Prusik knot
| Prusik knot | |
|---|---|
|
|
| Type | Clamping knot |
| application | |
| Ashley No. | 1763 |
| English | Prusik |
| List of nodes | |
The Prusik knot , also known as the Prusik loop, is a clamping knot that tightens under load and loosens again when relieved. It is named after Karl Prusik , a music teacher in Vienna who invented it in 1931. In the Ashley book of knots it can be found under number 1763 as a radial used knot, while the Prusik knot for use in the axial direction opened up new areas of application. The technique of ascending a rope with a Prusik loop is called "prusiken". If an ascender is used, one speaks of " jümarn ".
application
Ascent on the rope
The Prusik knot is used by mountaineers, cave explorers, and scouts to ascend on a hanging rope. For this purpose, two climbing loops are used, with a length of about 150 cm, which are alternately pushed up the rope.
Safety when rappelling
When rappelling , it is used as a safety device on the brake rope. The loose Prusik knot is carried by hand when abseiling and gets stuck if the climber lets go of the rope. A prusik is tied around both strands of the brake cable below the descender using an approximately 20 cm long cord . The other end of the sling is attached to the leg loop of the climbing harness. The construct is also called Kurzprusik because it should be so short that the cord cannot slip into the descender and would then have to be removed with great difficulty. To correct the length, the cord is knotted shorter or, in the case of endless loops, thrown through the bay three instead of twice (see below).
Construction of pulleys
In the case of crevasse rescue, a pulley block is built to pull up a climber hanging on a rope (Prusik called the pulley block "St.Bernhard"). The Prusik for the Münchhausen technique is used to rescue oneself from a crevasse .
In the case of rope bridges , the supporting rope is gripped with a Prusik and tensioned with a pulley system before it is attached to the anchor point.
Home and garden
Plants that grow extensively often need support. Bars made of bamboo material and plastic provide stable scaffolding for e.g. B. rubber trees. The attachment of the plant arms to the smooth bamboo can best be done with a Prusik knot. Pulling a smooth stick out of the ground also works with the Prusik knot, which has a good clamping effect on the smooth surfaces. The opposite of driving a plant stick (e.g. beanstalk) into the ground is also possible with a Prusik knot and a foot loop.
Prusik helps on a smooth bamboo stick
Prusik on a smooth iron rod that was firmly in the ground
Loop around the lever arm and the pull can begin
The long iron rod is completely pulled out
Driving a "beanstalk" into the ground with your whole body weight
"
Rope ladder step " (auxiliary solution) as a connection between two different ropes with a double-sided prusik
Knot strength
The knot strength is strongly dependent on the difference in rope diameter and the material and surface properties of the two ropes. The knot becomes firm with a difference in diameter from 1 to 1.5 to 1 to 5; but the greater the difference, the weaker the thin line. A good clamping (wedge) effect occurs only through a smaller rope diameter with which the knot is tied around the standing rope. With a 10 mm climbing rope , an accessory cord with at least 4 mm, max. 6 mm in diameter, or a narrow sling with a width of 12 mm.
Knot science
Knotting the Prusik
You put an endless loop of a thin rope around the thick rope as a loose anchor stitch . Then you drive the long loop around the rope again and put it back through the short bay. If you put weight on the loop, the Prusik knot jams on the rope. If you relieve the loop, the Prusik knot can be moved on the rope.
Endless loop
by the bay
finished
Gripped with one hand with an endless loop
Insert your hand into a hanging / attached loop from above, place a "loose" eye around your thumb, place a second eye in opposite directions with your fingers. Repeat both, then bring your thumb and fingers together and let the “thumb eyes” slide over the fingers. (Or put two eyes on the left and two eyes on the right - in opposite directions - close the Prusik knot with your thumb.
Gerard Hitch
A Prusik-like clamping knot can be tied more quickly if it is tied inwards with the endless loop. This saves you having to push through the loop end several times. As "Gérard-Hitch" by E. Gérard already published in 1922 in La Montagne
Systematics
The Prusik knot is an extension of the anchor stitch .
Alternatives
- The FB-Kreuzklemm , currently the simplest and most effective clamping knot according to tests by Bergwacht Bayern.
- The carabiner clamp knot (Bachmann) is easier to grip and move more easily, the cross clamp knot (Klemheist) for large differences in diameter
- Blake knot , heavier but safer knot in the SZT ( technical climbing )
- The FB tape clamp knot is easier to move and even holds on wire ropes .
- The Swabian clamping knot is a modification of the Prusik knot, it holds securely and can be easily loosened again. It was first documented by the multiple world tree climbing champion Bernd Strasser.
- In seafaring, the stopper is used, which is carried out with a single line instead of an endless loop.
Web links
- 1991: Nylon Highway No. 34 60 Years of Prusik History - PDF (3.32 MB)
- Climber hitches Clamp knots for climbers - PDF (2.41 MB)
- Prusik knot with an additional half knot
- National Tree Climbing Guide 2005 Edition Page 53, Fig. 51 Ascent with Prusik and The secure footlock method . (PDF file; 7.8 MB)
Individual evidence
- ↑ (1929) "Alpine Journal" 41; (1996) "History and Science of Knots" JC Turner p.161 Fig.18.
- ↑ Schwabisch Hitch: How to tie the Schwabisch Hitch Knot. Retrieved September 11, 2018 .