Author Topic: Two variations of the Zeppeln bend  (Read 12526 times)

xarax

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Two variations of the Zeppeln bend
« on: November 21, 2010, 06:06:33 PM »
Two variations of the Zeppeln bend
« Last Edit: January 30, 2011, 12:11:12 PM by xarax »
This is not a knot.

knot4u

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Re: Two variations of the Zeppeln bend
« Reply #1 on: November 21, 2010, 10:38:38 PM »
Zeppelin Bend = Zeppelin II ...correct?  The new name is more confusing, as opposed to less confusing.

Regarding Zeppelin Bend X, that's a different knot of course, beyond merely a variation in dressing.  My initial testing shows that it doesn't jam easily.  However, it does capsize easier than the beloved Zeppelin Bend.
« Last Edit: November 22, 2010, 04:52:13 AM by knot4u »

Dan_Lehman

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Re: Two variations of the Zeppeln bend
« Reply #2 on: November 22, 2010, 04:58:54 AM »
 After a tiresome exchange of opinions and negations with Dan Lehman (1), (where we were trying hard to tell something to each other, but not trying equally hard to listen and understand each other...), I was convinced that he is right after all : There are two distinct variations of the Zeppelin bend indeed, even though not the ones he had in mind !  :)

While happy to SEE (your cordage colors inevitably brighten my spirit)
you pursuing this topic,
I'll beg off your offer to a ride along the "not listening" road :
I listened well and responded,
and your post here at least puts some rub to your mocking "notice ... not three"
except of course in your continued denial of the obvious.

1) If one sets the R.Z. bend ("Rosendahl's Zeppelin) from a loose state with
rapid tensioning of the SParts,
it is quite possible --perhaps likely(?)-- that each SPart will pull the opposite
end towards itself (i.e., in the direction that the SPart pulls),
as with the knot loose during this transition there will need to be much movement
of the SPart and so a duration of *draw* upon this end it initially u-tuirns around.
(I've avoided saying "other rope's end" for one could be tying the ends of
a single rope together; but it's easier to illustrate with the distinctness of
your cheery ropes : the Orange line will hug the White tail to itself, and
vice versa (no, not The Vice Versa --let's not Reever this thread into that one).)

It would be helpful to see this in orange & white, too.  You can do it,
even if you must position the tails more deliberately (which is the one
sure way).

You can see one of my so-oriented knots here
(thread "Ashley's Bend #1452 and Its Ilk" )
http://igkt.net/sm/index.php?topic=1446.msg10047#msg10047
as well as a SmitHunter's bend variation (different tails orientation).

2) With appropriate minimal wasting of parts of one's precious lifetime
by pulling on the tails a bit, the above orientation I submit can put into
the SParts a more gradual curvature than in most other dressings; it can
be such that the hugged-close tail doesn't get pressed fully out of the
axis of trension, so that the SPart curves slightly around it towards
making its complete u-turn around its own tail.
Which is in contrast to the commonly presented form where the SPart
runs straight to the u-turn without much *deflection*.

3) One can see from this orientation that continued wasting of life pulling
upon the tails will begin moving them out of this orientation as each end's
Overhand is being drawn tighter/smaller, during which another somewhat
transient orientation occurs in which the tails lie adjacent/parallel in a plane
parallel to the axis of tension,
forcing the SParts to deflect harder against each collar to angle up around
them.  THIS form of SPart curvature resembles that shown by Inkanyezi
in his photos of the Carrick Bend --more hard-edged triangular than the
softer tear-drop oval or even bight-like-U in other orientations.

4) The orientation of tails in R.Z."X"  is asymmetrical ; it works symmetrically
for that False R.Z. bend because of that knot's different symmetry, with it
having same-handed Overhands.
And it is the sort of tails-exit variation that IMO improves the SmitHunter's Bend
by a similar curvature change and also getting the tails into a position that
better keeps the collars open, resisting jamming.

--dl*
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[Inkanyezi] gone

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Re: Two variations of the Zeppeln bend
« Reply #3 on: November 22, 2010, 03:56:11 PM »
Of course these musings go far beyond the practical aspect of knots, and more particularly beyond the practical aspects of the Zeppelin Bend.

As has been stated many times before, another orientation of any part in a given knot may result in a different knot or no knot at all, and when the Zeppelin's ends are crossed, inadvertenty or on purpose, the result is something else that is not the Zeppelin. It also loses symmetry, as one of the ends here passes through the turn of the other line, while the other does not.

Whether it is a good and useful knot might be tested, but it has a tendency to deform under load that is different from the Zeppelin.

For my own practical usage, there is no virtue in the different way of tucking the ends. I discarded the Zeppelin for practical reasons, and I cannot see any virtue in the different pattern that might be of better value. The one single reason for not including the Zeppelin in my toolbox is the complicated way of tying, which has not been improved. Other properties of the Zeppelin are excellent, but it needs too much attention to detail in the course of forming its pattern.

The "crossed ends" approach is different from the crossed ends in the Double Harness Bend, which does not lose its symmetry, but becomes something different, which is what's needed to make the Vice Versa. Arguedly, another knot will be formed by crossing the ends differently also in the harness bend, but the properties of the knot will not change a lot. The difference in the Double Harness Bend is seen as in one case the ends emerging at about right angles to each other, 45 degrees from the course of the standing parts, or the ends parallel to each other emerging at 90 degrees from the standing parts.

But just the same, a different knot is formed by tucking the ends in a different way.

The different orientations of the ends in the Zeppelin bend when formed in the original way do not change the tucks, but is merely a twist of the two ends together. The Carrick Bend has more distinct different aspects when ends emerge a bit different, as there are at least three rather distinct ways the ends may emerge all by themselves when drawing the knot tight. I don't know whether any of these really changes the behaviour of the knot, making it less stable, but two of them, the ones where the ends lie tightly together where they emerge, are neater than the third, where the ends are rather widely apart from each other. In practical use, there seems to be no difference. The knot has never failed me, and on a few occasions I have used it for several months. It still was easy to undo after a long Scandinavian winter.

Anyway, the X version is not the Zeppelin in my eyes, and any expansion of the idea will produce something else that might be a new knot, but not the Zeppelin. And my final verdict over the Zeppelin remains; it does not earn its way into the toolbox if it cannot find a convenient and dependable way of tying under harsh conditions and in total darkness.
« Last Edit: November 22, 2010, 04:44:57 PM by Inkanyezi »
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knot4u

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Re: Two variations of the Zeppeln bend
« Reply #4 on: November 22, 2010, 09:33:45 PM »
  Thank you knot4u.

Zeppelin Bend = Zeppelin II ...correct?  The new name is more confusing, as opposed to less confusing.

  Correct, most of the time...Because sometimes, in the process of tying the Zeppelin bend, while we push the b and q ends so they pass through the common opening, we cross them without even noticing it. If the opening is small enough, as in my pictures, and if the rope is stiff enough, this crossing remains as it is till the end of the tightening, so, at the end, we form the Zeppelin bend X. The loading itself, any loading, can not disentangle a crossed pair of

I've tied the Zeppelin Bend maybe about 500 times.  I can't recall ever tying the Zeppelin Bend X, neither on accident, nor on purpose.  You have a different knot there.  After reading your posts, I will still be calling the first knot you posted a plain old "Zeppelin Bend".  Anyway, I'd like to move on and analyze the Zeppelin Bend X you posted.
« Last Edit: November 22, 2010, 09:40:35 PM by knot4u »

Dan_Lehman

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Re: Two variations of the Zeppeln bend
« Reply #5 on: November 22, 2010, 09:41:14 PM »
Quote from: xarax
Is the bend shown in the pictures attached the infamous "third" variation of this pervasive "trio"?

No, it is the 2nd and what is usually shown is the 1st; your "X" is the 3rd.

Quote
1) If one sets the R.Z. bend ("Rosendahl's Zeppelin) from a loose state with
rapid tensioning of the SParts, it is quite possible --perhaps likely(?)-- that each SPart will pull the opposite end towards itself (i.e., in the direction that the SPart pulls)

Quote from: xarax
 As I have said many times, it depends upon ... .
[ergo] It is uncontrolled, so we may say it is, more or less, random.

It is more controlled to those who wish to seize control,
who dare to pull on the tails when dressing & setting the knot
to achieve a particular result.  (I am happy enough to not attach
to such possibility any great benefit, and to leave it of academic interest.)

Still, I might find myself taking some extra action, ...
Quote
2) ...by pulling on the tails a bit, the above orientation I submit can put into
the SParts a more gradual curvature than in most other dressings

  True. But isn't it more wise to go all the way, and cross the tails so the nipping loops run around a bulkier compound ?

As I will reiterate below, no, they are not the same knots;
and this "X" version is not symmetric, no matter you weaseling "s. breaking"!


Quote
4) The orientation of tails in R.Z."X"  is asymmetrical ...

Quote from: raving_lunatic
 No, they are not. The knot remains a 3D point symmetric knot. ( Otherwise, I would not dare naming it Zeppelin knot...) Each tail enters into the nipping "tube" in a specific orientation in relation to the other, swings around the other in an helicoid twist, and gets out in exactly the opposite orientation.

Let's put this quite practical-simply, not trying to hide the issue with
fancy terms : one tail exits through the collar of the other rope,
the other tail does NOT.  THAT is asymmetric, from my perspective,
and I don't care to excuse it by some reference to "s. breaking".
Which is what Inkanyezi has also explained:
Quote from: Inkanyezi
It also loses symmetry, as one of the ends here passes through the turn of the other line, while the other does not.

The difference has clear practical effect : in your pictured knot, XaraX,
the white rope --within limitations of setting/elongation...-- can draw its
tail towards rolling over the orange tail, white SPart drawing rightwards ;
but not so for its opposite number, as the orange tail is held against
such like draw by both legs of the white rope's collar.

Or, put another way, whereas the Orange Spart turns towards the viewer
and the White away, both tails exit towards the viewer ("upwards"),
both cross OVER the other as their final cross,
but this knot's symmetry requires that they be opposite in this.

As they are in the version I have been talking about which you have also
now shown, which preserves symmetry in the tails.

Quote from: Inkanyezi
Of course these musings go far beyond the practical aspect of knots, and more particularly beyond the practical aspects of the Zeppelin Bend.

Perhaps, except insofar as test data become available and are cited and
... depend upon such variation (which effect we only conjecture in their
absence, at this time).  And it is fair, yes, to question the practical importance
of such data, vs. a common Rule of Thumb about conventional ropes losing
50% strength when knotted, and keep you loads below 20%.  --fair enough.

 - - - -

Now, the asymmetric tails-crossing might have some application in the
R.Z. eyeknot, which differs in loading one tail.  I'm not sure I find a
particular orientation to use.

--dl*
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« Last Edit: November 22, 2010, 09:51:05 PM by Dan_Lehman »

Dan_Lehman

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Re: Two variations of the Zeppeln bend
« Reply #6 on: November 22, 2010, 10:02:44 PM »
... it does not earn its way into the toolbox if it cannot find a convenient and dependable way of tying under harsh conditions and in total darkness.

Whoa, this seems a severe criterion for having something in the toolbox!
--almost like saying "if it cannot make an eye, ..." : point being that tools
have their own particular purposes, and why have ALL of them needing
this severe one?  In the condition you describe, are you going to be
joining anchor rodes?  --likely not, and so why preclude a possibly
"best" knot (in terms of strength, abrasion resistance, ...) from being
used just because that knot might not be easily tied at Force 9?

How would you tie a messenger line to a cable?
Might you have a way you prefer,
and one other that though not so desirable is easily tied?

--dl*
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[Inkanyezi] gone

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Re: Two variations of the Zeppeln bend
« Reply #7 on: November 23, 2010, 12:03:25 AM »
/.../  my gut feeling tells me that, like many other people, you just do not like the Zeppelin bend...

On the contrary, I do like the looks of the knot, and I do like its behaviour, it's just that my preferred knot is so much easier to tie, particularly in darkness.

And of course it has snuck into my toolbox in a way, because I learned it, and I don't forget easily, but the reason for not using it is that I need a bend very seldom, and then I don't want to bother with looking at it while making it. So it might eventually be used some day, it's just not that likely.
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[Inkanyezi] gone

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Re: Two variations of the Zeppeln bend
« Reply #8 on: November 23, 2010, 07:47:55 PM »
/.../  It is amusing that people that consider the knots as tools, as practical instruments, disregard the functional symmetry of the Zeppelin X bend and insist that the most important thing is its geometrical asymmetry /.../

i have only seen such reasoning from you, xarax. While I do regard knots as tools, I don't give a rat's ass whether they are symmetric or not. I used the "symmetry" argument only as a means of identification, to distinguish one knot from another.

Also, assumptions of why a particular knot is "stronger than other knots" are not fruitful. For practical use, knots are tested, to find out whether their properties suit the purpose. Theoretical reasoning might be fine, but has little to do with practical knots. There is a board on the IGKT forum for knot theory, but I won't theorise over any particular helix or fill and its possible virtues within a knot.
« Last Edit: November 23, 2010, 08:17:06 PM by Inkanyezi »
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Dan_Lehman

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Re: Two variations of the Zeppeln bend
« Reply #9 on: November 23, 2010, 08:21:24 PM »
Also, assumptions of why a particular knot is "stronger than other knots" are not fruitful.
For practical use, knots are tested, to find out whether their properties suit the purpose. ...

The problem we face here is in the poorly reported, and I think also
poorly designed testing and understanding exactly what was in fact
tested.  The continual, obvious examples (which sadly raise little
questioning from those purporting to be interested in the data) are
of Fig.8 eyeknots and the like, where it is unknown which end
has been loaded !  Beyond this comes the question as to whether the
usual, slow-pull testing has relevance to practical applications --or should
testing be of a different sort, e.g., of cyclical slightly-higher-than-working_load
forces with the assessment being made as to the condition of the cordage
after some numbers of cycles (or of peak force recorded upon some
dynamic loading assured of achieving rupture of the conditioned knot) ?!

--dl*
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DDK

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Re: Two variations of the Zeppeln bend
« Reply #10 on: November 23, 2010, 09:15:22 PM »
Interestingly, the geometric symmetry of the "X" bend under discussion is neither the point inversion symmetry of the Zeppelin Bend nor the axial inversion symmetry of the Smith/Hunter's and Ashley Bend.  It could be considered a marriage of both symmetries, i.e. a marriage of the Smith/Hunter's with the Zeppelin.

. . .  As a practical knot, the Zeppelin X bend is symmetric, as a geometrical figure it is not. On the contrary, the Zeppelin I bend is symmetric in both roles, so we can argue that it is more symmetric than the Zeppelin X bend indeed.
  It is amusing that people that consider the knots as tools, as practical instruments, disregard the functional symmetry of the Zeppelin X bend and insist that the most important thing is its geometrical asymmetry, . . .

From my experience, the use of the term "functional symmetry" would be regarded as nonsensical in the fields of science and engineering in that the exact correspondence of geometrical symmetry with function is assumed in such endeavors and is one of the reasons symmetry is such a useful tool (but like statistics, useful for those who know how to properly use it).

DDK

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Re: Two variations of the Zeppeln bend
« Reply #11 on: November 23, 2010, 10:39:22 PM »
Design of testing is of course a sidetrack that might be worth further investigation.

For my own practical use I do a few tests if there's a knot that I want to know certain properties of, one of them is flogging. Flogging invariably opens a sheet bend, given enough time. Flogging does not open a Carrick Bend in most soft and frictive stuff, although it is possible in springy stuff as kernmantle. Flogging also does not untie a Zeppelin.

As I am usually not very concerned about strength, always guessing that it might be decreased by half by any knot, I wouldn't test for strength, but for security. Repeated flogging and pulling with hard jerks will show whether the knot has a tendency to creep. The Zeppelin stands up well, the Carrick Bend too.

Of course manual testing of these properties is not very exact, but they give a hint of what the knot might withstand in practical use. Knowing that flogging will open a sheet bend, I wouldn't use it where it is subject to flogging, although it can be used if I am sure that the line will not flog. The single sheet bend has more tendency to creep than the double, but the Carrick Bend does not creep at all, so that's one of the main reasons for using it. However, for my mooring lines, I have a butterfly somewhere in the middle, to which I tie a spring with a double becket hitch. It will never flog, so creeping is not an issue.

And before a knot has been tried for security, I won't discuss what particular geometric feature in its structure that might make it more or less secure than another.

The first picture shows how I arrange my moorings when tying up between a buoy and a jetty. My lines to the jetty are attached far aft, mostly at the winches, and there's a spring forward from somewhere along the line. The knot is a butterfly loop and a double becket hitch.

The second image is how I arrange moorings when tying between Y-fingers. A line is drawn along the Y-finger, with some slack and an eyeknot at a suitable point. I take that eye a couple of turns around the winch either side and lock it by passing under the line and put the eye over the winch.

The idea is to avoid jerks when waves from passing boats rock the boat. When the boat is tied up like this, it has freedom to pitch without repeatedly slacking and jerking on its leash. Geometry too is a tool, and poor geometry in the arrangement of mooring lines may cause disasters. With this geometry, no extra elasticity is needed in the mooring.
« Last Edit: November 23, 2010, 10:47:40 PM by Inkanyezi »
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Re: Two variations of the Zeppeln bend
« Reply #12 on: November 24, 2010, 04:06:00 PM »
I know that I deviated from the original subject of the Zeppelin variations with my previous post, and it was on purpose, just because the discourse anyway strays away from the main theme of practical knots.

But I will make a small theoretical comment here. Contrary to what is said in #22, the curvature will not necessarily become less sharp when there is more fill in the Zeppelin, but curvature may increase, because the curvature that is relevant to strength is not necessarily the one within the knot, where the nub sits, but might be the one at the entrance of the knot, where the collar hugs the standing part. When a knot breaks, it seems always to be just outside but never inside its structure. The two images show a false picture, because there is no load on the junction when they were taken. When load is applied, the two standing parts will always be in line with each other. The deviation will gradually increase with increased fill, approaching a maximum of 90 degrees when the fill is infinite. The least curvature will be with the least fill inside the knot.

As the Zeppelin is amply secure (and strong, which has been tested) in its original form, any expansion only makes the knot more complicated to tie without adding significant properties neither to strength, nor security. There might of course be some extremely slippery material, where the doubling will significantly decrease any tendency to slip, but so far I have not seen a Zeppelin slip once it is set. Doubling might show some virtue when knotting HMPE, but again, it is only theory; to be sure, it must be tested.

So once again, it has been shown that assumptions may lead to wrong conclusions, and when there is a difference between the map and the terrain, the latter will always have preference over the former.
« Last Edit: November 24, 2010, 04:36:30 PM by Inkanyezi »
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Dan_Lehman

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Re: Two variations of the Zeppeln bend
« Reply #13 on: November 24, 2010, 05:37:03 PM »
Interestingly, the geometric symmetry of the "X" bend under discussion is neither

I continue to fail to see symmetry at all,
when --as has been stated now several times-- the tails
have different relations to the knot (and of course vice versa)
--one exits out through the collar of the opposite rope,
the other does NOT.  THAT, to me, shows Asymmetry (not "a symmetry")!?
Please explain the contrary position.

--dl*
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Re: Two variations of the Zeppeln bend
« Reply #14 on: November 24, 2010, 05:44:26 PM »
Not a Hallberg Rassy, but one of the very oldest tubs made of glass and resin, a Karlskrona-Viggen, designed by Per Brohaell, from 1965. The pit is aft.

But the layout of most small sailing vessels is similar, and on most boats you can find a convenient midship belaying point for mooring lines. A funny thing with the layout is that it cannot easily find acceptance, I believe this is due to its non-conformity. Many think that it will not effectively restrain the boat from sideways movement or yaw, but in usage it has shown its efficiency. Pitching is not restrained, but the boat will not easily shift position, and the bow will not drift sideways more than with conventional mooring. I have even tried the same method with a small row-boat, where between Y-fingers it was only tied by the stern, and it was quite as effective. Here in Sweden, tying up with the bow to the jetty is common, and "mooring springs" to enhance resilience is mostly mandatory, but I don't use them. (To avoid confusion, they are not spring lines, but mechanical springs, made of resilient material, used to permit resilient elongation of the line.)
« Last Edit: November 24, 2010, 05:49:06 PM by Inkanyezi »
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