on rappel

Rappelling or Abseiling is the skill of descending down a rope. It is actually a simple process, but is fraught with many hazards, some statistics state that about 25% of climbing deaths occur during rappelling, most commonly due to failing anchors or abseiling beyond the end of the rope.

At its core, rappelling is the act of using some sort of friction device or hitch to play out your rope in controlled fashion, under load, so that you can safely descend.

Rappelling is not rocket science, but you have to know what you are doing. The rope has to be properly anchored, you have to be properly attached to the rope and the device you are using to rappel with needs to be properly attached to YOU.

 

self-equalizing anchors

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.

 

prussik knots

“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.

 

ropecraft: tensionless anchors

As I wrote in my “about” page, I used to be a bit of an adrenaline junkie in my youth. One of my pastimes was rock climbing and rappelling. I’ve top roped, lead climbs, slack jumped, Australian rappelled, body rappelled, prusik ascended standing lines…the works. I no longer have the time, friends available or carefree lifestyle to do much of that anymore. I have sold off most of my climbing gear, leaving only enough to rappel if necessary or do a top rope climb. However, I do still enjoy reading and writing about the technical aspects of ropecraft, so every once and a while I will submit a tidbit of ropecraft knowledge.

Tensionless Anchors: Rigging in this fashion uses rope friction around an object to secure the load. This is one of the strongest riggings. It uses almost 100% of the ropes srtength.

As a knot or any tight bend in the rope reduces it’s load bearing strength by a known percentage, the tensionless anchor avoids strength loss by wrapping the line around an anchor such as this tree. In theory, enough wraps would hold the rope in place without being permanently tied to the object…that of course would be stupid, so the rope is tied off to an object to prevent unwrapping.