prusiks

Prusiks are friction hitches used on rope systems in climbing, rope access, and rescue work. Named after Austrian climber Karl Prusik, who described the knot in 1931, a prusik consists of a short loop of cord wrapped around a main rope so that it grips under load but can slide freely when unloaded. The hitch is designed to be adjustable along the rope and to tighten when weight is applied.

Construction and operation typically involve tying a loop of accessory cord around the working rope with several turns, usually three to five. The loop is placed around the rope in such a way that the wraps grip the rope when loaded, allowing the hitch to slide when not bearing weight. Variants and similar friction hitches exist, but the classic prusik is distinguished by its use of a loop and multiple wraps to create friction.

Uses include ascending a fixed line, progress capture in rope access, self-rescue scenarios, and as a backup or secondary retrieval method in belay and rappel systems. Prusiks are valued for being simple, reliable, and operational with a variety of rope diameters, provided the cord used for the hitch is appropriately matched to the rope.

Safety and limitations: prusiks rely on friction and are affected by rope diameter, cord diameter, moisture, dirt, and wear. They can be difficult to release if heavily loaded or jammed, and may slip or fail if the rope and cord are not compatible or if the knot is poorly loaded. They should not be relied upon as the sole arrest device in dynamic falls; use within a proper system and with appropriate safety practices.