Butterfly Bend
bend knot
The alpine butterfly loop's whole reputation rests on tolerating load from unpredictable directions without slipping or distorting - a property that riggers eventually adapted into a bend for joining two ropes. Wikipedia frames it as simply the butterfly loop with the loop cut, which is the clearest way to think about it.
The two rope ends are held together from the start and the whole knot is tied around the pair - there is no stage at which one rope is knotted and the other threaded in. The usual published method makes that explicit: join the two ends temporarily, so they behave as a single strand, wind the rope twice around your open hand with the join near your fingertips, fold the join back over the other turns and up underneath them, then slide the knot off and tighten. The temporary join comes off last. An alternative published method simply holds the two ends parallel from the outset and ties the butterfly around the pair.
The payoff is a bend that shares the alpine butterfly's genuine multidirectional load tolerance - useful anywhere the joined ropes might see a load pulling from an angle other than straight along their length, a real limitation of simpler bends like the sheet bend, which are built assuming a more predictable, inline pull.
It remains a specialized, less commonly taught bend precisely because most rope-joining needs don't actually require multidirectional tolerance - a straightforward sheet bend or double fisherman's knot handles the common case fine. The butterfly bend earns its place specifically where load direction genuinely can't be predicted in advance, and it's a knot most people find considerably easier to learn by watching someone tie it than by working from a written description alone.
Rigging crews building a temporary anchor system from multiple rope sections sometimes favor it over the zeppelin bend specifically because the folding technique is already second nature to anyone who regularly ties alpine butterfly loops mid-rope for anchor equalization - learning the bend variant is mostly a matter of adapting a motion already in muscle memory rather than acquiring an entirely new skill from scratch.
Because both ropes are captured inside the same folded-turn structure rather than one rope simply hooking through the other's loop, the finished butterfly bend also tends to sit noticeably bulkier than a sheet bend of comparable rope diameter - a real, felt tradeoff wherever the joint needs to run smoothly through a narrow gap, pulley, or crevice rather than simply hold two ends together in open space.
How to tie the Butterfly Bend
- 1Lay the two rope ends alongside each other, overlapping, and tape or tie them together temporarily so they behave as one strand.
- 2Wind the rope around your open hand twice, positioning the temporary join near your fingertips.
- 3Fold the join back over the other turns, then bring it up underneath them.
- 4Slide the knot off your hand and pull both standing parts to tighten.
- 5Release the temporary join. Check both ends emerge cleanly on opposite sides of the finished knot.
- 6Leave adequate tails on both ropes.
Strength & security
Adapting the alpine butterfly loop's folded-turn construction to interlock two ropes rather than form a single loop gives this bend the same multidirectional load tolerance the butterfly loop is known for - a real advantage when the joined ropes might be loaded from an unpredictable angle.
Cautions: Small positioning errors while tying produce a knot that looks very similar but is not secure - if the finished knot does not look symmetric, untie it and start again. It's also a less common, more specialized bend than the sheet bend or figure-eight bend, and the folded-turn tying method is one most people find easier to learn hands-on than from a written description alone.
Alternatives
- Zeppelin Bend
Both are less common bends prized for jam resistance and load tolerance; picking one over the other usually just comes down to which folding method a given rope worker finds more intuitive.
FAQ
What makes the butterfly bend different from a sheet bend?
It shares the alpine butterfly loop's ability to tolerate load pulling from unpredictable directions, where a sheet bend assumes a more straightforward, inline pull.
Is the butterfly bend hard to learn?
The folded-turn method is one most people find easier to pick up by watching it tied than by reading a description, similar to the alpine butterfly loop it's derived from.
When would I actually need a multidirectional bend like this?
Whenever the joined ropes might be loaded from an angle other than a straightforward inline pull - a genuine but relatively uncommon situation compared with everyday rope joining.
Does the butterfly bend sit bulkier than a sheet bend?
Yes, noticeably, since both ropes are folded into the same interlocked structure rather than one rope simply hooking through the other's loop - a real consideration if the joint needs to run through a narrow gap or pulley.
Can the butterfly bend join ropes of different diameters?
It works best with ropes of similar diameter, since the folded-turn construction assumes both strands behave similarly through the fold - a sheet bend or its doubled version remains the better choice for a significant size mismatch.
Is the butterfly bend commonly taught in general knot courses?
Rarely as a core skill - most general rope courses stop at the sheet bend and double fisherman's knot, leaving the butterfly bend as something climbers and riggers pick up specifically once they already know the alpine butterfly loop it's derived from.