Klemheist (Machard, French Prusik) Knot Details
History: The Klemheist is a derivative of the original Prusik knot (on left).
It appears to be identical to the knot described by Ashley for securing a loop to a vertical pole (ABOK # 1762, p 299). However, Ashley did not name this knot and did not describe the slide and grip feature.
Structure: The knot requires a "Prusik Loop" which is constructed by joining the two ends of a length of rope using a Double Fisherman's or a Triple Fisherman's.
Slide and Grip Knots: The Klemheist is a good example of the family of "Slide and Grip" knots. It may be the preferred choice when the load is known to be in one direction only. The Autoblock and the Bachmann perform a similar function but both require a locking carabiner.
Risk: Only pull on the Prusik Loop. Do not grip the knot itself and pull because the knot then slips. Similarly with the Bachmann: don't pull on the carabiner because this quickly releases the grip.
Variations: With these knots the number of turns should be increased or decreased to suit the ropes and the conditions, i.e., before using any Slide and Grip knot, test it to see that it both grips and releases well.
Rope Size: These knots must be made using a rope smaller than the load bearing rope, e.g., 5 or 6 mm cord around the climbing rope. The effectiveness of these knots diminishes as the sizes of the two ropes approach each other.
