A handy ropecraft skill to have is knowledge of how to set-up self-equalizing anchors. Many times while you are climbing or rappelling you will find that there are few solid “single-point” anchors available. Instead of a large, deeply rooted Oak tree you find that you have 2-4 smaller trees that just don’t leave you feeling confident. Or you could be setting up a belay point 800′ up with a series of cams or chocks being the only thing between a secure belay and screaming death. In these situations you will want to share the load between these anchors so that each of them is receiving only part of the load. You also want a system that will hopefully survive if one of your anchor points fail. Most self-equalizing set-up’s share the characteristics of the simple 2 anchor system I have illustrated below.
The first thing you do is take a loop of cord, rope, or tape and form a figure-eight. You then take a locking carabiner and clip it across the crossover point.
Two more “biners” get clipped to either side of the “eight”.
The two “anchor biners” are then attached to your anchors and the load is placed on the center carabiner. This splits the load forces equally between the two anchor points. If you have set your system up properly and one of the anchors fails, the center biner is still attached to the loop and will hopefully remain attached to your remaining piece of protection.
“Prusik” is a word that describes a knot and the action of ascending a rope using a “Prusik System”. Named after it’s inventor, Dr. Karl Prusik, the Prusik Knot is a friction hitch that allows a climber to ascend a standing line.
The Prusik is tied by wrapping a cord around the standing rope a number of times (usually 3-5 ), and then back through itself. This forms a barrel around the rope with a tail hanging out the middle. When the tail is weighted, the turns tighten and make a bend in the rope, securing the knot into place and allowing the climber to place his/her weight on the knot. When weight is removed, the loop can be moved up or down the rope by placing a hand on the barrel and pushing. Breaking the Prusik free from the rope after it has been weighted can be difficult and is easiest done by pushing on the “bar”. This unwinds the wrap to loosen the grip of the hitch, and allows the climber to move the knot.
A basic “Prusik System” is two knots. One knot which the climber attaches to his/her harness. This lets the climber “sit” on the standing rope. The second knot is placed above the first knot. The climber places his/her foot into the tail on this knot and uses it to “push” his/her weight up the standing line. The process is a “leapfrog” affair where the climber “steps” up on the “foot knot”…pulls up on the “sit knot”….sits on the “sit knot” and pushes the “step knot” further up the rope.