Author Topic: The Wireline hitch ?  (Read 4376 times)

cactusbush

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The Wireline hitch ?
« on: June 26, 2014, 04:11:09 PM »
Hello.  Newbie here.  Glad to find this forum this morning.   

I've a knot in question that that I've never encountered in any publication.  It is a friction hitch with similarities to the rolling hitch (1 & 2), taunt line hitch and Magnus or Magner's hitches.   
 
I learned this simple hitch by working for a wireline (oil field service) company.  Standing on the floor of an oil derrick, we would use a short rope and this hitch to temporarily elevate a blow-out preventer cap for example in the air so that we could work on the tool (suspended by cable) beneath it.   The wire cable itself was a woven steel cable (about 7/16 dia.) with insulated internal conductors, which ran from our winch - through pulleys - through the top of the derrick and down into the bore-hole (sometimes a mile or two deep). 

Attached to this post is a page I constructed a while back for a prospective book (not a book about knots).  [The attachment does not show in the pre-posting "preview" but hopefully it will appear on demand].   I wish to learn from the knowledgeable members of this forum  - if this knot is known or identified as something else.     

Cheers

   

xarax

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Re: The Wireline hitch ?
« Reply #1 on: June 26, 2014, 05:12:55 PM »
   Not bad ! With more "lower" wraps ( and, perhaps, with more "upper" wraps as well ), it grips nicely. The reason more wraps are worth the trouble, is that, as they are pushed on each other by this oblique riding turn, the friction forces between the adjacent wraps become much greater, and, at the end, all of them, the one carrying the Tail End included, are "locked" in place, without any further knotting. This is a mechanism that was not present in the "parent" Clove hitch, and, for me, at least, was completely unexpected : by the mere addition of more wraps, a change in quantity, we observe a new, emergent phenomenon, a change in quality.
   Of course, the optimum number of "lower" and "upper" wraps depends on the relative diameters of the hitching rope and the hitched "pole", and the friction characteristics of their surfaces.
   The very interesting thing in this hitch is that, although it can be "locked" quite tightly, it can also be released easily, and at a glance ! I have called it "quick-release hitch", not without any reason ! Few knots can pass from a very tight to a very loose state as easily and quickly as this one... Just give the wraps of the "lower" or the "upper" part a little light twist to "unwind" them, and the whole hitch will fall apart in no time, regardless of how tightly it was attached to the "pole". 
   See the Multi-wrap Clove hitch, shown at (1), and at the attached pictures.

1.  http://igkt.net/sm/index.php?topic=4139.msg25019#msg25019
This is not a knot.

xarax

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Re: The Wireline hitch ?
« Reply #2 on: June 27, 2014, 09:52:17 AM »
    In the first attached picture, one can see a two-wrap Clove hitch, and two yellow arrows, marked "L" and "U". The "L" ( from : "lower") arrow points at the one free end, which is the continuation of the one, the "lower" coiled part of the hitch - so, if this will be the end which we will decide to use as Standing End, it will pull directly the "lower" wraps. Similarly, the "U" ( from : "upper") arrow points at the other free end, which is the continuation of the other, the "upper" coiled part of the hitch - so, if we decide to use this other free end as Standing End, it will pull directly the "upper" wraps. What should we do ? Which one of the two free ends should we use as Standing end ? Which one of the two coiled parts of the hitch should we pull directly ?   
    I had always conjectured/believed that it is better to pull directly the coiled part which, after its own wraps will inevitably be deformed by the pulling ( = after they will become elongated / elliptical - from circular they were before the loading - and oblique, from perpendicular to the axis of the pole they were before the loading ), it will, in its turn, drag the other coiled part in such a way that :
   the wraps of the "first", directly pulled ( = pulled by the Standing End ) part, and the wraps of the "second", indirectly pulled ( = dragged by the "first" ) part, will remain parallel to each other.
   In the Multi-wrap Clove hitch this happens when we pull the "lower" coiled part - that is, if we use, as Standing End. the end corresponding to the 'L" arrow. To show this I tried to compare how exactly the same 2+2 wrap Clove hitch is deformed when it is pulled directly by its "upper" part, and when it is pulled directly by its "lower" part. I have tied them on the same ( literally...) rope, and around the same pole, and I had pulled them along the surface of this pole by their common, umbilical Standing Part, in the way shown in the picture ( that is, by applying the pull a simple Spanish windlass can deliver - which may be a humble, but not a weak rope mechanism !  :) )

  As shown in the picture, the wraps of the two parts of the hitch at the right side ( which was pulled by its "upper" coiled part ) did not remain parallel to each other, and were deformed and elongated much more. On the contrary, the hitch at the left side ( which was pulled by its "lower" coiled part ) remained "in one piece", less deformed, less elongated, and with all its wraps adjacent and parallel to each other. However, one may well argue that the difference in the final elongation of the two hitches tells nothing about their final gripping ability, and that a more pronounced elongation "is a plus, not a detriment"(1). In fact, in one similar case of a multi-wrap hitch, SS369 reported better results when, after the direct pulling of the "first" part, the "second" part was inclined towards a different direction - so its wraps did not remain parallel to the wraps of the "first' one, and as a whole, the hitch was elongated much more. 
   My intention here was to show the differences in the final forms of the two hitches, not to find out which one is able to withstand a stronger lengthwise pull. In order to measure the gripping power of each hitch, we should force it to slide along the surface of the pole much more, and the Spanish windlass I had used is not a suitable means to achieve this. The interested reader is kindly required to do his own trials, and report his results to us.
   
1. http://igkt.net/sm/index.php?topic=4224.msg26355#msg26355
« Last Edit: June 27, 2014, 12:29:57 PM by xarax »
This is not a knot.

cactusbush

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Re: The Wireline hitch ?
« Reply #3 on: June 27, 2014, 04:40:57 PM »
The interested reader is kindly required to do his own trials, and report his results to us.


It is welcoming to find someone passionate about a subject. 

There ought to be a rating for knots - that goes beyond mere efficiency.  I would promote a classification named something like "knot elegance".  The elegance of a knot would include subjective ratings of its simplicity, untie-ability (in most instances), practical application and effectiveness.  Many times in the past I have tried to recall and utilize a knot from my small repertoire - but have forgotten it.  Knots that are difficult to remember, difficult to undo or that use more cordage than is required for a given task are simply not as desirable.   

Work knots that would rate highly on my "elegance scale" - would be the bowline, clove hitch, constrictor, Prusik, Figure of eight loop, ossel hitch, the slipped-slip knot and this hitch which I have supposedly introduced as the Wireline hitch. 

* I know that the ossel hitch is an ancient knot.  Presumably no one knows how old it is but I suspect it might date back to the Neolithic Age.  Does it have an ABOK number ?
« Last Edit: June 27, 2014, 04:44:49 PM by cactusbush »

xarax

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Re: The Wireline hitch ?
« Reply #4 on: June 27, 2014, 05:46:08 PM »
   There ought to be a rating for knots - that goes beyond mere efficiency.  I would promote a classification named something like "knot elegance".  The elegance of a knot would include...

  Elegance, among the other things !  :) You should not underestimate aesthetics, which often reveal some quality of the knot that is also related to its "practical" efficiency : the simplicity of its form, for example, which means that its spatial 3D figure, and its planar 2D representation which often coincides with its tying pattern, can be memorized and remembered more easily, the knot can be not be tied wrongly without this error been noticed at a glance ( because any mistake/asymmetry would manifest itself immediately, like a fly in the ointment ), it can be inspected at a glance, its structure and the way it "works" can be easily understood, etc.

  Of course, the Clove and the Cow hitches, either the symmetric variations ( where the two coiled parts have the same number of wraps, like the common/single-wrap and the multiple-wrap Clove hitch, and the common Cow and Prusik hitch ), or the asymmetric ( where the one part has more wraps than the other, like the Rolling hitch, in its standard or its "reversely loaded" variation you show here, and the Magnus hitch ), are elegant knots, no question about that. The same is true for the Strangle and the Constrictor, and, of course, for the most beautiful fig.8 knot. However, this Icicle hitch you also mention, is not only an overestimated variation of the ( also overestimated ) Well Pipe hitch, but, to my eyes, it is NOT elegant ( and, of course, it is not beautiful...).
   Another multi-wrap hitch which is unquestionably elegant ( and I even dare to characterize it as beautiful - but beauty is in the eye of the beholder... :) ), is the Double Cow hitch (1) - a "tight" hitch / binder , where both ends the Tail End, but also the Standing End as well, are firmly "locked", so the hitch can accumulate any tensile forces happen to be induced into its wraps during a pre-loading or a loading phase, and retain them, even if /when it is not loaded any more.

1. http://igkt.net/sm/index.php?topic=4035.msg32089#msg32089

   Your Slipped-Slip loop reminded me of a bowline which is not well known, and it may even look ugly, ( but, because it is conceptually so simple, we can overlook its figure...). See (2).

2. http://igkt.net/sm/index.php?topic=4712.msg30447#msg30447

« Last Edit: June 27, 2014, 06:06:38 PM by xarax »
This is not a knot.

Dan_Lehman

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Re: The Wireline hitch ?
« Reply #5 on: June 29, 2014, 03:19:07 AM »
I've a knot in question that that I've never encountered in any publication.  It is a friction hitch with similarities to the rolling hitch (1 & 2), taunt line hitch and Magnus or Magner's hitches.
Welcome!
Please note that there is no "tauNt line"
--rather, it is "taut line" (aptly, for some
of its applications).

Clearly, what you present is the commonly
known knot loaded by its tail.  I'll guess that
this was found to be more secure in movement
of the nub, and that the gripping of the rope
upon the (thicker) wire was so ample that
many knots would work, and no aggressively
gripping structure was needed.


--dl*
====