Disclaimer: I’d like to make sure it’s understood that these are in no way to be taken as qualified instruction. I suppose that technically I should classify these as ‘reminders’, but it is possible to learn from them… Just make sure you check with someone that actually knows what they’re doing before you try and do them halfway up a cliff.
The alpine butterfly was designed for use in the Alps (shock), where teams of people need to tie into the same rope. It has several advantages for this use, the biggest one being that it can be loaded in any combination of the three possible directions, with the same strength in any possible way. It also resists jamming when heavily loaded. It’s a good knot. This is one of the ways of tying it, and I find it the easiest to keep track of. It has another benefit that we’ll get to later.
Start by taking a nice big bight of rope.
Twist the bight.
Twist it again, so that there’s an eye in the middle.
Pass the end of the bight underneath the entire thing, taking care not to move the eye with it.
Pass the end of the bight over the knot and down through the eye.
Pull all the lines tight to seat the knot.
This way of tying the alpine butterfly can also be used to tie the butterfly bend, joining to ropes. I’m not going to put instructions for this, as it’s precisely the same as for the standard knot. The only difference is that you have two tails, rather than one bight. Make sure the tails are a good length (1-1.5m at least) for joining ropes.