AMGA Certified Rock guide Elaina Arenz shares how to tie and when to use Autoblock, Kelmhiest, and Prusik friction hitches.

Normally when you climb in the gym you want to minimize the number of things clipped to your harness. You won’t need a belay device, PAS, nut tool or any of the other shiny accouterments that you may need when climbing outdoors. They can get hung up on features and volumes, they weigh you down, and can become a falling hazard to you or others spectating below.

However, when you climb outdoors, you need to be prepared for any number of situations that could arise. For example, maybe you need to clean an anchor and rappel down because a storm is rolling in and the fixed hardware is sharp so lowering wouldn’t be advisable. Or perhaps you’ve taken a whipper and are left dangling in space and you need to ascend the rope to get back on.

For these instances and many others you can dream up, there’s one extra item to consider carrying on your harness: a short length of cord and a small locking carabiner that will allow you to make a friction hitch. This simple, easy-to-use tool is like a Swiss Army Knife that can get you out of sticky situations and add security to many climbing systems.

Though these short loops of cord are commonly referred to as Prusik cords, the term Prusik actually denotes one of the three main types of friction hitches you can tie: the Autoblock, the Klemheist, and (of course) the Prusik. We will look at each one in depth, how to tie them, and the best uses and practices for putting them to work for you.

A number of climbing situations may require you to add some friction to the system for example, when you’re rappelling and need a backup on the brake strands, you need to lower a climber from the top of a pitch, or you need to ascend the rope or create a mechanical advantage to haul a load.

Let’s dive into material choice. There are three ways to go: Make your own loop, buy a pre-sewn option, or improvise with what you have on you. I’d recommend you go ahead and splurge on option 2—you won’t regret the decision as most are under $20.

Option 1: Make your own.

Buy a 40-inch length of 5mm cord. Tie the ends together with well-dressed double fisherman’s knots, ensuring that the tails are at least an inch long. Also, once you have your loop, you should be able to comfortably slip it over your head with a helmet on. If you get the length too long, you’ll run into other issues, which we’ll cover a little later.

Option 2: Buy a pre-made friction hitch loop.

Personally, I love the Sterling Hollow Block in the 13.5-inch length. For technical rock climbing, it’s the ideal choice because it’s light and compact. Plus, it has a high melting point, and as you may remember from your high school science class, a byproduct of friction is heat, and heating nylon can cause glazing or even melting of the cord. Lastly, the Hollow Block practically dresses itself and works well with all diameters of climbing ropes.

The Friction Hitches

Below, I’ve presented each of the three friction hitches in ascending order, from light to maximum friction, as well as their most common usages, how to tie them, and their notable pros and cons.

Autoblock: Light Friction

Most common usage: Backing up your brake hand during rappels.

How to assemble: Clip a small locking carabiner to your belay loop and then clip one end of your looped cord into the carabiner. Wrap the cord around the rope 3–4 times (depending on the diameter of your cord and rope), or as many times as necessary for it to bite down, then clip the other end of the cord back into the same locking carabiner.

Pros: Releasable under load, quick to set up.

Cons: Least amount of holding power of the friction hitches.

The Klemheist: Medium Friction

Most common usage: Any time you need more holding power than an autoblock but less than a Prusik; rope grab for ascending a rope and creating a mechanical advantage for haul systems; rappelling with extra weight (like a pack or an injured partner).

How to assemble: Take the bartack or joining knot and scooch it to one end. With the other end, start wrapping the material around the rope strand in the direction of the load. Wrap your cord around the rope 3–4 times and then pass the long end through the short-end loop above the wraps. Clip a small locking carabiner to the long end and pull. Note that the tail of the loop should fold over your wraps and squeeze them together.

Best Material: Sterling Hollow Block or 5mm cord of similar length tied into a loop—or, a nylon sling in a pinch.

Pros: More holding power than autoblock. Works well with cord or webbing like a nylon sling.

Cons: Only works in one direction. It’s directional, which means you need to pay close attention to which tail you fold over. If you do it incorrectly, it will work but is more likely to slip under load.

Three-Wrap Prusik: High Friction

Most common usage: Use this hitch when you need maximum holding power, like a rope grab in a haul system or for self-rescue applications. The plus with the Prusik is that it’s multi-directional so you can move it up or down the rope. The downside is that it’s not releasable under load, therefore not ideal as a rappel backup; it also takes more time to tie than the other hitches, and must be dressed perfectly or it will bind up and you’ll be fighting it every step of the way.

How to assemble: Place the knot/bartack on the rope, then with the opposite end begin carefully looping the cord around the rope and back through the center of your cord three times, making sure that each wrap lies nice and flat and the coils are parallel to one another. Clip a small locking carabiner to the loop emerging from the middle of the wraps. Start pulling. The knotted end will be farthest from the wraps, but shouldn’t interfere with the locking carabiner.

Pros: Multi-directional and has the highest amount of holding power out of the three.

Cons: Not great for rappelling as it isn’t easily releasable under load.

Key Takeaways:

1. Decide how much friction/holding power is necessary for the given task.

2. Dress your friction hitch so all the strands lie nice and clean, and no bartack or knotted ends interfere with the moving parts.

3. Test your hitch before committing to using it. Grab the rope and test if it slides through the wraps. If it slides, add more wraps. If it grabs and puts a slight bend or kink in the rope, then you’re good to go.

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