Editing Figure-eight knot

{{short description|Type of stopper knot used in sailing and climbing}}
{{About|the [[knot]]|the mathematical concept|Figure-eight knot (mathematics)}}
{{Other uses of|Figure 8|Figure 8 (disambiguation){{!}}Figure 8}}
{{refimprove|date=September 2014}}
{{Infobox knot
| image=Figure-eight knot.svg
| name=Figure-eight knot
| names=figure-of-eight knot, Savoy knot, Flemish knot, double stopper
| type=stopper
| strength=80%
| origin=Ancient
| related=[[Stevedore knot]], [[figure-eight loop]], [[figure-eight follow through]], [[directional figure eight]]
| releasing=Jamming
| uses=General-purpose stopper knot. Replaces the common [[overhand knot]] in many uses.
| caveat=
| abok_number= #420 #520 #570
| conway_notation=2 2
| ab_notation=4<sub>1</sub>
| instructions= [http://www.animatedknots.com/fig8_/]
}}
The '''figure-eight knot''' or '''figure-of-eight knot''' is a type of [[stopper knot]]. It is very important in [[sailing]], [[rock climbing]] and [[caving]] 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-eight will also jam, but is usually more easily undone than the overhand knot.

[[File:Figure eight knot.JPG|thumb|175px|When used as a stopper knot, the figure eight takes a more compact tightened form.]]

{{Quote|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 knot|overhand]], it does not have the same tendency to jam and so injure the fiber, and is larger, stronger, and equally secure.|''[[The Ashley Book of Knots]]''<ref>Ashley, Clifford W. (1944). ''The Ashley Book of Knots'', p.85. Doubleday. {{ISBN|0-385-04025-3}}.</ref>}}

The [[stevedore knot]] is an extension of simple figure-eight knot with an additional turn before the end is finally tightened.

== Different types ==

=== Figure-eight loop ===
{{main|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 ===
{{main|Flemish bend}}
The '''figure-eight bend knot''' is used to "[[Rope splicing|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 ===
{{main|Offset figure-eight bend}}
The '''offset figure-eight bend''' is a poor knot that has been implicated in the deaths of several rock climbers.<ref>{{cite web|author=Moyer, T.|title=Pull Tests of the 'Euro Death-Knot'|date= 2011|url=http://user.xmission.com/~tmoyer/testing/EDK.html}}</ref>

=== Stein knot ===
[[Image:Stein knot AKA stone knot.JPG|thumb|150px|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 [[Abseiling|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==
* In [[heraldry]], this knot is known as [[Savoy knot]].<ref>{{cite book |editor1-last=Turner |editor1-first=John Christopher |editor2-last=Van de Griend |editor2-first=P C |date=1996 |title=History and Science of Knots |url=https://books.google.com/books?id=ODtqDQAAQBAJ&pg=PA390 |location=Singapore |publisher=World Scientific Publishing Company |page=390 |isbn=978-9810224691 }}</ref>
* In the [[United States Navy]], a figure-of-eight badge was formerly worn by enlisted men who had successfully completed the apprentice rating.<ref>{{cite book |author=<!--Staff writer(s); no by-line.--> |title=Uniform Regulations: United States Navy |url=https://books.google.com/books?id=fJQtAAAAYAAJ&pg=PA62 |location=Washington |publisher=United States Navy Department |page=62 |date=1917 }}</ref> 
* In [[The Scout Association]] in the United Kingdom, awards for gallantry and long service are represented by a cloth figure-of-eight knot emblem in various colours.<ref>{{cite web |url=https://heritage.scouts.org.uk/wp-content/uploads/2019/07/Awards-Decorations-and-their-Emblems-of-The-Scout-Association-formerly-the-Boy-Scout-Association.pdf |title=A guide to the Medals and Awards of The Scout Association (UK)  |last=Ford |first=Peter |website=heritage.scouts.org.uk |publisher=The Scouts Heritage Service |access-date=20 April 2020 }}</ref>

==See also==
* [[Figure-eight knot (mathematics)]]
* [[List of knots]]

==References==
{{Reflist}}

==Further reading==
*{{cite book |last=Adams |first=Colin C. |title=The knot book: an elementary introduction to the mathematical theory of knots |publisher=W. H. Freeman |date=1994}}

{{Knots}}

[[Category:Climbing knots]]
[[Category:Caving knots]]