Square knot
| Square knot | |
|---|---|
|
|
| Type | connection |
| application | connect two equally thick ends |
| Ashley No. | 74, 1204, 1402 |
| strength | approx. 45% |
| Synonyms | Flat knot, reef knot, herakles knot, weaver flat knot, samaritan knot (Switzerland), reff stitch, double stitch, double knot, weaver knot, right knot (Austrian fire brigade) |
| English | Reef knot, square knot |
| List of nodes | |
The square knot (alternative names: double knot , reef knot , Samaritan knot , weaver knot ) is a knot for connecting two similar rope or thread ends.
history
The knot was known at least in the Neolithic Age. Ötzi's equipment shows a square knot.
The ancient Heracles knot probably corresponds to today's square knot. At that time it was also attributed mystical properties.
Until the revision of the fire service regulation 1 in 2006, the square knot was part of the fire brigade knot in Germany.
use
The square knot is the thinnest of all knots, which is why weavers prefer it to join the threads. He goes so smoothly through the eye of the strand of the heald frame . This is where the name Weberknoten comes from . It is suitable as a tie knot for tying up packages or bundles. Its use as a shoe binding knot is very well known (it is placed twice on top of the slip ). Basically, this knot is easy to learn and perform. It can also be secured with half strokes .
- Reef knot : When reefing a sail, the excess fabric is tied with a square knot.
- Samaritan knot : In bandages, the ends of the triangular shawl are tied with the square knot.
- Tying headscarves
The quality of the connection depends heavily on the material of the connected ends. The square knot is not suitable for connecting two ropes (e.g. climbing or safety ropes), it does not offer sufficient security.
The square knot can be opened either by pushing the ends together or by pulling the two ends of the same bay apart: Then it tips over for the anchor hitch and the other end can be pulled off. When placed on slip , it can also be opened under load.
The square knot has a knot strength of about 45%. When the polypropylene ropes are laid, the knot strength is around 36 to 42%. A braided polypropylene rope achieves a knot strength of 37%. With 0.5 inch diameter double-braided nylon rope, the knot came loose before the rope broke.
criticism
The simple design made the square knot very popular. Nevertheless, many experts consider it unsuitable for connecting ropes, especially when life, health or values depend on it. Even correctly tied, it is only of limited safety compared to other knots, especially with unequal ropes.
- If done incorrectly, the result is an old woman's knot , which is less resilient and difficult to loosen.
- If a square knot is tied incorrectly, the result is a diagonally loaded thief's knot , which “rushes through” under load (the ends are pulled into the knot) and is completely unreliable.
- In the case of one-sided loading (i.e. at both ends of the same sling; this is often the case when the line is previously pulled through a ring or around a pole) it tips over into an anchor stitch , which then loosens easily.
- When connecting lines of unequal strength, the square knot also tends to tip.
- Even with synthetic fiber ropes with their lower friction, the square knot is less reliable than natural fiber ropes .
The standard and reference work Ashley's book of knots also views the square knot skeptically:
“One of the best, but most frequently misused, knots is the square knot or reef knot. As a ribbon knot for reefing or recovering sails or for tying up packages, it is of inestimable value. But as a connecting knot (to tie two ends together) the square knot is likely to have more deaths and injuries than the failure of half a dozen other knots put together. "
For safety reasons, the square knot has also been removed from the fire service regulations.
Knot
The square knot is tied by putting two half knots on top of each other. It should be noted that they have different orientations - i.e. left over right and then right over left (or both vice versa). A square knot has its ends parallel and the knot is flat.
The fact that a square knot tips over to the anchor hitch when the load is incorrect can also be used to "choke": the straight rope is held and the anchor hitch is pushed as far as it will go. The knot is tilted back under tension. If there is strong rope friction, it will not tip back. Then a simple knot secures in the straight rope.
Connection of wires
The square knot is suitable for connecting tension wires (e.g. fences , knots ).
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Wrong way of knotting
- Twisted knot creates an old woman's knot . It is unreliable, can “rustle through” under load (the cords “wander” through the knot until the ends are reached and the knot opens) and, if it does not rustle through, it is difficult to open. On the other hand, a tightened old woman's knot tends to capsize a little less if it is loaded on one side (but it is not capsize-proof either). You can quickly recognize it by the fact that when it is tightened it does not look flat but rather rounded and the loose ends do not protrude parallel, but at an angle to the fixed ones.
- A diagonal load creates the unsafe thief's knot , which looks like a real square knot, but immediately rushes through under load. This knot cannot be created by tying, but it can be created by tying a square knot (if the tied end is first passed around the loose part).
Granny knot
Thief knot.
Art and advertising
The square knot is also shown as a connection symbol in art and advertising.
Stamp of East Germany (1984)
Stone square knot in Prien am Chiemsee
Logo of the G20 summit in Hamburg (2017)
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Alternatives
- Climbers use the teardrop- shaped sack stitch to abseil .
- The figure eight is a secure knot that is easier to open than the sack stitch after a load. Its shape is, however, chunkier.
- The Zeppelinstek is more difficult to knot, but very safe with a slight weakening of the tear resistance . It can still be released even after extreme stress.
- Schotstek and Zeisingstek are more suitable for securely connecting two ropes of different thickness .
- The fishing knot is suitable for connecting wet, slippery ropes .
- The Trossenstek is ideal for heavy and thick rope .
- Surgical knots and choke knots , which do not require a "finger on", are also suitable for tying .
Web links
Individual evidence
- ^ Christian Tröster: Museum guide: Internationales Maritime Museum Hamburg . ( limited preview in Google Book Search [accessed February 4, 2020]).
- ^ Lothar Schott, Manfred Ritter: Fire Brigade Basic Course FwDV 2 . 20th edition. Wenzel-Verlag, Marburg 2018, ISBN 978-3-88293-220-1 , pp. 139 .
- ^ Hugo Glafey (ed.): Textile Lexicon . Concise dictionary of all textile studies. Deutsche Verlags-Anstalt, 1937, p. 895 .
- ↑ Geoffrey Budworth: The best knots for everyday life, leisure and sport . Bassermann, Munich 2005, p. 15 (Original title: The Really Useful Knot Book .).
- ^ Geoffrey Budworth: Knot . Könemann, Cologne 1989, p. 134 (Original title: The Hamlyn Book of Knots .).
- ↑ JC Turner, P. van de Griend (Ed.): History and Science of Knots (= Series on Knots and Everything . No. 11 ). 1996, p. 190 ( limited preview in Google Book Search [accessed March 6, 2017]).