Autoblock vs. Prusik: What’s the Difference?

Rock climbing is a dangerous activity, but some aspects are known as super dangerous. Rappelling, or controlling your own descent down a rope, is one such aspect of rock climbing. Many accidents happen during the descent from climbs, and rappelling is one of the most common ways climbers get down from these climbs.

Luckily, there are some super simple ways to help minimize the risks associated with rappelling! Using a friction hitch, like an autoblock or prusik, can act as a backup and, if used properly, can even catch and hold your body weight if something were to happen to you while you are rappelling. As always, this article is intended to help clear any confusion and is not meant to be the only source teaching you how to use these tools. Please seek help from a qualified professional when learning how to climb.

What is an Autoblock in Climbing?

An Autoblock hitch, also known as a French prusik, is a specific hitch that is used in climbing to act as a third hand or a backup to help keep you safe while you are rappelling or performing any number of different rescue procedures. Although sometimes referred to as a knot, the autoblock is actually a hitch, meaning it would not exist without the rope it surrounds. Its goal is to help keep you safe in the unfortunate circumstance that something bad should happen to you while rappelling.

An autoblock is a multi-directional hitch, meaning that it will catch your weight if you pull up or down. This can serve a number of purposes in rescue scenarios, but it is not particularly useful if you are only using a third-hand hitch as a backup for you when you rappel. The main benefit of using an autoblock hitch is that it is easy to tie.

How to Tie an Autoblock Hitch

In order to tie an autoblock, you need to have the correct type of material to work with. Many climbing companies offer cords specifically designed to tie a friction hitch. The Sterling Hollow Block is the most popular cord on the market but is by no means the only option out there for climbers. You can also create your own using accessory cording and double fisherman’s knots, but this requires more skills and knowledge.

Take your chord and hold the knot if you have a home-tied chord or the bar tack if you have a store-bought cord against the rope you are tying the hitch around. Start wrapping the chord around your rope, making sure to keep all the strands lying flat and smooth as you wrap them down. Once you have a loop of cord tied into a circle around 1 foot in circumference, you can start practicing your autoblock.

When you reach the end of your loop, make sure you have a small loop left to clip your carabiner into. The carabiner should be a locking carabiner and will attach the top loop where your knot or bar tack is to the lower loop at the bottom of your hitch. The carabiner will then attach to the belay loop of your harness.

This is what your final autoblock should look like.

What is Prusik in Climbing?

A prusik hitch is another friction hitch commonly used in rescue scenarios and as a third hand or backup in rappelling. The prusik is a little bit more finicky to tie than the autoblock but is known to be very safe and strong. It, like other hitches, must be dressed properly to be safe and effective, meaning that the strands of the prusik cord are not crossed over one another and are lying flat.

How to Tie a Prusik Hitch

A girth hitch is what is shown at the top of the image above. This useful hitch is often used by non-climbers, although they don’t often know what it’s called. Taking a loop of rope and wrapping it around something else, you simply pull one end of the loop through the other and pull snugly. If you know how to tie a girth hitch, you are well on your way to being able to tie a prusik hitch.

In order to turn a girth hitch into a prusik hitch, all you need to do is keep feeding that initial loop through the same opening, wrapping it around the rope and back through the opening again. Make sure that you get all the strands of your prusik cord to lay smooth and not overlap, so it creates the most friction around your climbing rope.

3 Types of Prusik Hitches

There are tons of different options out there within the category of friction hitches. The three most common friction hitches are the klemheist, prusik, and autoblock. All hitches in this category are considered back-ups or third-hands and are typically used in rappelling systems, although there are many other uses.

1. Klemheist

The Klemheist is the only one of these three that we have not discussed as much in this article, and the main reason for that is that it is not multi-directional, making it slightly less useful and less common than the prusik and the autoblock. The klemheist is a super strong and secure friction hitch, and although it will usually catch well in both directions, it is only intended to be used in the intended direction, either up or down.

2. Prusik

As we’ve mentioned and discussed above, the prusik is a great multi-directional friction hitch. It is commonly used both in rappelling and rescue scenarios. It does take longer to tie than the autoblock and takes more effort to properly dress, but it is a great option nonetheless.

3. Autoblock

The autoblock is probably the most popular of these three hitches since it is so simple to tie, multi-directional, and strong. The more wraps around the climbing rope you put on an autoblock, or any friction hitch for that matter, the more friction you will create and the more grip the hitch will have. Autoblocks are quick to tie and quick to undo when you are done using them.

Pros and Cons of Autoblock and Prusik Hitch in Climbing

While figuring out how to use an autoblock rappelling can be challenging at first, it can also save your life. Regardless of if you choose to use an autoblock, prusik, or klemheist, using a friction hitch is a great thing to incorporate into your climbing practice. Here are some of the pros and cons of using these hitches, particularly when rappelling:

Pros

1. Keeps you safer

Tying a simple hitch can mitigate many of the common risks associated with rappelling. The main pro of using a friction hitch is that it will help keep you safer in the long run. A friction hitch will catch you if you get hit in the head while rappelling, pass out, or get stung by a bee and get distracted.

2. Help minimize the impact of mindless accidents.

Getting distracted and letting go of the rappel strand or getting your fingers pinched and letting go are both causes of mindless accidents that directly result from you not thinking carefully about what you are doing. While a friction hitch won’t prevent these accidents from happening, it will help mitigate the challenges that these accidents pose.

3. Allows for more control on your rappel

Using a friction hitch well can help make tough rappels, such as over a roof, a lot easier. It can take time to get used to rappelling with a friction hitch, but it can actually add a lot of control to your rappels. Rappelling with a friction hitch really can be like having three hands, thus giving friction hitches their common name of a third hand.

Cons

Takes extra time to tie

The only possible con of using a friction hitch in common climbing settings is the time it takes to tie the hitch. Given the amazing pros of using a friction hitch in your climbing and the number of major injuries it can help prevent, we don’t think that the extra 30 seconds it will take to tie the hitch will be an issue. Still, when asked why they don’t use a friction hitch, many climbers will say that it just takes too long. Check out the video below on how to tie an autoblock, a prusik and klemheist hitches.

Wrapping Things Up: Autoblock vs. Prusik: What’s the Difference?

Regardless of if you are using an autoblock, a prusik, a kleimheist, or a completely different friction hitch, we can’t recommend these simple hitches enough! They can be used in so many different situations when climbing and really can be the difference between life and death in a lot of cases. Make sure you take the time to really practice all the hitches and figure out which friction hitch works best for you.