AY Honors/Knot/Prusik
Many materials may be used to tie a prusik. The webbing illustrated is one choice, but many find round cord to work better. In many instances, adding more wraps increases the grip.
Applications
In addition to being a useful rope-grab for rope-rescue applications, Prusiks are popular for:
- "Rappel Backup"/"Self-Belay Below The Device": A Prusik is placed below the descender and controlled with the brake hand. It acts as an automatic 'dead man's handle' should the climber be incapacitated or require the use of both hands. Careful setup of the rappel backup is critical, or it will not work. An AutoBloc knot is most widely used in this application. This technique is used by some rappellers, and not by others.
- "Rappel Backup"/"Self-Belay Above The Device": A Prusik is placed above the descender and controlled with the hand not being used as the brake hand. This configuration allows for easier and faster transition from rappeling to climbing the rope, but can also result in the Prusik locking tight as the amount of friction required to hold the load at that point is far higher than that experienced by a self-belay below the device.
- "Prusiking" or ascending the line: Two prusiks used in tandem can be used to climb a fixed rope. One prussik is attached to the "belay loop" sewn onto the front of a harness and the other is attached to a longer length of cord reaching to one foot. With one loop attached to the rope above the other the climber can then stand up in the foot loop, slide the prusik hitch of the waist loop further up the rope and then "sit" down on it. Once sitting, they can slide the foot loop up the rope and repeat the process.
- "Escaping the Belay": In a lead-climbing situation, should the belayed climber become incapacitated in a position where they cannot be safely lowered to the ground, the belayer must escape the belay in order to effect rescue. With the belay rope locked off with one hand, the belayer can tie a prusik to the rope with the other hand, and transfer the load to a fixed anchor; thus allowing them to effect rescue or go get help.
- Various Rescue Applications Rope rescue teams such as in swiftwater rescue or in high angle technical rescue use a Prusik hitch as a 'ratchet' or 'progress capture device'. A prussik with a prussik minding pulley is used to hold a load while tensioning a line. The pulley advances the prussik up the line and prevents it from going back out. This can be used to raise a patient or tension highline for a Tyrolean traverse, or in boat-on-tether and similar rescue operations.
When To carry (climbing)
Prusik cords are carried by some climbers and not carried by others. The decision over whether or not to carry prusiks is a matter of personal taste and training. Prusiks are unlikely to be needed on short climbs where the climber can be lowered to the ground; conversely they may prove useful where the climber cannot be lowered (either due to the height of the cliff or due to a hazard underneath the climber). Contrary to popular belief, prusiks are not the sole preserve of Trad Climbers - Sport Climbers on multi-pitch routes sometimes also carry prusiks.
Prusiks can be improvised from other climbing equipment, such as slings, already carried by the climber. Some climbers carry prusik-specific cords so that they are always easily and quickly available in an emergency.
Some sources recommend that three prusik loops be carried. The logic being that two are required to ascend a rope, and the third allows for one to be lost, damaged, or dropped. Three loops also allow the climber to pass a knot in the rope should the need arise, a difficult task without a third loop.
References
- The Ashley Book of Knots discusses a knot of similar structure in the entry for drawing #1763
External links
- Prusik Knot at OZultimate.com canyoning with good pictures showing how it is tied.
- Prusik Knot used in Sailing for climbing a mast, with other notes.
- Many Varieties of Friction Hitches
- Discussion of Rappel Backups - Pros and Cons
- A detailed article, good pictures, several prusiks and ideas shown.
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