Author Topic: Pictures of Zeppelin Bend in Webbing  (Read 7181 times)

roo

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Pictures of Zeppelin Bend in Webbing
« on: May 31, 2012, 04:59:59 AM »
A couple of times I've mentioned that the Zeppelin Bend can make a clean-looking knot in webbing if tied with care.  I've attached a couple images for those who are curious and may not have webbing or other flat material beyond perhaps shoelaces.

The first picture is shown drawn up lightly and flat.  The second is shown after being strained.  I won't bother showing the backside of this symmetric bend, as that would be a bit redundant.  They're almost nice enough to wear on your collar. ;)
« Last Edit: May 31, 2012, 05:02:14 AM by roo »
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knot4u

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Re: Pictures of Zeppelin Bend in Webbing
« Reply #1 on: June 04, 2012, 05:33:24 PM »
Is it still easy to untie?

roo

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Re: Pictures of Zeppelin Bend in Webbing
« Reply #2 on: June 04, 2012, 05:57:33 PM »
Is it still easy to untie?
It has been in all the webbing that I've used.  I also like how it keeps the standing parts in a straight line.
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knot4u

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Re: Pictures of Zeppelin Bend in Webbing
« Reply #3 on: June 08, 2012, 08:37:00 PM »
Is it still easy to untie?
It has been in all the webbing that I've used.  I also like how it keeps the standing parts in a straight line.

That's more than could be said for the Water Knot, right? In other words, the Water Knot doesn't make the standing ends natural lie in a straight line.

Dan_Lehman

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Re: Pictures of Zeppelin Bend in Webbing
« Reply #4 on: June 08, 2012, 09:09:38 PM »
...  I also like how it keeps the standing parts in a straight line.

That's more than could be said for the Water Knot, right?
In other words, the Water Knot doesn't make the standing ends natural lie in a straight line.

???

Let's try to understand how the SParts could NOT be
in a straight line (given that they're all that bears tension)!?

--dl*
====

roo

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Re: Pictures of Zeppelin Bend in Webbing
« Reply #5 on: June 08, 2012, 10:24:42 PM »
...  I also like how it keeps the standing parts in a straight line.

That's more than could be said for the Water Knot, right?
In other words, the Water Knot doesn't make the standing ends natural lie in a straight line.

???

Let's try to understand how the SParts could NOT be
in a straight line (given that they're all that bears tension)!?

--dl*
====
It should be obvious that I'm referring to the state before loading.  By contrast, as knot4u notes, the Water Knot's standing parts start at an angle to one another before loading.
« Last Edit: June 08, 2012, 11:29:36 PM by roo »
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knot4u

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Re: Pictures of Zeppelin Bend in Webbing
« Reply #6 on: June 08, 2012, 11:49:56 PM »
Yes, the unloaded angle of the Water Knot looks to be about 135 degrees or less. That goes for rope too. See this pic for example:
http://meritbadge.org/wiki/index.php/Image:Water_knot.jpg
In contrast, the unloaded (and loaded) angle of the Zeppelin Bend looks to be about 180 degrees (straight line).

Another interesting example, the unloaded angle of a European Death Knot (EDK) looks to be about 0 degrees. See this pic for example:
http://www.istockphoto.com/stock-photo-11653999-euro-death-knot.php
When the EDK is loaded, it does seem the loading opposes what the knot naturally "wants" to do.

I'm not sure if any of this is a big deal. However, it is interesting to note the Zeppelin Bend is a fantastic bend for many applications. Perhaps the naturally straight angle of the standing ends is a testament to its performance.
« Last Edit: June 09, 2012, 12:02:46 AM by knot4u »

Dan_Lehman

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Re: Pictures of Zeppelin Bend in Webbing
« Reply #7 on: June 11, 2012, 07:30:58 PM »
Quote
naturally straight angle of the standing ends is a testament to its performance.

Rather, the cited "straight"ness is evidence of viewer perspective.
Consider that these SParts reach in to opposite sides of what
Xarax referred to as a "hinge", "pivot" line (IIRC) --so they must
deviate from the to-be-tension-aligned straightness in order to do
that, being curved at the collars.  Is this any better than curvature
in the water knot (which seems minor, in rope)?

I have discovered some ways to get a real straightness --absolutely
NO curvature until turning around material (and there curvature
is uniformly across the width of the tape --ideal!)--; but I suspect
that when push comes to shove (i.e., the severe forces toward
rupture point), the fact of non-rigid material being wrapped will
become clear, and a curvature across the tape width will obtain,
and "ideal" results won't, alas.  --nice to look at, though.  (And,
at least, there is not the *active* constriction of the SParts as
in the tape/water knot but something more *passive* --i.e., the
tape pressing into this deformable (but not constricting) collar.

Attached here is a photo of some end-2-end knots in both common
1" tubular nylon tape (the colored, larger stuff), and in 5/8" and 3/8"
(just one in latter) lubricasted-polyester cable-hauling tape.  The
familiar knot is shown for comparison purposes; note that this
knot is asymmetric --hence, the blue end lies "exterior"
(my term) and the yellow is mostly hidden by it.   In some
tapes --those that are stiff (possibly aged 1" tubular vs. new),
is one conjecture--, it would be the exterior end (blue, here)
that can be worked out of the knot in cyclical loading.

To redress this occasionally witnessed slippage, I discovered
a way to bring both tails out on the "interior" side, and the
knot is rendered symmetric by this revision.  (It is
easily tied by first making a loose fisherman's knot and
tying one overhand component so that its tail interlocks
with the first-tied component, and then dressing.)  Recently,
in looking at this revised, symmetric water knot, I wanted
to put the SPart's initial turn where the tail had been, but still
lying *exterior*.  This is seen in the 3/8" tape's knot, which
lies atop a yellow tape, upper-left, and above the original
symmetric revision in blue & yellow 2 knots down.  My
thought is that the turn of the SPart is more towards being
perpendicular to the axis of tension, and this might help
keep the force evenly distributed?
(A fellow once on RC.com tested the initial knot along with
the common one and IIRC there was slight plus to the former
--enough of a result to give some comfort that it wasn't a
weak alternative, at least.  Rupture seemed to come near
the point of entry, though one specimen showed the start
of tearing at the *peak* where SParts bend against each other.)


--dl*
====
« Last Edit: June 11, 2012, 07:47:11 PM by Dan_Lehman »