Author Topic: Second order retucked/enhanced harness midline loops and the equivalentEOL loops  (Read 4984 times)

alpineer

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Focusing on the midline loops shown in my previous reply, here is a method of tying the enhanced harness loop.
First you form a loop, a bight and second loop as shown in photo 1 from left to right.Then the right loop is placed on the left loop as shown in photo 2 and the bight passes like a toggle between the loops with the following pattern~up,down,up,down.If the left loop is placed on the right and the same steps are followed, then the reverse loop is created.
This is a simple easy to remember method of tying and once mastered it can be tied, dressed and inspected in a rather quick way.

IMO this knot bears a stronger association with the False Butterfly Knot than with the Harness Loop, which is how I came across it, trying to secure the FBK for 2-way through loading.
« Last Edit: May 07, 2020, 08:46:49 AM by alpineer »

tsik_lestat

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Good evening Alpineer

i am of the view that EHL, is a retucked version of 1050 harness loopknot, hence the name. You are prompted to tie the knot first and then remove some components, starting from the collar that encircles both eye legs. Then, flip the other collar, rearrange the eye legs, and you have brought the harness into light. Υοu can obviously reverse the process and tie the EHL starting directly from the harness.

I am having trouble to rule out EHL's bowline/harness inherence, and pin down its association with false butterfly that you are reporting. Nonetheless, you have prompted my interest, if you care to feed with more detail, or even illustrate a potential tying method, in order to clear up this traced origin.

I provide an image for your reference, so as to which knot you refer to as false butterfly.

Link : https://www.ropelab.com.au/wp-content/uploads/2015/09/Alpine-Butterfly-errors-1024x534.jpg

Given your climbing and knotting background, as well as your investigations on the midline concept, i can't help asking your estimation about the functionality of OP's midline, EHL, structure, compared to the alpine butterfly.

Thanks.
« Last Edit: May 07, 2020, 04:12:07 PM by tsik_lestat »
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alpineer

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Good evening Alpineer

i am of the view that EHL, is a retucked version of 1050 harness loopknot, hence the name. You are prompted to tie the knot first and then remove some components, starting from the collar that encircles both eye legs. Then, flip the other collar, rearrange the eye legs, and you have brought the harness into light. Υοu can obviously reverse the process and tie the EHL starting directly from the harness.

I am having trouble to rule out EHL's bowline/harness inherence, and pin down its association with false butterfly that you are reporting. Nonetheless, you have prompted my interest, if you care to feed with more detail, or even illustrate a potential tying method, in order to clear up this traced origin.

I provide an image for your reference, so as to which knot you refer to as false butterfly.

Link : https://www.ropelab.com.au/wp-content/uploads/2015/09/Alpine-Butterfly-errors-1024x534.jpg

Given your climbing and knotting background, as well as your investigations on the midline concept, i can't help asking your estimation about the functionality of OP's midline, EHL, structure, compared to the alpine butterfly.

Thanks.

Hey tsik,
It's #3 in the linked image.

To be clear, there's certainly a transformational relationship between the Harness Loop and your proffered knot. However, I think the FBK (perhaps more correctly referred to as the Half Hitch Loop) relationship is more direct. Starting from your "step 2" image, feeding the bight directly through the two small loops gives you the FBK/HHL.

« Last Edit: May 07, 2020, 07:26:57 PM by alpineer »

siriuso

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Hi tsik_lestat,

I have made a big mistake in my reply on May 05.

The text should be read as :

"The tying method is the same as ABOK#1142 Jar Sling Knot. With a different dressing, EHL is using the Sling's handle as the EHL loop, where as the JSK is using its center nub to hold object."

It should be JSK instead of ABK.

yChan

tsik_lestat

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@Alpineer

I was kind of leery of the structure you were suggesting, but i had to clear it up. Indeed, this maneuver forms the false butterfly, the very same Derek had tied in his first attempt.

However, i am still not seeing any structural propinquity in the core nubs of the two midline knot structures, in a geometrical and functional sense. Besides, the overhand links of the false/half hitch butterfly, are hardly pointing to the bowlinesque descent of EHL, but that's only my interpretation.

@Siriuso

Nothing to worry about, i perfectly understood what you meant in your previous reply.

So you are suggesting the jug knot tying method to form the EHL. I found it a bit more complex for my taste, when i came across to it, but that's a subjective matter. I shall have a look again to see if it acommodates any amendment, but I was counting on your ability to ferret out new tying methods  ;).
« Last Edit: May 07, 2020, 10:12:40 PM by tsik_lestat »
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alpineer

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Re tying methods for this knot, my hybrid style "loop on the hand w/X-crossing underneath" will get you one tied, dressed and set in 7 secs. Just make the "X" in the opposite direction with the other hanging strand and proceed from there with the appropriate over/under maneuvers. https://youtu.be/DYGdvL9-P30
« Last Edit: May 08, 2020, 06:34:08 AM by alpineer »

tsik_lestat

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Good day Alpineer

I see that you have attuned your hybrid tying method to form a false butterfly as well. Thanks for bringing this in, the only con i would add, is that is not so straight forward as tying the butterfly, because you have to brake the two loops apart and place one upon the other, continuing with the over, under maneuvers. However, it is more memorable, in the sense that one does not need to remember the chirality of the two small loops, i'll give you that.

Your hybrid method of tying the alpine butterfly is more suitable for me, as i find that you can easily adjust the size of the eye. It resembles with one of my own, but only in the final stage, where you are adjusting the size of the bight you are going to feed through the two loops. This very method, relies on a type of pretzel structure formation, but i think yours is quicker and easy to remember.
« Last Edit: May 08, 2020, 08:15:15 AM by tsik_lestat »
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alpineer

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@Alpineer
However, i am still not seeing any structural propinquity in the core nubs of the two midline knot structures, in a geometrical and functional sense. Besides, the overhand links of the false/half hitch butterfly, are hardly pointing to the bowlinesque descent of EHL, but that's only my interpretation.

I'm not sure how to interpret what you're saying re "bowlinesque descent". However, performing D.L.'s backflip/halter maneuver on the FBK produces two healthy B'lines; depending on the direction, either twinned or splayed.
« Last Edit: May 09, 2020, 10:06:23 PM by alpineer »

tsik_lestat

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However, performing D.L.'s backflip/halter maneuver on the FBK produces two healthy B'lines; depending on the direction, either twinned or splayed.

Good call Alpineer. I have just tied them and in this initial phase they look healthy to me too. I guess, i prefer the splayed version, but i am not sure about the EEL ability, as i have the sense that i have to load it from the weak link of the FBK for a stable structure development. I wonder, if they have been tied before. If not, they're waiting for your moniker  ;).

I'm not sure how to interpret what you're saying re "bowlinesque descent".

All i am saying is that the parent knot, is a TIB 1010 bowline. Check out how Alan Lee ties the Jug sling knot, starting from the tib 1010 variant. Link : https://www.youtube.com/watch?v=WBDn25h80KU.

All you have  to do to reveal EHL, is to flip the collar that encircles both eye legs, plus the nipping loop of the bowline. That said, even so i am refering to an end of line profile of the knot with this paradigm, the same stands for the midline structure, therefore i am tracing EHL's origin by laying emphasis on this equivalence, not only in a topological but in a functional sense too.

In other words, i have produced a retucked version of a bowline, or a second order bowlinesque type of knot, or a squared bowline, that inherits all its good properties like jam resistance, being simultaneously far more secure and stable than the parent.
« Last Edit: May 10, 2020, 12:38:58 AM by tsik_lestat »
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alpineer

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I think we've made our points, time to move on.

agent_smith

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Hello tsik_lestat,
I would like your permission to include your bi-axially loadable TIB eye knot ('EHL') in my paper on the Butterfly knot.
If you grant permission - I will need some historical info...eg discovery date, the inspiration that led you to its discovery and your real name, etc.
Also need any test data - ie any load tests that have been conducted in human rated EN ropes (eg EN1891 or Sterling HTP).

Of importance to me would be test data on bi-axial through loading (SPart-to-SPart) and also various types of eye loading.
Jam resistance data is of high importance to me...

You can PM me to let me know...



alpineer

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Given your climbing and knotting background, as well as your investigations on the midline concept, i can't help asking your estimation about the functionality of OP's midline, EHL, structure, compared to the alpine butterfly.

Thanks.

Mechanical functionality appears to be good. However, any advantage that it might conceivably have over the ABK re jamming immunity comes at the price of extra complexity. It would have to solve a problem that climbers experience on a regular basis in order to be considered. In situations where the ABK is typically used, I wouldn't think the forces enough to cause a jamming incident. Perhaps rescue loads on low stretch rope could initiate jamming. Agent Smith?

A curiousity of doubled back nipping structures is that they can cause the knot to have more than one possible dressing geometry, which may be of concern.
« Last Edit: May 12, 2020, 04:25:19 PM by alpineer »

alpineer

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This fellow managed to jam an ABK in an ill suited towing application.
https://igkt.net/sm/index.php?topic=6150.0

tsik_lestat

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@ agent_smith

Undoubtedly, it goes without saying,that you have absolute permission, to deal with this knot, in whatever way you desire, and i personally thank you for your intention to include it in your ABK's upcoming paper. I shall contact you to provide with every additional info i know. Mind you, there's not so much, as official test data conducted in human EN rated ropes, are rather scanty at the moment.

Some further contributions might be added, regarding the tying method of the midline mirrors, as well as a variation of an end termination profile, which adds even more security.

For those interested, the span loop midline structure, appears to accomodate the same tucking as EHL does, generating a bulkier profile, due to its more complex link.

@alpineer

Quote
However, any advantage that it might conceivably have over the ABK re jamming immunity comes at the price of extra complexity.

That's true, stability and jam resistance comes at the price of some bulkyness, along with some difficulty to form on stiff ropes, but nonetheless, i believe it operates on the margin of admissible and balanced complexity. I am of the view, that sometimes you got to go a bit more complex to achieve the desired functionality, but not going too far.

I'd also comment, that the flexibility of loading EHL's eye without observable jamming incidents, adds some extra versatility, in contrast with ABK's eye loading profiles that are likely more prone to jamming, as fellow climbers and testers report.

Quote
A curiousity of doubled back nipping structures is that they can cause the knot to have more than one possible dressing geometry, which may be of concern.


This particular dressing state, appears to be immensely stable, where the eye bight is firmly clamped, enjoying full constriction from both EHL's links, that can hardly deform under high strain.

Thanks for your evaluation, it's much appreciated.
« Last Edit: May 13, 2020, 11:21:17 AM by tsik_lestat »
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alpineer

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Quote
l wonder if they've been tied before.

Centuries ago, no doubt.