Knot of the Week Video: Learn How to Ascend a Rope Easily With the Prusik Knot - ITS Tactical
 
December 15, 2015Hitches

Knot of the Week Video: Learn How to Ascend a Rope Easily With the Prusik Knot

Knot of the Week Video: Learn How to Ascend a Rope Easily With the Prusik Knot

kotw-prusik-main

Today in our Knot of the Week HD I’ll be going over one of my favorite knots, the Prusik Knot. I refer to the fixed loop that’s created by first tying a Double Fisherman’s Knot as a Prusik Loop and I primarily use it as a backup during rappelling.

By wrapping the aforementioned loop around a larger diameter line, you create a versatile friction hitch that works by gripping the rope and providing friction to support a climbers weight. The Prusik is also referred to as an autoblock, which means that the “knot” can slide freely during a controlled descent, but will bind in the event of a fall; stopping your descent.

The Prusik’s use as an autoblock certainly isn’t the only one, it can also be paired with a second Prusik Loop to ascend a rope as well. The Prusik is used extensively in caving, climbing, rappelling and even rescue operations.

Prusik Knot » Hitches

(Strength: 4/Security: 4/Stability: 4/Difficulty: 4) See below for what these ratings mean.

With a Prusik Knot, it’s important not to use too small of a diameter rope when compared to the main line you’re attaching it to. It can slip if your cordage is too small of a diameter and you never want to use paracord when using the Prusik Knot as an autoblock. The number of wraps around the main line will determine how tight the grip on the rope will be when loaded and more than three wraps is considered excessive.

A pull from either direction on the Prusik Loop will cause it to bind, locking the knot. Another great use for the Prusik is ascending a rope, which can be done with two Prusiks. When Prusiking, one Prusik Loop is attached to a climbing harness and another longer Prusik Loop is attached below that you place a foot into. The technique is to stand up in the foot loop, sliding the harness Prusik up the rope and then sitting down in it. Now just slide the foot Prusik up the rope and repeat.

Depending on the type, some traditional mechanical ascenders can damage a rope and using Prusiks can be a great way avoid that damage and always have a lightweight means of ascending the rope with you. Unlike mechanical ascenders that only grip when downward force is applied, the Prusik can be loaded from either direction to grip.

Ratings

Strength/Security/Stability/Difficulty

Each knot will be assigned a rating from 1-5 (1 representing the lowest score) based on the following four properties:

Strength – All knots will weaken the strength of  a rope, however, there are knots that are stronger than others. The scale here will reflect how strong the rope remains with the specified knot.

Security – The security scale refers to how well the knot will stay tied, and resist coming loose under a normal load.

Stability – Stability refers to how easily the knot will come untied under an abnormal load (i.e. the knot being pulled in a direction it was not intended to) A lower score here represents instability.

Difficulty – The lower the number, the easier a knot is to tie.

Discussion

  • ben butler

    Last KOTW for the year?! There are two more Tuesdays in this year. But really, thanks for posting these. Been a while since I’ve done knotwork.

  • MattQuinterno

    ITS Crew,

    I know you guys post quite a number of videos about knots and climbing. I am also aware you tend to talk about climbing in a hostile or “tactical” environment, however I would suggest looking into how arborists or tree climbers work. As one myself, we have quite awesome methods for ascending vertical ascents and maneuvering around canopies. While everything we do may not apply to the tactical world, I bet there may be good techniques and or equipment which may just have other applications in different fields.

  • vettepilot427

    Brian,
    As a hunter, I think it would be of use to all of us to demonstrate how to create a safety line for a tree stand.  I would enjoy seeing the recommended knot for the main line around the tree and down to the ground.  You could also show this knot tied to the main line will allow you to safely ascend and descend while remaining clipped into your safety harness from the ground to the stand.

    It would be useful to have a video that showed how the knots and lines work together for a reliable and cost effective safety system.

    There are some commercial products, but I find that they are often too short to allow you to be fully attached to the safety system from the ground to the stand.  Also, I would want the ability to choose higher quality ropes for my system.

  • Steller Precision

    ITS,
    Thank you for taking the time to go over knots with us! Here are several comments on this awesome knot that I have used many times as climbing guide, search and rescue (high angle), trimming trees and bow hunting. 
    Once you have completed tying the double fisherman’s it is important to tighten the double fisherman’s as much as possible by standing on one end of the loop and pulling up on the other to make sure the tails of the double fisherman’s do not pull back to far into the knot thus making sure you have plenty of tail on each side for safety. 
    Depending on the diameter of the ascending/descending line and the diameter of the prusik loop will determine how many wraps are needed.  For example, if more friction is needed then add additional wraps as needed for stopping and if less friction is needed, for example a 11mm line with a very pliable 6mm prusik loop, then using two wraps may help with keeping the knot from locking up, but keep at least two wraps on the main line.  
    Before actually doing a rappel, test your prusik out and hang on a main line, preferably just above floor height, to make sure it is not out of arms reach if you were to “fall” or the knot were to lock up on the descent.
    Having a couple extra prusik loops on your harness as back up.  You can use them to tie to the main line as a foot loop to unweight a locked up prusik.
    To unlock the prusik, unweight it then pull on the portion of the double fisherman’s that creates the “little loop” across the wraps.  This allows the wraps to loosen and unlock from the main line.
    Practice with the prusik for descending BEFORE you actually rappel.  They  REALLY work well and lock up amazingly fast!  Important to tend the prusik at all times while descending.
    Thanks again for all your helpful tips!
    Merry Christmas to all!!

  • India_Actual

    FYI, the Prusik line should be 60%-80% of the diameter of the main line to create optimal friction.

  • randallhilton

    Bryan, thanks for TKOTW series!  It’s been decades since I last dangled off the side of a cliff and one day I realized that I had forgotten most of my knots. I stumbled into ITS via TKOTW during my reeducation. 😉  You’re one of the most thorough instructors on the web. 
    Why did I suddenly realize that I need to get all knotted up again? As an EMS (not rescue) first responder I’m keenly aware of how few resources we have if there is a broad scale incident.  Imagine calling 911 and getting an “all circuits busy” message! I realized that I may have to be the rescuer – or be a self rescuer. 

    I’m so impressed with the wealth of information I became a crew leader.  I appreciate what y’all are doing.

    • randallhilton Randall, thanks so much for your kind words and feedback. Knot tying is certainly a perishable skill and one I have to make myself keep up with as well, not just for my needs at work, but life in general. As you said, being prepared is important for anything that may come your way.
      Thanks so much for becoming a Crew Leader as well, your support means a lot to all of us here at ITS.

      Merry Christmas to you and yours,
      Bryan

  • Vern16

    Good ole prusik, that one will save you life…

  • QaisRasooli

    very useful thanks for sharing. each time i watch your video i learn alot. Thanks for all the effort you put into all this.

    Thank you,

    My name is Qais and I am writing from Afghanistan.

  • QaisRasooli

    the double fisherman knot should be close to the prusik knot to avoid and difficulty joining the loop to carabiner

  • India_Actual

    Or, when tying the Double Fisherman’s knot, capture the bottom strand of the loop in the knot. This creates a Prusik loop in which it’s impossible to accidentally load the knot. I don’t have a picture of mine, but take a look at these pre-fab Prusik loops. Where they’re sewn, imagine a Double Fishermans’s instead, and hopefully you’ll see what I’m talking about.

    https://pitchenginelive.blob.core.windows.net/dev/854a04d2-d116-491a-99ea-9f2f1e0132f6/fae7654b-6291-4366-a229-b0f32d1aa9ad.jpg

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