{"id":332,"date":"2024-12-31T08:19:54","date_gmt":"2024-12-31T08:19:54","guid":{"rendered":"https:\/\/swarm.craa.cz\/?p=332"},"modified":"2025-08-23T09:51:20","modified_gmt":"2025-08-23T09:51:20","slug":"strength-tests-of-the-polish-knot","status":"publish","type":"post","link":"https:\/\/swarm.craa.cz\/en\/strength-tests-of-the-polish-knot\/","title":{"rendered":"Strength tests of the Polish knot"},"content":{"rendered":"
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Year 1, Issue 1, 2024
swarm.craa.cz, ISSN 3029-7508
Safety, Work And Rescue Magazine
Pages 22-27, https:\/\/doi.org\/10.71319\/swarm2401.22-27<\/p>\n<\/div>\n\n\n\n

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\"Strength<\/a><\/figure><\/div>\n\n\n<\/div>\n<\/div>\n\n\n\n

Strength tests of the Polish knot<\/strong><\/h1>\n\n\n\n\n\n

Ond\u0159ej Belica<\/strong>1<\/sup> <\/strong>\"\"<\/a><\/sup>, Jan Smolek<\/strong>2<\/sup><\/strong><\/p>\n\n\n\n

1<\/sup> CRAA \u2013 Institute of Occupational Safety at Heights; obelica\"SWARMlezectvi.cz
2<\/sup> Czech Speleological Society \u2013 ZO 6-07 Ti\u0161novsk\u00fd kras<\/p>\n\n\n\n\n\n

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Type of Paper
<\/strong>Original research

Keywords<\/strong>
Anchoring, knot, knot efficiency, Polish knot, strength test.<\/em><\/p>\n\n\n\n\n\n

CC BY licensed Open Access article<\/em>
\"logo<\/p>\n<\/div>\n\n\n\n

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Abstract<\/strong>
Although the Polish knot is often used for anchoring in rope access, rope rescue and caving due to its advantages, there is a lack of information about its strength. The article deals with the strength and efficiency of the Polish knot, both when loading the front and rear strands of the rope coming out of the knot. It shows that the difference between the individual strands is insignificant. And although the Polish knot shows lower strength than the figure-eight loop, it offers other advantages.<\/em><\/em><\/p>\n\n\n<\/div>\n<\/div>\n\n\n\n

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Introduction<\/strong><\/h2>\n\n\n\n

There is no doubt today that tying a knot to a rope reduces the strength of the rope [1, p. 71]. Many tests have repeatedly confirmed this fact [2, p. 415]. Unlike the most common knots such as the figure eight loop [3, art. 4.1.1], the figure nine loop [3, art. 4.1.2] or the alpine butterfly [3, art. 6.1.2], which are tested relatively often and their strengths are generally known (and often stated in clear tables) [2, p. 415], the knot known in the Czech Republic as the \u201cPolonaise<\/em>\u201d [4, chap. 4.1; 4, p. 63] is somewhat neglected (and therefore there is no general awareness of its strength). It acquired this name due the translation of Techniques de la sp\u00e9l\u00e9ologie alpine<\/em>, where it was listed as \u201cN\u0153ud polonaise<\/mark><\/em>\u201d [6, p. 75].<\/p>\n\n\n\n

\"Polish<\/a>
Figure 1: Polish knot<\/strong><\/figcaption><\/figure><\/div>\n\n\n\n

In fact, it is a \u201cPolish knot<\/mark><\/em>\u201d [1, p. 73] sometimes referred to as a \u201cdouble lark\u2019s foot\u201d. In the well-known The Ashley book of knots<\/em> it listed a \u201cpile hitch<\/mark><\/em>\u201d [7, p. 217 and 307], or \u201csingle hook hitch<\/mark><\/em>\u201d [7, p. 314], or it is shown there without a name [7, p. 52].<\/p>\n\n\n\n

Due to the properties of this knot, it is a hitch (not a knot), but in this text it will be referred to as a \u201cknot<\/em>\u201d, or \u201cPolish knot<\/em>\u201d. Its advantage is mainly fast and easy tying and minimal rope consumption. And when used with a sufficiently wide connector (carabiner), its advantage is also easy and quick untying. On the other hand, it is not able to absorb impact forces (e.g. in the case of destruction of the anchor point, which can be compensated for by stretching a 10m section of rope) [5, p. 64].<\/p>\n\n\n\n

It is used in caving, rope access and rope rescue, most often for re-belay (re-anchor) or for anchoring.<\/p>\n\n\n\n

Although specialized literature describes the principle of its use and the method of tying, as far as practical use is concerned (i.e. which strand of the rope coming out of the knot is loaded), the literature does not mention. Neiter Marbach [1, p. 73] nor Kouteck\u00fd [5, p. 64] and in some cases nor Ashley [7, p. 52 and 306]. In the case of hanging the rope on a hook, Ashley shows the loading of the rear strand of the rope [7, p. 314], and in the second case (when tying the rope to a pole), the loading of both strands eccentrically. Mat\u00fdsek then shows the loading of the rear strand of the rope when used on a re-belay [4, k. 4.1].<\/p>\n\n\n\n

Since (with the exception of Mat\u00fdsek) there is no information about which strand of the rope should be loaded, there is also no information available about the behavior of individual strands under load.<\/p>\n\n\n\n

1       Equipment used<\/strong><\/h2>\n\n\n\n

1.1    Rope<\/strong><\/h3>\n\n\n\n

A new, low-stretch Truck rope in white, manufactured in June 2021 by the French manufacturer Courant, was used for the tests. The rope was certified according to the EN 1891, type A. The manufacturer provides the following information in the instruction manual:<\/p>\n\n\n\n