Prusik

Usage

The Prusik is a slide and grip hitch used to attach a loop of cord around a rope, primarily in activities like climbing, canyoneering, mountaineering, caving, rope rescue, and arboriculture. It functions as a friction hitch, allowing the loop to slide easily along the rope when unloaded but locking securely when weight is applied. This makes the Prusik Hitch particularly useful for ascending or descending ropes, securing loads, or performing self-rescue. The term "Prusik" refers to both the loop of cord and the hitch itself, and the action of using it is referred to as "prusiking." Tied by wrapping the loop of cord around the main rope several times, the Prusik is most effective when the cord is smaller in diameter than the rope. Its reliability and ease of use make it a fundamental knot for climbers and rescuers.

Warning

Verify tying technique with a skilled instructor where knot failure could cause property damage, injury, or death.

History

The Prusik Hitch is named for its alleged inventor, Austrian mountaineer Dr. Karl Prusik. It was shown in a 1931 Austrian mountaineering manual for rope ascending. It was used on several mountaineering routes of the era to ascend the final summit peak, where a rope could be thrown over the top and anchored so that climbers could attain the summit by prusiking up the other side of the rope. Although the Prusik Climb technique may be seen as outdated by some, the US Army still includes it in its annual Best Ranger competition. Rangers in the competition routinely make it up a 90 foot rope in under a minute.

Also known as

• Prusik Hitch
• Middle of the Rope Prusik

ABOK

• 1763

Structure

One component of the Prusik Knot is the Prusik Loop. This loop can be made using a short section of rope joined by a Double Fisherman's Knot. Alternatively, the loop may be purchased, already formed, from climbing shops. Due to its symmetric nature, Prusik hitches have the advantage of working in both directions. Most mechanical rope-grabs work like a ratchet, moving freely up the rope, but grabbing when a load is placed down on them. Traditional Prusiks will grab when pulled by the tail, either up or down, and will slide either way when pushed by the barrel.

Strength/Reliability

Prusiks provide a strong attachment that will not damage or break the rope. Prusiks are ineffective upon frozen wet ropes. This is due to the necessity of friction for the Prusik to function.
As a general rule, the diameter of the cord used in these types of friction hitches should be should be no more than 70% the diameter of the primary climbing line. However, this rule of thumb is dependant on the stiffness and type of material used in the cord. The heat generated from friction should also be considered as it can damage the cord.