The Alpine Butterfly Knot, also known as the Lineman’s Loop, is a secure and symmetrical loop knot formed in the middle, or bight, of a rope. It is utilized in technical fields such as climbing, rescue, and rigging because it forms a fixed loop without needing access to the rope’s ends. This mid-line rigging knot is simple to visually inspect for correctness once tied, making it a preferred choice for creating a mid-rope attachment point.
Unique Advantages of the Butterfly Knot
The Alpine Butterfly Knot is favored over simpler loop knots due to its mechanical properties under load. It can be loaded effectively in three directions: across the loop, and along either of the two main strands of the rope. This multi-directional stability is superior to knots like the Figure-Eight on a Bight, which are designed to be loaded in only one direction. The knot’s symmetry allows it to maintain integrity and strength regardless of the force direction.
A primary benefit is its ease of untying, even after bearing a significant load. Unlike many secure knots that jam tightly, the Alpine Butterfly Knot can often be released by flexing its “wings.” This feature is valuable in rescue or climbing scenarios where time is limited. The knot is also used to isolate a damaged section of rope by forming the loop around the compromised area, allowing the rope to be used while bypassing the damage.
Step-by-Step Tying Method
The hand-wrapping technique is a common method for forming this knot. To begin, hold the rope in front of you and wrap it around your open palm three times, starting closest to your wrist and moving toward your fingers. The three wraps should lie neatly across your palm, with the working strands exiting near your wrist and fingertips.
Identify the middle wrap, which is the second strand lying across your palm. Carefully lift this middle strand and tuck it underneath the strand closest to your wrist, moving it toward the outside of your hand. This action creates a small loop at the base of the wraps.
With the small loop formed, take that same strand and pull it up over the other two remaining wraps, folding it over the top of the hand. Bring the loop completely over the three strands and tuck it through the opening created by the original wraps. This final tuck locks the knot into its distinctive butterfly shape.
Once the tuck is complete, slide the assembly off your hand and begin to dress the knot. Dressing involves pulling on the loop and the two main strands simultaneously to tighten the structure. Ensure that all the strands are lying parallel and neatly, without any crossings or twists. The finished knot should present a clean, symmetrical three-leaf structure, confirming its ability to bear a load from any of the three points.