Author Topic: Alpine Zeppelin Loop - the ultimate tie-in knot?  (Read 755 times)

Moss

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Alpine Zeppelin Loop - the ultimate tie-in knot?
« on: June 14, 2019, 01:53:27 PM »
I discovered this knot the other day, which might replace my current tie-in knot for rock climbing.  It is a Zeppelin Loop with a retrace so that the bitter end exits the top, parallel and adjacent to the load strand. 

I expect this would be a good tie-in knot because it uses rope effiently, it looks sexy and is verifiable, easy to untie after loading, very secure and stable and resistant to ring-loading (as far as I can tell). 

Before I go testing this with my body, I thought I would check with the forum to see if I missed something.  Thanks for your thoughtful responses, video below:

https://youtu.be/aPdak4-Thb8

agent_smith

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Re: Alpine Zeppelin Loop - the ultimate tie-in knot?
« Reply #1 on: June 14, 2019, 04:10:21 PM »
Thank you 'Moss' for posting your work on this forum - it is appreciated.

I have viewed you video and can comment as follows:

1. Your suggested name is unnecessary - 'alpine Zeppelin loop' - not sure why you seek to add the word 'alpine'?
I already have issues with #1053 Alpine Butterfly - preferring just 'Butterfly' (per Wright and Magowan 1928).
The 'alpine' moniker is a fiction - added by some mountaineers because they felt it was exclusively used as a mid-rope tie-in knot for glacier travel.
Of course, #1053 can be used anywhere on or below the Earth's surface - it is not restricted for use in snow and ice environments!

If you really wish to attach a name to this structure, just leave it as a 'Double collar Zeppelin loop/eye knot', or something similar (or 'Moss Zeppelin eye knot').

2. At 5:44 in your video, you realize the Achilles heel of this Zeppelin loop/eye knot variant - and that is - it is fiddly to dress and set.
In adding the additional tucks of the 'working end' - it makes it somewhat fiddly to make adjustments - and to draw out any slack rope segments in the knot core.

3. At 6:06 - you mention the word 'strength' - please be aware that the MBS yield point of a knot (ie 'strength') is entirely irrelevant in the context of tie-in knots for climbing. There is no load that a climber can generate that will reach the MBS yield point of a knot! I'm not sure why you started to discuss 'strength' - you sounded somewhat vague in your discussion?

4. At 7:17, you mentioned that this eye knot might be "easier to untie - and even easy to tie".
For the average rock jock - any corresponding eye knot derived from the Zeppelin bend will likely be viewed as 'too difficult' (or declared too hard to check by a climbing buddy).
It will only gain traction for a small % of climbers who are knotting theorists or aficionados - but for the mainstream community - some struggle with #1047 F8 and/or various 'Bowlines'.

...

Every end-to-end joining knot (ie 'bend') has 4 corresponding eye knots - and the Zeppelin bend is no exception.
I would comment that the 2 corresponding eye knots formed from linking a tail to an SPart are stable and secure without any further gratuitous tucking maneuvers. In other words, it is somewhat redundant to try to lock down a Zeppelin structure - because it is inherently secure by default.

If you are interested in the Zeppelin bend and its corresponding eye knots, have a read of this paper here:
http://www.paci.com.au/knots.php (at #4 in the table).

Have you seen Alan Lee's 'Lee Zep Bowline'? - I would suggest that you examine this Bowline variant and try adding a mod to it.
Alan Lee has discovered some brilliant Bowline variations...
And Xarax modded the Lee Zep Bowline to create his 'Lees Link Bowline' - which I personally think is a marvelous creation.

roo

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Re: Alpine Zeppelin Loop - the ultimate tie-in knot?
« Reply #2 on: June 14, 2019, 04:28:29 PM »
I discovered this knot the other day, which might replace my current tie-in knot for rock climbing.  It is a Zeppelin Loop with a retrace so that the bitter end exits the top, parallel and adjacent to the load strand. 

I expect this would be a good tie-in knot because it uses rope effiently, it looks sexy and is verifiable, easy to untie after loading, very secure and stable and resistant to ring-loading (as far as I can tell). 

Before I go testing this with my body, I thought I would check with the forum to see if I missed something.  Thanks for your thoughtful responses, video below:

https://youtu.be/aPdak4-Thb8
If you like to use the Zeppelin Loop and would like to have additional security, I would rather go with the Double Zeppelin Loop where the final tuck is simply repeated.  For visualization, it's like the Double Zeppelin Bend (third image), but only one side has the repeated finish.  It's easy to remember and it avoids widening the shear mechanism which occurs with your modification to a small degree. 

Keeping the shear mechanism trim and tightly contained maintains the stability of the knot.

Also, I would prefer that the final length of rope be held tightly, but in your modification, the final bit of rope is inserted into a low tension region of the knot which may allow it to flog loose and back into a single Zeppelin Loop.

For both security and simplicity, the Double Zeppelin Loop will serve you better.
« Last Edit: June 14, 2019, 04:49:52 PM by roo »
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Dan_Lehman

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Re: Alpine Zeppelin Loop - the ultimate tie-in knot?
« Reply #3 on: June 14, 2019, 11:02:55 PM »
I discovered this knot the other day, which might replace my current tie-in knot for rock climbing.  It is a Zeppelin Loop with a retrace so that the bitter end tail exits the top, parallel and adjacent to the load strand. 

I expect this would be a good tie-in knot because
it uses rope efficiently,
it looks sexy and
 is verifiable,
easy to untie after loading,
very secure and stable and
resistant to ring-loading (as far as I can tell). 

For tie-ins, I'm looking towards some hundred
plus options, and the number can grow.

Re the zeppelin, it's not so "verifiable" except
by the initiated.  It's not all so simple to tie
(hence the appearances of the false z. from
time to time!).

One can stick with the fig.8 base and simply do
the "re-threading" from the SPart's/opposite end
of the knot, thereby getting both a more jam-resistant
knot AND one immune to --rather, almost designed FOR--
ring-loading.
(And, for good measure, this knot is readily given a
twin eye --to appease those of the German climbing
ilk who recommend the bowline on a bight for this
reason-- pretty easily.


--dl*
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Moss

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Re: Alpine Zeppelin Loop - the ultimate tie-in knot?
« Reply #4 on: June 16, 2019, 11:48:30 PM »
Thanks a lot for your feedback!  This forum is awesome.

Agent Smith, as far as the "Alpine" butterfly knot, you might be forgetting the full butterfly knot  ;D (see attachment) - just kidding.  Lee's link is a beautiful Knot, but for some reason I couldn't use it with confidence.  Perhaps if I tied it with a strangle knot backup (or whatever it's properly called), I could learn to trust it.

You're right of course that my knot lacks mainstream appeal and utility.  I think I got ahead of myself. 

The roo has excellent critiques about the structure.  Of course, I could tie it the opposite way -start with a Zeppelin tangle, then finish with an overhand retrace - but I probably wouldn't want to climb on a knot finished with just an overhand (just a mental block, same as with Lee's link)

As far as the double Zeppelin, I only have silly objections that the tail poking out the side doesn't look as cool and it might end up tickling me while i climb, haha.  It's a silly objection, I know.  Thanks for the suggestion, I will look into it.

Dan Lehman, the figure 8 ring is a really interesting idea, I'll definitely look into that as well.  Also, I would love to know why Germans would use dual loops.  Their climbing literature is the most authoritative I've found and I really enjoy it.  Do they finish their BoB's with a backup knot?

I will probably end up continuing to use the figure 8 & strangle knot backup - I would climb on any knot, even a half hitch, if it had a strangle knot backup.  I like the symmetry of the loop, plus I don't want to befuddle my partners.  But I will also keep experimenting with the suggestions you provided.

It's an honor and a pleasure conversing with you all.  Thanks again.

Dan_Lehman

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Re: Alpine Zeppelin Loop - the ultimate tie-in knot?
« Reply #5 on: June 17, 2019, 11:33:08 PM »
>>>>>>> the full butterfly knot  ;D (see attachment)
Where did THAT fly in from ?!  --quite impressive!!   :o

Quote
Dan Lehman, the figure 8 ring is a really interesting idea, I'll definitely look into that as well.  Also, I would love to know why Germans would use dual loops.  Their climbing literature is the most authoritative I've found and I really enjoy it.  Do they finish their BoB's with a backup knot?
1) The finishing with a "back-up" knot might in some
cases be simply viewed as "tying off an adequately long tail
out of the way" more than some thought that security
needs it.  But in some other venues, it might be a good
plan for anticipating a major goof in the main knot
coming for whatever reason, esp. understandable in times
of stress & with maybe limited hands-use & a tricky rope.

2) The additional eye I will surmise is made for simple
redundancy.  If the 2nd eye comes unsecured --i.e. the
tail comes out of the knot--, then there is an assuredly
lonnng tail, and one that while still threaded through
the harness should flap about and thereby warn the
climber of that degree of loss of knot integrity.

(When looking over such 2-eye knots, one needs
to remind oneself that there should now be only
25% load per eye leg (!), half of the usual half
of the load --and what might THIS imply ... ?! !)

Quote
I will probably end up continuing to use the figure 8 & strangle knot backup - I would climb on any knot, even a half hitch, if it had a strangle knot backup.  I like the symmetry of the loop, plus I don't want to befuddle my partners.  But I will also keep experimenting with the suggestions you provided.
3) I recall on one knots discussion on RC.com (back when
things were discussed there) where a woman climber
reported that sometimes here strangle knot --of course
not actually using that name(!)-- came untied (!).  !?

You should try the offset fig.8 eye knot I've described
above, and might even prefer the slightly smaller
offset overhand (EDK) version,
where the 2nd eye's returning leg just gets tucked
out through other eye legs --or whatever looks snug.
(Though in using it qua belay loop, one  needs to take
care NOT to use just one --or not the wrong one-- eye!)


As for being happy to tie off with a hitch,
and taking assurance from some secure safety knot,
I would really want to see some tests in which these
were what held :: what I'm thinking of is how much
damage(?) might be done by slippage of the rope
through the harness as the hitch tightened or as
the failed main knot shifted forces onto the safety
--and got some similar slippage of rope through
the harness nylon.

One might use a hitch qua eye knot ::  Heinz Prohaska
proposed adopting the anchor bend as the to-become
eye knot base, as it --like his Prohgrip/Blake's hitch--
could pretty securely grip just a tucked-through-once
strand, should one have a "Lynn Hill moment" and
have tie-in interrupted and not concluded (at just this
tucked-the-end-once point).  The finish would be some
wrap & exit like that for the bowline.


--dl*
====

Moss

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Re: Alpine Zeppelin Loop - the ultimate tie-in knot?
« Reply #6 on: June 18, 2019, 07:34:09 PM »
Quote
...then there is an assuredly
lonnng tail, and one that while still threaded through
the harness should flap about and thereby warn the
climber of that degree of loss of knot integrity.

This is similar to my preference for a tail parallel to load strand, it provides a quick visual check that calms my nerves, and also allows a backup tied on the load strand.

Quote
(When looking over such 2-eye knots, one needs
to remind oneself that there should now be only
25% load per eye leg (!), half of the usual half
of the load --and what might THIS imply ... ?! !)

A stronger connection?  Because bowlines break in their legs?

Quote
3) I recall on one knots discussion on RC.com (back when
things were discussed there) where a woman climber
reported that sometimes here strangle knot --of course
not actually using that name(!)-- came untied (!).  !?

I suppose this might have been an anchor hitch and not a strangle knot.

Quote
You should try the offset fig.8 eye knot I've described
above, and might even prefer the slightly smaller
offset overhand (EDK) version...

I will attach pictures of how I tied these knots, just so I'm sure we're on the same page.

Quote
One might use a hitch qua eye knot ::  Heinz Prohaska
proposed adopting the anchor bend as the to-become
eye knot base, as it --like his Prohgrip/Blake's hitch--
could pretty securely grip just a tucked-through-once
strand, should one have a "Lynn Hill moment" and
have tie-in interrupted and not concluded (at just this
tucked-the-end-once point).  The finish would be some
wrap & exit like that for the bowline.

I do that all time for rigging a ground anchor with a tree and the climbing rope (usually three wraps around the tree and with a bight)!

Dan_Lehman

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Re: Alpine Zeppelin Loop - the ultimate tie-in knot?
« Reply #7 on: June 18, 2019, 10:06:30 PM »
Quote
(When looking over such 2-eye knots, one needs
to remind oneself that there should now be only
25% load per eye leg (!), half of the usual half
of the load --and what might THIS imply ... ?! !)
A stronger connection?  Because bowlines break in their legs?
No no, although I had such thinking for some old
test report that had interlocked bowlines being
stronger when the interlocking was not simple
eye-through-eye but a square knot.

But, no, I mean that as one thinks of the central
nipping turn having the SPart at 100% load and
the outgoing eye leg at 50% there needs to be
some explanation of where the other 50% goes
--friction, heat ... -- and now change this latter
loading to 25% and ... ?!  (!!)

Quote
I suppose this might have been an anchor hitch and not a strangle knot.
No, I think she was better than that --and
"recognizably" so.  But just not putting enough
force on the back-up to set it well.  (In some
stiff ropes, this can be a challenge, and the
ropes are pretty smoothly sheathed.)


Quote
I will attach pictures of how I tied these knots, just so I'm sure we're on the same page.
Yes on the overhand (but lacking a 2nd eye),
but not-so-much on the fig.8, which IMO works
better HERE (offset) with the other of twin strands
being the SPart --the one running *interior*.  It
gives better balance, and then the oddly reentering
twin will come over and reach farther to turn around
the eye legs.


--dl*
====

Moss

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Re: Alpine Zeppelin Loop - the ultimate tie-in knot?
« Reply #8 on: June 22, 2019, 01:30:08 AM »
Quote
But, no, I mean that as one thinks of the central
nipping turn having the SPart at 100% load and
the outgoing eye leg at 50% there needs to be
some explanation of where the other 50% goes
--friction, heat ... -- and now change this latter
loading to 25% and ... ?!  (!!)
Are you saying there is more friction?  Sorry, you might have to spell it out for me, haha.

Anyway, I really like the figure 8 ring.  Is it safe either way?  And I think I got it right - the tail is on the inside of the loop. 

What about if it is tied badly?  Because it is a supposed strength of the conventional figure 8 loop that it is useful when tied poorly.

agent_smith

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Re: Alpine Zeppelin Loop - the ultimate tie-in knot?
« Reply #9 on: June 22, 2019, 03:01:20 PM »
Quote
I will probably end up continuing to use the figure 8 & strangle knot backup - I would climb on any knot, even a half hitch, if it had a strangle knot backup.

I would comment that #1047 F8 eye knot is inherently secure - and therefore, the addition of a double overhand strangle tied around the SPart is for cosmetic or psychological reasons only.
Of course, I assume that the life critical knot is tied in EN892 or EN1891 conforming rope (or equivalent/better eg Sterling HTP static).

A hitch would make no sense... and in fact would invite unacceptable risk (assuming the intention is for a 'tie-in' knot to a climbing harness). Whats required is a non-slipping fixed eye - anything that has a tendency to cinch or act like a noose will cause frictional damage to the harness in a free-fall (risk of burn-through).

per Dan Lehman:
Quote
You should try the offset fig.8 eye knot I've described
I have some difficulty in using the term 'offset' to denote the #1411 derived F8 eye knot structure. It also leaves it open for the other tail-to-SPart linkage and how to distinguish between the two.
The term 'offset' refers to the core of the knot being displaced from the axis-of-tension. He we see the axis of tension not being aligned lineally from SPart to SPart. In fact, the load is split 3 ways in all 'single-eye' knots (100% via the SPart and 50% divided across each of the 2 'legs' of the eye... or further divided if 2 eyes etc). It is partially offset...
Every end-to-end joining knot (ie bend) has 4 corresponding eye knots - and 2 of them can be formed by linking a tail to an SPart (the other 2 by linking SPart to SPart and Tail to Tail).

Quote
This is similar to my preference for a tail parallel to load strand, it provides a quick visual check that calms my nerves, and also allows a backup tied on the load strand.
This comment reminds that there are in fact a number of inherently secure fixed eye knots - which do not require any form of 'backup stopper knot' (eg a double overhand strangle tied around the SPart). Inherently secure 'Bowlines' are (in my view) well adapted for use in life critical applications.
In other words, why use a tie-in knot that isn't inherently secure? Its paradoxical to choose a tie-in knot that is perceived to be acceptable but nevertheless cant be trusted unless it is 'locked down' with further tail maneuvers.

Quote
I do that all time for rigging a ground anchor with a tree and the climbing rope (usually three wraps around the tree and with a bight)!
The #2047 Tensionless hitch is an exceedingly simple but elegant method of anchoring a rope.
Adding turns around a tree sets up a relationship with the Capstan equation.
Not clear on what you mean by "and with a bight"?
It is sufficient to add a double overhand strange around the SPart to secure the turns (no carabiners needed).
« Last Edit: June 22, 2019, 03:45:45 PM by agent_smith »

roo

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Re: Alpine Zeppelin Loop - the ultimate tie-in knot?
« Reply #10 on: June 22, 2019, 05:33:24 PM »
I will probably end up continuing to use the figure 8 & strangle knot backup - I would climb on any knot, even a half hitch, if it had a strangle knot backup. 
Pay no heed to Agent Smith's scare-mongering on the use of hitches.  His nylon-melting myth has been busted numerous times:

https://igkt.net/sm/index.php?topic=6081.msg40871#msg40871
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agent_smith

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Re: Alpine Zeppelin Loop - the ultimate tie-in knot?
« Reply #11 on: June 22, 2019, 11:58:15 PM »
Quote
Pay no heed to Agent Smith's scare-mongering on the use of hitches.  His nylon-melting myth has been busted numerous times:
Awesome - I was wondering when roo would try to weigh-in...and here he is :)

It is also somewhat of a troll comment - and would cause this topic thread to divert to a debate on the dangers of frictional wear on a harness - which in turn has life critical consequences.
I would also comment that the IGKT forum has a duty to disseminate information that promotes safety at height - and providing information about life critical tie-in knots constitutes advice.

My advice to any rock climber - particularly for the case of lead climbing - where a free fall is always a risk, tying-in with a knot that other than a fixed eye is inviting unnecessary risk.

I am going to make the assumption that roo is not an experienced lead climber (on rock / big walls / mountains) - because if he were, he would know from experience that cyclic wear on synthetic harness tie-in points can lead to catastrophic failure (an example of which is the Todd Skinner tragedy).

If a lead climber tied in with a knot that acts like a noose - and cinches up at the moment of impact - it would cause frictional wear to the harness.

I would be more than pleased to take roo on head-to-head to argue this salient point (but in a separate thread topic so as not to hijack this one).

Added interesting link to harness wear: https://www.blackdiamondequipment.com/en/qc-lab-strength-of-worn-belay-loops.html
Link to dyneema / nylon slings: https://dmmclimbing.com/Knowledge/March-2012/Knotting-Dyneema%C2%AE (although a different failure mechanism, it does illustrate the effect of a knot in a sling)
« Last Edit: June 23, 2019, 12:05:31 AM by agent_smith »

Moss

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Re: Alpine Zeppelin Loop - the ultimate tie-in knot?
« Reply #12 on: June 23, 2019, 05:06:54 AM »
Actually, I expect the half hitch (configured as a nipping loop, held in place--albeit not securely--by a strangle knot on the load strand)) would act as a friction hitch, essentially turning your tie-in loop into a purcell prusik of sorts.  Not that it's a good idea, just to say that Purcells do survive the sheath melting that occurs as it ABSORBS IMPACT in a fall.  I've tested this in the field, you can see the melted sheath at the end: https://youtu.be/5mHj8eIW7t8

Also, it's to say the strangle hitch is reliable because it is so prone to jamming, and it's an anchor hitch if it does loosen. 

Also, the reason that sometimes two knots is better than one--to my mind--is that it creates redundancy.  Also, if they are two "easy" knots vs one "difficult" one, it could be argued that the former is preferable.

All that said, it relates to my newest preference for a tie-in knot.  This also relates to Dan's mention about the double loop tie-in used by Germans.  I think one great reason to do that is redundancy in the PROCESS of tying in!

Today I led a 100ft trad climb.  At 50ft I realized that I had tied only the bottom tie-in point.  I made myself safe with an anchor and retied my knot.  I had used the figure 8 loop with a strangle backup.  My belayer was a novice, so a more experienced partner might have spotted my mistake.

For now, I will be moving to the bowline on bight with strangle backup.  To tie it, I will have to pass the rope through my tie-in points twice, so I have an extra chance to notice that mistake. 

« Last Edit: June 23, 2019, 07:27:31 AM by Moss »

Dan_Lehman

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Re: Alpine Zeppelin Loop - the ultimate tie-in knot?
« Reply #13 on: June 23, 2019, 07:58:46 PM »
Quote
But, no, I mean that as one thinks of the central
nipping turn having the SPart at 100% load and
the outgoing eye leg at 50% there needs to be
some explanation of where the other 50% goes
--friction, heat ... -- and now change this latter
loading to 25% and ... ?!  (!!)
Are you saying there is more friction?  Sorry, you might have to spell it out for me, haha.
?!  Look at the rope's passage from entry of the
SPart into the knot and that part's exit to be the
"outgoing" eye leg : the latter we presume to have
(about, as friction can allow differences) 50% of the
overall tension on the knot, so where did the other
50% of the SPart's full load go?

Now, if your eye knot has TWO eyes, then that segment
of rope noted above goes from 100% -> 25% --a greater
difference which needs accounting for.  And in traditional
materials, I suppose that friction is up to the task.  But
I'd not be surprised if one did some few FF-1 drops on
such a knot and then found that the outgoing eye leg
--i.e., that directly following from the SPart, not the
2nd eye's leg(s)-- actually had >25%.
(There is a video of loaded HMPE with a dbl.bwl. just
feeding rope through the knot from this leg-SPart strand,
showing the >50% load on it and imbalance resulting
in rope flow around the smooth metal pin!)

Quote
Anyway, I really like the figure 8 ring.  Is it safe either way?
And I think I got it right - the tail is on the inside of the loop. 
In you photos above, the offset overhand eye knot is correct
(SPart going *interior*), but that for the fig.8 is opposite
(SPart going *exterior*).  IMO, the former is a simpler and
decent knot for this "twin-eye" tucking.  (Which "tucking" is
to indicate that it's not expected that this redundant "eye"
is up to taking a full load, or really contributing much to
holding --though I think it will indeed take some load,
but needs the other eye & knot parts to compress tightly
around its simple poking through the knot--
but that it is a SLACK-SECURITY measure.)

Quote
What about if it is tied badly?
Because it is a supposed strength of the conventional figure 8 loop that it is useful when tied poorly.
See above.
It always amazes/saddens/vexes me that these twin-part
("traced"/"re-woven") knots are so very often presented
w/o hint of SPart-v-tail distinction.  Yes, it seems that
the fig.8 eye knot performs pretty well no matter how
imperfectly tied (though note that "imperfect" doesn't
describe any particular geometry, and one such
version can't speak for others!).


As to "offset" used re the eye knots, while they do not
have the same fact of that adjective themselves,
I use it to show that the rightly named end-2-end
*joint* can be seen as the "corresponding" such
knot to the eye knot.
(And now you've got me thinking about actually
making some eye knots that DO have an offset profile!)


--dl*
====

smirnov_wasilii

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Re: Alpine Zeppelin Loop - the ultimate tie-in knot?
« Reply #14 on: September 10, 2019, 06:56:20 AM »
Вот очень похожий узел и мой способ его вязки основанный на трансформации петли Светлана.
Here is a very similar knot and my way of knitting it is based on the transformation of the Svetlana loop.
https://www.youtube.com/watch?v=rVT3wke6muI
 и еще
https://youtu.be/c_UzV1SWo_s
« Last Edit: September 10, 2019, 07:03:12 AM by smirnov_wasilii »