Author Topic: Mirrored Pretzel bowline  (Read 8371 times)

X1

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Mirrored Pretzel bowline
« on: March 08, 2013, 01:18:30 AM »
  There are many double nipping loop bowlines where we can use the tail to form a second collar around one leg of the eye, and then retuck it through both nipping loops, in order to make them wider and rounder ( because they now encircle three rope diameters). This way we get a double nipping loop / double collar bowline that is a very safe end-of-line eyeknot, as we do not only confront slippage with another line of defence ( by the second collar) , but we also improve strength ( by the wider and rounder nipping loops ).
   See the first and second attached pictures for an attempt to implement this strategy in the case of the Pretzel bowline ( the "long" Pretzel bowline, shown at the third and fourth pictures). Although this strategy is simple and sound, and the initial bowline is a secure, easy to remember and tie knot, and a nice, fluid one, this "mirrored Pretzel bowline" is - well, not exactly an ugly mess with segments of rope going all over the place and crossing each other in a wild tangle, but something very near this... :) I have tried every cosmetic surgery I could think of - there are numerous ways to combine the possible variations of the pretzel, with the possible orientations of the legs of the collars and the possible arrangements of the diameters of those legs into the nipping loop... but I have not found anything that could generate a decent knot, with clear lines the eye can easily follow and the hand can easily dress. The interested reader is kindly requested to try his hand - I might have missed something, or a simple variation that I can not think of right now may improve the original knot. I always believed that the Pretzel double nipping structure would have been more fertile, but I just can not see how to marry it with a second collar, and get a good looking knot...

Luca

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Re: Mirrored Pretzel bowline
« Reply #1 on: March 08, 2013, 02:05:02 PM »
Hi X1,

I have just tried  tying and dressing in pedestrian way exactly as the collar is doubled in the mirrored Girth hitched Bowline that agent_smith shows in his beautiful Analysis of Bowlines,or in the more symmetrical way that you show here:

http://igkt.net/sm/index.php?topic=3994.msg23760#msg23760

I also tried to cheating a little,setting the pretzel so that from behind ... oops :-\,  from the front, looks almost like fig. 34 in the agent_smith's document, making the crossing of the pretzel clearly visible only from the front ... oops :-\, from behind. However,in these ways,although the mirroed Girth hitched perhaps has a more "clean" look, I find that it is not so terrible to look at,why you dislike?
I am also curious about this: in the images above,the pretzel's portion of  rope adjacent  to the standing part of the mirroed version crosses passing over, while it passes under in the one-collar version, what is the reason?

                                                                                                        Thanks and bye!
« Last Edit: March 10, 2013, 02:14:49 AM by Luca »

Dan_Lehman

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Re: Mirrored Pretzel bowline
« Reply #2 on: March 08, 2013, 05:51:37 PM »
Hi X1,

I have just tried  tying and dressing in pedestrian way exactly as the collar is doubled
in the mirrored Girth hitched Bowline that agent_smith shows in her ...
Whoa!  Let's correct some things :
"mirrored bowline" is a (pseudo-)bowline with the
larkshead/girth hitch base, roughly resembling the
bowline reflected (and contrasted with the Janus
variant in which half of the knot is reflected);
and Agent_Smith is "his" not "her", in possessive!   ;D


As for the knots here, I don't consider them at all "bowlines",
though they are simple variations on the others (and viable
in similar applications, and so on).  What else to call them,
then?  --well, down that endless rabbit hole I'll not dive, now.


--dl*
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X1

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Re: Mirrored Pretzel bowline
« Reply #3 on: March 08, 2013, 06:42:02 PM »
it is not so terrible to look at... why do you dislike it?

   First, we should always remember that de gustibus et coloribus non est disputandum... I like Monica Belucci and I dis-like Nicole Kidman, for example.  :)
   However, I have thought about that, and I have decided that there is a reason about it : In the one-collar version, one does not pay much attention to the asymmetry of the nipping structure, while, at the mirrored, duplicated two-collar version, the eye seeks the symmetry of the two ends ( around the collars ) at the middle of the knot s nub, too - and it remains disappointed, because it does not find it. Moreover, at the same time, this asymmetric double nipping structure occupies now the centre of the "stage", with the two collars at its two sides - so anything not perfectly smooth in it, even a minor discrepancy from absolute symmetry, is, in a sense, "magnified", regarding the amount of attention it attracts.
   One might well ask : Why, then, you do not just use a "symmetric" Pretzel, where each leg leave the bight from different sides of its plane ? I feel that the "symmetric" Pretzel nipping structure is too "relaxed / open", its parts are not in contact, and do not cooperate with each other as much as they should, to keep itself in a closed, compact form, that would not need much aid from the collar structure. If, instead of the "symmetric" Pretzel, we use as a nipping structure one of the two asymmetric Pretzels, we can keep one of the legs underneath the other, so this nipping structure, although more asymmetric, would be more self-sufficient in ts effort to remain a closed form and do not degenerate into an open helix. Do not forget that we are searching for something at least as robust and efficient as the Girth hitch structure of the standard Mirrored bowline. I believe that the "symmetric" Pretzel, when it will be heavy loaded, it would have to rely to a very tightly interweaved collar structure, otherwise it will run the danger to 'open" up. I always prefer a nipping structure which is as self-sufficient as possible, and would be able to remain closed without transferring too much strain on the collar structure. The collar structure has one primary purpose, to remain attached on the standing part ! If a lot of its potential is dissipated, and "wasted", in its secondary purpose - which is to help the nipping structure remain in a closed form - I think that its primary purpose would have to be compromised a little bit...

I am also curious about this: in the images above, the pretzel's portion of the rope adjacent to the standing part of the mirrored version crosses passing over, while it passes under in the one-collar version... Is there a reason for this ?

   Remain curious, keep looking at the details, and demand a reason !  :) 
   In the one-collar version, we should try three things :
   1. Drive the tail through the nipping loop at a location away from the crossing point - in the Pretzel double nipping structure case, away from the two crossing points of the Pretzel ( the contact points of the limbs of the Pretzel with its spine / belly )
   2. Tie the Pretzel in a way the continutaion of the Standing end be in direct and extended ( helical) contact with the tail - so, it would better pass "under" the continuation of the eye-leg-of-the-Standing part, than "over" it.
   3. As noticed by Dan lehman, before he had forgotten it (1), the curvature of the continuation of the Standing end into the knot s nub should better be as smooth as possible.

   Now, the situation in the 2-collars version has been changed - so perhaps it would be prudent to change the way we tie the Pretzel, too !  :)
   I had tied it this way for a more concrete reason : The "middle" segment that goes through the nipping loop, the one that is collaring the two limbs of the Pretzel, should better pass through a path as close to the those two limbs as possible - and collar them in a symmetric way. Doing this, the "openings" of the two collars, between the two ends of this segment and the two limbs of the Pretzel, would be small. I do not want large openings, that give the impression of a loose knot, and may also be dangerous, too - because they are potential wide-open "handles" that can be caught up somewhere...
 
   Let me correct some things : The only pseudo-bowlines would be the bowlines that are intentionally pretending that are true bowlines, while they are not. I have defined what I think a bowline is, and I follow my definition. Dan Lehman is free to follow his, but this does not makes me a liar and him a Chosen carrier of the truth... :) Pseudo- means something that is a lie, and I think that I know what a pseudos ( ψευδος ) means, much better than Dan Lehman... His speciality is vegetables ( this Turnip should be really tasty !  :) ), but some words are all Greek to him.   
 
   1. http://igkt.net/sm/index.php?topic=2050.0     
« Last Edit: March 08, 2013, 07:33:24 PM by X1 »

X1

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Re: Mirrored Pretzel bowline
« Reply #4 on: March 08, 2013, 07:27:54 PM »
   One may well ask : OK, let us have a double nipping loop, and a double collar... Why are you not satisfied with just adding a second collar to the common double bowline, and you are looking for all those odd double nipping structures - the Pretzel, for example ?
   There are two reasons for it :
   1. We are looking for a nipping structure that would be convoluted enough, in order to present some self-supported "closure", so it will not run the danger to "open up" and degenerate into a helix when it would be heavily loaded. We want to rely on ( and use ) the collar structure to help the nipping structure for this only to a very limited degree.

   2. I have seen that the simple two-coils nipping "tube", can not constrict the tail in a sufficiently secure way. Two nipping loops, in contact or/and aligned to each other, form a straight "tube", that helps rather than blocks the slippage of the segments that penetrate them ! I do not know why this happens, and I believe we should test this before we can jump into premature conclusions. The reader is kindly requested to tie the apparently secure mirrored double nipping loop / double collar bowline shown at the attached pictures, and see what I mean. As we can not PULL the tail - even a not-very-efficient nipping structure, when it is accompanied by the collar(s), is very resilient - we can PUSH it, and try to feel the resistance its constriction by the double nipping structure imposes on this push.
   Compare the structure of the shown bowlines to that of the midspan bend, shown at (1).
 
   1.  http://igkt.net/sm/index.php?topic=3020.0
« Last Edit: March 08, 2013, 07:38:57 PM by X1 »

Luca

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Re: Mirrored Pretzel bowline
« Reply #5 on: March 10, 2013, 02:13:11 AM »
Hi,

Hi X1,

I have just tried  tying and dressing in pedestrian way exactly as the collar is doubled
in the mirrored Girth hitched Bowline that agent_smith shows in her ...

 Agent_Smith is "his" not "her", in possessive!   ;D

Oh .. ehm .. :-[ Unfortunately I continue to be an English(and not only!)-ignorant;I wrote in(my poor)English,but I reasoned in Italian:in the Neo-Latin languages,​​is given a masculine or feminine gender also to the names of inanimate things:"analisys" in Italian is a feminine term, and in Italian the possessive adjective that accompanies it consequently adapts to it becoming feminine.So,when I wrote"her", in my mind was referring to "analysis", not to agent_smith!
Agent_smith,I apologize for the misunderstanding and for my ignorance! (I've edited my previous post)

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Luca

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Re: Mirrored Pretzel bowline
« Reply #6 on: March 10, 2013, 08:41:14 PM »
Hi Dan,

  the Janus variant in which half of the knot is reflected

Reflected or duplicated ? :-\

                                                                  _________________________________

Hi X1,and thanks for your answers!

I like Monica Belucci and I dis-like Nicole Kidman, for example.  :)
 
 

 As actresses, right? ;D

Now, the situation in the 2-collars version has been changed - so perhaps it would be prudent to change the way we tie the Pretzel, too !  :)

As regards the one-collar version,I imagined that you had chosen to cross the portion of the pretzel adjacent to the standing part passing it under , because in this way it remains in direct contact with the second leg of the loop and the tail, maybe having more"nipping" faculty,because the standing part bears the 100% of the load, while the other crossing portion of the pretzel is adjacent to the first leg of the loop, that bears the 50%.Now, I agree that in the two-collar version, the situation has changed, but this situation is not however reversed,for this reason I wondered  about the reversal of the pretzel.


   I had tied it this way for a more concrete reason : The "middle" segment that goes through the nipping loop, the one that is collaring the two limbs of the Pretzel, should better pass through a path as close to the those two limbs as possible - and collar them in a symmetric way. Doing this, the "openings" of the two collars, between the two ends of this segment and the two limbs of the Pretzel, would be small. I do not want large openings, that give the impression of a loose knot, and may also be dangerous, too - because they are potential wide-open "handles" that can be caught up somewhere...

 I am not able to follow you here, I'm not able to understand how the manner to cross the pretzel in one way or another,can significantly influence the "holes" within one or the other of the collars.

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X1

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Re: Mirrored Pretzel bowline
« Reply #7 on: March 10, 2013, 11:41:53 PM »
... you had chosen to cross the portion of the Pretzel adjacent to the standing part passing it "under" , because in this way it remains in direct contact with the second leg of the loop and the tail, maybe having more "nipping" ability.
.. . however, this situation is not reversed. For this reason I wondered  about the reversal of the Pretzel.

   Oh, that was a joke, that was meant to remind something I wrote for another problem.. at another thread ... :) :

 " At the time he made his first choice, the (knot tyer) used ALL the information he was offered at that stage (knot)... At the second stage (knot), he was offered another, new piece of information, relevant to the problem, which was not available to him before. This new information was neither included in nor deductible from the one he already had.
   Just because he had used every piece of information he had while he made his first choice, and now he has an additional, new one, the ONLY way to actually incorporate it into his given new sum of information, is to change his first choice. If he does not, it would mean one of three things :
   He has ignored the new information - which is obviously not the best thing to do, in whatever problem !
   He thinks that he had already included this information when he made his first choice. However, this would mean that the new information was not new - which is wnot the case.
  You do not know in advance how and why you have offered another piece of information... That should not interfere with your decisions. All you should do, all you have to do, is to take the new information into account - if it is not a re-phrased variation of the original information, of course. Just because you had used all the information you had in the first place exhaustively ( you used every piece of it... ), and because now you have another, new piece of information, you have to "add" it somehow to the one you already had. If you add something to something ( both being not-zero ), you get something different ! So, with the different information you now have, you should act differently... The ONLY way you can act differently, is to change your first choice.
  You should change your previous choice every time, just because every time you acquire a new piece of information, and the only way you can do something about it, the only way you can actually change your actions because the information that is related to them has changed, is to change your previous choice."


  Now, the fact is that the situation has changed, indeed : the path followed by the tail previously, which was chosen so that the tail would be nipped as efficiently as possible by the continuation of the standing end, is not the path of present tail any more - so there is no point in insisting on the previous "over-under" crossings. It is always the last part of the working end that should be nipped harder, because this is the last line of defence against slippage - and the last line of defence should be the stronger one ! Now, the path near the crossing points is taken - it is occupied by the segment that collars both limbs, so the openings of the collars would not be very wide. Therefore, we should drive the present tail through one of two remaining paths. I have chosen this particular path, because I felt that, following this and not the other one, it would be safer from any interference by the motion of the eye-leg-of-the-bight, during ring loading. Staying very close to eye-leg-of-the-standing-part, and "under" the eye-leg-of-the-bight ( "under", in relation to the first picture ), the tail will not run the danger to be dragged/pulled by them when they will open up, during ring loading. Imagine how the eye-leg-of-the-bight will move in this case : It will be stopped by the more robust nipping structure, and not by the collar structure - so it will not pull the last segment of the collar structure, the tail, out of its last refuge.

how the manner to cross the Pretzel in the one or the other way can significantly influence the "holes" within one or the other of the collars.

 Tie the two variations ( with climbing ropes, that are somewhat stiff ), and you will see... The two limbs of the Pretzel you have to collar are not symmetric in respect to its two rims ! The two possible paths the first legs of the collars should follow are different, and the more stiff the material, the less "easy" and "tight" those U-turns around the two limbs would be. The "smoother" path for each and exery segment of the standing part is the one shown - and I know this because I have tied/tried all the others !  :) 

X1

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Re: Mirrored Pretzel bowline
« Reply #8 on: March 18, 2013, 06:33:38 PM »
... the simple two-coils nipping "tube", can not constrict the tail in a sufficiently secure way. Two nipping loops, in contact or/and aligned to each other, form a straight "tube", that helps rather than blocks the slippage of the segments that penetrate them ! I do not know why this happens, and I believe we should test this before we can jump into premature conclusions.

   On the contrary of what one might had expected, the "mirrored" ( should I say "anti-mirrored" - from "anti-symmetric" ? ) bowline shown at the attached pictures seems to me a much tighter knot. Is the absence of friction between the rims of the two nipping loops that makes this difference ? The slightly wider first curves of the ends ? I can not tell. Although it takes a little more to tie and set, I would prefer this double nipping loop / double collar "mirrored" bowline, than the one shown at Reply#4.

P.S. Perhaps the name " Double Collar Water bowline ", or even " Double Collar Clove Hitch(ed) bowline" would be a better name for the knot presented in this post. "Anti-symmetric" or "anti-mirrored" could also connote different knotted structures.
« Last Edit: March 22, 2013, 10:15:54 AM by X1 »