More details about the The Alpine Butterfly (or Lineman's Loop)
Features: The Alpine Butterfly, or Lineman's Loop, (ABOK # 1053, p 191.) provides a secure loop in the middle of a piece of rope. Load can be safely applied: from the loop to either end of the rope; between the two ends with the loop hanging free; or, to the loop with the load spread between the two ends.
Uses: It is useful anytime a secure loop is required in the middle of a rope. A good example is when a line of hikers wish to hook on along the length of a shared rope.
Tying it: It is commonly tied, as shown, round the hand. To make the process easy, keep the second crossing of your hand near your finger tips and away from the two ends - this is the critical turn which will form the loop. Pick it up, and wrap it round the other two strands. When completed it is best to pull on the loop and both ends to "set" the knot.
Advantages: It is more stable than either the Bowline on a Bight or the Figure of Eight Loop - both of which may roll over. In addition, even after a heavy load, the Alpine Butterfly remains reasonably easy to undo.