General > Practical Knots

The basic elements of any practical knot.

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Inkanyezi:
Regarding the practical knot as a machine that converts tensile force into pressure, which builds up and maintains friction that impedes slip, might be a starting point for working on the challenge. I think one of the simplest structures to study in this regard would be the Gleipnir, from which you could continue to the bowline and its eskimo form, as well as the variants of intertangled overhands and the Carrick Bend.

Working along those lines, it might become clearer what features make knots do their work and why they sometimes fail. We might possibly arrive at a definition to what "nip" really is, and maybe where within the knot structure we would prefer to locate it for different purposes.

Still, I think the subject is largely theoretical, although theory and practice should go hand in hand when trying to acquire more knowledge about any subject.

xarax:
   I have proposed 4 basic elements that can desribe / explain, in a general way, the function of almost every practical knot.
   1. Rope embace(s)-twists. ( example: reef family of bends, surgeon bend)
   2. Nipping loop(s). (example : Gleipnr binding knot, Gleipnir hitch)
   3. Riding turn(s.) (example : Hitches with riding turns, Clove, Strangle, Constrictor)
   4. Colar(s) (example - along with 2 -: bowline)

   It would be very interesting, and most helpfull, if we could measure the actual friction, induced by those elementary friction mechalisms, on the rope strands that go through/under them.
   We can further describe those elements, in a more quantified way, if we take into account the specific angle of the relative rotation of the ropes. ( See attached pictures, for some general cases). 

DerekSmith:
Hi Xarax,

Welcome back to this topic.

Isn't picture 1 the equivalent (mirror) of picture 3 sans one white rope?  Just tension the orange rope and it converts to the 360 wrap...

Derek

xarax:
   Thank you Derek,  
   Those images are representing friction mechanisms, tightened, final parts of knots, as they appear on various places of tightened knots, they are not themselves loose, initial knots ... :) Image 2 belongs to the classic friction mechanism of the reef family of knots, evidently. Give it another 180 degrees, and you get the friction mechanism of the surgeon knot ( the first of the two). The nipping loop of image 3 belongs to the simple bowline, the Gleipnir, and, if, instead of the two white ropes ( the two legs of the collar of the bowline - the two legs of the Gleipnir) we have a pole, it represents the full riding turn of a hitch. My purpose was to show different angles and notations of the rope turn in a rope embrace-twist or a rope nipping loop. The precise angle of rotation of the plane of the nipping loop, in relation to the rope strands that pass through it, was not meant to be shown in those pictures. ( I tried to keep the pictures as simple/abstract as possible). For example, you should rotate the nipping s loop plane (almost) 90 degrees, and the rope strands axis 180 degrees, to have an image of the Gleipnir nipping loop.
   Look at a practical knot as a succession, along the rope length, of various rope mechanisms, that reduce the tension forces - and the motion those forces would generate had they were left free to act - from the standing end s 100%, to the tail s 0%. How does this miracle happen ? The tension forces are reduced, dissipated, disappear, through those friction mechanisms, which are the basic elements of almost every practical knot.

xarax:
  A (ingenious) hitch, invented recently by SS369, helped me realize that, in this thread, I had not considered the "oldest" "basic element" known to man, and the most useful one ! It is, essentially, the same friction mechanism that keeps the threads/warp yarns from slipping through a weaved fabric, a human invention well known to every prehistoric housewife that have lived thousands of years ago...:) In fact, weaved fabrics are nothing else/more than the repetition of this mechanism along and across the area of the cloth. I call it the "ww" element/friction mechanism, ( the weft and warp threads mechanism ), but any suggestion for a more appropriate name would be mush appreciated. It is not made by nipping loops, collars, riding turns or rope embraces/twists, so it can be considered as a fifth "basic element", along with those other four. ( In fact it was, probably, one of the first tangled-rope made tools that were used by man, and, certainly, the first I should have described ! )

   The series of the attached pictures show how we arrive, using this ww mechanism, from a 3-warp yarns fabric, to a ww friction hitch. If we double the wefts, so that the one is crossed with the other at each node of the weaved structure, we get a most efficient ww friction hitch, the one devised by SS369. If we follow the path of the white rope/warp, we can see how is is squeezed in its belly, when it passes over the wefts, how it is squeezed in its back, when it passes underneath them, and how it is squeezed in its shoulders, when it passes in between them. This squeezing is the trick of the ww friction mechanism. We can think of many other similar hitches, even a whole class of knots that utilize this same mechanism - or any combination of this mechanism with the other four .

   After the publication of the "SS brakehitch" ww friction hitch, I made a little litterature search, and I have discovered that a similar hitch could have been invented by D. Smith, had he replaced the pole of his KC hitch with a rope. (1) Also, the ABoK # 1755b and ABoK#1758 hitches are similar hitches, them too tied on a pole. But it is around a rope that this hitch, and any other similar hitch that is based on this friction mechanism, works at its best, better than any other fiction hitch I know.

1) http://igkt.net/sm/index.php?topic=542.0

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