Author Topic: "Lehman8" and "Zeppelin loop " - which is more difficult to untie ?  (Read 20500 times)

xarax

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   I am really curious, which of those two systematically ( I would say, relentlessly...) advertised/promoted loops is worse, regarding un-tiability. As they both include "closed" knots ( rope-made self-locking "tension ratchets" ), overhand / fig.8 knots tied on the Standing part before / after the eye, they are perfect examples of why the bowline ( and its derivatives) is the King of knots, while they are only some, let is say that way, would-like-to-become princes ( but, for the time being, "locked" in an altogether different kingdom  :) :) :) ).
   Taking into account that they become difficult to untie too early, after they are loaded by a small, only, portion of the MBS of the knot ( perhaps because they were designed to do so in the first place...), as roo correctly points out, their testing is just plain realistic, and the tester would not "put [him]self at risk of serious injury". Therefore, I wonder why nobody had performed this test till now ! :)  This enables some really bad, malicious guys, who just practice "rubbish keystrokes of derision", while they live and "work in a space w/o gravity or materials and just knot their minds tight against tangible aspects", but only prefer to speak out the truth about the knots they had tried, to criticize those loops unfairly !
    I will offer a pot with delicious raspberry jam to the need-not-be-so-brave knot tyer who will test those two distant-future princes of knots, and compare how difficult they can be untied even after moderate loading.
« Last Edit: June 20, 2015, 02:07:17 PM by xarax »
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agent_smith

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Re: "Lehman8" and "Zeppelin loop " - which is more difficult to untie ?
« Reply #1 on: June 19, 2015, 10:30:16 PM »
Quote
This enables some really bad, malicious guys, who just practice "rubbish keystrokes of derision", while they live and "work in a space w/o gravity or materials and just knot their minds tight against tangible aspects", but only prefer to speak out the truth about the knots they had tried, to criticize those loops unfairly !

Not sure about the taunts and vitriol but, I could give this a shot maybe on Sunday.

The problem Xarax is that all of these types of tests cost money and time.

And I have in general terms backed away from simplistic strength testing over the years. However, I do support strength testing if its well thought out and advances our understanding of certain knot geometries.
For example, testing single helix nipping structures against double helix nipping structures with both having the standard 2 rope diameters inside the nipping structures.... And then - moving on to the 3 rope diameters inside a single helix nipping structure and then followed by 3 rope diameters inside a double helix nipping structure and so on.... I would support this type of progressive testing to identify what effect one change has over another.

The other aspect related to strength testing that I support is zeroing in on what makes a particular knot structure jam resistant. So - while applying force to a knot, perhaps stopping at a certain milestone of force and then determining if the knot can still be untied (relatively easy) by hand - and without resorting to the use of tools.

I think I have some 7mm or 8mm climbing accessory cord lying around.... I've still got a load cell and also a 2 ton lever hoist.

You see Xarax, a load cell is not cheap ($$$). Breaking larger diameter cord costs money and is not without risks and, it all takes time. Maybe that's why you don't see a lot of well documented knot tests??

xarax

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Re: "Lehman8" and "Zeppelin loop " - which is more difficult to untie ?
« Reply #2 on: June 19, 2015, 10:58:51 PM »
testing single helix nipping structures against double helix nipping structures with both having the standard 2 rope diameters inside the nipping structures.... And then - moving on to the 3 rope diameters inside a single helix nipping structure and then followed by 3 rope diameters inside a double helix nipping structure and so on....

   It would so nice to test all those things, would nt it ?

zeroing in on what makes a particular knot structure jam resistant. So - while applying force to a knot, perhaps stopping at a certain milestone of force and then determining if the knot can still be untied (relatively easy) by hand

   I had proposed the 1/2. 1/3 and 1/4 of MBS of the unknotted rope as those benchmarks / milestones.
   The problem here is that a knot can be untied using many "tricks" : by pulling bights, by rotating parts of the knot relatively to others, by pushing ends inward, etc. How can we tell if such a manoeuvre is "easy" or not ?

Breaking larger diameter cord costs money and is not without risks and, it all takes time. Maybe that's why you don't see a lot of well documented knot tests??

   Let us be sincere ! It is NOT that ! I know dozens of sports and hobbies which require MUCH more money, for equipment, running expenses, repairs, etc. - and MUCH more time !
   Our problem is that we are too few, period ! Knotting is out of fashion, young people just do not see the point of this activity, which seems akin to an era long gone and forgotten... Also, not-so-young knot tyers can not learn new tricks any more, they do not try to tie new knots, they try to convince themselves that they already know anything worth knowing, and they keep parroting the same things over and over again, in an effort to believe they are still alive.

P.S. You don't need any load cell ! You can just use a hydraulic bottle, and record the pressure.
« Last Edit: June 19, 2015, 11:16:45 PM by xarax »
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Mobius

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Re: "Lehman8" and "Zeppelin loop " - which is more difficult to untie ?
« Reply #3 on: June 27, 2015, 01:25:40 AM »
   I am really curious, which of those two systematically ( I would say, relentlessly...) advertised/promoted loops is worse, regarding un-tiability. As they both include "closed" knots ( rope-made self-locking "tension ratchets" ), overhand / fig.8 knots tied on the Standing part before / after the eye, they are perfect examples of why the bowline ( and its derivatives) is the King of knots, while they are only some, let is say that way, would-like-to-become princes ( but, for the time being, "locked" in an altogether different kingdom  :) :) :) ).
   Taking into account that they become difficult to untie too early, after they are loaded by a small, only, portion of the MBS of the knot ( perhaps because they were designed to do so in the first place...), as roo correctly points out, their testing is just plain realistic, and the tester would not "put [him]self at risk of serious injury". Therefore, I wonder why nobody had performed this test till now ! :)  This enables some really bad, malicious guys, who just practice "rubbish keystrokes of derision", while they live and "work in a space w/o gravity or materials and just knot their minds tight against tangible aspects", but only prefer to speak out the truth about the knots they had tried, to criticize those loops unfairly !
    I will offer a pot with delicious raspberry jam to the need-not-be-so-brave knot tyer who will test those two distant-future princes of knots, and compare how difficult they can be untied even after moderate loading.

Well xarax, I was brave enough. However my results will be easily dismissed (by some) I suppose  ;)

Both knots were tied and dressed properly I believe, I spent quite some time making sure I did both knots justice. I loaded both the Zeppelin Loop and the Lehman8 to slightly greater than 50% MBS (~100kg in my stiff 3mm braid). Both knots did not noticeable slip and were easily untied after this high load.

To put the above result in perspective: I also tied a Figure 8 Loop and loaded that to 100kg as well and now I cannot untie that knot by hand. In the past I have tied numerous bowlines and trialled them for jamming, all the ones I trialled could be untied. I have recently trialled some  "constrictor" style (TIB, PET) loops in a recent thread only to find I could not untie those. I have tied the Zeppelin bend and heavily loaded it in the past and successfully untied it, though that was actually quite difficult. The point being is that my trials seem to support previous findings eg. Findings such as: Bowlines can be untied and the Figure 8 loop has the propensity to jam.

To answer xarax's question, the Lehman8 was slightly the more difficult to untie, though easier than some of the bowlines I have tackled. I am starting to get a good feel for what jams and what does not, and some of the 'why'.

If Mark does do some trials of the two knots above, in larger diameter rope, then I will be very interested in the result he gets.

Cheers,

mobius


Mobius

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Re: "Lehman8" and "Zeppelin loop " - which is more difficult to untie ?
« Reply #4 on: June 27, 2015, 09:14:41 AM »
   Both knots... were easily untied after this high load.
   I have tied the Zeppelin bend and heavily loaded it ... and successfully untied it, though that was actually quite difficult.

   So, the so-called "Zeppelin loop" was easily untied, but the Zeppelin bend was not.
   I do not feel any need to "easily dismiss" that result - it can well be dismissed by itself ! And it is worth much more than one mere pot of raspberry jam !  :) :) :)
   

   the Lehman8 was slightly the more difficult to untie

   "Slightly" ! However, since it was " easily untied ", we should better say that it was just not as easily untied as the so-called "Zeppelin loop". I really can not predict if Dan Lehman would feel happy or not with that result ... :) :) :)

LOL, I knew you would find a way to justify your apparent ignorance about these two knots.

The experience I had was that Zeppelin loop tightens on one side of the nub a lot more than the other, leaving the less loaded side easy to untie first. As for the Zeppelin bend, how would you know what the comparative ease of untying the Zeppelin bend vs Zeppelin loop is, you tell us you never trial knots? You have rubbished two knots for no good reason it seems and do not even have the good graces to acknowledge that you may have made a mistake. You originally were quite adamant that both knots were poorly constructed jamming knots and I have just provided empirical feedback that these two knots are very likely to both be just the opposite of that. Maybe it is time for you to start rethinking things?

As for my saying slightly more difficult vs slightly less easy, Dan can ask me about that if he feels at all affronted.

Cheers,

mobius

Edit: added an image of the version of the Figure 8 loop I trialled (and could not untie). I always had trouble with what the preferred version was supposed to be, I don't think it is this one though. The collar nearest the eye remains relatively slack, though despite this the rest of the nub remains very solid and is way too tight to loosen by hand. I do not see why other versions of the Figure 8 loop would fair much better than this one under heavy load, in terms of untying them.
« Last Edit: June 28, 2015, 05:30:06 AM by mobius »

xarax

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Re: "Lehman8" and "Zeppelin loop " - which is more difficult to untie ?
« Reply #5 on: June 27, 2015, 11:38:18 AM »
  a way to justify your apparent ignorance about these two knots.
   :)
 (  Dan Lehman and roo would be really GLAD with your indisputable, incontestable deep knowledge of knots, in general, and of their superb knot-frog-princesses, in particular. And with the fact that you would had been able to untie / kiss them so easily - ( after you had loaded them with 100 kg !  :) )

 
  The experience I had was that Zeppelin loop tightens on one side of the nub a lot more than the other, leaving the less loaded side easy to untie first.

   THAT is a great advantage, indeed !  :) If you had added two more interlocked overhand knots on top of the already interlocked two ones, you would had been able to untie first the last one of them, even more easily:)
   ( For the interested reader : I had pointed out that great disadvantage of the fake, so-called "Zeppelin loop" a number of times. :
   
...a very tight, compact, rock solid first overhand knot, that has immobilized the eye leg of the Tail without any involvement of the second loose overhand knot, which is locked before / without been able to lock.
  With the start of the loading of the eye-knot, the overhand knot tied on the Standing part, which is pulled by both its limbs,"closes" faster than the overhand knot tied on the Tail, which is pulled by its one limb only. Therefore, at some point, the main overhand knot "locks" around the secondary one, before the later has given the opportunity to do the same around the former. The loss of symmetry of the original Zeppelin bend has grave consequences for its crippled imitator, which people that do not use their mind s eyes can not "see". The original genuine Zeppelin knot works so well because the two links are in such a perfect balance the one in relation to the other, that they are loaded equally, they close around each other at the same time, they lock and they themselves are locked at the same time, and they suffer the strain of the tensile forces in tandem, re-distributing them along the common "pivot" made by the pail of tails. Nothing of the above is happening with the evil imposter of the Zeppelin family of knots - and its ugliness, its tying complexity, its asymmetric dressing very of its final form, are only evidences of a knotting crime committed the moment some thought it would be so easy to kiss a prince, and do not transform it into a frog... 
Another, not so-evident shortcoming of this low quality merchandise is that, if the first overhand knot, the one tied on the Standing Part before-the-eye, happens to "close" first ( and it does so, most of the times, if this is not prevented manually and properly, during the tightening and shrinking of the knot ), the second overhand knot, the one tied on the continuation of the returning eye leg, may remain slack, thus making it redundant, and not contributing in any constructive and beneficial way to the distribution and absorption, within the nub, of the tensile forces coming through the Standing End.
a common problem of those eyeknots based on interlocked overhand knots or fig.8 knots : they "close" prematurely, and so they leave some segments of their nubs rather loose = not utilised = redundant, even near their maximum loading...
« Last Edit: August 08, 2015, 06:01:33 PM by xarax »
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Dan_Lehman

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Re: "Lehman8" and "Zeppelin loop " - which is more difficult to untie ?
« Reply #6 on: June 28, 2015, 04:38:35 AM »
Quote
tied a Figure 8 Loop and loaded that
This is the common text in general,
and we are none the wiser about what geometry
was involved --for any such knot, there are, as has
been noted, twin parts and which if these plays
which role is left unstated.

As for my feelings re this test, I guess I could try
to deflate the higher flying zeppelin with some
missiles ... , but it's much what I might expect of
the two.  In the balance, IMO the Lehman8 is the
more slack-secure of the two, and if it can be loosened
and untied in normal usage, that's fine, no matter its
ranking.

As for any difficulty untying the zeppelin end-2-end knot,
I'd want to see the jammed structure : had it capsized
(as can the bowline)?  For it, also #1408, should be
easily loosened in most cases.


--dl*
====

xarax

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Re: "Lehman8" and "Zeppelin loop " - which is more difficult to untie ?
« Reply #7 on: June 28, 2015, 09:55:09 AM »
   the Lehman8 ... if it can be loosened and untied in normal usage, that's fine, no matter its ranking.

   I notice the careful way you attempt to escape - almost silently:) :)

   Of course, if by "normal" usage you mean a light loading, and in the technical meaning of the verb "can", the Lehman8 knot "can" be untied, indeed ( notice that, just as you do, I do not say : "untied easily" ! ). However, we should always keep in mind that the easiness or not of the untiability of a knot depends also on its shape, regarding the "handles" on the outer surface of the nub it offers to our fingers : Can we grab s bight / riding turn, and pull it out of the nub ? Can we "shake", in a "fodling" way, or twist one part of the nub in relation to another, and move it back and forth or rotate it, until we loosen it ? Can we PUSH an end inwards, to feed material into the nub ? ( This depends also on the stiffness of the material - with soft, lengthwise compressible materials, we do not have this option ). Moreover, and I have to point it out here again, it depends on the SIZE of the line - simply because, to untie a knot without a marlinespike or another tool, we use out FINGERS !  :)
   Now, about the quality of this "trial", which has no relation to a scientifically sound test / experiment whatsoever, you are right you keep silent. After all those years, it would be funny ( and unfair ...) if you would had to defend the quality of your knot based on such attempts... I am sure you have tried this knot much more carefully than that ( and loads heavier than 100kg !  :) ), and you, too, like me, have realized that it can NOT be untied easily, and, of course, not as easily as most of the many decent secure bowlines we already have - but you feel some sentimental affiliation to your brain "child" from which you can not distance yourself... I understand that, and I may even say that I respect that ( after all, I suppose we are all humans - although I can not rule out the possibility that there are some robots walking/collecting money among us, too  :) ), and this is one more reason I do not publish the results of the "trials" on the "new" knots I happen to tie ( and which, although they, too, can not be characterized as decent "tests", they are less superficial ). It is difficult indeed, and perhaps impossible, for a knot tyer to be an objective judge of a "new" knot he had tied, and, with the years, he may even be willing to forgive some shortcomings if it, rather than forget the knot altogether - as I had suggested you should better do, with your infamous Lehman8.
« Last Edit: June 28, 2015, 09:59:40 AM by xarax »
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Dan_Lehman

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Re: "Lehman8" and "Zeppelin loop " - which is more difficult to untie ?
« Reply #8 on: June 29, 2015, 07:49:12 PM »
   the Lehman8 ... if it can be loosened and untied in normal usage, that's fine, no matter its ranking.

   I notice the careful way you attempt to escape - almost silently:) :)
No "escape", by whatever hearing!
Rather, a putting into proper perspective
--and out of some inane "ideal" state.

This knot was intended for use by rockclimbers,
who have a known range of materials (for climbing
lines --note that when they included HMPE material
into support lines they gained unknowns!)
and forces (human mass in typical falls while (not
quite) climbing).

Quote
Of course, if by "normal" usage you mean a light loading, and in the technical meaning of the verb "can", the Lehman8 knot "can" be untied, indeed ( notice that, just as you do, I do not say : "untied easily" ! ).
I don't think that the usage I'm looking to could
be well described as "light".  And esp. that done by
Mobius (est. 50%) is far from light --100kg
being a big bite of available tensile strength.  That
you (X) should harp on this is really troubling.
(And in contrast, when you even braved mentioning
your own testing, you did not dare disclose your method
and hence you loading %, et cetera!?)

As for "easily", let's leave it as "relatively easily,
in comparison to the standard tie-in fig.8 eye knot.
But there will be better/worse-set tokens of this knot,
as I remarked vs. Agent_Smith's rather loosely set
knot (which he nonetheless was able to untie).

Beyond this, I think that one can take the tail
further into the knot so to inhibit the loaded
collar part from moving into a jamming position
(where it aligns with S.Part between it and a
part on opposite side and can tighten hard & pinch).


--dl*
====

xarax

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Re: "Lehman8" and "Zeppelin loop " - which is more difficult to untie ?
« Reply #9 on: June 30, 2015, 01:10:19 AM »
   This knot was intended for use by rockclimbers, who have a known range of materials ( for climbing lines ... and forces ( human mass in typical falls while (not quite) climbing).

   As I understand, those ropes are not 3mm  :) , and those forces are far lighter than the 50% of the MBS of the ROPES used by rockclimbers. I do not doubt that, on thin cords or under light loadings, even the Lehman8 eyeknot can be untied easily  :) - but I was NOT talking about thin cords or light loadings !
   Moreover, as I had mentioned time and again, knots are NOT meant to be used only by climbers ! In construction, transportation and boating, the applied loads are much more unpredictable, and can often reach such high percentages of the MBS of the ROPES on which they are tied.

And esp. that done by Mobius (est. 50%) is far from light --100kg being a big bite of available tensile strength.  That you (X) should harp on this is really troubling.

  IMHO, 50% is HEAVY loading, and I had mentioned it more than once - so you had failed to notice it more than once, too.
   However, it is really troubling me, that you have not understood AGAIN ( or, that you still insist or pretend you do not understand ) anything about the reason this "trial" is dismissed by itself ! ( Especially when, under the same "experimental" conditions, the conclusion drawn were that the Zeppelin bend was more difficult to untie than the so-called "Zeppelin loop" ! )

   We ( humans  :) ), WE UNTIE KNOTS USING OUR FINGERS ! So, when the load by which we tighten a certain knot is so light ( 100kg ! ), we should not allow ourselves to jump into ANY conclusions about the easiness with which we may be able to untie it - simply because we can ALWAYS apply the weak force required to untie a lightly tensioned knot, irrespectively of what percentage of the MBS of the line this light load represents.
   For a semi-static ropes used in many professional applications, the 50% of the MBS is 850-1900kg. See, for example :
   http://www.beal-pro.com/2014-2/anglais/cordes-semi-statiques.html
   Are you telling me that, if you can untie without much difficulty a knot tied on a thin 3mm cord, tensioned by 100kg, you will be able to untie the same knot, tied on a 9-12.5 mm rope, when it will be tensioned by 850 -1900 kg ? ( What else will you try to imagine, to defend a lost case and a better-be-forgotten knot, I wonder... Using a fraction of the time you lose in pointless keyboarding, I believe you could tie a better new knot ! )

P.S.
As for "easily", let's leave it as "relatively easily, in comparison to the standard tie-in fig.8 eye knot ".

   Noope ! The standard tie-in fig.8 eyeknot, does NOT represent the standard in the easiness of un-tiability of eyeknots !  :) The fig.8 eyeknot is difficult to untie after heavy loading.
   The standard of the un-tiability of such knots is the bowline - when we evaluate an eyeknot regarding its un-tiability, we should compare it to the bowline - the comparison to the fig-8 eyeknot should be limited to security, IMO.
« Last Edit: June 30, 2015, 01:40:12 AM by xarax »
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Dan_Lehman

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Re: "Lehman8" and "Zeppelin loop " - which is more difficult to untie ?
« Reply #10 on: July 01, 2015, 10:52:25 PM »
However, it is really troubling me, that you have not understood AGAIN ( or, that you still insist or pretend you do not understand ) anything about the reason this "trial" is dismissed by itself !
More stuff thrown by one who himself cannot bother
to describe his own trials

I do not publish the results of the "trials" on the "new" knots
I happen to tie ( and which, although they, too, can not be
characterized as decent "tests", they are less superficial )


No, you don't --neither results, or more important, method.
Rather, you whine about everyonelse's (more "superficial" than vapor!)!

Quote
   Are you telling me that, if you can untie without much difficulty a knot tied on a thin 3mm cord, tensioned by 100kg, you will be able to untie the same knot, tied on a 9-12.5 mm rope, when it will be tensioned by 850 -1900 kg ? ... [some deleted]
In fact, yes, sometimes the smaller material is more
of a challenge to loosen than the larger, as the larger
gives fingers purchase; sometimes, no, it is as you
suggest, a scaling problem --rope & forces scale up,
but one's fingers are the same fingers.

But untying knots loaded well in excess of recommended
forces just isn't one's greatest concern --it would be why
such forces occurred : what has been mistaken!?

Quote
As for "easily", let's leave it as "relatively easily, in comparison to the standard tie-in fig.8 eye knot ".

   Noope ! The standard tie-in fig.8 eyeknot, does NOT represent the standard in the easiness of un-tiability of eyeknots !  :) The fig.8 eyeknot is difficult to untie after heavy loading.
   The standard of the un-tiability of such knots is the bowline - when we evaluate an eyeknot regarding its un-tiability, we should compare it to the bowline - the comparison to the fig-8 eyeknot should be limited to security, IMO.
Perhaps you should consider the Beal reference URL you sent,
and the inclusion in its rope data --which has a remarkable consistency
to it per rope diameter(!)-- of two knots : viz., fig.8 & fig.9 (eyeknots).
Their inclusion is because they are state-of-the-practice, standard
knots.  And in looking to that, I so devised the "Lehman8" as being
an easier-to-untie like knot.  The bowline is not unknown, but in many
such user-areas, unchosen; the knots Beal gives are commonly iused.


--dl*
====
« Last Edit: July 02, 2015, 01:23:03 PM by SS369 »

xarax

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Re: "Lehman8" and "Zeppelin loop " - which is more difficult to untie ?
« Reply #11 on: July 02, 2015, 06:09:45 PM »
   More stuff thrown by one who himself cannot bother to describe his own trials

   I do not WANT to describe my own "trials" - because such "trials" ( like the ones performed by mobius, for example ), which are nothing but incompletely and/or wrongly and falsely performed tests, do not tell ( and do not prove, of course ) any-thing about knots ! At most, they only provide incomplete and/or wrong / false indications/hints, which can be "explained" in any way one wishes ! They can easily be misleading, and conceal, unintentionally or intentionally, rather than reveal, the shortcomings of knots. Do I have to "describe" how I know that the Zeppelin bend is a much more easy to untie knot, after even moderate loading, than the so-called "Zeppelin loop" - as mobius, who performed such "trials", claims ? And even if I "describe" one comparative "trial" of those two knots, on a 3mm line, under a 100kg load, with any result whatsoever, would this tell or prove anything ? Or would it only enhance any erroneous prejudices/beliefs one may have about those two knots, and so feed one more knot myth ? On the other hand, would it be difficult for anybody who would wish to cast doubts or even ridicule and dismiss beforehand those "trials", to do it ?
   
   Noope - I am afraid I happen to have higher standards about what a scientific experiment, a "test", is, or should be ! Especially a test which involves complex phenomena, in this demanding field of material science (1).
   If I were able to perform scientifically sound tests, I would first had tested some knots tied by myself, which, IMHO, are interesting, or even good - and not the worst knots tied by Dan Lehman, which, IMHO, are mediocre, at best ! Myself, I do not expect anybody else to test the knots I happen to tie - especially if this "else" does not bother to say a f.. word on 99% of them ( and, for the remaining 1%, he only boasts that he, too, had tied them, long before me  :) :) ).
   So, yes, I would nt "bother" to describe "trials" on mediocre knots, which are not tried even by the knot tyers who had tied them in the first place !
   
 1. https://en.wikipedia.org/wiki/Materials_science

   Are you telling me that, if you can untie without much difficulty a knot tied on a thin 3mm cord, tensioned by 100kg, you will be able to untie the same knot, tied on a 9-12.5 mm rope, when it will be tensioned by 850 -1900 kg ? ... [some deleted]

   In fact, yes, sometimes the smaller material is more of a challenge to loosen than the larger, as the larger gives fingers purchase;

   So, you are telling that the fact that the Lehman8 eyeknot can be untied easily after it is tied on 3mm cord, and it is tensioned by 100kg, proves that it can also be untied easily after it will be tied on a 9-12.5 mm rope, and it will be tensioned by, say, 1400 kg... ( because that ( 9-12.5 mm) is the size used in climbing and rescue, which are the applications the Lehman8 was supposed to be designed for...)
   OK. Tell it to Beal, to include your suggestion in its brochures  :) :) :) .

  Their inclusion is because they are state-of-the-practice, standard knots.
  The bowline is not unknown, but in many such user-areas, unchosen; the knots Beal gives are commonly used.

  The state-of-practice, standard knots are NOT meant to also represent the standards regarding the easiness of their untiability ! "I" know that the fig.8 and the fig.9 knots are commonly used ( although "you" do not know that I know it...  :) ) - but that DOES NOT mean that they are used because they are easy to untie ! This DOES NOT mean that they set the standards of easily untied knots ! The fact that the bowline is un-chosen, DOES NOT mean that it is un-chosen because it is difficult to untie !  :) :)
« Last Edit: July 03, 2015, 12:17:34 AM by xarax »
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Dan_Lehman

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Re: "Lehman8" and "Zeppelin loop " - which is more difficult to untie ?
« Reply #12 on: August 05, 2015, 09:17:38 PM »
   Both knots... were easily untied after this high load.
   I have tied the Zeppelin bend and heavily loaded it ... and successfully untied it, though that was actually quite difficult.

   So, the so-called "Zeppelin loop" was easily untied, but the Zeppelin bend was not.
   I do not feel any need to "easily dismiss" that result - it can well be dismissed by itself !
Rather than engage gratuitous derision,
one should have better sensed the clue
to a problem/mistake, and made a query
more on the tone of my ...
Quote
As for any difficulty untying the zeppelin end-2-end knot,
I'd want to see the jammed structure : had it capsized
(as can the bowline)?  For it, also #1408, should be
easily loosened in most cases.
...,
as I am now apprised of the surprising (IMO for
Mobius) but otherwise seen in various places
mistaken knot masquerading at the zeppelin
--that more-like-SmitHunter's-structure.

Mobius, you should examine your Slide#3 in which
you show both zeppelins --eye & end-2-end-- and quickly
see the difference!  (I recall going some several rounds
w/someonElse over the supposed jamming of Ashley's
bend #1452
until realizing that he'd mis-dressed it
into a jamming version.


--dl*
====

Mobius

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Re: "Lehman8" and "Zeppelin loop " - which is more difficult to untie ?
« Reply #13 on: August 06, 2015, 01:44:38 PM »
   Both knots... were easily untied after this high load.
   I have tied the Zeppelin bend and heavily loaded it ... and successfully untied it, though that was actually quite difficult.

   So, the so-called "Zeppelin loop" was easily untied, but the Zeppelin bend was not.
   I do not feel any need to "easily dismiss" that result - it can well be dismissed by itself !
Rather than engage gratuitous derision,
one should have better sensed the clue
to a problem/mistake, and made a query
more on the tone of my ...
Quote
As for any difficulty untying the zeppelin end-2-end knot,
I'd want to see the jammed structure : had it capsized
(as can the bowline)?  For it, also #1408, should be
easily loosened in most cases.
...,
as I am now apprised of the surprising (IMO for
Mobius) but otherwise seen in various places
mistaken knot masquerading at the zeppelin
--that more-like-SmitHunter's-structure.

Mobius, you should examine your Slide#3 in which
you show both zeppelins --eye & end-2-end-- and quickly
see the difference!  (I recall going some several rounds
w/someonElse over the supposed jamming of Ashley's
bend #1452
until realizing that he'd mis-dressed it
into a jamming version.

--dl*
====

Thank you for this feedback Dan. Indeed, I have made a mistake tying the Zeppelin Bend in the Slide#3 you refer to and I show again below. I think what happened was that I swapped the ends of the 'q' around and the tail was the horizontal rather than the vertical crossing. I thought the 'b' 'q' method of tying the Zeppelin was easy... not so for me it seems, when I have not practiced it enough. Perhaps I am not totally alone in this.

Whatever the case, the trials that I conducted with the 'False' Zeppelin Bend did not indicate it as a particularly good bend. I have recently upgraded my test rig and will redo the Zeppelin Bend in both 3mm Poly Braid and now 6mm PE/PP material and see what transpires. I will share the results with you all, probably in a new thread.

I am glad I usually go to the trouble of photographing the knots I trial (for verification). I commend Dan for seeing my mistake, I had looked at the image below a number of times and just not seen the discrepancy. I have fallen victim to an "evil impostor", my apologies to all.

Cheers.

mobius.


roo

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  • Posts: 1926
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Re: "Lehman8" and "Zeppelin loop " - which is more difficult to untie ?
« Reply #14 on: August 06, 2015, 03:29:49 PM »


I am glad I usually go to the trouble of photographing the knots I trial (for verification). I commend Dan for seeing my mistake, I had looked at the image below a number of times and just not seen the discrepancy. I have fallen victim to an "evil impostor", my apologies to all.

Your b&d bend seems secure, so it's more of a benign impostor.  Its jamming is inconvenient, but not much of a hazard.  With more use of the Zeppelin Bend, I'm sure you'll get used to verifying the correct outcome with a quick check of both sides.
« Last Edit: August 06, 2015, 06:40:14 PM by roo »
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