The prusik loop guide has some basic criteria to follow for choosing the right size of cord to use when you are making prusik loops.
Prusik Loop Material Guide
Prusik loop material should be approximately 60% to 80% of the standing line diameter. If the hitch is too small, the hitch will be tight, making it difficult to free and then move the loop. If the diameter is too large, the hitch will not tighten up enough to grip and will slip.
Flexibility is important. A cord that is too stiff will not allow the hitch to tighten enough to grip the standing line. In life safety applications such as rescue and belays, many authorities recommend the use of two tandem triple wrap Prusik hitches. Many authorities suggest using 8mm cord for 1/2″ rope and 7mm cord for 7/16″ ropes.
It is ultimately your responsibility to determine, select and use accessory cord and rope combinations that will work reliably in any life supporting situation, taking into account your experience, level of training and environmental conditions.
More about the Prusik Knot
The Prusik knot is a friction hitch commonly used in rope rescue, mountaineering, climbing, canyoneering, and more. It is easy to make on the go, making it a go-to knot for enthusiasts and professionals alike. In this guide, we will explain how to make a Prusik hitch and different ways to apply it in your adventures.
How to make a prusik knot
- First, you’re going to need to tie the ends of your rope together so you have a loop to work with. Lay the ends parallel and pointing away from one another. Create a double fisherman’s knot by coiling one end of the rope twice around the other piece of the rope lying next to it. There should be an X formation on one side and two diagonal lines on the other side. Pass the free end back through the coils under the X so that it forms a knot. Repeat this process for the other end of the rope.
- Pull the long sides of the rope next to the knots so the knots come together. At this point, you should have two X’s next to each other on one side and four diagonal lines on the back of that.
- With your static loop created, you can set up a Prusik hitch around the line you’re attaching to. Put the loop behind the line and pull the double fisherman’s knot through the loop. Wrap on the inside of the loop three times and pull through tightly. At this point, you should have a line running through the knot, and the knot should look like three lines, the pulled-through loop, and three more lines. The back should look like six vertical lines running next to each other with a long horizontal line on top.
How a Prusik Knot Works
Prusik knots are designed to move freely on a line as you climb. When they are not put under intense force or friction, they can slide up and down with ease. If the end of the rope is pulled suddenly, the friction of the knot will create enough tension to hold the load in place (you, a bag, another person, etc.). Prusik hitches are bidirectional, meaning that they can move forward or backward along the line without any issues. Some knots are designed to only go in one direction.
How and When to Use a Prusik Knot
There are many applications for Prusik knots. In rappelling, they can act as an autoblock to hold a climber in place when he needs to use both hands or in the event of an emergency. Climbers can use two Prusiks along a fixed rope to ascend or descend. The lower knot acts as a foot loop while the top one is controlled by the hands.
Prusik hitches are easy to make for an emergency, as long as you have the right size rope for the job (see next section for details). You can attach a carabiner to the loop of the knot to attach to your harness or another person in a rescue mission. Make sure you attach the carabiner to the actual rope, not the double fisherman’s knot. You may need to adjust the rope’s positioning slightly so that the barrel knot isn’t directly in the center of your loop.
Choosing the Right Rope for a Prusik Hitch
In order for a Prusik knot to create tension, the rope used to make it needs to be the right size and material. As a general rule of thumb, the diameter of your Prusik loop material should be 60% to 80% of the standing line diameter (about 2/3rds). If you use a rope that is too thin, it will tighten easily along the line and will be difficult to move freely. If you use a rope that is too thick, it will not have enough friction to lock up when you need it to.
In addition to choosing the right size of rope for your Prusik loop, you need to choose the right material. If the cord is too stiff, it will not be able to tighten quickly enough to anchor itself into the line. The stiffness may also make it difficult to create the loops for the knot itself. To be on the safe side, test the rope you plan to use before you take it climbing so you can make sure it will protect you at all times.
Pre-Sewn Prusik Loops: A Non-Knot Alternative
No matter how well a knot is tied, it has the potential to come undone. A worn part of the rope or basic human error may cause the knot to slip when it is not supposed to. While this is usually not the case with a Prusik hitch, it is something to be wary about during a life-or-death situation like rappelling from a high cliff or rescuing an injured person.
If you are planning to use your Prusik frequently for these scenarios, you may consider buying some pre-sewn Prusik loops. These are especially beneficial for Prusik minding pulleys. The knots themselves are sewn together to make them sturdier and far more durable. The stitching is covered by a plastic sleeve to protect the knots from abrasion, making the system last even longer. For more information or to find materials to make your own not, check out the Prusik cord options here at Rock-N-Rescue.