How to Tie an Autoblock Knot

An Autoblock knot is a friction hitch that can grip in any direction. Climbers and hikers use it for rappelling as a safety back-up knot. It goes below a rappel device and moves down the rope during a descent. It then cinches the rappel rope when the climber stops.

The Autoblock knot is also known as the French Prusik knot.

Quick Tying Guide: Autoblock Knot

Autoblock Knot Step by step

To tie an autoblock knot, wrap the hitch cord around the rappel ropes four to five times. Use up most of the cord during your wraps to create friction. Then, use a locking carabiner from your harness leg loop, clip both ends, and lock the carabiner. Finally, straighten out all the wraps so they’re not crossed.

The Pros and Cons of an Autoblock Knot

The biggest advantage of using an autoblock knot is its added safety when climbing. If the rappeler accidentally lets go of the brake line, the autoblock will immediately grip the rope and stop the descent. 

The cons of using an autoblock knot is that it can easily be released, even under stress. 

Knots similar to an Autoblock Knot

Prusik knot—A Prusik knot is a friction hitch used to attach a loop of cord around a rope. It works in both directions—up and down.

Klemheist knot—A type of friction hitch used for climbing. When weight is applied, this knot grips the rope. When the weight is removed, the rope can move. 

Bachmann knot—This knot is an easy-to-reset friction hitch used in mountaineering. 

Girth hitch knot—The Girth knot attaches to a sling or webbing strap loop to a harness or rope. 
Clove hitch—A strong and adjustable knot that attaches a rope to an object for a short time.

Autoblock Knot

Step 1:

Wrap your hitch cord around your rappel ropes four to five times or until you’ve used most of the cordage.

Step 1a:

Autoblock Knot Step 1a

Step 1b:

Autoblock Knot Step 1b

Step 1c:

Autoblock Knot Step 1c

Step 2:

Autoblock Knot Step 2

Step 2a:

Autoblock Knot Step 2a

Clip both ends of the autoblock hitch cord into the locking carabiner on the harness leg loop. Lock the carabiner to ensure that the cord doesn’t come undone. Lastly, arrange the wraps so they are organized and not crossed.

About the author
Oscar is a freelance writer who writes about traveling, hiking, and the outdoors. In his free time, he enjoys trekking in the mountains and camping in remote areas all across Europe.