Author Topic: Look alike loops  (Read 68428 times)

alanleeknots

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Re: Look alike loops
« Reply #15 on: November 14, 2012, 12:59:48 PM »
Hi All, I work on my loops have found some interesting discovery.  picture A 1 Both loop the frond view look exactly the same.
Picture B 2 is two in one loop, just to move the nipping loop to the left or right,
picture C3 is loop IMG_009, move the nipping loop to other side, it will become very bad,  so do loop IMG_004.
Thanks  alan lee.
« Last Edit: November 14, 2012, 01:03:19 PM by eric22 »

kd8eeh

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Re: Look alike loops
« Reply #16 on: November 15, 2012, 05:08:48 AM »
Here, i am considering mostly the bend formed by tying a lark's head around a lark's head tied in the other rope, but the easy to untie bend and several other bends follow this trend.

If there are collars tied around the standing part of the rope, then those collars may, in many cases, be pulled outwards to give slack in the rope and hence make it easy to untie.  there could be a case where these collars are just an auxiliary part of another knot that will be hard to untie on it's own, but so long as they are not, the collars seem to be the means by which a knot is untied.  now, a jamming mechanism may be ultimately responsible for the slack there, but based on how these two things are coupled, i would speculate that collars in the rope are part of the jamming mechanism or crucial to it's function.  So, the best way i see to evaluate the roles collars play in looseness of a knot would be to see how they are related to jamming mechanisms.

So far, the most common jamming mechanism I can isolate is either trying to have the rope bend in two opposing directions as tension is placed on each strand, at least within the realm of knots that are generally considered good.  This generally requires a collar to provide the rope with a strand to bend, or at least many knots that i have identified to jam like this have collars (bowline, zeplin knot, alpine butterfly, carrick bend), but doesn't always in cases like a glumpir knot.  so, i don't know the topological correlation here, but i suspects something does exist still, as many of these knots do require a collar, and my counterexample, the glumpir, is often very difficult to untie.

Another jamming method is to try and rotate something that can't be rotated.  A good example of a knot that binds like this is a whatknot.  So far as i know, there is no particular correlation between this and having collars in the rope.

Another jamming method is to just pinch one strand really really hard.  Most knots that are typically insecure will jam like this, and this just makes them a pain to untie.  I question whether this is even considered  jamming, but some knots, like an overhand on a byte as a loop, bind like this.

This is not a complete list, but it's just some observations of mine.

alanleeknots

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Re: Look alike loops
« Reply #17 on: November 15, 2012, 05:32:39 AM »
  Hi All,  I have two loops here, out of this kind of structure I don't know what it called,
  I don't know if it any good.

  Thanks  alan lee.

X1

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Re: Look alike loops
« Reply #18 on: November 15, 2012, 12:24:35 PM »
   There is no reason to form a crossed-coils double nipping loop, and then to drive the working end only through one of those two coils. The crossed-coils nipping loop is already weaker, as a nipping mechanism of a bowline, than a normal, parallel-coils double nipping loop - which, in its turn, it may be weaker than the common single nipping loop !
   So, its addition in your loops seems redundant to me. I had transformed those two loops a little bid, by replacing the crossed-coils double nipping loops with parallel coils double nipping loops, and driving the continuation of the eye-leg-of-the-bight through both of them - but I have seen that they suffer from another problem. The rope is not nipped very well at the last/third passage of the working end through this double nipping loop - so this last passage seems redundant, too. As I had noticed, it is better if the last passage of the working end through the nipping loop, the last line of defence against slippage, is also the last to give up in an extreme loading, so it should better be the hardest one.
   For a crossed-coils double nipping loop PET loop, where this configuration of the two coils has an important role to play, see (1).

  An unreasonably convoluted knot, is a bad knot, by definition. Another problem with the very complicated knots is that they can be dressed in many ways, and the stiffness and friction coefficient of the material itself alter their final tightened form too much ! We do not want knots that their tightened forms would depend sooo much on the material on which they are tied on - because we would not be able to visualise/remember any such knot in advance, before we would have already tied it on a specific material !  In short, beyond a certain degree of complexity, a convoluted knot can not be a practical knot, for many reasons.

1. http://igkt.net/sm/index.php?topic=3951.0
« Last Edit: November 18, 2012, 11:06:56 PM by X1 »

kd8eeh

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Re: Look alike loops
« Reply #19 on: November 16, 2012, 03:16:41 AM »
The second knot appears to me to be some type of eskimo bowline, with a double loop instead of a single loop and an extra nipping turn on the tail end.

alanleeknots

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Re: Look alike loops
« Reply #20 on: November 17, 2012, 09:49:49 AM »
Hi Xarax,  I am Sorry, I work on my rope very late that night, I post the wrong loop IMG_888 , and the other one is IMG_88 two "8" structure, this is the one I intend to post.

 
   Regarding the first two loops :
   There is no reason to form a crossed-coils double nipping loop, and then to drive the working end only through one of those two coils. The crossed-coils nipping loop is already weaker, as a nipping mechanism of a bowline, than a normal, parallel-coils double nipping loop - which, in its turn, it may be weaker than the common single nipping loop !
   So, its addition in your loops seems redundant to me. I had transformed those two loops a little bid, by replacing the crossed-coils double nipping loops with parallel coils double nipping loops, and driving the continuation of the eye-leg-of-the-bight through both of them - but I have seen that they suffer from another problem. The rope is not nipped very well at the last/third passage of the working end through this double nipping loop - so this last passage seems redundant, too. As I had noticed, it is better if the last passage of the working end through the nipping loop, the last line of defence against slippage, is also the last to give up in an extreme loading, so it should better be the hardest one.
   For a crossed-coils double nipping loop PET loop, where this configuration of the two coils has an important role to play, see (1).

   Regarding the last, third knot :
it looks like it is not that bad.
   To me, an unreasonably convoluted knot, is a bad knot, by definition - and this knot shown here is closer to be such a knot, than any of the many you have presented !  :)
   Moreover, when I tie it on various stiff materials, it does not fold like the one you show in the picture - another problem with the very complicated knots. They can be dressed in many ways, and the stiffness and friction coefficient of the material itself alter their final tightened form too much ! We do not want knots that their tightened forms would depend sooo much on the material on which they are tied on - because we would not be able to visualise/remember any such knot in advance, before we would have already tied it on a specific material !  In short, beyond a certain degree of complexity, a convoluted knot can not be a practical knot, for many reasons.

http://igkt.net/sm/index.php?topic=3951.0
Thanks   alan lee.

X1

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Re: Look alike loops
« Reply #21 on: November 17, 2012, 09:54:07 PM »
   This may be even more convoluted than the previously posted one, and consume even more rope length, but it is much simpler  :) ! Why is that so ? Because here I see a pattern, and a reason. So, my mind can pay attention to the shape, as millions of years of evolution had taught it to do, and remember it. The pattern is that of the two "8" shapes, interlinked to each other. The reason is to tie a nipping structure that is as convoluted and complex as the collar structure ( or vice versa).
   I do not like this particular one, but I am sure that you can find other "8" structures, that would be linked to each other in a "88" nub in a more harmonic way, with fewer voids, confined within a more compact volume.
   My "golden standard" for such "88" structures is the Tweedledee bowline :
   http://igkt.net/sm/index.php?topic=3989.msg23724#msg23724
   

alanleeknots

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Re: Look alike loops
« Reply #22 on: November 28, 2012, 02:06:38 AM »
Hi All,  I have two "8" structure loops here, have 3 ropes diameter on the nipping loop and seem like nipping the tail quite nice.

Thanks   alan lee

X1

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Re: Look alike loops
« Reply #23 on: November 28, 2012, 05:01:11 AM »
I have two "8" structure loops here

  I would nt characterize them as shape "8" based nipping loops - they look more like Pretzel-like nipping loops, which you have already used in the past. The shape "8" is more symmetric, and more " fluid" . However, the Pretzel-like nipping loop offers also two openings, the one above the other, through which we can drive the working end of the collar structure, following many different paths. In the loops you present here, I think that the potential of the Pretzel-like structure has not been exploited as much as it could : The working end follows a convoluted path, that makes the knot difficult to dress and tighten, but, at the same time, it is not nipped in the course of this path in as many points as it could. During a ring loading, a short tail will run the danger to be pulled out of the knot s nub. Also, the knot is based on a difficult to memorize structure, with no apparent pattern, or clear idea...
   ( My golden standard of the various Pretzel-like bowlines remains the one at the attached pictures. Easy to tremember, tie, dress, tighten, and with a transparent structure. I had asked a number of sailors to learn how to tie it - and they did, quite quickly and easily... It has an easy to understand pattern, which is visible from both sides, so the knot can be tied and inspected easily.)
« Last Edit: November 28, 2012, 05:03:55 AM by X1 »

alanleeknots

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Re: Look alike loops
« Reply #24 on: November 29, 2012, 10:29:06 AM »
Hi All, I have a loop here, just something to see,even thought it will lenghten the tail coller little bit, I think it still able grip on the tail nicely.
Thanks for the comments, I learn little more each time with the loop I had posted.    alan lee.
« Last Edit: November 29, 2012, 10:48:22 AM by eric22 »

X1

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Re: Look alike loops
« Reply #25 on: November 29, 2012, 05:34:12 PM »
  Many of those crossing knot + overhand knot based loops are very secure, very interesting knots, and I believe that they have not received the attention they deserve - probably because they try to grow under the shadow of the bowline ! :)
 See :
 http://igkt.net/sm/index.php?topic=3944.msg23427#msg23427
 http://igkt.net/sm/index.php?topic=4095.msg24585#msg24585
 http://igkt.net/sm/index.php?topic=4095.msg24592#msg24592


alanleeknots

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Re: Look alike loops
« Reply #26 on: December 05, 2012, 02:59:01 AM »
Hi All,  I have a loop here, have 3 ropes diameter on the nipping loop, and all 3 legs are nipping on the tail.
I think over all is quite nice.

Thanks,    alan lee

X1

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Re: Look alike loops
« Reply #27 on: December 05, 2012, 05:38:53 AM »
   I do not see what you gain by using this very convoluted Pretzel-like nipping structure. that is topologically equivalent to a figure 8 knot... If you transform this loop into a bowline-like (PET) loop, by using a simpler Pretzel-like double nipping loop, and a Myrtle, not an " Eskimo" collar structure, you may tie the loop shown in the attached pictures.
   
« Last Edit: December 05, 2012, 05:42:57 AM by X1 »

alanleeknots

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Re: Look alike loops
« Reply #28 on: March 16, 2013, 11:05:38 PM »
Hi All,   I notice two of the loops I have presented above, there are some room to make some change and improvement.

first set of photo just alter the tail  little bit, it make the loop little more secure and stable.

second set is good looking and quiet secure loop, After heavy object loading on the loop, she still easy enough to untie.
Interesting after I finished with the loop just before I am going to post it, founded out it is one of my loop ( Lee Zep X bowline (V) )rigged it up side down.

Third set also good looking and quiet secure loop. After heavy object on the loop, it seem to have hard time to untie it,
but if you tie the loop with little longer tail , when you untie it, as the last photo, slack off the standing part and pull the tail to the left again the right eye leg, she will come apart.  Hope to hear from you.

Thanks alan lee.


X1

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Re: Look alike loops
« Reply #29 on: March 17, 2013, 01:27:39 AM »
   Hi Alan Lee,
   The eyeknot shown at the right side of the first picture is much better than the one shown at the left, that is for sure. As you say, the last part of the tail is now secured more efficiently in its new position - where it is squeezed by two different segments of the nipping structure, not only by one, as it happened in the previous version. However, I still do not believe that this particular overhand-knot "collar structure" preserves the integrity and the compactness of the crossing-knot nub very well - it seems that ring loading can force the overhand knot to be loosened, and, if that happens, the crossing knot s nub is deformed quite a bid : it "opens up" (more than I would like), and the whole eyeknot is transformed into a peculiar "Eskimo"- looking bowline, where the second eye leg first makes a U-turn around the crossing knot s nub and the first eye leg, and then it enters into the nipping loop from the other side, and collars itself again ! A still secure knot - but a knot which works now in a different way, and has lost its initial compactness.
   I do not understand why you have abandoned your very secure and nice bowline-like loops, and started tying loops based on a single or double overhand-knot nipping structure, like the ones shown at the second and third attached pictures !  :) They are not more secure than the Lee Zep X "bowline", they are not easier to tie or untie, they are not bowline-like knots, and, last but not least, they are not beautiful any more !