A Step-By-Step Guide to Tying and Using a Prusik Knot

Rock Climber Tying-In to a Climbing Rope
Henrik Trygg / Getty Images

The Prusik knot is a friction knot or hitch that is tied around a climbing rope with a thin length of cord. When a climber’s weight is loaded onto the knot, it tightens and cinches onto the rope. Prusik knots, commonly used in pairs or with another friction knot like a Klemheist knot or ​Bachmann knot, allows the climber to ascend a fixed rope by sliding the knot up the rope.​

Prusik knots are primarily used by climbers in emergency situations when it is necessary to ascend a fixed rope. These situations include lending aid to an injured climber above, ascending up an overhanging face after falling, or extricating oneself after falling into a glacial crevasse. Every climber needs to know how to tie a Prusik knot. With practice, it can be easily tied with one hand, a good skill for emergencies.

You will need a 5-foot length of 5mm or 6mm nylon cord that is made specifically for climbing. Avoid buying spectra cord since it can melt if the knot slips

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First Step to Tie a Prusik Knot

Use a thin cord between 5mm and 6mm in diameter.
Put the loop of thin cord behind the fixed climbing rope. Photograph © Stewart M. Green

To tie a Prusik knot you need what climbers call “Prusik slings,” which are two lengths of thin cord (preferably 5mm or 6mm in diameter). The thinner the cord is in relation to the thickness of the climbing rope, the greater the ability of the knot to cinch onto the rope. It’s best to make the Prusik slings about two feet long, although some climbers like having one of the slings longer. Tie the ends together with a double fisherman's knot, forming a closed loop.

The first step to tie a Prusik knot is to take the loop of cord and place it behind the main climbing rope.

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Step 2: How to Tie and Use a Prusik Knot

A girth hitch is a basic knot for attaching cord or sling to an object.
The second step is the make a girth hitch with the thin cord on the climbing rope. Photograph © Stewart M. Green

The second step to tie a Prusik knot is to take the loop of cord behind the climbing rope and bring half of the loop through the other half of the loop and form a girth hitch.

A girth hitch is a basic knot for attaching a sling or cord to any object, including a tree, piece of climbing gear, or, in this case, the climbing rope. Note that the knot in the small cord is on the outside of the hitch.

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Step 3: How to Tie and Use a Prusik Knot

The more wraps on the rope, the tighter the knot will cinch.
Now you wrap the loop of cord around the rope two or three more times. Photograph © Stewart M. Green

The third step to tie a Prusik knot is to bring the loop of cord back through the girth hitch on the climbing rope two to three more times, forming a barrel with the tail of the cord hanging out from the middle. This is simply done by wrapping the loop of cord through the inside of each previous wrap. After you’re done wrapping the rope, tighten the knot and dress it by carefully arranging all the wraps of cord so they’re next to each other and not crossed.

How many wraps of cord you put on the knot is up to you. Usually, three is sufficient. The more wraps you put on, the more the Prusik knot will cinch onto the climbing rope. It’s best, especially if you haven’t used a Prusik knot much, to test the knot by weighting it. If it slips, add another wrap. If it’s too hard to push up the rope, take away a wrap. If you leave the knot a bit loose, it is easier to slide up the rope.

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Using a Prusik Knot for Ascending

A Bachmann knot slides up the rope more easily than a Prusik knot.
A climber uses a Bachmann knot (top) and Prusik knot (bottom) for ascending a fixed rope. Photograph © Stewart M. Green

Okay, you’ve tied the Prusik knot. Now is the hard part—how to use it.

The Problem With Prusik Knots

The big problem with Prusik knots is that they can grip the rope so tightly that they are difficult to release and slide up the rope, whereas the Klemheist knot and Bachmann knot are easier to release. If your Prusik knot is too tight to push, loosen it by pushing the center loop or tongue into the knot.

Ascending a Fixed Rope

Most of the time climbers will use mechanical ascenders to climb ropes, especially on big walls. But two Prusik knots, used in tandem with one for the right hand and one for the left, are the best way to ascend a fixed rope in an emergency. Many climbers will use another friction knot like a Klemheist knot or Bachmann knot in tandem with a single Prusik knot since the Prusik, as noted above, can tighten up. The top Prusik cord is attached to the belay loop on the front of your harness while the other cord is attached to a longer sling for one of your feet. Some climbers prefer to attach both Prusik slings to the harnesses as well as have foot slings for each foot. Either way, you need to remember to always tie into the end of the rope. Never trust your life to a Prusik knot.

Basic Prusikking Technique

The basic technique of Prusikking is to weight the bottom Prusik knot by standing up in your foot sling. Now slide the barrel of the top Prusik knot up the climbing rope until it’s tight against your harness. Sit down in your harness, tightening the knot and allowing it to bite into the rope. Next, hang from the top knot and slide the lower Prusik knot up the rope until its cord is tight against you. Repeat the process and you’re on your way up the rock. It is not, however, as easy as it sounds. Practice using it first at a small local cliff. Learn how long the cords to your waist and for your foot sling should be.

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Using a Prusik Knot for Rapelling Back-up ad Self-Rescue

Besides ascending a rope, a Prusik knot is also useful as a rappel backup knot and for self-rescue and escaping a belay.

Prusik Knot as Rappel Back-Up Knot

Prusik knots are sometimes used as a rappel backup knot either below or above your rappel device. It is better, however, to use the Autoblock knot for a back-up since it is easier to tie and untie and runs more smoothly as you rappel. The Prusik knot can snag and tighten while you’re rappelling, making it difficult to loosen and slide down the rope.

Use a Prusik Knot for Self-Rescue

Prusik knots are ideal for self-rescue situations where you need to escape from your belay anchors in an emergency situation. For example, you and Joe are climbing a big route in Yosemite Valley. He falls and becomes incapacitated due to a head injury. You can’t lower him to the ground since you’re 600 feet off the ground. What do you do?

  • The first thing you have to do is to escape from the belay so you can render assistance.
  • You hold Joe’s rope in your belay device with one hand.
  • You tie a Prusik knot on Joe’s rope with your free hand.
  • You attach the free end of the Prusik knot to your anchors with a locking carabiner.
  • Now you can transfer Joe’s weight onto the Prusik knot and the fixed anchors rather than have it on your harness and belay device.
  • You are now free to Prusik up to Joe and give first aid or go for help.