conway Notation 2 2
A/B notation 41
Instructions

The figure-eight knot or figure-of-eight knot is a type of stopper knot. It is very important in both sailing and rock climbing as a method of stopping ropes from running out of retaining devices. Like the overhand knot, which will jam under strain, often requiring the rope to be cut, the figure-of-eight will also jam, but is usually more easily undone than the overhand knot.

Contents

The figure-eight or figure-of-eight knot is also called (in books) the Flemish knot. The name figure-of-eight knot appears in Lever's Sheet Anchor; or, a Key to Rigging (London, 1808). The word "of" is nowadays usually omitted. The knot is the sailor's common single-strand stopper knot and is tied in the ends of tackle falls and running rigging, unless the latter is fitted with monkey's tails. It is used about ship wherever a temporary stopper knot is required. The figure-eight is much easier to untie than the overhand, it does not have the same tendency to jam and so injure the fiber, and is larger, stronger, and equally secure.

The stevedore knot is the figure-eight knot with two half twists added before the end is finally stuck.

Different types

Figure-eight loop

The 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 bend

The figure-eight bend knot is used to "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.

Offset figure-eight bend

The offset figure-eight bend is a poor knot that has been implicated in the deaths of several rock climbers. [2]

Stein knot

Stein knot Stein knot AKA stone knot.JPG
Stein knot

The stein knot (also known as a stone knot) is a variation of the figure-eight knot. It is used to secure a rope that is already passed around a post or through a ring. It is quick and easy to tie and untie. It is a device rigging rather than a true knot. In canyoneering, it is used to isolate rope strands to allow one person to rappel while another is getting on the rappel, or allow rappellers the option of using a single or a double rope. It is also used in basketmaking.

Symbolic use

See also

Related Research Articles

Knot Method of fastening or securing linear material

A knot is an intentional complication in cordage which may be practical or decorative, or both. Practical knots are classified by function, including hitches, bends, loop knots, and splices: a hitch fastens a rope to another object; a bend fastens two ends of a rope to each another; a loop knot is any knot creating a loop, and splice denotes any multi-strand knot, including bends and loops. A knot may also refer, in the strictest sense, to a stopper or knob at the end of a rope to keep that end from slipping through a grommet or eye. Knots have excited interest since ancient times for their practical uses, as well as their topological intricacy, studied in the area of mathematics known as knot theory.

Butterfly loop Knot used to form a fixed loop in the middle of a rope

The butterfly loop, also known as lineman's loop, butterfly knot, alpine butterfly knot and lineman's rider, is a knot used to form a fixed loop in the middle of a rope. Tied in the bight, it can be made in a rope without access to either of the ends; this is a distinct advantage when working with long climbing ropes. The butterfly loop is an excellent mid-line rigging knot; it handles multi-directional loading well and has a symmetrical shape that makes it easy to inspect. In a climbing context it is also useful for traverse lines, some anchors, shortening rope slings, and for isolating damaged sections of rope.

Constrictor knot

The constrictor knot is one of the most effective binding knots. Simple and secure, it is a harsh knot that can be difficult or impossible to untie once tightened. It is made similarly to a clove hitch but with one end passed under the other, forming an overhand knot under a riding turn. The double constrictor knot is an even more robust variation that features two riding turns.

Sheepshank

A shank is a type of knot that is used to shorten a rope or take up slack, such as the sheepshank. The sheepshank knot is not stable. It will fall apart under too much load or too little load.

Figure-eight loop

Figure-eight loop is a type of knot created by a loop on the bight. It is used in climbing and caving where rope strains are light to moderate and for decorative purposes.

The Flemish loop or figure-eight loop is perhaps stronger than the loop knot. Neither of these knots is used at sea, as they are hard to untie. In hooking a tackle to any of the loops, if the loop is long enough it is better to arrange the rope as a cat's paw.

Zeppelin bend

A Zeppelin bend is an end-to-end joining knot formed by two symmetrically interlinked overhand knots. It is stable, secure, and highly resistant to jamming. It is also resistant to the effects of slack shaking and cyclic loading.

Sheet bend

The sheet bend is a bend. It is practical for joining lines of different diameter or rigidity.

Stopper knot

A stopper knot is a knot that creates a fixed thicker point on an otherwise-uniform thickness rope for the purpose of preventing the rope, at that point, from slipping through a narrow passage, such as a hole in a block. To pass a rope through a block, or hole, is to reeve it. To pull it out is to unreeve it. Stopper knots prevent the rope from unreeving on its own.

Matthew Walker knot

A Matthew Walker knot is a decorative knot that is used to keep the end of a rope from fraying. It is tied by unraveling the strands of a twisted rope, knotting the strands together, then laying up the strands together again. It may also be tied using several separate cords, in which case it keeps the cords together in a bundle. The traditional use of the knot is to form a knob or "stopper" to prevent the end of the rope from passing through a hole, for instance in rigging the lanyards which tension the shrouds on older sailing ships with standing rigging of fiber cordage.

Rope splicing Rope merging

Rope splicing in ropework is the forming of a semi-permanent joint between two ropes or two parts of the same rope by partly untwisting and then interweaving their strands. Splices can be used to form a stopper at the end of a line, to form a loop or an eye in a rope, or for joining two ropes together. Splices are preferred to knotted rope, since while a knot typically reduces the strength by 20–40%, a splice is capable of attaining a rope's full strength. However, splicing usually results in a thickening of the line and, if subsequently removed, leaves a distortion of the rope. Most types of splices are used on 3-strand rope, but some can be done on 12-strand or greater single-braided rope, as well as most double braids.
While a spliced 3-strand rope's strands are interwoven to create the splice, a braided rope's splice is constructed by simply pulling the rope into its jacket.

Ashleys stopper knot

Ashley's stopper knot, also known as the oysterman's stopper, is a knot developed by Clifford W. Ashley around 1910. It makes a well-balanced trefoil-faced stopper at the end of the rope, giving greater resistance to pulling through an opening than other common stoppers. Essentially, the knot is a common overhand noose, but with the end of the rope passing through the noose eye, which closes upon it. It may be multiplied to form a larger knot with more than three bights appearing around the knot. It is the result of implementing a double wall knot in one strand.

Offset overhand bend

The offset overhand bend is a knot used to join two ropes together. The offset overhand bend is formed by holding two rope ends next to each other and tying an overhand knot in them as if they were a single line. Due to its common use in several fields, this bend has become known by many names, such as thumb knot, openhand knot, one-sided overhand knot or flat overhand bend (FOB), though the terms "one-sided" and "flat" are considered incorrect.

Stevedore knot

The stevedore knot is a stopper knot, often tied near the end of a rope. It is more bulky and less prone to jamming than the closely related figure-eight knot.

The bight is given one more half turn than in the former knot [which itself is given, "one additional half twist," more than the figure-eight knot], before the end is finally stuck.

Prusik

A Prusik is a friction hitch or knot used to attach a loop of cord around a rope, applied in climbing, canyoneering, mountaineering, caving, rope rescue, ziplining, and by arborists. The term Prusik is a name for both the loops of cord and the hitch, and the verb is "to prusik". More casually, the term is used for any friction hitch or device that can grab a rope. Due to the pronunciation, the word is often misspelled Prussik, Prussick, or Prussic.

Figure-of-nine loop

The figure-of-nine loop is a type of knot to form a fixed loop in a rope. Tied in the bight, it is made similarly to a figure-of-eight loop but with an extra half-turn before finishing the knot.

Flemish bend

The Flemish bend, also known as a figure eight bend, a rewoven figure eight is a knot for joining two ropes of roughly similar size.

Yosemite bowline Loop knot often perceived as having better security than a bowline

A Yosemite bowline is a loop knot often perceived as having better security than a bowline. It has been pointed out that if the knot is not dressed correctly, it can potentially collapse into a noose, however testing reveals this alternative configuration to be strong and safe as a climbing tie-in.

Bight (knot)

In knot tying, a bight is a curved section or slack part between the two ends of a rope, string, or yarn. A knot that can be tied using only the bight of a rope, without access to the ends, is described as in the bight. The term "bight" is also used in a more specific way when describing Turk's head knots, indicating how many repetitions of braiding are made in the circuit of a given knot.

References

  1. Ashley, Clifford W. (1944). The Ashley Book of Knots, p.85. Doubleday. ISBN   0-385-04025-3.
  2. Moyer, T. (2011). "Pull Tests of the 'Euro Death-Knot'".
  3. Turner, John Christopher; Van de Griend, P C, eds. (1996). History and Science of Knots. Singapore: World Scientific Publishing Company. p. 390. ISBN   978-9810224691.
  4. Uniform Regulations: United States Navy. Washington: United States Navy Department. 1917. p. 62.
  5. Ford, Peter. "A guide to the Medals and Awards of The Scout Association (UK)" (PDF). heritage.scouts.org.uk. The Scouts Heritage Service. Retrieved 20 April 2020.

Further reading