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kf8mo
Aug 18, 2012, 10:57 PM
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I recently ran across a discussion of the Zeppelin bend (and its loop form), became intrigued, and did both more reading and some tying in rope and webbing. If what I've read is credible, the one source that called it "the best knot you've never heard of" may be right. It's very secure, like an 8, but doesn't jam and can easily be untied after loading (unlike an 8, water knot, or fisherman's). Supposedly, like an 8, it doesn't loosen when unloaded or when flogging as a bowline can. It doesn't capsize like an EDK, it doesn't creep when loaded cyclically like a water knot, it's symmetrical and easy to inspect for correctness like an 8 whether tied in rope or webbing. The one static loading test I found showed the Zepp loop superior to the rethreaded-8 in strength, but other than that I didn't find that anyone had done much lab testing on it.
There are lots of data and lots of debate (granted the heat:light ratio may be somewhat suboptimal) about the 8 vs bowline, fisherman's vs water knot, and EDK vs anything else, but searching here on Zeppelin gets mostly Led. Anyone use it, know why it's not used widely, have any test data on it?
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Rudmin
Aug 19, 2012, 11:07 PM
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The only documented climbing use for that knot which I know of is tying together core strands to rappel with. There was a thread here about it.
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knudenoggin
Aug 20, 2012, 5:40 AM
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kf8mo wrote: I recently ran across a discussion of the Zeppelin bend (and its loop form), became intrigued, and did both more reading and some tying in rope and webbing. If what I've read is credible, the one source that called it "the best knot you've never heard of" may be right.
Although it's a real challenge to test it against all the other knots
"you've never heard of!" 
In reply to: It's very secure, like an 8, but doesn't jam and can easily be untied after loading (unlike an 8, water knot, or fisherman's). Supposedly, like an 8, it doesn't loosen when unloaded or when flogging as a bowline can. It doesn't capsize like an EDK, it doesn't creep when loaded cyclically like a water knot,
Flogging testing is an undefined art --YMMV w/materials. But the
zeppelin end-2-end knot does seem nicely resistant to loosening,
at least in some mild conditions. I'm not sure I'd trust it to be
so for rather unknown & out-of-sight uses (in contrast to the
grapevine bend, e.g.). It has something to do with how the tails
exit perpendicular to the axis of tension and with a right-angle
turn, which makes them resistant to moving even in a relaxed
state.
The offset water knot (EDK) can simply be made capsize-proof,
for the usual use in abseiling (tie off the right tail with a stopper,
or put an extra turn in the choking strand), and serves that purpose
well, given its offset nature. The zeppelin offers nothing, here.
Creeping in the water-knot-in-tape is a mystery : some testing found
it to occur in stiffer tapes but not new tubular, and then only at low
loads (such as might come in abseil). There is a way to tie the
water knot symmetrically so that each tail will finish on the
interior side (testing found only the exterior tail of the known
water knot to be slipping). Aric made one test of this just for break
strength --not cyclical low-load slippage (which Moyer et al. did)--
and had that posted in The Lab, but it's gone, with him, now.
Of course, the common bowline should not be used without precaution
against loosening, of which there are many ways. What the bowline
offers is "PET"(ness) : "post-eye [formation] tying" --i.e., one can
for the eye to whatever size, AND THEN tie the entire knot; there
is no "first half" of the knot to tie and then re-thread, e.g..
(I've actually figured a variation of the zeppelin that does this,
but it's a case of *theoretical* play bordering on comedy --could
work, but hardly worth the bother.)
There is a chunkier version that TIB (tiable in-the bight (sans ends))
--essentially, implementing a different definition of "corresponding
eye-knot". This would not be a fun knot to tie-in with, though.
In reply to: it's symmetrical and easy to inspect for correctness like an 8 whether tied in rope or webbing.
Whoa : it's not all so easily inspectable in tape --at least not in being
a knot you've never heard of (or seen). It's not all so obvious what
is going on in the crunched center of the knot. (And I think it's a
dubious one for solid webbing rather than tubular.)
In reply to: The one static loading test I found showed the Zepp loop superior to the rethreaded-8 in strength, but other than that I didn't find that anyone had done much lab testing on it. There are lots of data and lots of debate (granted the heat:light ratio may be somewhat suboptimal) about the 8 vs bowline, fisherman's vs water knot, and EDK vs anything else,
And yet still when one looks at the test reports there are more
unanswered points than information --such as exactly how the knot
was tied (dressed & set). As you say, there's much noise in it.
In reply to: but searching here on Zeppelin gets mostly Led. Anyone use it, know why it's not used widely, have any test data on it?
I think we've both seen the one Treebuzz arborist's reporting, yes?
--that was the stronger-than-fig.8-eyeknot case (w/o knowing how
he dressed the latter). There was some other testing of A-vs-B
sort, with cheap polypropylene laid ropes, in which the zeppelin
came in among other interlocked-overhand-knots end-2-enders,
weaker than the grapevine & fig.8 (and anchoring fig.8 eyeknots
never broke (!)) --truck pulling specimen anchored to tree.
Beyond that, I'm not recalling much of anything.
But, really, in rockclimbing, end-2-end knotting is pretty well defined:
grapevine for semi-permanent sling formation in rope (and, by the
evidence of testing, also in tape; less permanence seems wanted,
here, though?!) ;
the offset water knot (EDK) or a secured variation, for joining abseil
lines --where being offset is the desired feature, and easy tying-- ;
and ... what else? (A cordelette actually doesn't NEED any joining
of ends : they can be brought out through the powerpoint knot and
left untied!)
The zeppelin eyeknot (of the known form : tail of first half taken
out to become eye and then brought back as joining end) might be
worthwhile for tie-in; but there are many ways of tying in, some
using known *technology* to bolster common knots.
*kN*
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hyhuu
Aug 20, 2012, 3:27 PM
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OP - What do you want to use the knot for? There are plenty of other neat knots out there but in climbing they are just not as useful. For simply joining 2 ropes for rapelling, it's hard to beat the simple EDK.
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bearbreeder
Aug 20, 2012, 4:08 PM
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exactomundo ... there arent a ton of knots that the average climber needs to know ... and honestly the simpler, the better
when yr cold, tired, hungry, in the dark, 12+ pitches up ... KISS
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ninepointeight
Aug 20, 2012, 5:53 PM
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I think the reality is that the EDK is just better. It pulls better, is easier to tie and inspect, and it's failure mode is incredibly easy to mitigate. There will be no surprises with the EDK because it has been widely used for ages.
If you start joining ropes like this when rapping I predict the following:
Your partner will think you're a sketchball.
Your partner will try to talk you out of rapping on ropes joined with that knot.
Your partner will insist you rap first.
Your partner will untie that knot and retie with an EDK or more common knot before they rap.
You'll take up gear solo-ing.
You're gunna die.
(This post was edited by ninepointeight on Aug 20, 2012, 6:08 PM)
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hyhuu
Aug 20, 2012, 7:19 PM
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hyhuu wrote: OP - What do you want to use the knot for? There are plenty of other neat knots out there but in climbing they are just not as useful. For simply joining 2 ropes for rapelling, it's hard to beat the simple EDK.
I forgot to add that I did use that knot once before but decided that didn't care for the big profile (compared to EDK) .
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crasic
Aug 21, 2012, 7:25 PM
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Why not just use a butterfly bend that every climber should know and not the zeppelin? It has the same basic structure and has all the benefits of the zeppelin with none of the obscurity.
Also, instead of an EDK, just use a flat double overhand (EDK wrapped twice). its as easy to tie as an edk, not much bigger than an edk, its stronger than an EDK, just as easy to inspect and doesn't slip like one.
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knudenoggin
Aug 24, 2012, 5:44 AM
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crasic wrote: Why not just use a butterfly bend that every climber should know and not the zeppelin? It has the same basic structure and has all the benefits of the zeppelin with none of the obscurity.
To put it another way, use known technology. But, as noted above
(or, as opined above), ... why use either? (Btw, I think you'll
fine the Z more slack-secure than the B .)
In reply to: Also, instead of an EDK, just use a[n offset dbl.overhand (EDK wrapped twice). its as easy to tie as an edk, not much bigger than an edk, its stronger than an EDK, just as easy to inspect and doesn't slip like one.
[nb: the knot isn't flat, but it is offset. :o]
Here's why : Occam's Razor, guided by an analysis of the needs for
the end-2-end knot, cuts out the 2nd wrap of the yellow rope (as you
present it in photos) --tucking that one out on the first pass, making
an overhand in the yellow rope--; the 2nd wrap is made only
in the red rope, which makes for a tighter choking at the knot's
offset throat (i.e., it's nearly a closed circle --minimal helix).
("stronger than the EDK" isn't quite right : they are equally strong,
in that both will hold abseil loading w/o issue.)
And, in (not uncommon) situations where the ropes are thick joined
to thin, you would put the thin rope in the position of the red,
and so the added knotting is done in the thinner line which saves
bulk a bit. (Similarly with the EDK, which would "roll" only by
the thinner line being forced out around the thicker, and for which
such rolling can be precluded by tying an overhand stopper around
with the thin tail around the thick, snug to the EDK .
Cf. http://www.rockclimbing.com/...set%20fig.9;#2091962
for an older discussion of this, and some images.
!! You're on the right track, good show!
*kN*
ps: In your image of the finished knot --lower-right--, the red tail
has moved out of best position (shown lower-left), going where the
draw of the loaded mainlines want to rotate it anyway;
it's best to set the knot against this, IMO.
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kf8mo
Aug 28, 2012, 9:16 PM
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knudenoggin wrote: In reply to: Why not just use a butterfly bend that every climber should know and not the zeppelin? It has the same basic structure and has all the benefits of the zeppelin with none of the obscurity. To put it another way, use known technology.
This was really the thrust of my original question. Known technology isn't always better technology, the organizational psychology literature is full of examples of how we tend to cling to the familiar even when superior alternatives are available. I was wondering if the obscurity of the Zeppelin bend is such an example, vs. yeah it's better but irrelevant because we already have good enough ones.
The Z and the B are very similar; ISTM that the only difference is that the Z is symmetrical. I don't know if that makes it more secure, or otherwise affects its performance, but it would be interesting to do some tests on it to see. Playing with both for a while, it does seem easier to inspect a Z and see immediately whether it's tied correctly.
I've tied Zs in various sizes of sling as well, and even though there's a "hidden" part inside, it's immediately obvious if it's not tied right. I haven't been able to find a way to mis-tie a Z in webbing that looks deceptively normal.
In reply to: Also, instead of an EDK, just use a[n offset dbl.overhand (EDK wrapped twice). its as easy to tie as an edk, not much bigger than an edk, its stronger than an EDK, just as easy to inspect and doesn't slip like one. [nb: the knot isn't flat, but it is offset. :o]
I tried tying an offset double overhand, and it was easy to tie and inspect. It was pretty nearly as bulky as a Z or B though. The plain EDK was definitely smaller than any of the three. Still, though it is strong and small, the EDK's tendency to capsize (which if I understand correctly is where the pejorative "Euro death knot" comes from) seems to limit it to use as a temporary knot, like for one rappel. I wouldn't want to use it for anything I wanted to stay tied for any length of time. As a sailor I would never use it to join two lines to moor my boat for example.
(The only difference between having your rap knot fail and having your mooring knot fail is that in the former case you're beaten to death on the rocks vertically by gravity, while in the latter case you're beaten to death on the rocks horizontally by waves. Either way, secure knots are good!)
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kf8mo
Aug 28, 2012, 9:22 PM
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knudenoggin wrote: kf8mo wrote: ... the one source that called it "the best knot you've never heard of" may be right. Although it's a real challenge to test it against all the other knots "you've never heard of!"
That would seem to require a certain degree of clairvoyance, yes
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majid_sabet
Aug 28, 2012, 9:32 PM
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looks scary
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