Author Topic: Bowline meets Zeppelin  (Read 6570 times)

Valentine

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Bowline meets Zeppelin
« on: October 24, 2013, 09:51:18 PM »
It looks like a popular activity here is to search for ways to make the bowline more secure, and this got me thinking. The Zeppelin knots are benchmarks of security and jam resistance while being rather simple and easy to tie, so it's not much of a stretch to consider whether some of their components could be used to reinforce the bowline. I saw some such hybrids in older threads here, but I didn't see one like this:



Upper left is the exploded knot. Upper right is the dressed knot seen from the same orientation as the exploded view (the tail points towards you). Lower right is the "back" view (the tail points away from you). Lower left is a view down the standing part as it enters the knot, showing how the knot has two spiraling collars instead of the bowline's one.

The inserted overhand knot forms a zeppelin-like rope hinge around the bowline's nipping turn and standing part before finishing with the bowline's turn around the standing part and through the nipping turn. When compacted (a process that may involve pushing into place a particular loop that sometimes settles into a metastable arrangement), the knot forms a hard ball that somewhat conceals its lineage. It's not a pretty knot by most standards, but it seems to be quite secure and indifferent to loading balance and loop width. With the straighter entry of the standing part into the knot, it should be somewhat stronger than the bowline, but I don't know how it compares to the Zeppelin loop. Adjusting its loop size seems to be easier than with the Zeppelin loop (the standing part's passage through the knot seems to be the loosest part of the knot after loading). It seems to be more difficult to untie than the bowline or the Zeppelin loop, but I haven't been able to get it to actually jam.

So what says the community? Is this a suitable knot for practical use, and how does it compare to some other bowline variants? Also, is there an established pattern of naming such bowline-based knots? If not, I propose "Graf bowline".

SS369

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Re: Bowline meets Zeppelin
« Reply #1 on: October 25, 2013, 12:04:48 AM »
Hi Valentine, thanks for the submission.
I like it.

First I would like to ask you to try this in something other than paracord. Then if you would photograph that and post it, it will help all.
I ask this because I have tied it a few times now in various cords and ropes and my finished product doesn't quite resemble what you've presented.
I get two opposing collars around the SP entry, whereas I don't see this in your photograph.

Other types of media may show you some of its attributes as well.
The example I've tied shows good resistance to ring loading, locks the tail pretty securely and untied easily enough tied in 1/4" braided nylon after 300 lbs. loading.
A bit fiddly to tie and dress, but that is not a drawback, to me.

SS

Valentine

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Re: Bowline meets Zeppelin
« Reply #2 on: October 25, 2013, 03:40:11 AM »
It's harder to see in the upper and lower right views, but the lower left shows how the standing part enters the knot. As requested though, here is the knot tied in old clothesline. It is in the same orientation as the lower left view of the first image, but the standing part has been cut near its exit from the knot. The clothesline is rubbery and much stickier than typical rope, so I couldn't draw it up as tightly (it's fiddly, as you said), so it lays a little differently from the first knot.


Valentine

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Re: Bowline meets Zeppelin
« Reply #3 on: November 27, 2013, 06:08:13 AM »
While trying out variations of the graf bowline, I found that this knot seems to be somewhat easier to untie:



It seems to grip itself as tightly as the graf bowline, but the tail is more easily accessed, and ring loading causes it to loosen slightly. Since this may make it less secure under unusual loading, it might not be preferable when a very stable loop is needed.

Also, here is a picture of the graf bowline mirrored so that the bowline structure is in its usually-shown chirality.


« Last Edit: November 27, 2013, 06:15:52 AM by Valentine »

xarax

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Re: Bowline meets Zeppelin
« Reply #4 on: November 27, 2013, 10:20:05 AM »
   The original bowline shown in this thread has no relation whatsoever to the genuine Zeppelin knot ( the Zeppelin bend ), either in its working ( not even a trace of a rope-made hinge mechanism here...), or in its looks ( obviously... :)). However, it is much better than the infamous so-called " Zeppelin loop", which is not even a bowline... So, by NOT resembling the fake so-called "Zeppelin loop" - which is neither a Zeppelin-like knot, nor a bowline-like knot, so one may wonder what exactly is it... :) - it seems that a loop gets less fake = more authentic, so its situation can not but improve !  :)
   The idea I can see here is this : A two-collar bowline, where the returning eye leg makes the first collar around the Standing end before it goes through the nipping loop, to make the second collar. We have seen something similar in the case of the "link bowlines" (1), where the returning eye leg makes a collar around the Standing end, too, but, at the same time, it encircles the crossing point of the nipping loop as well. ( The best example of such a knot is the Lee s link bowline, which, incidentally, started its life trying to resemble the Zeppelin bend, too - Lee calls its original, not-crossed-Tail variation, Lee Zep bowline. Not a Zeppelin-like knot either, of course, but a nice loop nevertheless (2) ).
   Now, the problem I see here is the path of the returning eye-leg to the first collar straight to the Standing end. WHY does it circumvents the nipping loop, and does not go through it ? I see no compelling reason for this... This way, we would had three rope diameters going through the nipping loop, which means that the Standing part would had followed a wider first curve, and the nipping loop itself would had been rounder.

1. http://igkt.net/sm/index.php?topic=4314.0
2. http://igkt.net/sm/index.php?topic=3908.0
   
This is not a knot.

Valentine

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Re: Bowline meets Zeppelin
« Reply #5 on: November 28, 2013, 08:26:35 AM »
The original bowline shown in this thread has no relation whatsoever to the genuine Zeppelin knot ( the Zeppelin bend ), either in its working ( not even a trace of a rope-made hinge mechanism here...), or in its looks ( obviously... :)).
In the first post, I said, "The inserted overhand knot forms a zeppelin-like rope hinge around the bowline's nipping turn and standing part before finishing with the bowline's turn around the standing part and through the nipping turn." As shown below, that is precisely what's going on here.



As in the Zeppelin knots, the overhand knot constricts on the tail when loaded, helping to lock it in place. I don't know what you mean by "rope-made hinge" if you don't see one, but what I mean is "a rope-formed structure involving two or more pinned connections arranged to form an axis about which part of the structure can rotate back and forth" ? i.e. a hinge made of rope. Such a structure is clearly found in the Zeppelin knots and in a half-tied graf bowline (the final tuck ruins the hinge by turning it into a moment connection).  The look of the knot is different from the Zeppelin knots because the rest of the knot is different, causing it to compact differently, but the initial tie-in of the graf bowline (before the bowline finish) is nonetheless the same as half a Zeppelin bend and the tail tie-in of the Zeppelin loop.

However, it is much better than the infamous so-called " Zeppelin loop", which is not even a bowline... So, by NOT resembling the fake so-called "Zeppelin loop" - which is neither a Zeppelin-like knot, nor a bowline-like knot, so one may wonder what exactly is it... :) - it seems that a loop gets less fake = more authentic, so its situation can not but improve !  :)
I would classify the Zeppelin loop as a secure bend which has been adapted as a loop knot. Like many other such loops, half the knot is more complicated than it has to be for a loop, but it still works fine. Some advantages of the Zeppelin loop over the graf bowline are its neater symmetrical appearance, its greater ease in untying, and more testing on diverse rope types. The graf bowline has more symmetric loading and is post-eye-tiable. I would consider its use vs the Zeppelin loop as situational based on the attributes required of a knot rather than a general assessment of the knots' "authenticity".

The idea I can see here is this : A two-collar bowline, where the returning eye leg makes the first collar around the Standing end before it goes through the nipping loop, to make the second collar. We have seen something similar in the case of the "link bowlines" (1), where the returning eye leg makes a collar around the Standing end, too, but, at the same time, it encircles the crossing point of the nipping loop as well. ( The best example of such a knot is the Lee s link bowline, which, incidentally, started its life trying to resemble the Zeppelin bend, too - Lee calls its original, not-crossed-Tail variation, Lee Zep bowline. Not a Zeppelin-like knot either, of course, but a nice loop nevertheless (2) ).
1. http://igkt.net/sm/index.php?topic=4314.0
2. http://igkt.net/sm/index.php?topic=3908.0
I like the link bowline, but I have a concern with the Lee Zep and Lee Zep x bowlines. Unlike the standard bowline and most variants, where the tail is arranged so that the movement of any other strands through the nipping loop under load causes the tail to tighten, these knots have it reversed, so that the tail is pulled into the knot. The standard bowline's arrangement is very secure for a single turn, and it's the feature that I would prefer to use for the terminal lock on speculative bowline variants.

Now, the problem I see here is the path of the returning eye-leg to the first collar straight to the Standing end. WHY does it circumvents the nipping loop, and does not go through it ? I see no compelling reason for this... This way, we would had three rope diameters going through the nipping loop, which means that the Standing part would had followed a wider first curve, and the nipping loop itself would had been rounder.
The reason is that I wanted to tie a bowline where the tail's tie-in treats the standing part and nipping loop like the opposite side of a Zeppelin knot, and as shown in the image above, that means that the eye hangs off the standing part without first passing through the nipping loop. What you describe is certainly a viable knot, but it's not what I was going for here. I did consider such arrangements when evaluating possible derivatives, but decided against pursuing them to maintain what seem to be advantages of bypassing the nipping loop. A wider, rounder loop is stronger and generally preferable, but that's not where a bowline typically breaks, so optimizing the knot for that was not a concern of mine. In contrast, what I wanted was a very secure knot, and any strength-enhancing features were largely incidental. In that consideration, the graf bowline's eye entry deposits its load on top of the nipping turn, directly compressing it and the tail even when just that leg of the eye is loaded. Likewise, without another pass through the nipping turn, the tail experiences greater pressure locking it in place (similar force over a smaller area), which I would expect to be advantageous in resisting shocks and cyclic loading.
« Last Edit: November 28, 2013, 09:19:08 AM by Valentine »

xarax

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Re: Bowline meets Zeppelin
« Reply #6 on: November 28, 2013, 11:04:56 AM »
In the first post, I said, "The inserted overhand knot forms a zeppelin-like rope hinge around the bowline's nipping turn and standing part ... As shown below, that is precisely what's going on here.

  No, it does not.  :) We are not talking about the topology of overhand knots here, but about their geometry. The links of the Zeppelin bend are, topologically, overhand knots, but they work differently than the links of the Hunter s bend, for example - which are, topologically, overhand knots, too. The overhand knot in your loop is hooked to = hooked within the nipping turn of the nipping loop of the eyeknot, as the one link of the Hunter s bend is hooked to = hooked within the other. Moreover, an overhand knot, in general, where the one end ( its Standing end ) is pulled and the other end ( its Tail end ) is made fast somewhere else, is NOT a hinge. The Tail end of this overhand knot, in particular : 1, makes a second turn, a collar, around the Standing end of the eyeknot, and, 2 : it is nipped by the nipping loop of the eyeknot. So, as the eye of the eyeknot is loaded and the returning eyeleg is pulled, this overhand knot can only contract, and constrict / strangle / choke everything that penetrates it, including its own tail : a hinge does not choke the pivot. Each ring of the hinge does not constrict the pivot from every direction, because it does not need to do this. On the contrary, the rings can rotate freely around the pivot = the pivot can rotate freely inside the rings, but this does not mean that the pivot can slip through the rings : The pivot does not slip through the hinge because it feels shear forces, not because it feels compression and friction forces. In a hinge, the mechanism works even if the rims around the pivot remain loose, because the fact that the pivot does not slip through the rim does not depend on the compression forces, and the generated friction forces, applied on it. On the contrary, in this particular overhand knot applies compression and friction forces to the lines that go through it, including its own tail, rather than shear forces.
   Anyway, this particular overhand knot does not work as the overhand knots of the Zeppelin bend. To see some eyeknots that are more Zeppelin-like, see (1). To see a Zeppelin-like bend, where the pivots do not slip even when the rings off the hinge are very loose, see (2).

1. http://igkt.net/sm/index.php?topic=4095.0
2. http://igkt.net/sm/index.php?topic=3716.msg21527#msg21527


1. As in the Zeppelin knots, the overhand knot constricts on the tail when loaded, helping to lock it in place.
2. I don't know what you mean by "rope-made hinge"

1. No, the tail does not remain in place because it is constricted by the overhand knot - as I tried to explain previously, yet another time.
2. Evidently !  :) But do not bother, you are not alone... The exact opposite might well be true : I may be the only one who understands what I am talking about. However, believe me, I am talking about something, that exists, even if I can not explain it to other people. I know knot tyers with dozens of years of knotting experience who had never thought about this almost obvious fact, and who, even now, can not understand it ( or refuse = are afraid to understand it, but that is another matter ). I believe that manipulating a Zeppelin bend in one s own hands for some time, rotating the two not-hooked =parallel rims around the pair of tails, will offer the feeling my wording evidently fails to convey.

the attributes required of a knot rather than a general assessment of the knots' "authenticity".

A friendly advice, coming from an old man : Do not underestimate authendicity, never. The authentic is true, by definition, the rest my well be imitations (Fr.) / fake = false. A knot, like anything else, has to be authentic = true, above all. ( This applies to knot tyers, too... :))

Like many other such loops, half the knot is more complicated than it has to be for a loop, but it still works fine.

  Like which other such loops ? If a knot is more complicated than it has to be for a loop, do not tie it !  :) Every complicated enough tangle of rope "works" - iff by "working" you mean that it dies not slip...
  Moreover, as I had explained elsewhere, and I believe you have read it, it does not even work well ! The one overhand knot closes up and locked before the other, making half of the knot obsolete, and forcing the other half to bear the total of the loading forces - not a good thing for the strength of any knot.


   I have seen that as the "main" first overhand knot, which is tied on the Standing part, is loaded first and more forcefully, it also "closes" and "locks" first, well before the second overhand knot, which is tied on the Tail. Consequently, this second overhand knot can well remain slag, with half of its structure not participating / contributing in the locking mechanism of the knot at all. The most evident result of it is 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. The interested reader who will load the eye-knot to its limits, will see this discrepancy between the two links, the second one remaining almost absent of the mutual entanglement. It is this lack of "balance" that characterizes even many secure bowlines. where the one, only, of the two links bears most of the strain - one can easily imagine what that will mean for the overall strength of a two links knot, which will depend on half of the available material.
   

A wider, rounder loop is stronger and generally preferable, but that's not where a bowline typically breaks...

  A knot does not break in the point of maximum tension. A wider, rounder loop can, supposedly, distribute and dissipate the tensile forces along a greater portion of the knot. That does not mean that a three-rope-diameters nipping loop will not break , and a two-rope-diameters will. Both knots will break at another point, probably outside the nipping loop, but the one will, supposedly, break after the other.

 
...without another pass through the nipping turn, the tail experiences greater pressure locking it in place (similar force over a smaller area), which I would expect to be advantageous in resisting shocks and cyclic loading.

   You may well be right on this. That is a debatable issue about which only NUMBERS ( = detailed, laboratory tests = experimental data ) can tell  :).
« Last Edit: November 28, 2013, 12:47:52 PM by xarax »
This is not a knot.

xarax

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Re: Bowline meets Zeppelin
« Reply #7 on: November 28, 2013, 12:46:07 PM »
...I have a concern with the Lee Zep and Lee Zep x bowlines. Unlike the standard bowline and most variants, where the tail is arranged so that the movement of any other strands through the nipping loop under load causes the tail to tighten, these knots have it reversed, so that the tail is pulled into the knot.

  You mean, any slippage of the returning eye leg ( which is adjacent to the Tail ), would tend to drag the line of the Tail end along with it - so a portion of the Tail will be consumed.
  Now, if the returning eye leg is pulled, downwards, so will be the Standing end, upwards - and at a faster rate than the returning eye leg, always - because, always, it is pulled by the 100% of the total load. That means that the nipping loop will close up and will be tightened, well before the "link" does the same, i.e., before friction forces between the returning eye leg and the Tail, induced on them by the shrinking encircling link, can become so large, that any slippage of the former can drag the later out of its place.
   I have tightened loose Lee Zep and Lee Zep X knots, by pulling both or any one of any eye legs, and I have not seen any significant consumption of the Tail - either this tightening was fast and abrupt or slow and gradual. In any case, I have not seen in this knot more Tail consumption than in the Zeppelin bend - and this is an indication of some resemblance between the two knots, not of some further difference.
« Last Edit: November 28, 2013, 12:55:39 PM by xarax »
This is not a knot.