Alpine butterfly knot
From Wikipedia, the free encyclopedia
| Alpine butterfly knot | |
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| Names | Alpine butterfly knot, Alpine butterfly loop, Lineman's Loop, Butterfly Loop |
| Category | loop |
| Origin | Ancient |
| Related | Farmer's loop, Manharness knot, Artillery loop, Span loop |
| Releasing | Non-jamming |
| Typical use | Used by climbers and mountaineers. Can be used to isolate a worn section of rope. |
| ABoK | #331, #1053 |
The Butterfly Loop, also known as the Lineman's Loop or alpine butterfly loop, is a "non-jamming loop on the bight", a loop which may be tied in a rope with two fixed ends, and can take loads on both ends of the original rope, and on the loop. The addition of "alpine" to the name appears to be fairly recent and superfluous.
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[edit] Usage
The Butterfly Loop has a high breaking strength and is regarded by mountaineers as one of the strongest knots to attach climbers to the middle of a rope, such that they have room to move around even when the main rope goes tight, and they can be supported in either direction from the main rope. The loop is typically attached to a climbing harness by carabiner.
It can also be used to isolate a worn section of rope, where the knot is tied such that the worn section is used for the centre of the loop.
[edit] Advantages
- Does not reduce the strength of the rope by very much
- Will not slip (after initial settling)
- Allows for the knot to be loaded three ways (each end of the main line and by the loop)
- Relatively easy to undo after loading (more difficult if wet)
[edit] Disadvantages
- Difficult to adjust the size of the bight
- Difficult to tie one-handed
- Requires some training/practice to master
