Since you can tie as many butterfly knots as you like on one line, the loop is an easy way to provide several anchors for any given reason. This can be particularly helpful for search and rescue ...

and is relatively easy to untie after it has been loaded by a fall. To tie into a harness with a Figure 8 Follow-through, tie a Figure 8 knot in the rope approximately 3 - 3.5 feet (1 - 1.5 meters) ...

With the right string, make a loop. Pass the left string ... In just a few easy steps, you can master the double knot ...

According to "Climbing: Knots" by Nate Fitch and Ron Funderburke, to tie a knot, there must be a tail or bight of rope to pass through a loop ... use is quick and easy. If you need to secure ...