Adjustable loop.

[SS369]

There's been some discussion about an adjustable loop for use with a tarp here > http://igkt.net/sm/index.php?topic=4962.0. So not to impose on that thread I'll offer this here.

Some time back I enjoyed a thread concerning a new anchor presented in this thread > http://igkt.net/sm/index.php?topic=4069. I like the simplicity and ease of tying (with bights) and it unties nicely.
Playing around with this configuration I happened upon an adjustable loop. Adjustable by pulling the tail.

It seems to draw up easily every time, holds very well,  and unties easily enough.
It would not necessarily be my pick for say a tent guy line or to hang a tarp, but it could.

SS

[xarax]

   Congratulations, SS369. ( I am not used to tell this very often, do I ?  )
   A real and rear gem, no question about it. It is based on one of the five so-called "fig.9" stoppers, the 5_2 (1). I am dying out of curiosity to tie all the others, but I am leaving it to you, as a homework !  Of course, you have to tie them on the Standing Part both ways/orientations, and then to pass the returning eye leg through all the combinations of the sides and the openings - it will take you some time ! 
   I had a theory, about complex stoppers which "absorb" some of the tensile forces arriving through the Standing End, and so "waste" a portion of them into their multiple turns - which tensile forces would otherwise be able to be transformed into friction forces, and grip the penetrating returning eye leg more efficiently - but, as it happens to all theories, it comes a time when we have to kiss them good buy !  (*)
   Recently ( on the occasion of the TIB adjustable loop tied Bipbip ), I had read again an old  post by a certain guy who has tied everything ( or tells that has tied everything, which is about the same thing... ). I had not understood to which of the 5 "fig.9" stoppers he was referring, but the coincidence is interesting (2).

1. http://igkt.net/sm/index.php?topic=4822
2. http://igkt.net/sm/index.php?topic=2996.msg17880#msg17880

   (*)
   P.S. My other theory, about the right angle ( 90 degrees ) being the optimum, still stands : in your loop, the returning eye leg is "hanged" by an L-shaped "handle', and this is what makes it so efficient.

   P.S. (2). Unless it is already published somewhere else, this thread should be moved straight to the "New Knot Investigations" section.

[xarax]

   The 5_1 stopper is more symmetric than the 5_2 ( See the attached pictures ). It turns out that the asymmetry of the 5_2 is, in fact, beneficial to the gripping ability of the knot, because it forces the returning eye leg to be less straight / more L-shaped - so the "handle" from which the eye is "hanged" has a better (= more suitable regarding its function) form. The (only) difference between the two stoppers is in the over/under relation of the segments at the point inside the red circle. ( See the third attached picture ). In the case of the shown 5_2,  the "under" segment displaces the continuation of the returning eye leg, so this continuation can not occupy its place, and become more straightened and less L-shaped.   

[xarax]

   The fig.9 (5_1) is the most simple "closed" knot, right after the overhand knot - because it is but the overhand knot retucked through the central opening. So, it can not be forgotten, and it can be tied-in-the end in a glance. That made me try to improve the TIB adjustable loop based on it, and I think the result is interesting. The only thing I have done is to rearrange the continuations of the eye legs into the "lower" collar, and that was sufficient to retain the sharp, L-shaped turn of the Tail End that is so important regarding the gripping ability of the nub. Of course, that means that the knot should be dressed carefully, otherwise the Tail End will run the danger to be straightened out, and the nub will not be able to have this useful right-angled "handle" to grip it.
   Regarding the TIB tying method, I have no idea how to simplify the method offered by SS369 - because I have a hunch it may be simplified, indeed. For the time being, I tie the knot only in-the-end, so I can now use the easily/quicly tied, and more good-looking symmetric 5_1, instead of the original 5_2 presented in the thread.
   I hope I will someday be able to compare those two fig.9-based adjustable loop knots with the Pretzel loop (1) and the various Helical loops (2), which do the same job.

1. http://igkt.net/sm/index.php?topic=4464.msg32659#msg32659
2. http://igkt.net/sm/index.php?topic=4949.0

[xarax]

   Speaking of adjustable loops, I remembered the most easily tiable PET adjustable loop I used to tie, before I met the Pretzel loop. Although it is more stable than the Clove hitch-based one, and perhaps even than the Girth hitch based one, it is not as stable as the Pretzel loop. Moreover, it is PET, but not TIB ( the fig.9-based loops shown in this thread are TIB, but they are not PET - to be transformed into TIB, it should be slipped, just as the Clove, Girth and Pretzel loops ), and it is meant to remain in one piece only while it is tensioned, which may be regarded as a disadvantage. However, it is an interesting knot, because it shows how a most simple "open" ( topologically equivalent to the unknot ) nipping structure can be extremely tight and well-balanced, so very efficient in gripping the returning eye leg - when this returning eye leg makes this right-angle, L-shaped deflexion, before it enters into the nub ( from the opposite side from which it exits from it, just like it happens in the "Eskimo" bowlines ), offering a "handle" from which it can be gripped and immobilized. ( See the attached pictures )
 
 1.  http://igkt.net/sm/index.php?topic=3315.msg19890#msg19890

[SS369]

I am wondering what influence, good or bad, the loop legs being parallel vs 90 degrees as they emerge from the nub?

Will the ensuing distortion of the knot enhance the properties or degrade them?

I guess the object around which it is tied will play a part in the answer.

SS

[SS369]

I wasn't bringing my questions up in regards to something you said. No, the exploded pictures (Thank you) instigated the thoughts.

I agree that an enlarged/lengthy eye is best to allow the eye legs the straightest run, just as in an anchoring situation where you don't want to exceed a certain angle (less than 120 degrees) between them.

SS

[xarax]

  I misunderstood your post, sorry. The last two pictures of my previous reply were meant to be tying diagrams only, not pictures of the "exploded" knot. I had taken them because the path of the Standing Part before-the-eye was not shown clearly in the previous two.The "circular" eye served only the "stylistic" attitude of the day, I guess. Such wide-spread returning eye leg would had slipped out of the nub easily : the L-shaped right-angle "handle" on it has been straightened out.

[Dan_Lehman]

   The fig.9 (5_1) is the most simple "closed" knot, right after the overhand knot - because it is but the overhand knot retucked through the central opening. So, it can not be forgotten, and it can be tied-in-the end in a glance

What I see in the photos of this post are NOT
fig.9 but dbl.overhand/strangle knots --nb!

Earlier, is what should be called the "reverse fig.9"
per its orientation of that named structure.

Finally, let me remind folks of the "quick8" eyeknot,
which is made with a fig.8 base, and secure at that.
(Which knot allows a simple further tail-tuck to give
better security.)


--dl*
====

[xarax]

What I see in the photos of this post are NOT fig.9 but dbl.overhand/strangle knots --nb!

   If you had read my previous posts, or if you had remembered what you might had read, you would had known that I call ALL the 5 ( = five ) knots ( the 5_1, 5_2, 6_1, 6_2, 6_3 ), in their stopper like, elongated form, fig. 9 knots. Most people, knot tyers included, are not able to distinguish them...
   They are, regarding topological complexity / number of crossing points, AFTER the fig.8, so I decided to call them fig. 9. The alternative is to call only the 6_1, 6_2 and 6_3 as fig. 9, and baptize the 5_1 and the 5_2, by the silly name fig.8.5 !  (*)
    So, before you see, try to think : you are not the only one who has eyes, you know...

P.S. Another idea would be to call the 5_1 and 5_2 as fig.8+1 knots - meaning : close to fig.8 in form, but with one aditional ( +1) crossing point.

[xarax]

the "quick8" eyeknot,

  I do not know which is this knot - could you, please, provide a reference or picture ?
  I only know the HFP adjustable loop, which is nothing but the fig.8 knot penetrated a-la-"Eskimo" - that is, the returning eye leg enters into the knot s nub - here, the fig.8 - through the opposite side/opening from which it exits from it. It is a fine adjustable loop ( in contrast to other mediocre knots this site contains...), but it is neither PET, nor TIB.

1. http://notableknotindex.webs.com/slippery8.html

[xarax]

Earlier, is what should be called the "reverse fig.9" per its orientation of that named structure.

   No, it can NOT be called that way.
   For two reasons :

   1. If we classify the "closed" knots by the (minimum) number of their crossing points, like the mathematicians do, the knots that have 6 crossing points ( the 6_1, 6_2 and 6_3 ) should be kept separate, and named differently, from the knots that have 5 crossing points ( the 5_1 and the 5_2, on which those two TIB adjustable loops are based ). So, if we retain the name "fig.9" for the knot(s) climbers and cavers call "fig.9", which are the knot(s) with the 6 crossing points ( the knots shown at (1) and at the attached picture ), we can NOT call by the same name either the 5_1 ( the known to us as "double overhand/Strangle" ) or the 5_2 ( shown at the Reply#2, and the pictures there ).

   2. If we decide to classify all the more convoluted than the fig.8 ( the 4_1) knot , collectively as "fig.9 knot(s)" ( as I said earlier, few people, knot tyers included, ever realize the differences...), we can not call the 5_2 as "reverse fig.9" - because, in that case, which, of the five, would be the "not-reversed" fig.9, and which the "reversed" ones ? If we chose this nomenclature, we should call all the 5 knots ( the "double overhand / Strangle included ) as "fig.9 knots" - and that is what I had done. I had thought that the introduction of one more name ( as the "fig.8+1" would had been...) was something that should better be avoided, and, in any case, it was not something I could bear the responsibility to do.

   If the author of those two adjustable loops wishes to name them differently ( as "fig.8+1", or even as "fig.9-1" adjustable loops )(*), I will be glad to follow his choice.

1. http://igkt.net/sm/index.php?topic=4764

(*)
P.S. Perhaps fig.9 / 5 ( and/or fig.9 / 6 ) , meaning a fig.9 form ( so, not a fig.8 form...), but with 5 ( and/or 6 ) crossing points.
It is tempting to use the "Strangle" similitude, but I do not like it, for a reason : the penetrating returning eye leg of those two loops is not immobilized the way it would had happened in a genuine Strangle-based hitch / adjustable loop. The mechanism by which the Strangle grips the penetrating pole/rope is different. 

[xarax]

   The structure of those two fig. 8.5 or fig. 9 adjustable loops ( where the gripping part is tied before the eye ) is similar to the structure of the adjustable loop shown in the attached pictures ( where the gripping part is tied after the eye ). It is a very easy and quick-to-tie gripping noose / hitch - however, for a more sure grip, I would prefer the Pretzel loop (1).

1. http://igkt.net/sm/index.php?topic=4464.msg32659#msg32659

[xarax]

  In general, we can argue that the adjustable loops where the "nipping part" is tied before the eye
  ( so its "higher" end, the continuation of the Standing End, is tensioned by the 100% of the total load, and the "lower" end, the continuation of the leaving eye leg, is tensioned by the 50% of the total load )
  and where the "nipped part" ( which is a more or less straight segment ) is located after the eye
  ( so its "lower" end, the continuation of the returning eye leg, is loaded by 50% of the total load, and the "higher" end, the Tail End, is not loaded at all ) 
   are more tight and secure knots than their corresponding "twins",
   where the "nipping part" is tied just before the Tail End, and the "nipped part" is located just after the Standing End.
   ( I know that this is an unacceptably looong sentence, but, believe me, it makes sense !  )
   A more tensioned nipping part can grip a nipped part more efficiently, and for a less tensioned nipped part, it is more easy to bend a little bit, and more difficult to slip out of the nipping part.
   However, if the Tail does slip, in the first case the eye opens up, and the loop is released, while at the second case the eye closes, and the loop becomes a noose, it shrinks and it encircles the hitched object more tightly... 

[xarax]

   An even simpler adjustable loop, where the Standing Part before-the-eye follows a helical path within the knot tied on the returning eye leg, like the loop at Reply#12 (1) and at (2).

1. http://igkt.net/sm/index.php?topic=4965.msg33532#msg33532
2. http://igkt.net/sm/index.php?topic=4949.msg32608#msg32608