Knot "implants"

[xarax]

  Your "test report" is a report, but not of a test ! 

   What would you know of either,
   as you present neither ? ! !
  (Your pipe dreams are from a not-a-pipe, even ! )

   
   I do not smoke ! ( Neither the stuff you do, nor anything else...)
   However, I do know what a test is - that is why I do not report as "a test", something which is not-a-test.
   A test should be repeated, and should be repeatable. That is how modern science separated natural events, from miracles. ( Of course, if you believe you are the Chosen One, by KnotGod Himself, to spell His will, that distinction does not make much sense to you... )
   You report a single event, you call a "test", on a cord, you call a "rope", made and used by your grand mother, during eighteenth century, and you tell us to believe it ? (  Two properly inscribed stone tables would had been more credible, IMHO ).

 

  Not commenting can be done if fewer keystrokes.

  In that, you have much to teach, indeed... For the 99 % of the knots I had presented in this post all those years, you had not written a single word.
  Zero keystroking ( = covering under silence ) is the other side of the same coin you own : Infinite Keyboarding ( = covering under noise ).
  I had commented on each and every knot you, or everybody else in this Forum, had presented, and I had replied in each and every comment you, or everybody else in this Forum, had been kind to offer to me - even if most of them were just desperate, lamentable attempts to prove something about knot tyers ( yourself, from the one hand, and everybody else, from the other... ), not about knots !
   However, in sharp contrast to you, I can not but be fair always, so I have to tell that I was glad you performed your "test" - even if you had been careful to accompany it with yet another of your "clever", "wise" ad hominem characterizations ("whacko"(sic)).

[Tex]

Personally, I think you two are arguing about nothing.  I suspect this CAN work in some cases, but I find it hard to believe that it WILL work in all cases.

But that's not what I wanted to say.  My little observation is that climbing rope stretches.  When stretched the linear density is less and so the amount of material per cm is less.  I would be very surprised if this does not result in a smaller cross section.

I would thus also be extremely surprised if it is not possible to force this compression and elongation by applying radial pressure instead of axial tension.  It's not even too hard to draw some connections between the sizes of the two forces based on required energy input.  Frictional inefficiency in translating one motion to the other could increase the force needed beyond the ideal prediction though.  It's possible.

[xarax]

climbing rope stretches. 
 I would be very surprised if this does not result in a smaller cross section.

  First : the "knot implant" is meant to be pulled out of the nub easily, by hand - and it is a very short segment of rope, so the net result of the stretch you mention on the area of its cross section is almost ZERO...
  Second : We would be GLAD to be able to stretch this segment, and force its cross section to become smaller ! This would had enabled us to pull it out of the nub more easily.
  What dL said is that the "knot implant" can not slip out of the nub easily, because, to do this, it has to pass through different rope-made narrow "gates", which squeeze its sides towards different directions, and "flatten" it accordingly. This continuous change of the shapes of "all" cross sections, of the one after the other, as they pass through all those "gates", consume energy, so it makes the movement of the entire segment more difficult. Which is true - but, provided that we do not need to pull out the "knot implant" very quickly, the material of the rope can "flow" through those "gates" without much difficulty.
   How do I know it ? Because I had tried to achieve the exact opposite, with not much success ! I had seen that, however tightly woven around a more or less "straight" ( re. the path it follows ) segment a nub is, it can NOT grip / nip it very efficiently ! The very few exceptions are the single helical coils ( the "nipping tubes" ) of the climbing friction hitches, the double, cross-gartered helical coils of the rat tail stopper-like hitches, and the adjustable loops based on the opposing bights mechanism. Provided that the "tight knot" into which we "implant" its Tail End is not one of those few knots, all the other knots, however tightly woven they might be, are not able to nip a penetrating segment of rope so efficiently that we will not be able to pull it out of the nub easily, by hand...
  Now, your comment about stretching would had made sense, indeed, in the following hypothetical situation : After we pull out and remove the "knot implant" from the nub of a tight knot, the cylindrical "hole" which remains is immediately "filled" with the material flown into it from the nearby segments, which become less stretched, so the area of their cross sections becomes larger, so there is this material "flood" which covers any remaining empty space, and the knot becomes, again, as untiable as it was before the removal of the "knot implant". Well, things might had been like this, but they are not. The segments of the nub around the "hole" do fill in the void, but, doing this, they become able to "breath", and so the whole nub becomes less dense, less tight, and more easy to untie. 
   There is a simple way to PROVE the value of this idea, but I had not refereed to it, because I know that it might sound alien to dL. and the other practical-knot-fundamentalists of this Forum... Instead of ONE "knot implant", insert TWO, or THREE, or as many as you wish ! At the end, after you would had pulled out and removed them, the nub will become as loose as you wish...     
 

[Tex]

My comment about stretching was only related to the more general sense of compression passed by and dismissed in previous confusion.  My point is not about the stretching either but using the fact that it CAN stretch as clear proof that it can also compress (real cross sectional compression, not cross-sectional distortion, although in 3D they are all distortions, unless the rope truly is volume compressible, also possible).

Real compression (even if small) of one part of the implant around an indentation or within a nip, would certainly cause it to be more difficult to remove.  Probably distortion would too, let alone actual bending inside the knot, that hasn't been mentioned (who says it stays straight?)  Impossible to remove thoug?  Not necessarily.  The obvious advantages with the implanted rope is that you can grab it more easily than the other internal segments and that is has somewhere to go .  It won't be any looser than those internal segments though.

Maybe sometimes that's enough.  Maybe sometimes it isn't.  I doubt there are any absolutes here.

[xarax]

...actual bending inside the knot, that hasn't been mentioned (who says it stays straight ? )

   If you are careful enough when/where you implant it, even if it was not straight enough at the first place, or if it had not remained straight enough afterwards ( during the tensioning of the knot ), at the end it will be straightened out enough - when it, by its turn, will become tensioned enough ( by the knot tyer, when he will be pulling it, in order to drag it out of its nest ). Now, I do not doubt that there are knots which, during tensioning, capsize locally or even compltelly, and no knot tyer can predict how exactly such a "knot implant" will be "swallowed", and how it will look at the very end of this "digestion"... I was interested mainly in the cases of the fig.8 eyeknot, the overhand loop, as well as of the Water bend ( where we can implant both tail Ends ).