Author Topic: Zeppelin Bend: Security and Strength  (Read 40405 times)

xarax

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Re: Zeppelin Bend: Security and Strength
« Reply #15 on: January 18, 2012, 08:35:00 AM »
Wow.  All bowline variations are everything to everyone ::).  It makes me wonder if you even read what you write.

   "I" write what I think is true, and you think that what "you" write is true. Some difference ! :)
    The secure bowline-like loops do not need an overhand knot tied on the standing part, they do not even need a closed nipping loop on the standing part, as we have seen recently (1). Of course, if one does not know them, or does not even want to learn them, he can always tie the first bend that crosses his mind, as a loop, and be satisfied with the cleverness of the result... To me, to be able to tie a secure loop around a ring or bollard, without having to tie an overhand knot on the standing part first, is a wonderful gift from the Knot Land offered to us, almost a miracle we are not allowed to ignore.
   I have explored the field of bends and the field of loops as well for some time now, and I have been driven to the conclusion that they are two quite different things we should not confuse. Bends are symmetric, two-loaded-ends knots, loops are not. Big, huge difference. A good bend can always serve as a so-so loop - as it happens in the case of the Zeppelin knot - but a knot tyer would never be deceived by the apparent similarity, and would never be satisfied with the "usefulness" of an ugly monster that does not belong to the one or the other field. We are talking about knots here, I suppose, not about "every-tangle-thing", and to knot tyers, not to "everybody'...otherwise we can always pass our free end around the object five, ten, or even a hundred times, and have our job done !
   So, yes, "I" write what I think is true, but there will be always people that are not interested in truth, and will not never ever read what I write. It makes me wonder  if they have ever read anything else, except what "they" think they have written...

1. http://igkt.net/sm/index.php?topic=3020.msg21688#msg21688
« Last Edit: January 18, 2012, 09:08:11 AM by xarax »
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Dan_Lehman

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Re: Zeppelin Bend: Security and Strength
« Reply #16 on: January 18, 2012, 05:59:14 PM »
/.../   Any secure bend can be transformed into a secure loop.

There is no point of doing this with the Zeppelin bend or with any other bend,
because we have dozens of secure bowline-like loops, which have the additional
great advantage to get completely untied the moment you pull out the tail.

Although I mostly agree on Xarax's post, I disagree on the last sentence. It is not always an advantage that a knot is very easy to undo by just withdrawing one tuck. The security of the Zeppelin Loop may well override this perceived disadvantage.

I don't think Xarax meant that one can simply undo one
tuck, but that having unreeved the tail, there is no *knot*
remaining in the rope (i.e., the nipping turn of the SPart
disappears) --unlike for most other eye knots, such as the
commonly used fig.8 eye knot & zeppelin eye knot.

But I do disagree that any end-2-end knot can produce
a suitable eye knot : the squaREef knot doesn't do this
--but, yes, it certainly is (like or not) an end-2-end "bend".

--dl*
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Dan_Lehman

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Re: Zeppelin Bend: Security and Strength
« Reply #17 on: January 18, 2012, 06:29:41 PM »
My interest in the Zeppelin Bend stems from explorations of failed bowlines.
!?  How have you explored failed bowlines ?

Quote
bitter ends,

Let's kill the "bitter" mis-use (it should refer to bitts);
"end" or, better?, "tail" will suffice, nicely.   ;)

As for (rock)climbers knowing about the bowline,
that is demonstrably not true, for all --hence some
of the issues your explorations might've found.
But awareness is growing (one hopes).

Quote
In looking at Ashley, Butterfly, Hunters (aka Rigger's) and Zeppelin Bends, I am impressed that whereas the first and third typically can jam, and the butterfly bend can be sometimes shaken free, the Zeppelin excels in all these areas.

The issue about the first "typically can jam" I hope
I've put to rest in a thread here, about 6 months ago?
There are various ways to dress the knot --which can
be varied per need--, including one dressing in which
there is no jamming.  I've put this to some testing
in normal materials.  And SmitHunter's bend has a
simple version that pretty well resists jamming (just
cross the tails ...).  Oh, by "Ashley", we should append
a qualifier to that --"1452".  He also introduced #1408
and #1425, which are jam resistant (the first being
what I regard as a symmetric "butterfly").

As to your conjecture about opposed tails giving some
benefit to security, I don't buy it so much.  There are
cases where tails move opposite each other, as well as
some cases where there is apparently some *assistance*
of slippage by ends moving together.  Here, I think that
the security comes from a hard nip relative to the forces
on the tails (irrespective of their direction of pull).  And
the slack-security (something Xarax seems to ignore,
as a quality aspect) comes from the particular angle at
which the tails reach their final tucks (so that they just
aren't so pulled towards loosening?!).

All that said, there are some quite simple bowline extensions
that do well to add security, maybe even a bump of strength
--putting a 3rd or 4th diameter in the central nipping loop--,
so that rope users can meet their needs with that knot.


--dl*
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[Inkanyezi] gone

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Re: Zeppelin Bend: Security and Strength
« Reply #18 on: January 19, 2012, 12:07:41 AM »
/.../   Any secure bend can be transformed into a secure loop.

There is no point of doing this with the Zeppelin bend or with any other bend,
because we have dozens of secure bowline-like loops, which have the additional
great advantage to get completely untied the moment you pull out the tail.

Although I mostly agree on Xarax's post, I disagree on the last sentence. It is not always an advantage that a knot is very easy to undo by just withdrawing one tuck. The security of the Zeppelin Loop may well override this perceived disadvantage.

I don't think Xarax meant that one can simply undo one
tuck, but that having unreeved the tail, there is no *knot*
remaining in the rope (i.e., the nipping turn of the SPart
disappears) --unlike for most other eye knots, such as the
commonly used fig.8 eye knot & zeppelin eye knot.

But I do disagree that any end-2-end knot can produce
a suitable eye knot : the squaREef knot doesn't do this
--but, yes, it certainly is (like or not) an end-2-end "bend".

--dl*
====

Like in the case of Xarax, I leave something to the reader's fantasy, and you might imagine that I didn't intend to say that any bend will make a good loop when one of the ends is taken back. However, in the case of the Zeppelin, the resultant knot is secure and easily untied. Like for most other knots, I am not particularly concerned about strength, but there is a difference between boating and rock climbing, both regarding materials and perceived security. After all, boating lines are sufficiently secure with a bowline; I have used it for fifty years without a single failure. Also I never had a mooring line break. I remember in my youth a halyard that broke, three strand cotton. I never used cotton for a halyard since.

So I'll stick to tying up my boat with a bowline in one end, and I know the Zeppelin and the loop form of it well enough, but there's little chance that I would use it other than as a demonstration.
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xarax

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Re: Zeppelin Bend: Security and Strength
« Reply #19 on: January 19, 2012, 08:56:55 AM »
I didn't intend to say that any bend will make a good loop when one of the ends is taken back.

  I do !  :)  And many of them - probably most of them - are better as loops (eye knots)  than as bends ( end-to-end knots) !
   Now, I also can discover  one or two  exceptions to this self evident truth, ( if I try as hard as Dan_Lehman did  :) ), but not many more... ( A handful of exceptions, in more than two hundred bends I have taken pictures of, AND all the bends posted in Ashley and/or Miles...can not falsify this general rule, I suppose.)
« Last Edit: January 19, 2012, 09:19:34 AM by xarax »
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youngknot

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Re: Zeppelin Bend: Security and Strength
« Reply #20 on: January 19, 2012, 03:34:16 PM »
I am grateful for all the references and especially Sweeney's web reference.  The alternative method is what I had worked out; the modification of the "b-q" method makes the derivation from the bend much clearer.  Good stuff!
It is clearly true as Xanax says, that taking one bitter end of a bend knot into a loop may utterly shift the forces into another shape, leaving many features and bringing on a whole collection of problems.  The Carrick Bend as tied, flat looks nothing like spilled and formed into a proper bend where force can be resisted.  In the summer of 1959, a Maine lobsterboatman, Elmer Osier, showed me the method of tying a bowline which begins with a slip knot waiting in the SPart and throws the free end around an approaching wharf and through it loosely, spilling it into a proper bowline.  At the time, I was quite impressed at how knots become sometimes what you least expect, and Xanax's points are well taken.  For my part, as a practicing ecologist, the Zeppelin Loop was new ground, at least worth trying, and although I think online discussions might approach overloading the ties that otherwise bind us, I do value everyone's contributions--thanks.

roo

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Re: Zeppelin Bend: Security and Strength
« Reply #21 on: January 19, 2012, 05:48:00 PM »
I am grateful for all the references and especially Sweeney's web reference.  The alternative method is what I had worked out; the modification of the "b-q" method makes the derivation from the bend much clearer.  Good stuff!
It is clearly true as Xanax says, that taking one bitter end of a bend knot into a loop may utterly shift the forces into another shape, leaving many features and bringing on a whole collection of problems.  The Carrick Bend as tied, flat looks nothing like spilled and formed into a proper bend where force can be resisted.  In the summer of 1959, a Maine lobsterboatman, Elmer Osier, showed me the method of tying a bowline which begins with a slip knot waiting in the SPart and throws the free end around an approaching wharf and through it loosely, spilling it into a proper bowline.  At the time, I was quite impressed at how knots become sometimes what you least expect, and Xanax's points are well taken.  For my part, as a practicing ecologist, the Zeppelin Loop was new ground, at least worth trying, and although I think online discussions might approach overloading the ties that otherwise bind us, I do value everyone's contributions--thanks.
The Zeppelin Loop is a good one.  You'll be hard pressed to find a loop that remains stable and secure in slick bungee under high strain and still remain easy to untie, for example.  Those benefits also translate into less radically elastic line.

The loop reduces one of the standing parts of the bend to 50% of the parent line load (from 100%).  It also increases the load on the one of the free ends of the corresponding bend from 0% to about 50%.  This does not adversely affect the core knot form in terms of either stability or its excellent jam resistance. 

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Dan_Lehman

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Re: Zeppelin Bend: Security and Strength
« Reply #22 on: January 20, 2012, 12:06:45 AM »
The Carrick Bend as tied, flat looks nothing like spilled and formed into a proper bend where force can be resisted.  In the summer of 1959, a Maine lobsterboatman, Elmer Osier, showed me the method of tying a bowline which begins with a slip knot waiting in the SPart and throws the free end around an approaching wharf and through it loosely, spilling it into a proper bowline.

Where some other commercial fishermen are concerned,
the tying of the carrick bend doesn't use that lattice-like
form, but is done by folding one end into shape and then
reeving the other through it (which can lead to some
different results if botched) --done like this, apparently,
in the stiff, hard-laid pot warp of Alaskan crabbers when
extending the lines.  (It is an application I think that would
suit the zeppelin end-2-end knot quite well.)  That
losterman probably used a fisherman's knot or maybe
water knot .  Some decades back, someone reported
in Knotting Matters that to his experience the lobstermen
around Boston were nearly divided into (warring) camps and
distinguished by which end-2-end knot they employed!

The marlinespike-hitch-into-bowline maneuvre can be some
help, but one should beware that sudden loading as has
been described here & elsewhere can lead to things
other than a well-formed eye knot --the capsizing might
not go as desired, given roughness & loading of the line!
YMMV.


--dl*
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Dan_Lehman

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Re: Zeppelin Bend: Security and Strength
« Reply #23 on: January 20, 2012, 12:10:56 AM »
Like for most other knots, I am not particularly concerned about strength,
but there is a difference between boating and rock climbing,
both regarding materials and perceived security.
After all, boating lines are sufficiently secure with a bowline;
I have used it for fifty years without a single failure.
Also I never had a mooring line break.  ...

I'm reminded of reading one sailor's remark concerning
strength that, even after a hurricane had ravaged some
marina(s) of moored boats, no lines broke at the knot (and
most didn't break), but elsewhere.


--dl*
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youngknot

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Re: Zeppelin Bend: Security and Strength
« Reply #24 on: January 27, 2012, 06:29:31 PM »
Thanks again for all the perspective and information.  To answer one question: I feel it is important making knot statements to relay with what range of cordage you have experience.  "Bowline" security in my experiences, ranges from monofilament line, through laid nylon and polypro stuff, to 7/16 kernmantle inelastic cave standing ropes (Bluewater II), coated with ice and limestone mud--- infrequently over about five decades.  I have never had a problem except with monofilament or new 7 mm nylon kernmantle, and only with jerking--by which I mean where the line is repeatedly relaxed alternating with drawn up tight and hard.  An unsecured bowline, well formed by hand, simply in the last two cases, after 10 - 30 jerks, unties.  As I mentioned in my first post, whenever I even suspect in any USE, that there is that possibility in store, I use some extra security, such as the Yosemite finish and perhaps a couple of half hitches.  I do not consider what others look at as exaggerated security a waste of time, even with numb fingers.  Well-formed bowlines with no added finishing I have never seen fail from untying in stout well-laid ropes > 1/2 inch - - but then, I've never owned a Zeppelin tossing in the wind.
I have previously worked alone, and having now thoughtful colleagues with whom to discuss knot matters is a privilege, again, thanks.
Regarding the other bends formed by two linked overhands, I was fascinated by their symmetry.  Owning no knot reference besides Clifford's remarkable 1944 achievement at hand, I began by studying overhand knots, proved to my satisfaction there are only two, I called L and D, for levo- and dextro-rotary (for the spirals formed, LH and RH threaded screws).  For morphology, I named the two crescent-shaped holes in overhands "A" (next to SPart) and "B" (by the tail).  The large opening I called "O".    So now I can write typing directions using these named holes and symmetry descriptors, by which to study the four bends I first mentioned. 
By coincidence,  the four arrange themselves alphabetically in my key:
1. tails emerge in same direction:
00    overhands same: Ashley Bend (Thanks Dan, #1452)
01    overhands mirror images: Butterfly Bend (these attributes are inevitable for the only one to be tied on a bight)
2. tails emerge opposite directions
10   overhands same: Hunter (aka Smith or Riggers)
11   overhands mirror images: Zeppelin or Rosendahls
Alphabetical, at least using these as names.
In closing, I'll note you all may likely know these curious facts --- and/or the exceptions of which I will soon be gratefully educated.  Thanks in advance. Regards.

xarax

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Re: Zeppelin Bend: Security and Strength
« Reply #25 on: January 27, 2012, 08:33:42 PM »
Regarding the other bends formed by two linked overhands, I was fascinated by their symmetry. 

Hi youngknot,

   There are dozens of interlinked-overhand-knot bends, and if we take into account all their variations, ( including the "double" ones ), there are dozens of dozens, indeed !
   You can find almost all of them in this forum, if you search for the relevant words, "bends", and "overhand". The Zeppelin bend stands in a class of its own, as you will find out.
   The most easy way for one to start, the way I suggest to people, is to form one reef knot "base", and re-tuck it. See the attached picture, for one of the eight such bases). That way you will get the Ashley bend (ABoK#1452), the Alpine Butterfly bend, the ABoK#1408 bend, the Hunter s bends, the Shakehands bends, and the Mark s bends. Those are the most well known bends, and a sure place to start one s journey to the world of bends.
   The same can be said for the bowline-like bends, where we have also the very nice compilation of bowlines by Mark Gommers, at (1). Search for "bowline", and you will discover many things here, that you are not going to find elsewhere.
   Welcome to the forum. We need new knot tyers, especially if they are young !  :)

1) http://www.paci.com.au/downloads_public/knots/02_Bowlines.pdf
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Dan_Lehman

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Re: Zeppelin Bend: Security and Strength
« Reply #26 on: January 27, 2012, 09:14:39 PM »
I feel it is important making knot statements to relay with what range of cordage you have experience.

Amen!!  It is amazing to watch a video of a double bowline
(with stoppered tail) just collapsing its eye as material *flows*
out of the knot through those double turns!!  --"Huh, it can DO that?!"
was my thought.  And the end-bound double bowline I thought
so secure (well set; and meaning "secure-when-slack", vs. jostling),
showed a lack of that in some slick, springy, laid polypropylene cord,
where all the engaged loops binding upon each other just loosened
simultaneously, after holding briefly (!).

Quote
I use some extra security, such as the Yosemite finish and perhaps a couple of half hitches.  I do not consider what others look at as exaggerated security a waste of time, even with numb fingers.  Well-formed bowlines with no added finishing I have never seen fail from untying in stout well-laid ropes > 1/2 inch - - but then, I've never owned a Zeppelin tossing in the wind.

Consider some of the bowline extensions presented in
the "paci" PDF file Xarax points to.  I can see taking one of
the "Janus" variations and extending that to make one further
collaring (of the SPart) and tucking of the tail (to point, now,
back towards the eye) --makes for a lot of unreeving to occur
AND not be noticed; maybe bumps strength, lessens wear?

As for "zeppelin", know this:  there is now considerable doubt
that (1) such an end-2-end knot was ever needed & used for
those airships, and (2) that Cmdr. Rosendahl had the slightest
awareness of it --there is writing from him to support this belief.
So, count one more knot myth, though it's a mystery of why it
was created (the myth), and where the knot might've originated.


--dl*
====

xarax

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Re: Zeppelin Bend: Security and Strength
« Reply #27 on: January 27, 2012, 09:39:35 PM »
As for "zeppelin"...count one more knot myth, though it's a mystery of why it was created (the myth), and where the knot might've originated.

   Myths are generated/created in all fields of human practice, why do they have to respect knotting ? I would like to contribute to this mythology a little bit, with two myths made by me :
  1. Zeppelin, the inventor of the Zeppelin airship, served in the US army as a volunteer. Rosenthal inherited the knowledge of the knot, along with the Zeppelin airships... :)
   2. Ashley knew the Zeppelin knot, but decided not to publish it, because it was invented by a (German) enemy :  The proof that he knew it, is ABoK#582 stopper - which is the Zeppelin bend turned into a stopper ( and so disguised ! )  :) (See 1)

1)   http://igkt.net/sm/index.php?topic=2816.msg17243#msg17243
« Last Edit: January 28, 2012, 05:20:53 AM by xarax »
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roo

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Re: Zeppelin Bend: Security and Strength
« Reply #28 on: January 27, 2012, 09:48:06 PM »

As for "zeppelin", know this:  there is now considerable doubt
that (1) such an end-2-end knot was ever needed & used for
those airships, and (2) that Cmdr. Rosendahl had the slightest
awareness of it --there is writing from him to support this belief.
So, count one more knot myth, though it's a mystery of why it
was created (the myth), and where the knot might've originated.
Rosendahl has been dead for quite some time (since 1977!).  Where's this evidence that he never had any awareness of the bend in question?  It sounds very fishy to me.

I also find it hard to believe that various grounding lines or other lines were never bent to other lines.   

See:
http://tinyurl.com/6qzqe4m
http://tinyurl.com/7g3hjtp
http://tinyurl.com/75weqr5
http://www.motherearthnews.com/homesteading-and-livestock/zeppelin-knot-zmaz80jfzraw.aspx#axzz2XLitgA8w
« Last Edit: June 26, 2013, 07:44:47 PM by roo »
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Dan_Lehman

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Re: Zeppelin Bend: Security and Strength
« Reply #29 on: January 29, 2012, 07:17:45 AM »

As for "zeppelin", know this:  there is now considerable doubt
that (1) such an end-2-end knot was ever needed & used for
those airships, and (2) that Cmdr. Rosendahl had the slightest
awareness of it --there is writing from him to support this belief.
So, count one more knot myth, though it's a mystery of why it
was created (the myth), and where the knot might've originated.
Rosendahl has been dead for quite some time (since 1977!).  Where's this evidence that he never had any awareness of the bend in question?  It sounds very fishy to me.

I also find it hard to believe that various grounding lines or other lines were never bent to other lines.

Apparently you don't read Knotting Matters !

In it, Dr. Giles Camplin, with a PhD. focusing on airships history,
recounts how he came to know about the "zeppelin" knot
--from a reprint of the 1976 Payne brothers' Boatingarticle
reporting what some "Joe Collins" is supposed to have said.
But in this particular (Wingfoot Journal) reprint, there was
a most intriguing footnote, which Giles recounts:

<<Lee Payne of Balboa, Calif., one of the
authors,  wrote to me  [Presumably the
Wingfoot Editor (1980)]
  about this article,
"Admiral Rosendahl wrote to me [Lee Payne]
to say that the Los Angeles? crew was trained
at Lakehurst rather than at Norfolk as stated in
the article, and that he had never heard of the
Rosendahl bend
but that 'it is slightly possible
that no one ever told me of it.  In any event I am
glad you think so highly of it.'  "

>>

--just in the nick o' time, given Rosendahl's life!
Enough said, though?
We must still wonder about the "Joe Collins" account.
Research can check to see if he exists as a bona fide
person in Naval files, as well as to check on the
alleged stations of sailors & training.

Further, in communication w/me about the issue,
Giles wrote
Quote
My further, more recent research into Airship Ground Handling
for my Ph.D thesis (2007) has now led me to find it very difficult to see
where and when this knot could've been used as a standard part of the
mooring procedure.


--dl*
====

« Last Edit: June 27, 2013, 06:14:49 PM by Dan_Lehman »