Author Topic: Hugo bend (a descendant/heir of the Zeppelin bend)  (Read 33421 times)

Luca

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Re: Hugo bend (a descendant/heir of the Zeppelin bend)
« Reply #15 on: November 14, 2012, 05:48:23 PM »
X1 Hi, and thanks to you for all in this forum! :D

   the Zeppelin bend, along with the Hugo bend presented in this thread, are members of a very small class of bends, which I use to call "rope-made hinges". The first curve of each link does not turn around the straight segments of the other link s standing part, and it is not hooked with the other link s first curve : it turns around a "pivot", made by the two tails. The "slipped overhand knots bend" (2) is another - and I do not know if even the "Oval bend" (2), belongs to this class or not. ( I do not mention the simplest bend possible, the Symmetric Sheet bend, which, together with the Whatknot, belong to a very special class ).

 
   

I think that this category of bends perhaps may include only knots that have the same type of high symmetry of the Zeppelin bend [symmetry that is not noticeable by looking at a single side of the knot,but it that turns out rotating the knot around an axis,or around the axis perpendicular to it, each of the six faces (front/back, top/bottom, right/left) of the knot, noting  in this way,that the opposite side to the other is a mirror version (I apologize in advance for how I wrote this stuff)].
I think this has to do precisely with the fact that the tails of each of the links make the first curve(or round turn)up/down(or around),at his own Spart, before touching/crossing the other link.
I should clarify my ideas before speaking in depth about these things, such as how become the symmetries,crossing (or not crossing) the(simmetrical) links of a bend,but for now the gist of my argument is this: rope-made hinge = Zeppelin-like simmetry [but no Zeppelin-like simmetry = rope-made hinge (For example, the Double Harness bend with opposite ends,I do not think that falls into the category)].
Is right?   

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X1

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Re: Hugo bend (a descendant/heir of the Zeppelin bend)
« Reply #16 on: November 14, 2012, 06:05:15 PM »
...rope-made hinge = Zeppelin-like symmetry
   Is [that] right?   

   No:)
   And I have a fresh proof for this !
   http://igkt.net/sm/index.php?topic=4116.msg24851#msg24851

...the Double Harness bend with opposite ends
   I do not think that it falls into this category.
   Is [that] right?   

   Right - for both Double Harness bends. Me too. But only because the first curve of each link turns around the other link s straight continuation of the Standing end. Symmetry has nothing to do with it. A hinge is a hinge is a hinge, be it more symmetric, less symmetric, or asymmetric, like the bend mentioned above.
« Last Edit: November 14, 2012, 06:08:50 PM by X1 »

Luca

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Re: Hugo bend (a descendant/heir of the Zeppelin bend)
« Reply #17 on: November 14, 2012, 07:26:39 PM »
...rope-made hinge = Zeppelin-like symmetry
   Is [that] right?   

   No:)
   And I have a fresh proof for this !
   http://igkt.net/sm/index.php?topic=4116.msg24851#msg24851

...the Double Harness bend with opposite ends
   I do not think that it falls into this category.
   Is [that] right?   

   Right - for both Double Harness bends. Me too. But only because the first curve of each link turns around the other link s straight continuation of the Standing end. Symmetry has nothing to do with it. A hinge is a hinge is a hinge, be it more symmetric, less symmetric, or asymmetric, like the bend mentioned above.

O.K.,but my idea was based on this (and actually I should first specify):

  *(1) We are interested on the class of symmetric bends here, which includes the great majority of bends. - i.e. the bends where each link s shape is / can be considered as, a symmetric transformation of the other s.

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X1

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Re: Hugo bend (a descendant/heir of the Zeppelin bend)
« Reply #18 on: November 14, 2012, 08:05:27 PM »
   I am interested in symmetric bends, and symmetric bends only - not for their aesthetics, but because of the fact that the rope segments of each link are evenly loaded, so they would reach their strength limit at about the same time - in a symmetric bend there would be no "weak link" ( I believe that this is a reasonable expectation, even after we take into account some more subtle effects, that can lead to a symmetry breaking). Moreover, I believe that any mistake in the tying of a symmetric bend would be noticed immediately, because the result would be evidently asymmetric, and would be caught by the eye at once. It is easier to spot an asymmetry within a symmetric background, than the opposite.     
   However, there are many degrees of symmetry !  :) Most of the known bends are symmetric ( for example, the Hunter s bend ), some are more symmetric than the others ( for example, the Zeppelin bend ), and some are maximally symmetric ( for example, the falsely tied Zeppelin bend ). We cannot judge or predict anything by the degree of symmetry alone. The Zeppelin bend is perfect, but the falsely tied Zeppelin bend, which is even more symmetric than the Zeppelin bend, is a lemon. If we cannot judge or predict something by taking into account a certain characteristic of it, what is the purpose of taking this characteristic into account in the first place ?
   The characteristic that I had proposed, the way the first curves of the Standing parts are attached into the body of the knot, has to do with the first curves, and the first curves with the strength of the knot, and the strength of the knot with the great disadvantage of all knots, for which we seldom speak : that they reduce the strength of the rope on which they are tied to about 50 %. That is the reason I believe it is not a secondary, irrelevant property of the knots, and it makes some sense to base our classification on this, indeed.

TMCD

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Re: Hugo bend (a descendant/heir of the Zeppelin bend)
« Reply #19 on: November 16, 2012, 01:26:01 AM »
I too like symmetrical bends, they are not only fun to tie but are also pleasing to the eye. My two favorite bends are the Zeppelin Bend being number one followed by the Double Harness Bend at number two. The Zeppelin Bend gets MUCH love as it should but the Double Harness Bend is probably a pretty special bend in it's own right and is undervalued.

I'd like for someone with the capabilities and resources to do some testing on the Double Harness Bend. Ashley flatly states it's more secure than the Harness Bend but doesn't provide much else. I don't think he included it in his bend tests in the book?? I've always thought of the DHB being about equal to the Double Sheet Bend in security but it's probably stronger. 

X1

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Re: Hugo bend (a descendant/heir of the Zeppelin bend)
« Reply #20 on: November 16, 2012, 03:05:40 AM »
My two favorite bends are the Zeppelin Bend, being number one, followed by the Double Harness Bend at number two.

  As there are many knots ( so, far more than we need ) and more than one knot tyers ( so, far less than we need ), I seldom agree with somebody 100 % !  :) So, I would remember this day...
  I prefer the more symmetrical DH bend ( the ABoK#1420 ), although the other one, in both variations, is probably more "practical".
  Also, I have to mention that I have another bend at number 0  :)( because it is not a "practical" bend ), the Symmetric Sheet bend. 

Dan_Lehman

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Re: Hugo bend (a descendant/heir of the Zeppelin bend)
« Reply #21 on: November 16, 2012, 06:54:13 PM »
Quote
I am interested in symmetric bends, and symmetric bends only
--not for their aesthetics, but because of the fact that the rope segments of each link are evenly loaded,
so they would reach their strength limit at about the same time - in a symmetric bend there would be no "weak link"
( I believe that this is a reasonable expectation, even after we take into account some more subtle effects,
that can lead to a symmetry breaking).  Moreover, I believe that any mistake in the tying of a symmetric bend
would be noticed immediately, because the result would be evidently asymmetric, and would be caught by the
eye at once
. It is easier to spot an asymmetry within a symmetric background, than the opposite.

I've tried to point out, previously, that these two assertions are
not assuredly true --indeed, that re visible recognition is clearly
quite false (both (a) that symmetry is readily perceived, and (b)
that asymmetric structures are difficult to see as correctly formed).

Re the assertion of symmetry's effects on knot forces, one must realize
that the actual nature of joined rope ends will often differ and such
difference can lead to different behaviors under force; it can in any
case be that one part gets the jump on the other in tightening,
and that such imbalance aggravates itself (the more one end
impedes by a tighter nip the other end's part getting equal force
delivered to nip the first, the first's advantage will be furthered).

It is also conceivable that differently shaped parts in an asymmetric
end-2-end knot nevertheless have similar strengths --and I put
forward the butterfly knot as a possible case in point (as well
as a variation derivable from the zeppelin knot).


I've always thought of the DHB being about equal to the Double Sheet Bend in security but it's probably stronger.

How can you hold this opinion?
Surely the DBH shows an entanglement/knotting
that goes beyond that of the DSB --with increased
pressure upon the nip of the tails, which receive force
only after the line leading to them makes fuller curves
than for esp. the bight-half's tail of the DSB (which,
you should note, has been found to slip).

Quote
Dave Richards notes that there was evident slippage in the cases of [static 12.7mm rope]
with the fisherman's knot and the double sheet bend, [dynamic 10.5mm rope ] with the
(single) sheet bend, and [accessory cord, 7mm] with both sheet bends (single & double);
he thus tied off the tails with either 2 half-hitches or an overhand stopper.

Now, Richards didn't test the DBH --of either form (tails together
or opposite); and there are options to how one places the tails,
as X1 has elsewhere noted).  But to my mind, there should be
a belief in its greater security based on appearance and analysis
of that, than of equal --esp. with regard to security when slack,
being jostled about and all (and consequently, much greater
difficulty at being untied).


--dl*
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TMCD

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Re: Hugo bend (a descendant/heir of the Zeppelin bend)
« Reply #22 on: November 16, 2012, 07:50:42 PM »
I stand corrected, Dan's statements certainly make sense regarding the DHB VS. the DSB. I would have to assume the DHB is considerably more secure AND stronger than the DSB, not sure why I even compared the two really.


X1

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Re: Hugo bend (a descendant/heir of the Zeppelin bend)
« Reply #23 on: November 16, 2012, 08:11:57 PM »
these two assertions are not assuredly true
--indeed, that, re visible recognition, is clearly quite false
(both (a) that symmetry is readily perceived, and (b) that asymmetric structures are difficult to see as correctly formed).

   Yes, they are not assuredly true.
   No, it is not clearly quite false !

   Moreover, they are much more true than they are quite false...
   I could refer to scientific studies that measure the great ability of the "eye" to recognize, subconsciously, in fact, almost to measure   - the asymmetries of a human face, and perceive as "beautiful" a face with less asymmetries (1). If we take 100 pictures of women, and merge them to one, where each characteristic would be the mean of all, the resulting face would be judged as beautiful by the great majority of men. Why "Because the asymmetries would have been smoothed out .

It is also conceivable that differently shaped parts in an asymmetric end-2-end knot nevertheless have similar strengths

   Yes, it is conceivable, indeed, but, statistically, it is highly improbable.

   We have seen that even minor differences in shape lead to great differences in strength - and you go even beyond this, and you point out, correctly, that some other subtle results can distort the symmetric distribution of forces even in the cases of identically shaped links. The conceivable possibility that all those differences will cancel each other out, and the two links will be left with similar strengths, would materialize very rarely, if ever.

1. Jones, B., Little, A., Penton-Voak, I., Tiddeman, B., Burt, D., & Perrett, D. (2001). Facial symmetry and judgements of apparent health: Support for a "good genes" explanation of the attractiveness-symmetry relationship . Evolution & Human Behavior, 22(6), 417-421.

   P.S. The Alpine Butterfly bend and all the variations of the Zeppelin bend are suredly more or less symmetric bends - the single or double Sheet bend, and the bends presented at (2) and (3) are clearly not.
1.   http://igkt.net/sm/index.php?topic=3656.msg21113#msg21113
2.   http://igkt.net/sm/index.php?topic=4116.0
« Last Edit: November 16, 2012, 08:43:41 PM by X1 »

Luca

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Re: Hugo bend (a descendant/heir of the Zeppelin bend)
« Reply #24 on: November 17, 2012, 12:36:35 AM »
Hi X1,


   However, there are many degrees of symmetry !  :) Most of the known bends are symmetric ( for example, the Hunter s bend ), some are more symmetric than the others ( for example, the Zeppelin bend ), and some are maximally symmetric ( for example, the falsely tied Zeppelin bend ).


At the end,I continue to keep wondering if it is possible that there is a symmetric bend,that does not have the same kind of symmetry of the Zeppelin bend,that it can be considered a rope-made hinge.(EDIT:maybe the very beautiful bend by kd8eeh is an example of this?):

http://igkt.net/sm/index.php?topic=4016.msg24885#msg24885


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« Last Edit: November 17, 2012, 02:02:30 AM by Luca »

X1

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Re: Hugo bend (a descendant/heir of the Zeppelin bend)
« Reply #25 on: November 17, 2012, 03:36:46 AM »
I continue to keep wondering if it is possible that there is a symmetric bend, that does not have the same kind of symmetry of the Zeppelin bend, that can be considered a rope-made hinge

  Me too ! :)

  The falsely tied Zeppelin bend is such a knot, that is for sure. It is also more symmetric than the Zeppelin bend. Also, the "slipped overhand knot bend" is a rope-made hinge, evidently. The two variations of the recently presented ZB bend and the three Double Zeppelin bends, too.
  The SS bend and the Whatknot are close ( In fact, the SS bend can be considered as a more symmetric Whatknot  - because the Whatknot itself is symmetric, although it does not look so ). The Oval bend is fifty-fifty. The Hugo bend is 75% (?)... :)
  Some of the pseudo-Zeppelin loops shown at (1) can be considered as rope-made hinges. The Angler s loop, and a couple of the Lee bowlines also use the tail as a pivot - although not only as a pivot. 
  May be you can explore the bends and loops you know, and discover some more that I have escaped my attention or have been deleted from my memory.  However, we should not be too confined in any theoretical scheme. The only real benefit would be the deeper understanding of the mechanism itself, that can lead to the discovery of knots we do not know yet - or to an explanation, even prediction, of something that was not explained or predicted, in the behaviour of knots we already know.
 
 1.  http://igkt.net/sm/index.php?topic=4095.0
     
« Last Edit: November 17, 2012, 03:38:20 AM by X1 »

Dan_Lehman

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Re: Hugo bend (a descendant/heir of the Zeppelin bend)
« Reply #26 on: November 17, 2012, 07:17:40 AM »
these two assertions are not assuredly true
--indeed, that, re visible recognition, is clearly quite false
(both (a) that symmetry is readily perceived, and (b) that asymmetric structures are difficult to see as correctly formed).

   Yes, they are not assuredly true.
   No, it is not clearly quite false !

   Moreover, they are much more true than they are quite false...
   I could refer to scientific studies that measure the great ability of the "eye" to recognize, subconsciously, in fact, almost to measure   - the asymmetries of a human face, and perceive as "beautiful" a face with less asymmetries (1).

You have quickly --or is it adroitness, here?-- forgotten the
issue : ease of recognition ... --not what is perceived as beauty.
So, studies show "great ability" of the eye to recognize asymmetry:
QED for me?!  --not what you meant to say, but said it anyway.

And above, you note that recognition ...
Quote
of high symmetry of the Zeppelin bend
is not so readily apparent, as it is ...
Quote
[symmetry that is not noticeable by looking at a single side of the knot,

QED II (for me, not you).

Quote
It is also conceivable that differently shaped parts in an asymmetric end-2-end knot nevertheless have similar strengths

   Yes, it is conceivable, indeed, but, statistically, it is highly improbable.

   We have seen that even minor differences in shape lead to great differences in strength - and you go even beyond this, and you point out, correctly, that some other subtle results can distort the symmetric distribution of forces even in the cases of identically shaped links. The conceivable possibility that all those differences will cancel each other out, and the two links will be left with similar strengths, would materialize very rarely, if ever.

Where have we seen these results?!

Rather, the improbability is that one will match in tying
--if even having *symmetrically natured ropes* (where two)--
the symmetry of ideal,
and that these subtle differences will deny the ideally
symmetric knot of its supposed perfect equalization.
What is at question, then, is more a matter of stability,
and there's nought to say that asymmetry will be weaker
--one can't take a thing (supposed strength of a shape) and
just put it into a different context and expect the same
result (that the shaped thing really has its same shape).

(E.g., CLDay reports that testing showed overhand knots
to be stronger in one handedness vs. the other --or maybe it
was that the fisherman's knot so orienting them was so--;
that could (mis?)lead one to conclude that the opposite-handed
(i.e., with component overhands of each handedness)
fisherman's knot would assuredly be bad, as it has one
component of either handedness; but that's omitting the
fact that in so orienting the components to be opposite in
handedness, one builds a different knot --those components
are in a different (albeit similar) context!  Now, frankly, I'll
guess that it is enough similar that the has-the-weaker-form
condition yet is determinant, but it bears testing; maybe that
weakness is slightly ameliorated --or maybe aggravated!)

Quote
Facial symmetry and judgements of

Send them a Janus bowline !   ;D


--dl*
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X1

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Re: Hugo bend (a descendant/heir of the Zeppelin bend)
« Reply #27 on: November 18, 2012, 12:23:33 AM »
the issue : ease of recognition ... --not what is perceived as beauty.

   I can not say that a symmetric thing is more easily recognizable than an asymmetric one. In fact, I had never said such a thing.
   However, that was NOT the issue, but you have forgotten it.  :) The issue was to determine if a thing/knot we know in advance that is supposed to become/look symmetric at the end of the tying procedure, will be easily recognized as mistakenly tied if it will be mistakenly tied, or not. And if a thing/knot that we know in advance that it is supposed to become/look asymmetric in the end, will be easily recognized as mistakenly tied, if it will be mistakenly tied, or not. I have argued that, if the thing/knot that was supposed to become symmetric at the end, turns out to look  asymmetric, and ugly, because it was tied wrongly, that would be recognized with great ease, at a glance. It will be like a fly in the ointment ... On the contrary, if a thing/knot that was supposed to become asymmetric at the end, is wrongly tied, it will most probably look asymmetric- so it would not differ from what it was supposed to look ! How would the eye be able to distinguish between an ugly, asymmetric thing, and another ugly, asymmetric thing ? It is like some ointment on the fly... It will not, so the knot tyer runs the danger to tie the knot wrongly, and, because the end result will still be ugly and asymmetric, fail to recognize it ( the mistake, not the ugliness ! )
   You see, beauty has played an evolutionary role as well - to say nothing about the beauty in the symmetries of the natural laws.
   Beauty matters !  :)

And above, you note that recognition ...
Quote
of high symmetry of the Zeppelin bend
is not so readily apparent, as it is ...
Quote
[symmetry that is not noticeable by looking at a single side of the knot,

   Yes, but the fact that the Zeppelin bend is more symmetric than the bend presented at (1), is noticeable at a glance !
   So, if you say that the more or less apparent symmetry of the Zeppelin bend, or of any other symmetric bend, is LESS apparent than the asymmetry of the knot presented at (1), you should/will visit an eye doctor sooner than later !  :) QED ( for the doctor...)

these subtle differences will deny the ideally symmetric knot of its supposed perfect equalization.
  I do not deny this... but I had never spoken of "perfect equalization" . It seems that you find hard to deny the simple comparison of the differences between the relative strengths of the two links in the cases of a symmetric and of an asymmetric knot, and you call the cavalry of the absulute !  :)

Send them a Janus bowline !   ;D

You take a Janus bowline, and I will take the Tweedledee bowline...
(We will share the Athena...)

1. http://igkt.net/sm/index.php?topic=4116.0
« Last Edit: November 18, 2012, 12:28:45 AM by X1 »

Dan_Lehman

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Re: Walking Beauty (M. A16 - ABoK#1063)
« Reply #28 on: November 19, 2012, 03:27:26 AM »
   One other bend where the first curve of the one link turns around a tail,
and it is not hooked to the first curve of the other link, is the Walking Beauty
( M. A16 - ABoK#1063)( See the attached picture ).
/.../
   I do not like the Walking Beauty - not, of course, because it is a beauty,
but because it walks... :).  The two links can not form a stable, compact whole,
without being pretensioned quite forcefully.  So, when unloaded, this bend remains
in a loose, unstable form most of the time, especially if it is tied on stiff material.
...

Hmmm, in a quick check in flexible solid-braid cord,
I was liking the slack-secureness of this knot, seeing
that loading didn't increase that security --i.e., didn't
over-tighten (jam) it.  I'll take your word that in some
firmer material, such security doesn't come easily.

However, OTOH, I also like how this knot can be left
less tightened, for pure ease of untying --after, e.g.,
use to join bigger ropes used for towing a vehicle out
of being stuck.  I like how the SParts are deflected
around the twin wraps and then make their U-turns
which nip the tails --thinking this initial bending over
twin (not a single) parts of rope is kind to the rope
and efficient in strength.  And then, as noted, this
loose form will be readily untied.

.:.  So, a tool to be used appropriately.

--dl*
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agent_smith

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An intelligent discussion on bends (end-to-end joining knots)
« Reply #29 on: November 20, 2012, 12:42:53 AM »
Have to say that I really like this thread - there is some really interesting technical content here.
For example:

Quote
It may sound a little too abstract or general to some, but ALL bends ( end-to-end knots) belong to three, and three only, broad categories. *(1)
   The most important part of any bend is its Standing parts first curves. It is there where the loaded bend will make it or brake it. So, it is reasonable to classify bends according to the specific characteristics of those curves, and not of the rest of their two links entanglement.
   The first curve of each link of a bend can make a turn ( can bend ) around :
   1. The other link s straight part of the standing part - the straight continuation of the standing end.
   2. The other link s first curve of the standing part.
   3. The other link s tail.

And, the thread has hasn't degenerated into a slanging fest (which has really brought my interest back to the IGKT forum again).

I have to study this material and see if any of it can be tested.

Mark