Alpine butterfly knot is a midline knot that is easy to untie after it has been loaded. The problem with knots that are easy to untie, is they untie easy. We discovered while pull testing this that it slips, though at fairly high forces. We also discovered that if you tie it slightly wrong, it still works... sort of. Learn about this knot in this video and what it can do, can't do and then go have fun and use it.
Paci by Mark Gommers' first PDF available on this website "Knots" has a good section about butterfly knots and page 67 is what we referenced at time stamp 2:00.
Rope Test Lab's detailed article on butterflies. This shows even more use cases than we covered. We tested the "wrong" ways of tying the knot from this article starting at 17:49.
Brent Roth shows how tie a butterfly knot on a double rappel to do an isolated twin system. This is really handy in climbing if one person has a grigri and the other an atc. It's also helpful in getting more people down a canyon if you aren't trying to pre-build in a rescue option with twin releasable options.
The butteryfly knot is #1053 in the Ashley's Book of Knots
Despite the fact we demonstrate it slips, it's generally at high forces and can make for a great bend, or joining two ropes together. It is easy to untie and just like the EDK or Overhand knot, it's important you leave long enough tails. You can see Rope Access Channel demonstrate that in this EPISODE
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***Used 10.0 Beal spelenium static which usually breaks 17-19kn when pulled 8 to 8
Untie Tests - at 4kn and 8kn it was easy to untie
Testing the properly tied butterfly with 8's terminating each end and the butterfly in the middle
16.23kN breaking in the butterfly
14.80kN breaking in the butterfly
15.11kN breaking in the butterfly
Pulling on the butterfly itself and then broke it at the figure 8 on the end at 18.55kN
Slip Tests - some of our tests with the Beal 10.0 static rope slipped once it hit 9kn and to clearly demonstrate the slip effect pulled on 5mm 12 braid dyneema watching it slip at 2kn
If you make a big bite an tie an overhand so you have a loop to clip while passing the butterfly knot, pulling on that loop broke the knot at the butterfly giving us 18.55kN
We got an old rope from the death slabs from Half Dome with permanent butterfly knots to isolate the core shots and it broke at the butterfly at 6.95kN and 8.72kN.
Tied wrong, the butterfly broke at 14.41kN, and 17.63kN. Tie your butterfly correct but these ones held
Ring loading the butterfly broke it at 27.87kN.
Butterfly to butterfly broke one of the knots at 17.95kN
Behind the Scenes
Still tinkering with the format of these videos, this was a test in having a balance between showing the knot and what you can do with it and doing break tests in all those configurations. Since I was going to Prusik Peak, i wrote the script for narrating the video so I could film it there just for fun. I also did additional tests when John Fioroni from ExtremeGear joined me at the lab for a caver's perspective on the knot. @_max_it_out_ got me those half dome core shot ropes 6 months ago. Being that the lab was still in CA and I had so many episodes filmed last time I went there, I couldn't finish this episode until I went back 6 months later. This episode has been in the works almost all year. But that is how most things are, it takes a long while to get ramped up, and then we get to the point to where we can make one knot video a week instead of 2 a year.