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The Prusik knot (named after Karl Prusik, who invented the knot in 1931) is a clamping knot with which you can secure yourself to a rope with a loop. The Prusik knot wraps itself around the main rope in such a way that it can move freely without strain. As soon as you pull on it, it tightens and holds on to the main rope.
It is used as a safety device and as a climbing aid.
The best rope for a Prusik Knot
The diameter of the rope of the Prusik sling should be less than 70% of the diameter of the rope to which we want to attach the Prusik knot, but at least 30%. Usually you will get a diameter of 4 to 6 mm. The length should be about one meter, but may vary depending on the application.
If the diameter of the rope of the Prusik loop is too small, the knot becomes too tight. If it is too large, the knot becomes too loose, which means that there may not be enough friction.
In addition to the diameter, the texture and flexibility are properties that can influence the knot strength.
Since the knot is held by the friction between the ropes, it is of course preferable if the surface is rough rather than smooth. Good flexibility ensures that the rope can wrap properly around the main rope.
Learn in this article what you have to consider when choosing a climbing rope or check out Amazon directly* for special rope for prusik loops.
How to Tie a Prusik Loop – Double Fisherman’s Knot
With the double Fisherman’s knot you can knot a rope to a loop. This is the first step to make the Prusik knot, because you need the loop first.
Lay the two rope ends on top of each other in such a way that the respective ends point in the opposite direction. Basically, the double Fisherman’s knot consists of two counter-rotating overhand knots which are pulled firmly against each other.
Start on one side by guiding one rope twice around the other. It is important that the second loop goes back in the other direction over the rope. Then you go through both loops with the end through the middle next to the other rope. Now you just have to pull the rope as tight as you can and make sure that a small piece of the rope sticks out at the end. The end result is a cross on one side and the pieces of rope are parallel on the other side.
Now you repeat this in the same way on the other side.
Then you pull the knots against each other so that they are really tight. The tighter you pull the knots against each other, the better. Then the double Fisherman’s knot becomes rock-solid – the knot is designed so that it doesn’t give way during traction, but becomes even tighter.
How do you tie a Prusik knot?
After you have built the loop you can now make the Prusik knot. Put the loop behind the rope and thread the Double Fisherman’s knot twice through the loop. Now pull the Double Fisherman’s knot until the loop is completely closed. Make sure that the individual loops around the rope are parallel to each other so that as much friction as possible can be built up.
How does a Prusik Knot work?
The idea behind the Prusik knot is that it can move freely on the rope without tension, but no longer with tension. The Prusik knot can run in both directions of the rope.
As soon as you pull on the knot, it contracts and creates a high friction so that it does not slip any more.
When do I need the Prusik Knot when climbing?
Originally the Prusik knot was used to climb up a rope. This is also called “prusiking”. You use two of these knots as a ladder and alternately pull one further up.
This technique is always extremely useful when you can no longer climb out of a situation and only have your own rope as a resting point. If you are trapped in a crevasse or have fallen into the rope at an overhang, you can climb up again with the Prusik knot.
The Prusik knot is also used as a brake safety device when abseiling. The climber carries the loose knot on the rope with him. If he lets go, it pulls together, brakes the climber and holds him on the rope.
If you notice that for some reason you can’t go on while abseiling, you can fight your way back up with a Prusik knot.
Practice the Prusik Knot before you need it!
Before you get into an emergency situation outdoors while climbing and have use for the Prusik knot, you should practice it first in a safe environment. Familiarize yourself with his behavior when it is movable and when it is tight. The more often you tie it, the faster and better you will get.
The Prusik knot is a very useful knot. If you regularly go climbing outdoors, you should definitely add this knot to your skillset.
It can help you out of dangerous situations or support you on a climbing route that has turned out to be too long or too difficult. As long as you have one or two loops (or accessory cord) with you, you can always build yourself an emergency ladder and work your way up the rope with ease.
Attention: You have to take care of your safety when climbing! The information on climbtheearth.com only helps you to learn. Before you climb, you should make sure that you have been properly instructed by an expert and that you follow all safety precautions.
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