Author Topic: Omnidirectional-loaded loop with omnidirectional tails?  (Read 1732 times)

agent_smith

  • Sr. Member
  • *****
  • Posts: 1173
Re: Omnidirectional-loaded loop with omnidirectional tails?
« Reply #15 on: May 06, 2020, 01:56:59 AM »
Hmmm jimmyh, lets see...where were we?

Quote
Out of curiosity, was this a genuine misunderstanding, or a roundabout way of reminding me of the proper nomenclature?
Neither.

Quote
Sorta seems that last line there sorta invalidates your point here, don't you think?
No.

Quote
Certainly you seemed to think so upthread.
No - I didn't.

Quote
Depends on what you're tying it with. Try loading paracord that way with body weight and then untying it. No knot jams if you load it lightly enough in thick enough line.
I didn't realise that we were focusing on cords such as paracord (or any other myriad of non human rated rope).
But thank you for pointing out that #1053 Butterfly eye knot is potentially difficult to untie after subjected to body weight.
In human rated EN1891 and EN892 ropes (including Sterling HTP), I have found the complete opposite.
Maybe you might need to specify each and every type of rope?

Quote
is the same thing that steered me away from discovering "#551 tied with a bight".
Or indeed #582 might be the topological basis for tying it 'with a bight' - and this indeed might bare fruit for further explorations.

Quote
Doesn't make 1053 a good knot for general purpose omnidirectional loading. I learned that one the hard way.
Strange - I have found the opposite.
#1053 is a very good omni-directional knot provided any eye loading doesn't exceed around 2kN-2.5kN threshold (in EN human rated ropes).
Paracord performs differently (obviously).

Quote
in the butterfly loop there are two interlocking overhands. There's one of each type, and the one that jams more is the one that doesn't have the incoming and outgoing lines separated.
Interlocking (no).
Interlinked? Yes.
By each 'type' are you referring to chirality (ie handedness)?
With jamming mechanism for #1053 - I think you are specifically referring to eye loading profile (not bi-axial loading profile). Load could be directed one direction of the other - depending on orientation. The exact mechanism that induces jamming when eye loaded is not fully understood - but relates to how load is injected from both eye legs into the knot core.
When the eye is loaded, it aligns itself automatically with [a] SPart. That SPart is the 'normal' or counter-balancing force against the loaded eye. One of the eye legs forms a simple overhand knot around the SPart - and it is here that the mechanism for jamming likely propagates.
I am currently writing a new paper on the Butterfly knot - which will compliment my other 2 papers (Zeppelin bend and Riggers bend) - making it a trio of related papers.

Quote
You mean "by you"? Or are you claiming to know that no one else has ever investigated it either? The latter seems like quite a bold claim :p
This is a strange and curious remark.
This is quite bold of you to engage with me in such a manner.
I looked for a research papers and/or jam threshold testing of #551 tied with a bight - but, could find none (for human rated EN ropes).
Your presentation is axially rotated variant of #551 and I couldn't find any papers on that subject matter either.
I am considering investigating #582 (tied with a bight) - to probe its jamming threshold (in EN human rated ropes).

EDIT NOTE: Some ideas added for the original poster.
The twisted Butterfly is something I have had in the pipeline for over a decade...I'm almost done wrapping up a series of tests to probe its jamming threshold (in EN human rated ropes).
The #582 derived eye knot (based on the Zeppelin bend) is also something I had investigated several years ago. I think it might make an appearance in the next update of my paper on the Zeppelin bend. I haven't investigated jam resistance in #582 (tied with a bight).
« Last Edit: May 06, 2020, 06:23:11 AM by agent_smith »

jimmyh

  • Jr. Member
  • **
  • Posts: 24
Re: Omnidirectional-loaded loop with omnidirectional tails?
« Reply #16 on: May 06, 2020, 08:12:28 AM »

Quote
Quote
Out of curiosity, was this a genuine misunderstanding, or a roundabout way of reminding me of the proper nomenclature?
Neither.

You knew what I meant AND you weren't trying to tell me what the accepted way of saying it is? I don't suppose you'd help me understand where you're coming from here?



Quote
Quote
Certainly you seemed to think so upthread.
No - I didn't.

You brought up the butterfly loops propensity to jam when you thought it was irrelevant? Again, I'd love to understand where you're coming from, but I can't make sense of these seemingly contradictory statements.

Quote
I didn't realise that we were focusing on cords such as paracord (or any other myriad of non human rated rope).
But thank you for pointing out that #1053 Butterfly eye knot is potentially difficult to untie after subjected to body weight.

We're not. Neither are we focusing on body weight and less or human rated ropes, in particular. Both paracord and greater than 2.5kN are relevant to the full set of uses of omnidirectional eye knots, though of course they do not encompass the full set, and rarely encompass each other at all.

It's as if you said "Yes, mammals go in the water BUT - only for a quick drink. Mammals do not live in the water. Were you aware of this fact?", I said "Depends on the mammal. Look at whales, for instance", and you responded "I didn't realize we were focusing on whales". We're not focusing on whales, we're focusing on the entire set of mammals, to which whales (and seals, and yes, Rhinos/etc) belong.


Quote
is the same thing that steered me away from discovering "#551 tied with a bight".
Or indeed #582 might be the topological basis for tying it 'with a bight' - and this indeed might bare fruit for further explorations.

Yes, you can tie the analogous knot for 582 as well, and that's where I started. Unfortunately, I don't remember why I ended up not preferring that one.

Also, since you seem to be picky about proper word usage:  https://www.grammar-monster.com/easily_confused/bare_bear.htm :)

Quote
Quote
Doesn't make 1053 a good knot for general purpose omnidirectional loading. I learned that one the hard way.
Strange - I have found the opposite.
#1053 is a very good omni-directional knot provided any eye loading doesn't exceed around 2kN-2.5kN threshold (in EN human rated ropes).

It's good for a lot of things, yes. And if your specific use case involves less than 2.5kn on EN human rated ropes, I'm sure you're fine.

In general, neither of those are guaranteed. I'm sure if I only needed to stress my rope to body weight it would have been fine even though it didn't have any special ratings. Sometimes things call for more force than that.

Quote
By each 'type' are you referring to chirality (ie handedness)?

No. A loose overhand looks like a pretzel, and there are three openings. If you pass a line through the center one, the resulting knot is more prone to jamming than if you pass it through either of the other two. The zepplin bend has both overhands passing through the gap closest to the standing part, Ashley's bend has both passing through the gap closest to the tail. The butterfly bend has one through the center gap as well as one that passes through nearer to the tail. It is that center one that causes most of the trouble. If you eye load it so that the "Ashley type" overhand is closer to the standing part which is taking the tension it is less prone to jam than if you eye load it in the other direction. Even still, when it does jam it is mostly the "non-Ashley type" that is causing the jamming.


Quote
Quote
You mean "by you"? Or are you claiming to know that no one else has ever investigated it either? The latter seems like quite a bold claim :p

This is a strange and curious remark.

It's really straight forward. You know what you have investigated, but you don't have any way of knowing that it hasn't been investigated by anyone else except insofar as that no one has told you about it. It's quite bold to assume that if anyone has ever done such an investigation, you would know.

Quote
This is quite bold of you to engage with me in such a manner.

What, exactly, is "this manner" to you?

To me, it looks like I offered up a valid solution in a perfectly understandable way, and you have been bending over backwards to be hostile to me ever since. I'm not sure what I did to offend you since you've come off to me as hostile right out the gate, but my impression is that the combination of not appearing shaken by your criticism and the willingness to draw attention to what appear to me to be glaring contradictions in your posts hasn't helped.

I'm sure you wouldn't *want* people to cower in response to you, nor to pretend to agree with what strikes them as wrong so as to avoid challenging your beliefs, and so I'm sure things look different from your perspective. At the same time, I'm not aware of anything else in the way I'm engaging with you that could provoke such a reaction. Can you explain to me what I'm doing wrong so that I can stay on your good side? I'd rather we be friends and get along.

With respect to it being a "bold" way to engage with you, I don't think it's as bold as you think. I'm engaging with you fully and completely, but neither aggressively nor disrespectfully. With all due respect, I don't see any reason to be intimidated by you. Am I missing something that would change my mind? Is there a reason we can't be light hearted and playful here?


Quote
Your presentation is axially rotated variant of #551 and I couldn't find any papers on that subject matter either.
I am considering investigating #582 (tied with a bight) - to probe its jamming threshold (in EN human rated ropes).


I still think you're on the wrong track with comparing it to #551, and I don't see how you think it an axially rotated variant of #551. To me, it looks more like an axially rotated #1452, which is what I was searching for when I found this one. It is mechanically more similar to #1452 as well, and that's why it shares the non-jamming properties.

agent_smith

  • Sr. Member
  • *****
  • Posts: 1173
Re: Omnidirectional-loaded loop with omnidirectional tails?
« Reply #17 on: May 06, 2020, 10:26:00 AM »
I think this narrative is drifting to something of a personal nature.
I am not sure how long this thread will remain open for business?

Be that as it may, I'll provide some quick replies...

per jimmyh:
Quote
I don't suppose you'd help me understand where you're coming from here?
No - sorry.

Quote
Again, I'd love to understand where you're coming from, but I can't make sense of these seemingly contradictory statements.
The notional concept of contradiction lies only in your own narrative - not mine.
I'm forming a view that you wont be able to get past this seeming contradiction.

Quote
We're not. Neither are we focusing on body weight and less or human rated ropes, in particular.
I didn't know that there was a "we" in this narrative?
I thought you raised the issue of paracord to support a proposition for jamming?
I know that I didn't introduce paracord into my narrative.
#1053 Butterfly is vulnerable to jamming when eye loaded - but this of course is entirely dependent on the magnitude of loading and the type of rope material.
I do mostly speak in terms of human rated ropes - because there is a specific standard to which they are manufactured - as opposed to non human rated materials - where this is far less rigor.
And it follows that testing and commentary based on the use of rope material that conforms to a world standard is more likely to be repeatable by others. Also, the Butterfly is a knot that is used in life critical applications - and human rated ropes are therefore very relevant.
Quite frankly, I don't waist my time testing or investigating knot performance in non human rated ropes . Others are entitled to their own personal views...

Quote
Also, since you seem to be picky about proper word usage:
You could correctly state that I am 'picky' about concepts - not grammar or spelling.

Quote
It is that center one that causes most of the trouble.
?
You might want to look more closely at jamming mechanisms in Riggers bend versus Riggers X bend - and compare to Zeppelin (which pivots about a central toggle axis - sort of like a hinge mechanism as Xarax prefers.).

Quote
The butterfly bend has one through the center gap as well as one that passes through nearer to the tail. It is that center one that causes most of the trouble. If you eye load it so that the "Ashley type" overhand is closer to the standing part which is taking the tension it is less prone to jam than if you eye load it in the other direction. Even still, when it does jam it is mostly the "non-Ashley type" that is causing the jamming.
An interesting proposition that I find myself in disagreement with.
You should start an entirely new thread topic to explore jamming in knots. This is straying way off topic.
There is a lot more going on with knots (as machines) than you describe in your narrative.

Quote
It's really straight forward.
? It would seem that your narrative isn't as straight forward as it appears on the surface.
Your continued preference to assert boldness is misplaced. I am happy for you to continue to believe in boldness.

Quote
...and you have been bending over backwards to be hostile to me ever since.
?
And here the real underlying motivation behind your posts has been revealed.
You have formed a view about "hostility" that is manifestly wrong.
The notional view of "hostility" exists only in your mind - and does not exist in my mind.

Quote
I'm sure you wouldn't *want* people to cower in response to you, nor to pretend to agree with what strikes them as wrong so as to avoid challenging your beliefs...
And here we are again getting down to what is driving you.
I am happy for you to believe that this is some form of contest as to who has the greater knowledge.
I certainly don't hold or harbor any of these views.
I see this all the time in technical forums - where contests of who has superior command of knowledge are commonplace. Its often the principal driver for these back and forth posts between 2 individuals. Language is a factor - and its accurate interpretation - where face-to-face interaction is missing.

Quote
With all due respect, I don't see any reason to be intimidated by you. Am I missing something that would change my mind? Is there a reason we can't be light hearted and playful here?
?
Again - these views you have formed are manifestly wrong.
I have no malice or no ill will - I merely type the facts as I see it.
You may interpret my version of 'fact' as a form of personal attack (which it isn't).
I would suggest to you that you actually want to engage in a contest of knowledge - one where you believe that you must not back down from? Maybe you see me as an adversary?

Quote
I still think you're on the wrong track with comparing it to #551, and I don't see how you think it an axially rotated variant of #551.
You are perfectly entitled to form your own views.
There is no law or rule that would prevent you from forming an entirely different view to mine.

Dan_Lehman

  • Sr. Member
  • *****
  • Posts: 3903
Re: Omnidirectional-loaded loop with omnidirectional tails?
« Reply #18 on: May 06, 2020, 08:57:41 PM »
It gets a bit bulky, but for omnidirectional loading I've had good luck with this one tied in a bight.
Perfectly understandable en vacuo, even,
and certainly in the context of the OP !   ::)

The form is roughly that of what Harry Asher
named "shakehands" and can be found in ABoK
in #1048 IIRC?

FYI, a 2-eye version can be formed, where each
eye is in the place of a shakehands tail.  (And similar
things can come from other of the interlocked-overhands
end-2-end joins such as #1408 & zeppelin.)


--dl*
====

jimmyh

  • Jr. Member
  • **
  • Posts: 24
Re: Omnidirectional-loaded loop with omnidirectional tails?
« Reply #19 on: May 07, 2020, 02:07:42 AM »
>I'm forming a view that you wont be able to get past this seeming contradiction.

If you don't even attempt to explain, then yeah, probably. I'm pretty stuck at explaining that one myself.

I don't think it has to be that way though. My ears are open, I promise. Or we could just drop it, if you don't feel like explaining yourself.

>I do mostly speak in terms of human rated ropes - because there is a specific standard to which they are manufactured - as opposed to non human rated materials - where this is far less rigor.

So you trade applicability for rigor. Makes sense for some things, like scientific study. Less for others, like actual application to the full scope of knot use.

>You could correctly state that I am 'picky' about concepts - not grammar or spelling.

Well, I think the concepts that the words "waist" and "waste" point to are as different as the concepts of "tying without using the end of the rope" compared to "tying with a bight of rope as if it were a single strand".

If there were a confusion around actual concepts, this response would make sense. But that would take something like "since I don't have access to the end of the rope, I need to make a knot by making a bight and tying something with that as if it were one strand", since there would be a genuine conflation between concepts and introducing the distinction would allow things like the butterfly loop to be seen and used. As it stands, you claim to not be confused about which concept I was referring to, but objected to my use of the word "in" instead of "with".

But it doesn't matter. It was mostly a playful tease, and we can drop this one too.

>You might want to look more closely at jamming mechanisms in Riggers bend versus Riggers X bend - and compare to Zeppelin (which pivots about a central toggle axis - sort of like a hinge mechanism as Xarax prefers.).

>An interesting proposition that I find myself in disagreement with.
You should start an entirely new thread topic to explore jamming in knots. This is straying way off topic.
There is a lot more going on with knots (as machines) than you describe in your narrative.

I'm not sure what you're getting at here. Obviously the abstraction I offered doesn't explain all knot behavior, and abstractions in general tend to be leaky. Still, it actually works in the example you offered. Put more bulk in the right part of the knot and you get less jamming, as predicted. Only one of the two proposed mechanisms holds here, but that's fine.

Are you willing to say a bit more about why you disagree, exactly, and how you see it?


>It would seem that your narrative isn't as straight forward as it appears on the surface.

Still seems pretty straight forward to me. It's bold to make non-existence claims without evidence. Shrug.

>And here the real underlying motivation behind your posts has been revealed.

No, not motivation. I'm not hurt by it, nor do I share the feeling of hostility. I do perceive it pretty clearly though, and I'm guessing that everyone else does too. I can even explain it, if you'd like, but I'd rather to talk about knots and that's why I've only been responding to the other stuff to the extent necessary to keep the conversation working.

For example, I didn't bring up your apparent hostility until you commented that it was "bold of me to engage with you in this way". If that's not coming out and explicitly making the conversation about the offense you're taking, then I'm not sure what it is. If you want to insist without explanation that it's not that, I'm happy to pretend that it didn't happen and stick to knots.

>I see this all the time in technical forums - where contests of who has superior command of knowledge are commonplace. Its often the principal driver for these back and forth posts between 2 individuals. Language is a factor - and its accurate interpretation - where face-to-face interaction is missing.

Do you have any insight on how best to deal with these types of situations? I'll share what I've noticed, and you can let me know whether this squares with your experience, or if you've noticed something different.

In any conflict there are always at least two active participants enabling it. There isn't always more than one "aggressor", but there's always another party unwilling to cede the (perhaps implicit, and perhaps objectively unreasonable) demands and allow friction. Like childhood disputes over whose turn it is with the toy, everyone tends to think the other side is the unreasonable one, and there's often a ton of projection, so you get silly things like "Why are you making a big deal out of this? Just drop it [and give me what I want]" (the silliness being that they could just as easily drop it themselves, if they weren't at least as unwilling to do what they think is wrong). The only way I ever see these things resolved is when both participants (either through self awareness or through character attributes or whatever) refrain from presupposing their correctness and engage with a willingness to change their own minds.

I see it manifest in a couple different ways though. Sometimes you see people who are fairly dismissive towards each other who are nonetheless so confident that they are right that they're willing to get into the nitty gritty and show that they aren't wrong. When this happens, it tends to lead to great discussions and even great relationships, but it's harder to pull off because it requires the security to refrain from posturing/withdrawing/mentally contorting when challenged and a willingness to let "superior command of knowledge" land where it lands even when it isn't necessarily comfortable.

The other more common way I see these things work out is for people to just care less about being seen as "the expert" and being more interested in learning from other people, regardless of whether that other person is an "expert" or sees themselves that way. Postel's law is a good one.

I'm sure you have plenty of insight into knots that I don't have, and I'd be happy to learn from you. I'm not going to pretend to be convinced when I'm not, but I'm completely happy to learn when I've been wrong even if it's something that I've been confident about. I hope that's enough, but if there's anything else you can think of just lemme know.


>I would suggest to you that you actually want to engage in a contest of knowledge - one where you believe that you must not back down from? Maybe you see me as an adversary?

Honestly no, I think you're assuming too much here. I'd much rather have constructive sharing of knowledge. In order to do that though, we have to be able to point out each others errors when they're made or else how do you even converse? If that reads as an adversarial challenge to you and/or you're not open to being wrong, I'm really not sure what to do about that. "That's a bold statement" doesn't imply an adversarial mindset, and it didn't come from one. It's actually a fairly respectful and open minded way of pointing out what your claim actually implies.

When I asked what you'd like me to do, I wasn't being rhetorical. Do you want me to jump straight to "agree to disagree" and not even try to resolve disagreements? Is there some way I can engage with you so that we can talk through disagreements about knots without you perceiving me as being "too bold" or "trying to compete for superior command of knowledge"? I'm willing to consider it, whatever it is.

>You are perfectly entitled to form your own views.

I think that goes without saying. Everyone is entitled to their own views, even if they're a bit uninformed and wrong sometimes. The point of sharing views is so that people can get together and voluntarily make them a little less so.

I've shared a heuristic I use which is quite successful in predicting the propensity of overhand based knots to jam, and which led to the design of the non-jamming omnidirectional knot above. If you have anything object level to say about that heuristic, other better heuristics, the knot I presented, or other omnidirectional loops, I'd love to hear it.

I hope you don't decide to pull away from the object level discussion.

jimmyh

  • Jr. Member
  • **
  • Posts: 24
Re: Omnidirectional-loaded loop with omnidirectional tails?
« Reply #20 on: May 07, 2020, 02:09:50 AM »
Quote
Perfectly understandable en vacuo, even,
and certainly in the context of the OP !   ::)

Thanks Dan, it's refreshing to be afforded some charity :)

Quote
The form is roughly that of what Harry Asher
named "shakehands" and can be found in ABoK
in #1048 IIRC?

Yes! This looks exactly like the corresponding bend, and I didn't have that reference before.

Quote
FYI, a 2-eye version can be formed, where each
eye is in the place of a shakehands tail.  (And similar
things can come from other of the interlocked-overhands
end-2-end joins such as #1408 & zeppelin.)

I'm not sure if I follow. How would you go about tying this one?

agent_smith

  • Sr. Member
  • *****
  • Posts: 1173
Re: Omnidirectional-loaded loop with omnidirectional tails?
« Reply #21 on: May 07, 2020, 03:13:10 AM »
per jimmyh:
Quote
If you have anything object level to say about that heuristic, other better heuristics, the knot I presented, or other omnidirectional loops, I'd love to hear it.
The moment your narrative moves on to technical matters - I am happy to engage.
When it strays to personal narrative - I disengage.

In this instance, I will engage.

However, its getting difficult to stay on target with helping the OP.

In point form:
1. The #551 illustration I referred to (and indeed #582) are all blueprints for tying some quite famous end-to-end joining knots.
You can play around with both of these concepts and derive rotated, inverted and other modifications. Ashley missed the significance of these 2 knots in particular.
One can also play around with #577, #579 and #584 (ie all tied with a bight).

2. Some very clever knotting colleagues (who lurk in the shadows) alerted me to #2868 in ABoK (chain Sinnet) - which is topologically identical to your presentation.
Many people use this technique to 'daisy chain' their climbing/abseiling ropes.

3. I am a fan of the Zeppelin bend - and so I naturally gravitate toward #582 (so called blimp knot - but Ashley published it before Budworth - calling it a 'lanyard knot'). Anything that can be derived from the remarkable Zeppelin bend is going to be of interest. Hence why I posted #582 tied with-a-bight. It can potentially also function mid-line where it is subject to through loading from SPart-to-SPart. However, this induces an offset loading profile - where the knot core is offset from the axis of tension. These types of loading profiles require diligent assessment to determine if they remain stable. My presentation in offset loading profile has not been investigated with any rigor - so it remains in the realm of academia (for now).

4. The twisted variant of #1053 Butterfly that I also offered needs a round of testing to determine jam resistance in both through loading and eye loading (in EN human rated rope).

5. The early post by 'Groundline' probably deserves the award for best and fastest reply that addresses the OP's question. #1053 is a proven workhorse of knots. Its used extensively in the rope access industry and also by climbers and rescue technicians. Jamming threshold when eye loaded (in EN human rated ropes) is around 2.0kN - 2.5kN (give or take). Needs to be fully investigated. Dan Lehman likes to point out that crossing the eye legs of #1053 (per Wright & Magowan 1928) might boost jamming threshold to 3.0kN? No one has undertaken any serious testing in EN human rated ropes - except maybe Richard Delaney...but his test results are not free in the public internet space (you have to pay to get access).

6. Rightly or Wrongly, I have no interest in non human rated rope material. I am an advocate for testing with EN human rated ropes - because they are built to a defined and tightly controlled standard. Going to your local hardware store to purchase el cheapo cord and testing that and then publishing results makes it near impossible for others to repeat the claimed test results. Using ropes that meet a certain specified standard makes it easier for other testers to try to repeat your results. Also, there are many people who have an interest in knots used in life critical applications - and so ropes that conform to an EN standard will produce meaningful test results.

7. With specific regard to your original presentation (which was not shown tied with-a-bight or in offset loading profile) I think there are better offerings. Its hard to beat #1053 given its widespread deployment in the past 70 years. tsik_lestat has offered up an interesting presentation in his post (EHL). This offering is (in my view) superior to yours - particularly in through loading profile (SPart-to-SPart)....it isn't offset.
« Last Edit: May 07, 2020, 08:28:28 AM by agent_smith »

Dan_Lehman

  • Sr. Member
  • *****
  • Posts: 3903
Re: Omnidirectional-loaded loop with omnidirectional tails?
« Reply #22 on: May 07, 2020, 07:22:14 PM »
Re your imaged / lower knot,
that re-tucking of the eye bight
is a way to take what we might call
the "non-Alpine butterfly" knot into
decent stability (that knot where the
overhands don't interlock, which MIGHT
show some separation of parts thus if
loaded on one of the SParts).

 :)

jimmyh

  • Jr. Member
  • **
  • Posts: 24
Re: Omnidirectional-loaded loop with omnidirectional tails?
« Reply #23 on: May 08, 2020, 05:20:45 AM »
Quote
The moment your narrative moves on to technical matters - I am happy to engage.
When it strays to personal narrative - I disengage.

Does this mean I'm free to disagree and point out [what I see as] your technical errors without you saying that I'm being "too bold" again? I guess we'll find out :)

Quote
In this instance, I will engage.

Good. I'm glad.

Quote
1. The #551 illustration I referred to (and indeed #582) are all blueprints for tying some quite famous end-to-end joining knots.
You can play around with both of these concepts and derive rotated, inverted and other modifications. Ashley missed the significance of these 2 knots in particular.
One can also play around with #577, #579 and #584 (ie all tied with a bight).

Is there any reason to suspect 577/579/584 will result in good properties?


Quote
2. Some very clever knotting colleagues (who lurk in the shadows) alerted me to #2868 in ABoK (chain Sinnet) - which is topologically identical to your presentation.
Many people use this technique to 'daisy chain' their climbing/abseiling ropes.

While you *can* daisy chain in the way that iterates on the knot I presented, that puts in a half turn per stage, and isn't how daisy chaining is normally done. Daisy chaining as normally done and as presented in 2868 is iterated crossing knots, not overhands.

I suspect that modifying the knot I presented to have a crossing knot second stage will still result in good properties, but I haven't played with it enough to verify.

Quote
3. I am a fan of the Zeppelin bend - and so I naturally gravitate toward #582 (so called blimp knot - but Ashley published it before Budworth - calling it a 'lanyard knot'). Anything that can be derived from the remarkable Zeppelin bend is going to be of interest
.

Agreed. I think the only real downsides relative to the one I presented are that you can't tie it as simply as a 2 stage chain sinnet, and it takes special care to dress whereas the one I presented self dresses pretty well just by tensioning the eye and standing parts.


Quote
5. [...]Jamming threshold when eye loaded (in EN human rated ropes) is around 2.0kN - 2.5kN (give or take).

In other words, ~10% of tensile strength. We've been over this though. Other than jamming when eye loaded more than lightly (especially in one direction) it's a great knot. I use it far more than the one I presented ("Shakehands with a bight" isn't quite right. "Shakehands loop"?)


Quote
6. Rightly or Wrongly, I have no interest in non human rated rope material. I am an advocate for testing with EN human rated ropes - because they are built to a defined and tightly controlled standard. Going to your local hardware store to purchase el cheapo cord and testing that and then publishing results makes it near impossible for others to repeat the claimed test results.
Even if hanging on them is your only use for knots and you need the associated rigor to make sure you don't fall to your death, you're still missing a lot of advantages if you don't do preliminary play/study with small line.

Small scale tests are far easier to do and therefore the feedback rate is higher. In the time it takes you to ponder how you're going to set up your jamming threshold test I can do it with small line without leaving the couch and tell you what your answer is going to be. Yes, I won't be able to get within 3% and yes, if you change material to dyneema or something you might get wildly different results. However, at the end of the day a bowline is a bowline and nylon is nylon. I'll eat my words if you can find a nylon rope of any kind on which a simple bowline jams at 10% tensile strength. The certifications are for making sure of what you already know and ruling out odd surprises, not for learning new things.

Fast feedback for exploration. Rigor for nailing down.

Quote
4. The twisted variant of #1053 Butterfly that I also offered needs a round of testing to determine jam resistance in both through loading and eye loading (in EN human rated rope).

This is a good example. Let me know if you want to know what your test will say ;)

Quote
Its hard to beat #1053 given its widespread deployment in the past 70 years.

Yes, if the eye loading is going to be <10% of the line strength 1053 is my preferred choice as well (deja vu?). Just because all you do with ropes is hang on them doesn't mean that's all that exists or that it's what OP will do.

Quote
tsik_lestat has offered up an interesting presentation in his post (EHL).

Lestat's EHL does look like an interesting one, and for all I know could be a great alternative. Thanks for pointing it out. I just have to figure out how to tie it.

Quote
This offering is (in my view) superior to yours

Your latest suggestion is interesting for the same reason that SS369's is; it's a small modification to the otherwise go-to knot which improves on that knot's weak point. In cases where you only need a modest increase in jam resistance over what 1053 provides, I'm sure it's great and I might even use it myself. The problem is that, assuming I'm tying this correctly (pass the eye through the center again, no?), when you actually load it heavily, it jams too.

So it depends on what you're looking for in a knot. If you know the loads are going to be reasonably low relative to the strength of your line, and you would rather use less line, your knot is better. If you want one knot that you don't have to think about because it works for every situation, it is objectively inferior.

Quote
particularly in through loading profile (SPart-to-SPart)....it isn't offset.

I share your distaste and suspicion for offset loading, and it can definitely cause problems. However, there are a couple problems with the idea of using it as a strict rule-out criteria.

First, the bad news: you can't really escape it. If you want to have a TIB eye knot that doesn't have some unused eye "tail" somewhere, you're going to get offset loading in *some* loading profile. The latest one you offer, for example, just trades so that it is offset in ring loading instead of through loading. Again, if you have a specific use in mind this might be fine. If we're talking about a knot that is good for true omnidirectional capability, you're going to have to relax that requirement.

The good news is that you can. Offset (ring) loading 1053 doesn't seem to cause any problems. Neither does offset loading the tentatively named "shakehands loop", when dressed properly. After snugging it up, I haven't been able to get it to jam on through loading let alone capsize (though it can jam if left too loose before loading). I haven't tested all the way to failure, but I've tested it at tension that was able to get 1053 and even your modification thereof to jam and it was totally fine.

You can wait until you get a rigorous test with EN human rated rope before you believe it if you want, but it won't be any less true in the meantime.

agent_smith

  • Sr. Member
  • *****
  • Posts: 1173
Re: Omnidirectional-loaded loop with omnidirectional tails?
« Reply #24 on: May 08, 2020, 10:18:51 AM »
Per jimmyh:

This thread topic is taking on the character of a contest of knowledge.
I think you need to start an entirely new topic post.

Post your propositions in a new topic.

Very briefly: (and I think this concludes the contest)
Quote
While you *can* daisy chain in the way that iterates on the knot I presented
?
There are several different ways of chaining a rope (climbing rope or otherwise).
I didn't know that it was necessary to expand upon that basic point with notional concepts of twist/induced torsion?

Quote
I think the only real downsides relative to the one I presented are that you can't tie it as simply as a 2 stage chain sinnet, and it takes special care to dress whereas the one I presented self dresses pretty well just by tensioning the eye and standing parts.
and so?

Quote
In other words, ~10% of tensile strength.
and so? I prefer to quantify in terms of % of the knots MBS yield point.

Quote
Small scale tests are far easier to do and therefore the feedback rate is higher. In the time it takes you to ponder how you're going to set up your jamming threshold test I can do it with small line without leaving the couch and tell you what your answer is going to be.
This statement has the character of a contest of knowledge and experience.
It needs to be elaborated on in an entirely new topic post.

Quote
Fast feedback for exploration. Rigor for nailing down.
This statement has the character of a contest of knowledge and experience.
It needs to be elaborated on in an entirely new topic post.

Quote
This is a good example. Let me know if you want to know what your test will say
This statement has the character of a contest of knowledge and experience.

Quote
Your latest suggestion is interesting for the same reason that SS369's is; it's a small modification to the otherwise go-to knot which improves on that knot's weak point.
?
This statement has the character of a contest of knowledge and experience.
Small modification by who's version of reality?

Quote
The problem is that, assuming I'm tying this correctly (pass the eye through the center again, no?), when you actually load it heavily, it jams too.
You assume incorrectly. No - it doesn't jam as you purport.

Quote
I share your distaste and suspicion for offset loading, and it can definitely cause problems
No - you dont "share" my "distaste" - because I don't actually have a "distaste".
My point is that knots loaded in an offset loading profile require a higher burden of proof. The tester needs to be diligent - to confirm stability.

Quote
First, the bad news: you can't really escape it. If you want to have a TIB eye knot that doesn't have some unused eye "tail" somewhere, you're going to get offset loading in *some* loading profile.
?
This statement makes no sense. Might need a diagram to clarify what you mean by 'eye tail'.

Quote
The good news is that you can. Offset (ring) loading 1053 doesn't seem to cause any problems.
?
Your notional understanding of what 'offset' is (within the context of an end-to-end joining knot) - appears to be incorrect.
#1053 Butterfly isn't an offset knot per se... that is, the derived Butterfly bend isn't 'offset'. But, 'ring' loading the eye of a #1053 Butterfly would be an example of inducing an 'offset' loading profile on the knot core. In a sense, take #1053 Butterfly and then cut the eye. The 2 cut legs of the former 'eye' - if bi-axially loaded - would now be an offset loading profile.
But, I am not sure what all of this has to do within the broader topic of this thread?

Quote
Neither does offset loading the tentatively named "shakehands loop", when dressed properly.
?
All bends have corresponding eye knot(s). The shake hands bend isn't offset...but, it is possible that some of its derived eye knots might exhibit the character of offset where the eye is circumferentially loaded. I'd have to see images of these derived eye knots. Again, you would cut the eye which now creates 2 'legs' - which when bi-axially loaded, might induce an offset loading profile on the knot core.
and related comment...
Quote
I haven't tested all the way to failure, but I've tested it at tension that was able to get 1053 and even your modification thereof to jam and it was totally fine.
#1053 Butterfly is jam resistant in through loading (SPart-to-SPart) loading.
My alleged 'modification' that you allude to isn't a simple modification to #1053. My presentation has 4 rope diameters around which the SParts turn and is also jam resistant in through loading. It also holds up very well to eye loading (haven't had time to heavily eye load as yet).

Quote
You can wait until you get a rigorous test with EN human rated rope before you believe it if you want, but it won't be any less true in the meantime.
This statement has the character of a contest of knowledge.
« Last Edit: May 08, 2020, 02:08:01 PM by agent_smith »

Dan_Lehman

  • Sr. Member
  • *****
  • Posts: 3903
Re: Omnidirectional-loaded loop with omnidirectional tails?
« Reply #25 on: May 09, 2020, 02:25:52 AM »
Quote
Small scale tests are far easier to do and therefore the feedback rate is higher. In the time it takes you to ponder how you're going to set up your jamming threshold test I can do it with small line without leaving the couch and tell you what your answer is going to be.
Would that this were so,
but you need like rope & forces and I don't
accept the transferability of % behavior of
one rope to another (we see already the cases
contradicting this).

Quote
Quote
First, the bad news: you can't really escape it. If you want to have a TIB eye knot that doesn't have some unused eye "tail" somewhere, you're going to get offset loading in *some* loading profile.
?
This statement makes no sense. Might need a diagram to clarify what you mean by 'eye tail'.
I take it to mean that the knot needs to have
EVERY *end* (= "exiting from nub strand")
separate, no twin.  In the butterfly, e.g., one
finishes by ... drawing out a >>bight<< which
bight legs are "twin"'d and so can be ring-loaded
to be in *offset* orientation re the knot.

.:.  It's an interesting conjecture --provably true/false?
Well, heck, now your tying up my evening thinking!
(Right after I invent the perpetual-motion device.)

Quote
Quote
The good news is that you can. Offset (ring) loading 1053 doesn't seem to cause any problems.
?
Your notional understanding of what 'offset' is (within the context of an end-to-end joining knot) - appears to be incorrect.
#1053 Butterfly isn't an offset knot per se... that is, the derived Butterfly bend isn't 'offset'. But, 'ring' loading the eye of a #1053 Butterfly would be an example of inducing an 'offset' loading profile on the knot core. In a sense, take #1053 Butterfly and then cut the eye. The 2 cut legs of the former 'eye' - if bi-axially loaded - would now be an offset loading profile.
Right, you've got it (the sense of "offset loading").
And I think that the butterfly might, like e.g.
#1052, flype into a version of itself?!

Quote
All bends have corresponding eye knot(s).
How's this working for the squaREef knot!?


This character has the knowledge of a contest of statements.


 ;)

jimmyh

  • Jr. Member
  • **
  • Posts: 24
Re: Omnidirectional-loaded loop with omnidirectional tails?
« Reply #26 on: May 09, 2020, 02:48:15 AM »
Quote
This thread topic is taking on the character of a contest of knowledge.
To use your phrasing, the idea it's a "contest of knowledge" to *me* only exists in your narrative. It doesn't exist in mine, nor, I expect, in anyone else's.

An alternative way you might consider viewing it is "disagreeing" or "showing you things that you don't seem to have considered", and in that alternative perspective you may consider saying "here's why I don't think that is true" or "ah, good point" (depending on which is appropriate).

If you're too focused on "the contest" to actually get into a discussion where we can actually explore disagreements, then I guess we can't do this. Oh well.



Quote
Small scale tests are far easier to do and therefore the feedback rate is higher. In the time it takes you to ponder how you're going to set up your jamming threshold test I can do it with small line without leaving the couch and tell you what your answer is going to be.
This statement has the character of a contest of knowledge and experience.

I'll pick this first one as an example, but the point is the same for the rest.

Yes, I think you're doing it wrong and that the way I'm advocating is better. I think that is fine, since it's about knots, it might actually be true, and it is not adversarial. Sharing knowledge is all about showing each other how we can be doing things better, and if you think you know a better way of doing something and that I'm making a mistake, I would love to hear it.

Yes, if you're going to make it into a "contest" and take that side, I think you're going to end up losing this one and so I wouldn't recommend it. I don't think it makes me "better" than you or that the resulting "contest" is of any importance, however. There's no gloating over "winning" and no shame in "losing" such trivialities as it is completely toxic to frame "who gets to learn" as "who has to lose". I'm happy to "lose" contests here if that means I get to learn, and I suggest you adopt a similar attitude. No one else here, either in my previous interactions or all the reading in between, seems to share this sensitivity.


Quote
Small modification by who's version of reality?

I meant it as a compliment, not as a diminishment. If you can take a well known and well-performing knot and add one simple operation that improves it, that is *better* than doing something entirely new that will need both vetting and committing to memory.

For example, one of my favorite knots I've learned here is the simple "Lehman lock" to the bowline, since it is such a simple and physically small modification that works so cleanly and doesn't have the dressing ambiguity of the Yosemite finish. It is my go to for secure eye knots in everything except climbing (where I suspect that it might work fine, but it's easy enough to add another pass through), and even as a midline eye knot when I know the direction of loading. Even my preferred tie in knot is simply a "small modification" of Lehman's small modification, and that additional modification itself could be seen as an alternative implementation of his ideas demonstrated in his EBDB. "Small" is good, in this context.

Quote
You assume incorrectly. No - it doesn't jam as you purport.

This comment actually does "have the character of a contest of knowledge and experience" above and beyond asserting a novel concept that I happen to disagree with. Because instead of introducing a new argument or perspective to further the discussion towards agreement and learning, it's just a flat out "nuh uh" and posturing as if your say so is worth more than mine. If you were more interested in learning than not-losing you might instead ask "Did you actually succeed in getting one to jam? Under what conditions? How did you tie it, exactly?" and see if you can't replicate it.

Again, assuming I have tied it correctly (eye through the center again, right?), it does in fact jam at sufficient tension in eye loading (which, as you've admitted, you haven't tested yourself). I have a jammed knot sitting on my table and I can mail it to you if you'd like. Fair warning, it isn't in EN human rated rope, but it does exist and hint pretty strongly about what you're going to find in your rope.

Quote
This statement makes no sense. Might need a diagram to clarify what you mean by 'eye tail'.

It is a little hard to follow, I'll try again. If you tie a bowline with a bight you end up with three eyes; the eye of the parent knot forms two while the tail forms one.

If a knot is TIB, you make it by pulling a bight through things and looping around and shit. When you pull it through something, that "intermediate knot" now has an "eye" that is functioning like a "tail". With some things, like the butterfly loop, this eye is the eye to be used and the knot is done. In others, like a bowline on a bight, it is looped around and snugged up so that there is no eye left and no "tail". However, when doing this, you cannot loop it around *only one* of the standing parts without passing the end through and making it no longer TIB. If you keep things TIB and loop around both, then both of those standing parts will now exit the knot through the same bight and tension between them will offset load the loop. The choice just becomes where you would like the offset loading to be, or whether you'd like to give up TIB.



Quote
Your notional understanding of what 'offset' is (within the context of an end-to-end joining knot) - appears to be incorrect.
[...] 'ring' loading the eye of a #1053 Butterfly would be an example of inducing an 'offset' loading profile on the knot core. In a sense, take #1053 Butterfly and then cut the eye. The 2 cut legs of the former 'eye' - if bi-axially loaded - would now be an offset loading profile.
But, I am not sure what all of this has to do within the broader topic of this thread?

No, you get it fine. Ring loading is offset loading for 1053. You don't have to cut the other end because the knot can't know the difference.

The relevance is that the thread is about loops that can be loaded and perform well omnidirectionally. One of these directions the load can be applied is for the eye to be pulled apart in ring loading, which induces an offset loading profile on 1053. Since every TIB knot presented (and I argue that all possible) are offset loaded under some direction of loading, saying "this knot is worse because it's offset loaded" can only be a valid decision criteria if you narrow your set of applications from "omni" to "less than omni" -- or at least prioritize certain loading directions over others.





Quote
>
Quote
You can wait until you get a rigorous test with EN human rated rope before you believe it if you want, but it won't be any less true in the meantime.
This statement has the character of a contest of knowledge.

That's what it feels like from the inside when you make a bold statement that is wrong and then dig in when someone points out that it is wrong. It's entirely possible to entertain corrections without viewing them as an affront or digging in, and this is a very valuable skill to develop and put to use.

For example, I have said definitively that there exist no TIB eye knots without an unused eye that are not offset loaded in at least one direction. This, like your statement, is kinda bold as it is a statement of impossibility. You could prove me wrong (assuming I'm wrong) by simply showing me a counterexample. If you tell me that I'm flat out pong wrong there, I would be *excited* to be corrected. I wouldn't take it as you "wanting to compete" because so long as you can actually show me where I went wrong, "wanting to share knowledge with peers" would be just as fitting an explanation and it would be silly (and defensive) to jump to assuming the worst instead of assuming the best. One doesn't have to identify with or fight to preserve their beliefs when they're wrong, nor does one have to be even slightly bothered when the other person *is* secretly or not so secretly getting off on having "one upped" them. If you genuinely teach me something surprising, I'm happy for you to have that if it's important to you; you'd have earned it, after all. If it's not, great.

I am simply saying that big knots in some material behave similarly to small knots in the same material, and therefore the test in big rope will be well predicted by the results of the quick and informal test with the small rope. You can take it personally and disengage if you want, but I promise you that it isn't necessary and that it's not a personal statement. It's just a statement about the behavior of knots in rope.

jimmyh

  • Jr. Member
  • **
  • Posts: 24
Re: Omnidirectional-loaded loop with omnidirectional tails?
« Reply #27 on: May 09, 2020, 02:56:14 AM »
Quote
Would that this were so,
but you need like rope & forces and I don't
accept the transferability of % behavior of
one rope to another (we see already the cases
contradicting this).

I'm glad you don't. That makes it interesting :)

It obviously isn't going to be a *perfect* match, but how far off have you seen it get when comparing (for example) nylon vs nylon? I would be pretty shocked if a simple bowline could be made to jam in any nylon rope, or if a double overhand could be made to resist jamming in any nylon.

On the other hand, if a knot breaks at 50% tensile strength in one rope and 65% in another of the same material I wouldn't be too surprised.

Quote
.:.  It's an interesting conjecture --provably true/false?
Well, heck, now your tying up my evening thinking!
(Right after I invent the perpetual-motion device.)

It sounds like you understood what I was getting at. I suspect it's provably true, though turning my intuitive and visual (and not foolproof) "proof" into something formal and rigorous has never been my strong point. I'll have to think if I can get closer to that.
« Last Edit: May 09, 2020, 02:57:01 AM by jimmyh »

agent_smith

  • Sr. Member
  • *****
  • Posts: 1173
Re: Omnidirectional-loaded loop with omnidirectional tails?
« Reply #28 on: May 09, 2020, 03:20:31 AM »
per jimmyh:
Quote
To use your phrasing, the idea it's a "contest of knowledge" to *me* only exists in your narrative. It doesn't exist in mine, nor, I expect, in anyone else's.
?
The last part of your sentence is what is known as using 'social proof' as a base from which to win an 'argument'.
This whole back n forth posting is peculiar and isn't normal.
This has all the hallmarks of a person seeking to engage in a contest of knowledge - because it has progressed beyond any notional concept of reasonableness.

Quote
Yes, I think you're doing it wrong and that the way I'm advocating is better. I think that is fine, since it's about knots,
This isn't about knots - its taking on the character of something entirely different and is far removed from the original question posted.

You should start a new topic post.

Quote
I think you're going to end up losing this one and so I wouldn't recommend it.
?
Happy to be declared the loser.
I lost - you win.

Quote
If a knot is TIB, you make it by pulling a bight through things and looping around and shit. When you pull it through something, that "intermediate knot" now has an "eye" that is functioning like a "tail". With some things, like the butterfly loop, this eye is the eye to be used and the knot is done. In others, like a bowline on a bight, it is looped around and snugged up so that there is no eye left and no "tail". However, when doing this, you cannot loop it around *only one* of the standing parts without passing the end through and making it no longer TIB. If you keep things TIB and loop around both, then both of those standing parts will now exit the knot through the same bight and tension between them will offset load the loop. The choice just becomes where you would like the offset loading to be, or whether you'd like to give up TIB.
You need to start a new topic thread.
This is a discussion that is far removed from the simplicity of the OP question.

Quote
For example, one of my favorite knots I've learned here is the simple "Lehman lock" to the bowline, since it is such a simple and physically small modification that works so cleanly and doesn't have the dressing ambiguity of the Yosemite finish. It is my go to for secure eye knots in everything except climbing (where I suspect that it might work fine, but it's easy enough to add another pass through), and even as a midline eye knot when I know the direction of loading. Even my preferred tie in knot is simply a "small modification" of Lehman's small modification, and that additional modification itself could be seen as an alternative implementation of his ideas demonstrated in his EBDB. "Small" is good, in this context.
You need to start a new topic thread.
This is a discussion that is far removed from the simplicity of the OP question.

Quote
The relevance is that the thread is about loops that can be loaded and perform well omnidirectionally. One of these directions the load can be applied is for the eye to be pulled apart in ring loading, which induces an offset loading profile on 1053. Since every TIB knot presented (and I argue that all possible) are offset loaded under some direction of loading, saying "this knot is worse because it's offset loaded" can only be a valid decision criteria if you narrow your set of applications from "omni" to "less than omni" -- or at least prioritize certain loading directions over others.
You need to start a new topic thread.
This is a discussion that is far removed from the simplicity of the OP question.
Circumferential loading of the eye of #1053 Butterfly isn't an accurately explanation of an offset loading profile.
Offset loading was devised to explain end-to-end joining knots that are through loaded from SPart to SPart - where the knot core is displaced from the axis of tension.
Circumferential loading of an eye (ie hoop stress) of a Butterfly isn't an entirely accurate description in my view. Also, it is in the realm of academia because the eye of a Butterfly isn't intended to be circumferentially loaded. However, cutting the eye and then loading the two former eye legs in 180 degree opposition now creates a knot core that is displaced from the axis of tension.

jimmyh

  • Jr. Member
  • **
  • Posts: 24
Re: Omnidirectional-loaded loop with omnidirectional tails?
« Reply #29 on: May 09, 2020, 04:04:27 AM »
Quote
However, cutting the eye and then loading the two former eye legs in 180 degree opposition now creates a knot core that is displaced from the axis of tension.

The behavior of a knot in ring loading is the exact same as it is when you cut the eye legs before pulling on them. I can show you a picture of a butterfly loop in one of these two configurations, and unless I zoom out enough to include the clipped ends or intact eye, you won't be able to see any difference because there isn't one. Either it works both loadings or it works for neither, as they are the same thing.

Quote
Also, it is in the realm of academia because the eye of a Butterfly isn't intended to be circumferentially loaded

"Omni" means "all". Either it's good for all loadings or it it's a poor suggestion for OP. Take your pick.

Personally, I think it's a decent suggestion for this thread because it's simple and does decently well at all loadings, even if not spectacular at all. There is no "intent" baked into a not anyway. They're just structures that are sometimes better for some things than others.

EDIT:
>This whole back n forth posting is peculiar and isn't normal.

After getting around to reading some more of the current threads, it appears that this *is* normal for you now (though I thought it wasn't in the past?). Since it doesn't seem like a fluke, I think I'm no longer going to put any effort into trying to make a conversation work with you. If it works, then great. If not, I'll just stop responding.
« Last Edit: May 09, 2020, 05:01:21 AM by jimmyh »