Bob Wightman

The Prussik Knot

The Prussik knot is the best known of a family of knots that are used to attach a moving "clamp" to another rope. This clamp may be used to either ascend the rope or provide a form of backup when abseiling. Easy to form, it has been superceded in recent years by its more advanced cousins.

Attribute Notes
Ease of Tying Very easy to tie.
Recognisable Very good in this respect.
Also known as None known.
Usage Security whilst abseiling. Ascending ropes. The Prusik (and its variations) are the only method that permits the ascending of double or twin ropes, all mechanical devices work on single ropes.
Advantages Simple, easily understood.
Disadvantages Can jam under load. Cannot be moved whilst under load.