Author Topic: Helical loops  (Read 10137 times)

xarax

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Helical loops
« on: July 04, 2014, 06:15:07 PM »
   When the ( common, standard ) bowline is heavily and unfavourably loaded  ( "unfavourably", regarding its "balance", the alignment and distribution of the tensile forces running along its three limbs ), its nipping loop may "open up", and degenerate into an open helix. Therefore, if the nipping loop of a bowlinesque eyeknot IS an open helix already, then this eyeknot has nothing more to fear !  :)
   It turns out that, if the knot tied on the Standing Part after the eye ( post the eye ) is wrapped and squeezed by a helical structure tied on the Standing Part before the eye, the returning eye leg can be firmly attached to the line, without being entangled within a "closed" nipping loop. ( If we do not trust the single helical turn, we can always add another one). I have shown a number of such "helical" loops, where the knot tied on the Standing Part after the eye is a fig.8, a Constrictor, a Strange, etc, ( 1)(2)(3) . They seem to be secure, good-looking, and probably very strong eyeknots as well ( strong, because the first curve of the Standing part is very wide ), and I believe they should be examined further.

1. http://igkt.net/sm/index.php?topic=3020.msg21688#msg21688
2. http://igkt.net/sm/index.php?topic=3020.msg22086#msg22086
3. http://igkt.net/sm/index.php?topic=4343.msg27191#msg27191
« Last Edit: July 04, 2014, 06:16:21 PM by xarax »
This is not a knot.

xarax

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Re: Helical loops
« Reply #1 on: July 05, 2014, 11:38:28 AM »
   The Strangle is also a tight knot which can be tied on the returning eye leg ( the Standing Part after the eye ), inside the core of the helical nipping loop. The advantage in this case is that the two collars are wider, as they now turn around two rope diameters - the disadvantage is that, when the eyeknot is ring-loaded, the second/"lower" collar is forced to widen even more, and the nub may be deformed a little bit.
« Last Edit: July 05, 2014, 11:39:43 AM by xarax »
This is not a knot.

xarax

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Re: Helical loops
« Reply #2 on: July 05, 2014, 11:41:08 AM »
  The Strangle core, squeezed inside the surrounding helical coil.
  Note : If the "yellow" segment passes under the "red" one, before it exits from the nub ( so, if, inside the helical coil, those two segments are twisted around each other - as they are in an ordinary Strangle - and not parallel to each other ), the loop becomes TIB ( See the second attached picture ). However, this does not mean much, because there does not seem to exist a simple way we can tie this knot in-the-bight. The only advantage is that we can un-tie it easily. Now, I can not imagine a situation when, although we have to tie the loop in-the-end, we would gain something because we can un-tie it in-the-bight, without using the ends...
« Last Edit: July 05, 2014, 03:12:55 PM by xarax »
This is not a knot.

xarax

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Re: Helical loops
« Reply #3 on: July 05, 2014, 05:22:03 PM »
   Even a very simple structure ( much simpler than a Constrictor or a Strangle ) can become sufficiently tight around itself, so securely self-locked, if it is squeezed inside the helical nipping coil. See the attached pictures of a helical loop based on an S-shaped knot tied on the returning eye leg. The way the pair of the eyelegs, on the one hand, and the pair of the Standing and Tail Ends, on the other, are interweaved within the "lower"/second and the "upper"/first collars, respectably, explains the efficiency of this very simple locking mechanism.
This is not a knot.

xarax

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Re: Helical loops
« Reply #4 on: July 07, 2014, 11:38:31 AM »
   One of my favourite helical loops is the one shown at the attached picture : the knot tied on the returning eye leg is the 5_1 stopper (1). As I had mentioned in Reply#2, this loop is TIB - but I have not found an easy way to tie it in-the-bight - so perhaps I should only say that it is UTIB ( un-tiable-in-the-bight:). The reader who would like to tie and try all those loops for the first time, should better tie them first on a short piece of rope, in the "reversed" way : starting from a somewhat tightly dressed knot / stopper he would decide to tie on the returning eye leg, after the eye ( tightly dressed, so it will retain its initial form though out the tying procedure ), then forming the eye, and then driving the Working End "backwards", towards the Standing End : first tucking it through the second/"lower" collar by the one or the other side of it, then forming one, two or even three left- or right-handed helical nipping turns around the stopper, and finally tucking it through the first/"upper" collar.
   I have no idea which one of all the numerous combinations would be proven to be the more stable and strong, under heavy loading - because that is the raison d etre of those loops, IMHO... Most of them are beautiful knots, because of this elegant helical belt around their slim waist, and because of their symmetry. Moreover, the helical coil can be translated along the Standing End very easily, so, even if they are fixed loops, the size of their eye is easily adjustable, However, even those advantages may not be enough, if these loops do not offer something more than what a simple secure, TIB, easily tied and untied bowline does - and I believe that this may be better stability and/or greater strength. 

   1.  http://www.math.jussieu.fr/~koseleff/knots/kindex1.html
« Last Edit: July 07, 2014, 11:40:15 AM by xarax »
This is not a knot.

xarax

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Re: Helical loops
« Reply #5 on: July 07, 2014, 01:56:27 PM »
  To tie a not only TIB, but easily-TIB helical loop, we have to use yet another collar - which may seem too much, regarding the required ropelength... I am always reluctant to use such a not-functioning, structurally, collar, which is needed only to facilitate its tying by the knot tyer, but plays no role in the security and/or strength of the knot itself.
  See the knot shown in the attached pictures : to tie it in-the-bight, after we form the helical "tube" and the eye of the loop, we have to form a bight, reeve it "upwards" through the helical coils, and tie the first/ "upper" collar with-the-bight, then reeve it through the helical coils again, this time "downwards", and finally reeve the eye of the loop through it.
This is not a knot.

enhaut

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Re: Helical loops
« Reply #6 on: July 18, 2014, 07:20:40 PM »
 :o
Just one person?
This thread needs a visitor.
Since I am polite, I dont come empty handed;
this loop utilized 2 inversed helical loops, and as in your offerings (expect the last) the tag end comes out nicely pointing upward.
This tag end makes some hard turns to finish this way, maybe weekening the rope at some point.
I have tried without success to jam it using soft rope, the bottom nipping turn (near the big eye) always stay supple and pliable.

xarax

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Re: Helical loops
« Reply #7 on: July 18, 2014, 07:53:27 PM »
   In those loops, the helix is formed on the Standing Part before the eye ( on the "nipping structure", where it replaces the nipping loop of the common bowline ), not after the eye ( on the "collar structure", where it replaces the collar of the common bowline ).
   Moreover, the conjectured/claimed advantage of this mechanism, is the wide curvature of the continuation of the Standing End, which bears 100% of the load. If one uses a double helix, he would be forced to use two narrow "helical tubes", which would take back any advantage there may had been offered in the first place.
This is not a knot.

Luca

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Re: Helical loops
« Reply #8 on: July 19, 2014, 03:47:16 AM »
Hi enhaut,

The first picture below represents an exploded version of what seems to me to be your loop above.
The second picture represents the presumed loop before starting to load it.
The third picture represents the presumed loop after a no so high loading.
The fourth represents a lightly exploded version(because in the third image  perhaps not it appears very clearly what happened) of the loop after the load(in all three the pictures with the black background the standing end is the strand of rope at the bottom right).
So it seems that in this case a nipping loop that wraps around a single diameter of rope, not only causes a problem with regard of the strength of the knot, but perhaps even more (if I executed the knot as you show) for its stability.

                                                                                                                                         Bye!





xarax

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Re: Helical loops
« Reply #9 on: July 19, 2014, 09:17:54 AM »
  @Luca

  I see you have discovered the CAMERA:) Great invention ! However, you should not forget the laws of optics ! ( 1: How the light - of the flash, for instance - is reflected on the surface, so you should better tilt the camera a little bit, not point it perpendicularly on the surface, and the object lying on this surface. 2 : How we take focused pictures ) :)
   As I said in my previous post, this loop has no relation to a Helical loop whatsoever. If we should include it in a broader class of bowlines, we can say that it is a form of the Braided bowline tied by SS369 (0), where the continuation of the returning eye leg and the Standing End ( the Standing Part "above" the nipping loop ) are braided to each other.
   Another similar bowline is the Double Harness loop (1), where the one link ( the corresponding to the "collar structure" ) is retucked once more - although differently than it is in the Valentine s bend (2).

0. http://igkt.net/sm/index.php?topic=4283
    http://igkt.net/sm/index.php?topic=4701
1. http://igkt.net/sm/index.php?topic=3984
2. http://igkt.net/sm/index.php?topic=4662.msg30140#msg30140 
« Last Edit: July 19, 2014, 09:29:25 AM by xarax »
This is not a knot.

enhaut

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Re: Helical loops
« Reply #10 on: July 19, 2014, 01:36:10 PM »
Thanks Luca,
You almost got it right.
Look at my exploded version, the tag end goes between the two helixes.
These are the hard turns I was talking about.
Maybe you can explain what a high loading is in case I want to try it myself?
How old is your rope?  :P

Anyway as Xarax pointed out it is a form a Braided bowline and I am glad to know it, thanks!

Ps, Luca, I had to use a flash too (morning here) but I did it holding a piece of paper in front of the bulb deflecting the hard light 8)

enhaut

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Re: Helical loops
« Reply #11 on: July 19, 2014, 07:01:04 PM »
Black tape, who cares?
Not the place to expose niceties.
It's totally on purpose, for didactic reasons one should at first glance establishes where the tag end lies.

Luca

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Re: Helical loops
« Reply #12 on: July 22, 2014, 01:28:40 AM »
Hi xarax and enhaut,

I see you have discovered the CAMERA:) Great invention ! However, you should not forget the laws of optics ! ( 1: How the light - of the flash, for instance - is reflected on the surface, so you should better tilt the camera a little bit, not point it perpendicularly on the surface, and the object lying on this surface. 2 : How we take focused pictures ) :)

I had to use a flash too (morning here) but I did it holding a piece of paper in front of the bulb deflecting the hard light 8)
 

Thank you. For me, that I don't have practically any experience with photography(either digital or analog), it's like having just broke through a door... for now I'm going around the rubbles of this door ...please be patient,I hope to explore over and to do better in the future...(but in any case it is the camera of a smartphone that I did not pay so much ...)

You almost got it right.
Look at my exploded version, the tag end goes between the two helixes.
These are the hard turns I was talking about.

Thanks for your picture of the exploded knot:I think I got the knot in the right way:in my ugly picture maybe is not very clear as it comes out the tail, but in my opinion is as in your picture, which, it is true, shows an exploded version of the knot that is more respectful of his real geometry(but the hard turns ( that I personally not really like in a loop, especially with regard to his nipping turn) should be visible in my second picture above).

Maybe you can explain what a high loading is in case I want to try it myself?

I think that do not know what it means "high loading" :-[ (maybe it sounds like " loading from the top"? ;D), perhaps "heavy loading" is more correct, but also this I do not even know what it means;maybe I know what it mean a " not so heavy loading ".
Anyway not only xarax has its own laboratory,I too have my laboratory( ::))(the picture below:for now it is better that you continue to use the dark glasses .. 8)):I use this represented version of the Trucker's hitch,grabbing the end of the rope,with the back on the floor,with the knees bent and the feet against the side of the couch, after that,I stretch out my body as much as possible, pulling the end of the rope(the couch is robust, yet for now I am confident that the armrest will not flights against my face ... :o)

How old is your rope?  :P

I love my old, white(well,not more so white)rope! And it's not so old, is that it has made ​​a life full of excesses!

Anyway as Xarax pointed out it is a form a Braided bowline and I am glad to know it

Some details on the trials that I have made with the loop that you showed us(perhaps in some cases it may be useful to use a worn rope to highlight the flaws of a knot? :-\):I tried the loop four times: three times it happened what I show with the images above(the time that has not happened,the phone rang while I began to load the loop;I went to answer the call, and when I came back,I finished loading the loop, which in this case was not capsized(! ???)).

                                                                                                                       Bye!






 
















« Last Edit: July 22, 2014, 04:58:15 AM by Luca »

enhaut

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Re: Helical loops
« Reply #13 on: July 22, 2014, 02:47:44 PM »
Luca
You made a different loop.
Look carefully please at the attached pictured.
On your rendition of the loop I have traced white lines, when the flow is disrupted it means that the strand goes under, ok?
Consider the exits you will understand.

xarax

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Re: Helical loops
« Reply #14 on: October 17, 2014, 03:54:08 PM »
   To this day, I have not managed to figure out an easy way to tie the TIB Helical loop based on the Strangle, shown in previous posts, in this and other threads. It can be tied sooo easily in-the-end, and can be untied sooo easily in-the-bight, but not vice versa !  :) :)
   Of course, one can always tie the two-collar version of the Helical loop based on the simple S-shaped collar structure, shown at Reply#5 (1), which can be tied easily in-the-end as well as in-the-bight - but I do not really like the redundant, functionally, second collar around the Standing End... ( The same thing I had confessed for a beautiful, yet a little bit portly lady, of the genuine Zeppelin clan, shown at (2)). Without the second collar, the loop is still TIB, but the collar structure becomes too simple and rather loose - it can not keep the two collars ( the "higher", around the Standing and Tail Ends, and the "lower", around the eye legs ) at a fixed distance to each other : I feel that the helical coils of the nipping structure, under heavy loading, will "spread" along the nub ( which, in its turn, will become very elongated...), their angle with the lines of the "core", the collar structure around which they are coiled, will become too small, and so they will lose their firm grip on them : then we will need many more wraps to obtain the same result, because lines that meet each other obliquely, and not with angles near the optimum angle ( the right angle ), can not "bite" each other hard and deep, so they tend to slide on each other. ( Moreover, the "lower" collar becomes too narrow...). In any case, any simple S-Shaped collar structure can not be as compact, tight and secure as the Strangle-based collar structure. So, I would be glad if anybody out there would be able to discover some way to do this -  the Helical+Strangle loop is a new, very interesting TIB loop, and it would be a pity if its TIBness can not be utilizable...

1. http://igkt.net/sm/index.php?topic=4949.msg32622#msg32622.
2. http://igkt.net/sm/index.php?topic=4095.msg28458#msg28458
« Last Edit: October 17, 2014, 07:14:54 PM by xarax »
This is not a knot.