The Alpine Butterfly Bend. is a knot used to join the ends of two ropes together. It is the analogous bend form of the butterfly loop, in that it is the butterfly loop with the loop cut. The observation that the butterfly loop is secure enough to isolate a worn or damaged section of rope within the loop indicated that the bend form of the knot would be similarly secure.
Safty. A properly tied butterfly bend should be as secure as the equivalent loop form. However, subtle positioning errors during the above shown tying method can result in a similar looking but insecure bend knot.
A study different bends showed that the butterfly bend was the strongest and consistent across different ropes. The study, however, recommended the Double fisherman's knot because the butterfly bend was almost impossible to untie after a significant load of about 1,000 lbs. was applied.