Editing Butterfly loop

{{short description|Knot used to form a fixed loop in the middle of a rope}}
{{Infobox knot
| name         = Butterfly loop
| image        = Alpine_butterfly_loop.jpg
| caption      = A butterfly loop with a [[carabiner]].
| names        = alpine butterfly knot, butterfly knot, lineman's loop, lineman's rider
| type         = loop
| origin       = 
| related      = [[Alpine butterfly bend]], [[farmer's loop]], [[artillery loop]], [[span loop]]
| releasing    = Non-jamming
| uses         = Fixed loop on the bight. Isolating a worn section of rope.
| caveat       = 
| abok_number  = #331, #532,<ref name="ashley_note_87">Entry #532 on page 87 of ''[[The Ashley Book of Knots]]'' shows a diagram of the butterfly loop under the name [[harness loop]]. Ashley appears to have illustrated or named the incorrect knot in this case.  The harness loop is shown and discussed as a distinct and specific knot throughout the rest of the book.</ref> '''#1053'''
| instructions = [http://www.animatedknots.com/alpinebutterfly/]
}}

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 [[List of loop knots|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<ref name="On Rope, p. 49"/> and has a symmetrical shape that makes it easy to inspect.<ref name="On Rope, p. 49">{{cite book |title=On Rope; North American Vertical Rope Techniques |edition=New Revised |first=Bruce |last=Smith |year=1996 |location=Huntsville, Ala. |publisher=[[National Speleological Society]] |author2=Allen Padgett |isbn=1-879961-05-9|page=49}}</ref>  In a climbing context it is also useful for [[Traverse (climbing)|traverse]] lines, some [[Anchor (climbing)|anchors]], shortening [[Sling (climbing equipment)|rope slings]], and for isolating damaged sections of rope.<ref name="ACTp73">{{cite book |title=Alpine Caving Techniques; A Complete Guide to Safe and Efficient Caving |url=https://archive.org/details/alpinecavingtech00marb |url-access=limited |last=Marbach |first=Georges |year=2002 |location=Allschwil, Switzerland |publisher=Speleo Projects, Caving Publications International |author2=Bernard Tourte |others=English edition translated and adapted by Melanie Alspaugh |isbn=3-908495-10-5|page=[https://archive.org/details/alpinecavingtech00marb/page/n73 73]}}</ref>

==History==

The earliest known presentation of the knot was in A.A. Burger's 1914 work ''Rope and Its Uses'', included in an [[agricultural extension]] bulletin from what is now [[Iowa State University]].<ref name="aksday80">{{citation|first=Cyrus Lawrence|last=Day|title=The Art of Knotting and Splicing|edition=4th|location=Annapolis|publisher=Naval Institute Press|year=1986|pages=80–81}}</ref>   Burger called the knot a '''lineman's rider''' stating it was often used by "[[Lineman (technician)|linemen]] and especially telephone men". The knot's security and ability to withstand tension in any direction are both discussed.<ref name="Burger1914">{{Cite journal|first=A.A.|last=Burger|title=Rope and Its Uses|pages=24–25|year=1914|url=https://books.google.com/books?id=Ju4sAAAAYAAJ&pg=RA1-PA24|publisher=Iowa State College of Agricultural and Mechanic Arts|journal=Extension Bulletin 24|volume=XIII|issue=8|location=Ames|access-date =2010-09-09}}</ref>

The knot's association with [[mountaineering]]—and with [[butterflies]]—originates from a 1928 article in ''[[Alpine Journal]]'' by C.E.I. Wright and J.E. Magowan.<ref name="hsok-ch9">{{Citation| last=Warner| first=Charles| year=1996| contribution=A History of Life Support Knots| editor-last=Turner| editor-first=J.C.| editor2-last=van de Griend| editor2-first=P.| title=History and Science of Knots| series=K&E Series on Knots and Everything| location=Singapore| publisher=World Scientific Publishing| volume=11| pages=157–160| isbn=981-02-2469-9}}</ref>   The authors claim to have developed the '''butterfly noose''' themselves while attempting to improve the selection of knots available to climbers.   The name is "so styled on the basis of a more or less fanciful resemblance imagined in the form of the knot."  In the second part of the article they express dissatisfaction regarding their earlier use of the word "noose," since the knot is non-collapsing, and refer to the knot as '''butterfly loop''' or simply '''butterfly'''.<ref name="WandM_AJ">{{cite journal |last1=Wright |first1=C.E.I. |last2=Magowan |first2=J.E. |year=1928 |title=Knots for Climbers |journal=Alpine Journal |publisher=[[Alpine Club (UK)|Alpine Club]]|location=London |issue=40 |pages=120–140, 340–351 }}</ref>  Wright and Magowan call the butterfly loop "new," along with several other of their knots, in the sense they were unable to identify any earlier record of them. However, they prudently added that it "might be rash to claim they have never been used before."<ref name="WandM_AJ_140">Wright & Magowan, p. 140.</ref>

[[Clifford Warren Ashley|Clifford Ashley]] presented the knot in 1944 (text & image #1053), calling it the '''lineman's loop'''; he attributed its first publication to J.M. Drew, but made no specific reference as to the source of this claim.<ref name="ashley191">{{citation |last=Ashley |first=Clifford W. |title=The Ashley Book of Knots |year= 1944 |publisher=Doubleday |location=New York |page=191 }}</ref>  A 1912 article called "Some Knots and Splices" by Drew appears in the bibliography of ''[[The Ashley Book of Knots]]''.<ref>Ashley, p. 595</ref>   A 1913 reprint of this Drew article does not mention the butterfly loop.<ref>{{cite journal |last1=Drew |first1=J.M. |year=1913 |title=Some Knots and Splices |journal=Irrigation Age |location=Chicago|publisher=D.H. Anderson Pub. Co.|volume=28 |issue=1 |pages=212–220 |url=https://archive.org/details/irrigationage28federich}}</ref>  Nor does Drew's 1942 book Ropework : Knots, Hitches, Splices, Halters --and presumably earlier edition 1936 (but which has 66pp vs. 58 for 1942?!)-- own book on knots present this knot.  But in his contributed "Chapter 12 Rope Work", pp.202 .. 252 to Lester Griswold's Handicraft does present the knot. (Curiously, Ashley gives no hint that this book which he twice praises contains a full knots chapter written by Drew!)

==Use==
[[Image:AlpineButterflyTwoTwistTyingSequence1200w.jpg|thumb|upright|right|Among high quality knots, the butterfly loop is perhaps the easiest to remember how to tie correctly. Start by simply making two twists in the same direction to form the two loops. Then wrap the outer loop around the standing part and pull it through the hole of the inner loop.]]
[[Image:Alpine butterfly on the bight howto.jpg|thumb|upright|right|Alternate method of formation using wraps on the hand.]]
The loop is typically attached to a climbing harness by 2 [[carabiner]]s together with gates to opposite sides from each other.

It can also be used to isolate a worn section of rope, where the knot is tied such that the worn section is isolated in the loop (which of course does not receive a carabiner nor bear any loads in this case).<ref name="ACTp73"/>  The loop portion is isolated when the other two legs are loaded, and in fact the butterfly can be tied as a bend with the ends emerging where the loop would be.<ref name="pdsmith">{{Cite book|title=Knots for Mountaineering, Camping, Utility, Rescue, etc|last1=Smith|first1=Phil D.|orig-year=1953|year=1955|publisher=Desert Trail|location=Twentynine Palms, CA}}</ref><ref name="budult">{{Citation|first=Geoffrey|last=Budworth|title=The Ultimate Encyclopedia of Knots|location=London|publisher=Hermes House|year=1999|page=77}}</ref>

Errors in tying the butterfly loop can produce a similar looking but inferior knot, the so-called "false butterfly", which is prone to slipping. However, some sources suggest this behavior can be exploited purposely for shock absorption.<ref name="ACTp73"/>   Wright and Magowan called this less secure loop knot the "half-hitch noose".<ref name="WM126">Wright & Magowan, p. 126</ref>

==Advantages==
* Forms stable, secure loop after initial setting
* Allows for the knot to be loaded three ways; by each end of the main line and the loop
* Relatively easy to untie after loading (more difficult if wet){{Citation needed|date=October 2010}}
* Size of loop can be adjusted more easily than with bulkier or more complex loop knots
* Easy to inspect<ref name="On Rope, p. 49"/>
* Can easily be tied with gloves on
* Can easily be tied one-handed

==Disadvantages==
* Difficult to tie around a solid ring or similar object, as when a rethreaded figure eight is needed
* Improper tying can result in similar looking but inferior "false butterfly" knot
* Works best with softer ropes<ref name="On Rope, p. 49"/>

==Variations==
The '''double butterfly loop''' has two non-collapsing loops, allowing for two clip in points, both of which have the same advantages and disadvantages of a single-loop butterfly.<ref name="pdsmith"/><ref name="tossguide65">{{Cite book|first=Brion|last=Toss|title=Chapman's Nautical Guides: Knots|location=New York|publisher=Hearst Marine Books|year=1990|page=65|isbn=0-688-09415-5}}</ref>

==See also==
*[[List of knots]]

== Notes and references ==
{{reflist}}

==External links==
* [https://www.netknots.com/rope_knots/butterfly-knot/ Alpine Butterfly Knot]
* [http://www.animatedknots.com/alpinebutterfly/ Butterfly Loop animation]

{{Knots}}

{{DEFAULTSORT:Butterfly loop}}
[[Category:Climbing knots]]
[[Category:Caving knots]]
[[Category:Knots of modern origin]]