Climbopedia

Figure eight: Difference between revisions

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{{Infobox knot
{{Infobox knot
| image = File: Fig8.jpg
| image = File: Fig8.jpg
| image_alt = Figure-eight loop
| other_names = Figure 8, eight
| other_names = Figure 8, eight
| pros = Reliable, easy to inspect, low decrease of the rope strength
| pros = Reliable, easy to inspect, low decrease of the rope strength
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}}
}}


The Figure-eight loop is the most used knot for tying-in and one of the two widely accepted knots for tying-in at the end of the rope (the second being the re-threaded bowline).
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The '''Figure-eight loop''' is the most common way how to tie onto the rope. Together with a re-threaded bowline, it is one of the two widely accepted knots for tying-in at the rope end. It is popular for its reliability and visual clarity, which makes it easy to inspect. It can be difficult to untie after bigger lead falls, especially if it was not properly [[#Preventing from getting stuck|pre-tightened]]. Closely related figure-8 bend knot is [[#Rolling|prone to roll]].


== Tying ==
== Tying ==
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This method is the most commonly used method for tying-in onto a rope end.
This method is the most commonly used method for tying-in onto a rope end.


{{#invoke:FlexGallery|gallery_with_widths
{{#invoke:FlexGallery|gallery_with_widths_alt
|File: fig8_step1.png
|File: fig8_step1.png
|90px
|90px
|Take a bight of a rope and turn its one end around the other, making a full 360° turn (1)
|Take a bight of a rope and turn its one end around the other, making a full 360° turn (1)
|rope bight with one end twisted around the other
|File: fig8_step2.png
|File: fig8_step2.png
|90px
|90px
|Pull the rope through the upper eye (2), creating a figure-eight knot
|Pull the rope through the upper eye (2), creating a figure-eight knot
|twisted rope bight with an arrow pointing through the top loop
|File: fig8_step3.png
|File: fig8_step3.png
|180px
|180px
|Pull the rope through both eyes of a harness next to the belay loop (3)
|Pull the rope through both eyes of a harness next to the belay loop (3)
|figure-eight knot with an arrow from the rope end through the harness eyes
|File: fig8_step4.png
|File: fig8_step4.png
|180px
|180px
|Continue by following-through... (4)
|Continue by following-through... (4)
|rope with figure-eight knot, one rope end is pulled through harness and being directed to follow the knot through
|File: fig8_step5.png
|File: fig8_step5.png
|180px
|180px
|... the original figure-eight (5)...
|... the original figure-eight (5)...
|rope with figure-eight knot, one rope end is pulled through harness and being directed to follow the knot through
|File: fig8_step6.png
|File: fig8_step6.png
|180px
|180px
|... knot (6)
|... knot (6)
|rope with figure-eight knot, one rope end is pulled through harness and being directed to follow the knot through
|File: fig8_step7to10.png|180px
|File: fig8_step7to10.png|180px
|Tighten the rope ends one at a time (7,8,9,10)
|Tighten the rope ends one at a time (7,8,9,10)
|loose figure eight tied on a harness, arrows pointing out from the knot
|File: fig8_step11.png
|File: fig8_step11.png
|180px
|180px
|Inspect the knot and check if the loop is threaded through the harness correctly (11)
|Inspect the knot and check if the loop is threaded through the harness correctly (11)
|tightened figure eight on a harness, eye icon
}}
}}


The inspection described in the last step should be also done as a part of the partner check.
The inspection described in the last step should be also done as a part of a partner check.


=== On a bight (tie in in a middle) ===
=== On a bight (tie in in a middle) ===
[[File: fig8_mid_step1.png|100px]]
{{#invoke:FlexGallery|gallery_with_alt|100px
[[File: fig8_mid_step2.png|100px]]
|File: fig8_mid_step1.png
[[File: fig8_mid_step3.png|100px]]
|Take a bight of a rope and do a bend (1)
[[File: fig8_mid_step4.png|100px]]
|rope bight with an arrow
[[File: fig8_mid_step5.png|100px]]
|File: fig8_mid_step2.png
[[File: fig8_mid_step6.png|100px]]
|Make a full 360° turn of the bend around the rope strands (2)
 
|bent rope bight with an arrow around the bight
'''Steps description''': Take a bight of a rope and do a half-turn around itself (1,2). Then pull the bight through the loop made by the turn (3) and slightly tighten the knot (4). If the knot is malformed, dress it properly for easier checking (5) and once finished, inspect the knot (6).
|File: fig8_mid_step3.png
|Pull the bight through the loop made by the turn (3)
|bent rope bight tangled around the rope strands with arrow pointing through a loop
|File: fig8_mid_step4.png
|Slightly tighten the knot (4)
|Very loose figure eight
|File: fig8_mid_step5.png
|If the knot is malformed, dress it for easier inspection  (5)
|figure eight
|File: fig8_mid_step6.png
|Inspect the knot (6)
|dressed figure eight with an eye icon
}}


== Preventing from getting stuck ==
== Preventing from getting stuck ==
Figure 8 tends to get hard to untie in some cases. To prevent the issues, always dress the knot and tie the form where the load strand goes in a bigger diameter around closer to the center of the knot as illustrated below. This variant also has a slightly higher loading limit (10% difference, both variants are completely safe).<ref>{{cite web | url=https://www.lezec.cz/clanek.php?key=841 | archive-url=https://web.archive.org/web/20240226094325/https://www.lezec.cz/clanek.php?key=841 | archive-date=26 February 2024 | url-status=live | title=Metodické ústřižky III. | publisher=EnergyCloud Trade, s.r.o. | first1=''John'' Jiří | last1=Žižka | first2=''Bolek'' Karel | last2=Kříž | date=16 September 2002 | website=lezec.cz | access-date=16 August 2025}}</ref> As well studied and well-documented/illustrated by Hard is Easy,<ref>{{Cite AV media | people= Hard is easy | date=29 August 2020 | title=Why Figure 8 knot is NOT hard to untie! | url=https://www.youtube.com/watch?v=QAr-uHd8h8o | publisher=Hard is Easy | access-date=16 August 2025}}</ref> if the figure 8 is not dressed and tightened properly before loading it, it tends to malform substantially after taking a fall, resulting in a knot which is hard and sometimes even almost impossible to untie. Rope parameters (diameter, stiffness) also play a role. Last very important parameter discovered was if the load strand goes on the top of the knot, or in the middle of the knot.
In some cases, Figure 8 tends to get hard to untie. To prevent this issues, always dress the knot and tie its form where the load strand goes in a bigger diameter around the center of the knot, as illustrated below. This variant also has a slightly higher loading limit according to some sources (10% difference, both variants are completely safe).<ref>{{cite web | url=https://www.lezec.cz/clanek.php?key=841 | archive-url=https://web.archive.org/web/20240226094325/https://www.lezec.cz/clanek.php?key=841 | archive-date=26 February 2024 | url-status=live | title=Metodické ústřižky III. | publisher=EnergyCloud Trade, s.r.o. | first1=''John'' Jiří | last1=Žižka | first2=''Bolek'' Karel | last2=Kříž | date=16 September 2002 | website=lezec.cz | access-date=16 August 2025}}</ref> The issue of figure 8 getting stuck was well studied and documented/illustrated by Hard is Easy.<ref>{{Cite AV media | people= Hard is easy | date=29 August 2020 | title=Why Figure 8 knot is NOT hard to untie! | url=https://www.youtube.com/watch?v=QAr-uHd8h8o | publisher=Hard is Easy | access-date=16 August 2025}}</ref> If the figure 8 is not dressed and tightened properly before loading it, it tends to malform substantially after taking a fall. Malformation leads to a knot state in which the figure 8 is hard and sometimes even almost impossible to untie. Rope parameters (diameter, stiffness) also play a role. Last very important parameter discovered was if the load strand goes on the top of the knot, or in the middle of it.


[[File: fig8_tighten.png|200px]]
{{#invoke:FlexGallery|gallery_with_alt|200px
[[File: fig8_goodstrand.png|200px]]
|File: fig8_tighten.png
[[File: fig8_uglystrand.png|200px]]
|By properly pre-tightening the knot before loading, you minimize the chance of getting it stuck
|hand on a figure eight knot, arrows pointing in direction the rope leaves the knot
|File: fig8_goodstrand.png
|Allegedly slightly stronger variant. It is easier to untie after a fall
|figure eight with one strand highlighted
|File: fig8_uglystrand.png
|This variant is more prone to get stuck after big lead falls
|figure eight with other strand highlighted, warning symbol
}}


== Rolling ==
== Rolling ==
[[File:fig8_roller.png|200px|left]]
[[File:fig8_roller.png|200px|thumb|left|When the ropes coming from the figure&nbsp;8 are pulled in the opposite directions, the knot might capsize and roll over itself|alt=figure eight bent with a warning symbol and arrows illustrating capsizing direction]]
The Figure 8 bend knot can capsize and roll over itself already around 3 kN of force (then it snaps). For that reason it is not an ideal knot for tying two ropes together.<ref name=Edelrid2023>{{cite web | url=https://edelrid.com/eu-en/knowledge/knowledge-base/knots-for-connecting-ropes-when-rappelling-comparison | title=Knots for connecting ropes when rappelling - a comparison | publisher=EDELRID GmbH & Co. KG | first1=Florian |last1=Hellberg | date=14 August 2023 | website=edelrid | access-date=16 August 2025}}</ref> There are speculations that the using of Figure 8 bend knot during rapelling is the reason why overhand-bend knot is known as an European Death knot in US.<ref>{{cite web | url=https://user.xmission.com/~tmoyer/testing/EDK.html | archive-url=https://web.archive.org/web/20250729104327/https://user.xmission.com/~tmoyer/testing/EDK.html | archive-date=29 July 2025 | url-status=live | title=Pull Tests of the "Euro Death-Knot" | first1=Thomas | last1=Moyer | date=11 September 1999 | website=xmission.com | access-date=16 August 2025}}</ref>
The Figure 8 bend knot can capsize and roll over itself already around 3 kN of force (then it snaps). For that reason it is not an ideal knot for tying two ropes together.<ref name=Edelrid2023>{{cite web | url=https://edelrid.com/eu-en/knowledge/knowledge-base/knots-for-connecting-ropes-when-rappelling-comparison | title=Knots for connecting ropes when rappelling - a comparison | publisher=EDELRID GmbH & Co. KG | first1=Florian |last1=Hellberg | date=14 August 2023 | website=edelrid | access-date=16 August 2025}}</ref> There are speculations that the usage of Figure 8 bend knot during rapelling is the reason why the overhand-bend knot is known as an European Death knot in US.<ref>{{cite web | url=https://user.xmission.com/~tmoyer/testing/EDK.html | archive-url=https://web.archive.org/web/20250729104327/https://user.xmission.com/~tmoyer/testing/EDK.html | archive-date=29 July 2025 | url-status=live | title=Pull Tests of the "Euro Death-Knot" | first1=Thomas | last1=Moyer | date=11 September 1999 | website=xmission.com | access-date=16 August 2025}}</ref>


== References ==
== References ==
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