This excellent bend has all the advantages and disadvantages of the alpine butterfly. It’s quick and easy to tie and holds well under load.
It’s also easy to tie wrong: only use this knot if you’re confident in your ability to tie and inspect it.
It is almost identical to the alpine butterfly, so learning one means learning both.
Ropelab has an excellent article on the alpine butterfly with good information about tying and inspecting it.
1Although it isn’t necessary, we find it helpful to temporarily tie the two ends together with an overhand knot.
2Make a twist in the bight.
3Make a second twist in the bight, going in the same direction as the first.
In both twists, the top rope travels from SW to NE and the bottom one travels from NW to SE.
4Flip the second twist over the first one.
5Pull the center of the second twist under the twist and up through the middle of the first twist.
6Carefully snug the knot by pulling simultaneously on the standing parts and the tails.
If you tied the ends together in step 1, you can untie them now.
This knot doesn’t appear in ABOK.
The alpine butterfly bend is almost identical to the alpine butterfly, which is ABOK # 1053 (Lineman’s Loop).