How to tie the Autoblock Knot. The autoblock knot is a rope device that serves as a safety knot during rappelling. The autoblock is often made using a friction hitch which can slide freely over the rope during a controlled descent. But the knot will jam in the rappel device in the event of a sudden drop which will stop the decent. Always use an autoblock knot on the rope as a safety backup when rappelling.
Scroll to see Animated Autoblock Knot below the illustration and tying instructions.
- Wrap your Autoblock Hitch cord four or five times around the rappel ropes. Use a thin cord such as 5mm or 6mm static cordage. Use up most of the cord on the wraps. The more wraps that you use, the more friction generated.
- Then clip both ends of the cord into the locking carabiner on your harness leg loop. Lock the carabiner so the cord can’t come undone. Finally, arrange all the wraps so they’re neat and not crossed.