Auto Block
Also known as:French Prusik, Machard Knot
Description
A friction hitch used as an auto-locking backup for rappelling. Similar to a Prusik but uses a single wrap with the tail tucked through the loop. Grips firmly when loaded but slides when manually controlled.
Common Uses
Rappel backup (auto-block belay), ascending rope, progress capture in rescue systems.
How to Tie
- 1Take a cord loop and place it around the rappel rope below the belay device.
- 2Wrap the cord around the rope 3-4 times, working downward with wraps parallel and flat.
- 3Pass the bottom of the cord loop through the wraps (like the Klemheist).
- 4Connect the loop to your leg loop with a carabiner. It should slide when pushed and grip when weighted.