Author Topic: I'm looking for an adjustable loop that won't slip--any ideas?  (Read 17790 times)

djbrenne

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Hi,

I'm brand-new to this forum, and don't have a whole lot of knot-tying experience.

I'm looking for a loop that I can adjust the size of, but will remain at that size after adjustment until I want to adjust it again. The loop would be usually under tension, but there are times when it would be slack, and I don't want the loop adjusting its size by itself in the event that it does go slack. I've tried an Adjustable Grip Hitch, which serves my purpose reasonably well--except that I'm tying very small thread (nylon, 0.36 mm / 0.014" diameter) in a very tight space, and even with a jig I made up it's difficult to tie properly without taking 10 minutes or more... The point of the loop is to adjust the tension in the string by changing the effective length.

If anyone has an idea of a simpler knot that serves the same purpose, or another method of string tensioning altogether I'd be glad to hear about it.

roo

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Re: I'm looking for an adjustable loop that won't slip--any ideas?
« Reply #1 on: May 14, 2015, 12:03:21 AM »
Hi,

I'm brand-new to this forum, and don't have a whole lot of knot-tying experience.

I'm looking for a loop that I can adjust the size of, but will remain at that size after adjustment until I want to adjust it again. The loop would be usually under tension, but there are times when it would be slack, and I don't want the loop adjusting its size by itself in the event that it does go slack. I've tried an Adjustable Grip Hitch, which serves my purpose reasonably well--except that I'm tying very small thread (nylon, 0.36 mm / 0.014" diameter) in a very tight space, and even with a jig I made up it's difficult to tie properly without taking 10 minutes or more... The point of the loop is to adjust the tension in the string by changing the effective length.

If anyone has an idea of a simpler knot that serves the same purpose, or another method of string tensioning altogether I'd be glad to hear about it.

Try an HFP Slippery 8 Loop
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Dan_Lehman

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Re: I'm looking for an adjustable loop that won't slip--any ideas?
« Reply #2 on: May 14, 2015, 07:44:59 AM »
Try an HFP Slippery 8 Loop.

Ah, David Poston --vague recollections of him, yes.

And was I at that time aware of my "quick8"
--which is simply what is presented but with the
tail running through the opposite direction
(and suprisingly holding well!) !?

But this structure requires that one has a pretty
good idea of some range of needed adjustment
--or you tie with a really lonnnng tail!
Whereas with the Adjustable hitch, one can just
slide the knot farther and farther out the S.Part
of the *noose*.

--dl*
====

xarax

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Re: I'm looking for an adjustable loop that won't slip--any ideas?
« Reply #3 on: May 14, 2015, 12:52:19 PM »
   The Dave Paston s adjustable loop is much more secure than the quick8 adjustable loop, IMHO. The L-shaped curve, the "handle", on the returning eye leg does a marvellous job, in all such "Eskimo-like" loops.
   However, both of them are clearly inferior, as adjustable loops and as knots ( they are not TIB, for example...), than the simple Pretzel loop, shown in the attached picture.
   Will anyone of the gentlemen that had suggested those two loops EVER tie and try the Pretzel loop ?  Noope ! Will they ever "see" that it is more secure, more stable/balanced, more simple, more clever, more versatile knot ? NEVER !  :) :) :)
   Knot tyers are those who tie their own knots - and ignore everything else... ( However, this is probably the case with artists, in general ? )
« Last Edit: May 14, 2015, 12:53:21 PM by xarax »
This is not a knot.

Mobius

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Re: I'm looking for an adjustable loop that won't slip--any ideas?
« Reply #4 on: May 28, 2015, 12:56:06 PM »
Hi djbrenne,

This link https://docs.google.com/presentation/d/1t-0bR8AlFeRkraqoRLC7ODwEVJAwxY0e-J-UQCBLA_M/edit?usp=sharing shows an adjustable loop I may have discovered and thought I had no real use for (or for anyone for that matter). I had to call it something, so for now it is a 'Locked Transom Loop'. I'm quite happy to change that if this isn't a new knot.

Later It occurred to me that the simple overhand knot sliding mechanism part could easily be sandwiched between the the two eye collars and 'locked'. When the knot cinched the opposing sliding parts of the knot would want to tighten against each other in a similar way a Fisherman's Bend does. Unlocking it and resizing the eye via the overhand will remain easy if you tie this knot with a suitably long tail and just tug it free after loading and slid it again.

The tying method I show is 'tiable in the bight' (TIB). If that is not suitable for you can find a way to tie it 'around an endless rail' from the expanded knot views I also show. Doing it that way won't be so nice and I have not worked on a tying method for that. Edit: You can tie a rather unusual pre-knot shaped like an 8 to start with, then pass the end around an endless rail and back through the pre-knot and then do an overhand around the standing part. This method is convoluted enough to put most off this knot I suppose.

This knot is not 'post eye tiable' (PET) for what that missing quality may mean to you and I have not tested it on my rig. If you want to do something critical with it I can trial it for you, however any trialling I do is only intended to be a guide, not a guarantee.

Cheers,

mobius

Edit: Added two more images that show the knot dressed in a better form, probably the best. I trialled the knot in this form and it held its structure and eventually broke at 140Kg (3mm poly braid breakload 200Kg). The final image is the broken knot.

Edit: Removed first image, the 'best dressing' images are better and renamed this knot to:  'Locked Transom Loop'. The figure 8 like pre-knot is a Transom/Strangle knot.
« Last Edit: June 14, 2015, 09:41:36 AM by mobius »

Sweeney

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Re: I'm looking for an adjustable loop that won't slip--any ideas?
« Reply #5 on: May 29, 2015, 10:36:46 AM »
However, both of them are clearly inferior, as adjustable loops and as knots ( they are not TIB, for example...), than the simple Pretzel loop, shown in the attached picture.
 

Nice knot Xarax which holds well and is quick and easy to tie.

xarax

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Re: I'm looking for an adjustable loop that won't slip--any ideas?
« Reply #6 on: May 29, 2015, 10:52:12 AM »
   I believe that the more complex / convoluted the nipping / gripping nub becomes, the less efficiently it can nip / grip a penetrating line. In a complex / convoluted nub, a considerable portion of its overall constricting power will be "wasted' within itself. Some segments of the nub which surround the penetrating line will not be directly pulled and tensioned by the Standing End, and so they will not squeeze the penetrating line very much. On the contrary, some of them will form a kind of a "protective shield" around it, and they will absorb a part of compression which otherwise ( in a simpler, less tangled but more tightly closed around itself nub ) would had been able to reach it directly, and press/squeeze them a more unobstructed, so more efficient way.
   Multiplying the points and increasing the total area of contact between the nipping / gripping nub and the penetrating line, is a poor strategy. In fact, what we should better do, is the exact opposite : fewer points, smaller area, so greater, more efficient concentration of the pressure applied by the nipping / gripping nub on the surface of the penetrating line. This way the cylindrical surfaces of the adjacent segments will be squeezed locally, they will settle into a saddle-shaped forms , and this will multiply the friction forces between them. Otherwise, the two segments will run the danger to slide on each others flat surface, and the total friction forces will be reduced.
   The great example of this is the nipping / gripping efficiency of the opposed bights locking mechanism : Few points and small area of contact - but of unobstructed, direct contact, between a short segment of the penetrating line and the fully tensioned segments at the first curves / tips of the two bights.
   
   Of course, the shape of the path of the penetrating line is of paramount importance, too. An L-shaped path, plays the role of a "handle", by which the nipping / gripping nub can 'hold" the penetrating line more easily. ( A U-shaped path is even more effective, but it can not be used in adjustable loops, because either it will prevent any pull of the Tail End during the adjustment of the size of the eye, or it will force the nub itself to be deformed badly during this adjustment, and allow the U to become straightened out, and release the penetrating line. )   
    Another way we can increase friction on the penetrating line, is, simply, to use a knot that we know it jams ! I have seen that the humble Clove hitch, when tied around a segment of a compressible material / a rope, "closes" around itself very tightly, and "works" as a tensile forces accumulator, a rope-made ratchet which absorbs all induced through its ends tensile forces, but then "locks" them securely inside its two wraps.
   In short, to increase friction, we should either increase quantity of friction= increase the number of helical turns around a nipping / gripping coil, just as we do in climbing hitches - OR increase quality of friction = reduce the complexity of the nipping / gripping nub, reduce the number of points and the area of contact between this nub and the penetrating line, but :
1. Be sure that the segments of the nub which come in contact with the penetrating line are at the direct continuation f the Standing End, and so maximally loaded / tensioned. It is the first curve which does most of the job, the segments of the nub after this play a secondary, only, role.
2. The penetrating line follows an L-shaped path within the surrounding nub.
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alanleeknots

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Re: I'm looking for an adjustable loop that won't slip--any ideas?
« Reply #7 on: May 29, 2015, 11:53:29 PM »
Hi All,
         I have this convoluted wan't slip adjustable loop here, can support heavy load and easy to readjust loop.

        First test, with 1/2 inch solid braid nylon rope, after loading with 650 lbs. I find no problem to loose the nub and readjust the loop.
        Second test with 1/4 inch solid braid nylon rope, after loading with 650 lbs. I found little harder to loose the nub for readjusting
        loop. (I guess alots of knots when we tie it with smaller size rope and loaded heavily can create some difficulty to untie) 
 
       Xarax can you please tell me something.
     
       謝謝  alan lee.
« Last Edit: May 30, 2015, 12:05:03 AM by eric22 »

alanleeknots

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Re: I'm looking for an adjustable loop that won't slip--any ideas?
« Reply #8 on: May 30, 2015, 12:00:55 AM »
Hi All,
         I like the look of the loop, but it will jam even with medium load.       
       
         謝謝  alan lee.

« Last Edit: May 30, 2015, 12:04:30 AM by eric22 »

Mobius

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Re: I'm looking for an adjustable loop that won't slip--any ideas?
« Reply #9 on: May 30, 2015, 12:57:59 AM »
..... (I guess alots of knots when we tie it with smaller size rope and loaded heavily can create some difficulty to untie) 
 
            謝謝  alan lee.

I concur with that statement FWIW. I am only trialling 3mm poly braid, however knots that are supposed to be 'easy untying' can take some patience to free by hand after a load. I came to the conclusion that any knot I could spend a few minutes on and actually untie by hand was 'easy'. Eg. a Zeppelin Bend after load using my material still takes some patient prying apart.

Cheers,

mobius
« Last Edit: May 30, 2015, 01:06:59 AM by mobius »

xarax

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Re: I'm looking for an adjustable loop that won't slip--any ideas?
« Reply #10 on: May 30, 2015, 02:22:00 AM »
   @Alan Lee
   I had replied to your posts at Reply#6 - which I wrote after I had read the first versions of your posts, and I had seen the first pictures of your knots.
   In short, I do not like the facts that :
   1 : The "higher" limb of the overhand knot is not pulled directly by the continuation of the Standing End, which carries the 100% of the load - therefore the overhand knot itself can not close very forcefully / tightly around itself, and around the penetrating line.
   This rather complex / convoluted nipping / gripping structure is made of two distinct, almost separate parts, placed the one after the other :  a "higher" crossing knot-based one ( the second line of defence against the slippage of the penetrating line ) which is OK ( its first curve does encircle the end of the penetrating line, exactly as it should ) - AND a "lower" overhand knot-based one ( the first line of defence against the slippage of the penetrating line ) which I find more weak than it should be : this weakly loaded overhand knot remains rather loose, and its participation in the combined nipping / gripping action of the whole structure on the penetrating line is almost insignificant ! In other words, I have the feeling that the help it offers against the slippage of the penetrating line is not worth the amount of material it consumes...
   2 : The curve at the end of the penetrating line / returning eyeleg is too smooth and wide : for best results, it should be more L-shaped. You may had placed this overhand knot not (only) to help the crossing knot in the nipping / gripping of the penetrating line, but (also) to achieve a sharper, narrower curve, but I think that the result was not as pronounced as we would had wished.  See some nipping / gripping structures as complex / convoluted as this, but based on double overhand knots, where such L-shaped curves make more secure "handles", at :
http://igkt.net/sm/index.php?topic=2996.msg17841#msg17841
http://igkt.net/sm/index.php?topic=2996.msg17842#msg17842
http://igkt.net/sm/index.php?topic=2996.msg17843#msg17843
« Last Edit: May 30, 2015, 02:24:49 AM by xarax »
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Mobius

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Re: I'm looking for an adjustable loop that won't slip--any ideas?
« Reply #11 on: May 30, 2015, 06:34:38 AM »
I trialled the Pretzel Loop in 3mm poly braid. The first diagram is how I tied it. I cinched this form as tightly as I could, bearing in mind you cannot tighten the nub using one of the eye legs since it isn't fixed. Perhaps this is going to be a disadvantage for some adjustable loops where you cannot 'lock' the eye legs prior to load.

The knot moved so much during the trial it changed structure into the form I show in the second image (sorry for the image quality I kept retaking shots and no matter what I did with my camera and lighting it turned out less than ideal).

I think it fair to say the knot collapsed (it somehow ended up almost inside out, though you won't see that I think from my image), though it did seem to reach a stable form eventually. I was able to undo this collapsed stable form and return the knot to its original structure easily.

Cheers,

Mobius

Edit: Just did another trial and dressed the knot differently than the first trial. This time the knot held form to over 105Kg. I didn't take it to break, I wanted to see if it untied easily, it did.
« Last Edit: May 30, 2015, 09:00:23 AM by mobius »

Mobius

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Re: I'm looking for an adjustable loop that won't slip--any ideas?
« Reply #12 on: May 30, 2015, 08:14:09 AM »
I trialled the knot roo suggested. The HFP Slippery 8 loop was easy to tie (image shown below, just to make sure I did it right). The knot held it's form throughout the loading and broke at ~150Kg. That is the highest break I have seen on my rig with the 3mm poly braid I am using.

Cheers,

mobius
« Last Edit: May 30, 2015, 08:16:38 AM by mobius »

xarax

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Re: I'm looking for an adjustable loop that won't slip--any ideas?
« Reply #13 on: May 30, 2015, 01:25:37 PM »
   As I had tried to explain in Reply#6 (1), ANY simple enough, stable knot would nip/grip a penetrating line / a returning eye leg very efficiently, if this line enters in it and exits from it in the proper, optimum "Eskimo" like way, and follows an L-shaped path. The only thing we should avoid, is a too convoluted / too complex nub, which will absorb a great portion of the tension that otherwise would had reached the penetrating line more directly, without being dissipated across a larger area of the nub, or being obstructed by loosely tensioned segments. Back in 2011 I had tied all the possible variations of such knots, based on a Double overhand knot core, but then I had abandoned them because I had focused on TIB knots ( which could also be used in PET adjustable loops ) (2)(3)(4). An example of such a PET loop, which may be considered as a variation of the "Eskimo" bowline itself ( a "doubled" variation ), was presented at (5).
   Is this search for tighter nipping / gripping nubs over ? Not at all ! There may be many very efficient such nubs waiting for us out there - however, personally, I have concentrated my efforts on the TIB ones, so my options are fewer.
   The most simple Double overhand knot - based adjustable loop, is shown at the attached pictures. Notice the L-shaped "handle", and the contact between its tip and the most heavily loaded / tensioned part of the Standing Part of the nub, its first curve.   

1. http://igkt.net/sm/index.php?topic=5322.msg35742#msg35742
2. http://igkt.net/sm/index.php?topic=2996.msg17841#msg17841
3. http://igkt.net/sm/index.php?topic=2996.msg17842#msg17842
4. http://igkt.net/sm/index.php?topic=2996.msg17843#msg17843
5. http://igkt.net/sm/index.php?topic=4340.msg27168#msg27168
« Last Edit: May 30, 2015, 01:28:21 PM by xarax »
This is not a knot.

Mobius

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Re: I'm looking for an adjustable loop that won't slip--any ideas?
« Reply #14 on: May 30, 2015, 01:58:16 PM »
Tex started this thread http://igkt.net/sm/index.php?topic=5358.0 and the knot he describes there is, I believe,  a simple Noose Knot with a half-hitch securing it. The image below is what I think the knot he describes looks like. if so this simple knot seems to be a reasonable candidate for the required application.

A similar idea to the knot I proposed, however it is far less convoluted, though maybe not as secure. It is certainly easy to tie, size, and then cinch and 'lock' the eye in place.

Cheers,

mobius