Author Topic: Testing Lee's locked Yosemite Bowline  (Read 1994 times)

alanleeknots

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Testing Lee's locked Yosemite Bowline
« on: November 01, 2017, 06:12:55 AM »
Hi All,
         Even though Xarax is no longer with the forum, he is always there to give me his valuable input, come to this point,
         I have said many thanks to him.     謝謝  alan lee

         https://www.youtube.com/watch?v=xADp-BqpB8I&t=134s

         

         Edit ; This  is a New Bluewater rope.
« Last Edit: November 01, 2017, 06:24:57 AM by eric22 »

agent_smith

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Re: Testing Lee's locked Yosemite Bowline
« Reply #1 on: November 01, 2017, 08:46:08 AM »
This is really good to see Alan :)

We really need to test Bowlines with 2 rope diameters inside the nipping loop to establish a baseline result.

Then, we need to test Bowlines with 3 rope diameters inside the nipping loop.

Proposed tests in attached photos (you can ignore the measurements - just be consistent across all tests...making sure all measurements are the same.

We need to answer this question:  "What effect does the number of rope diameters inside the nipping loop have on a Bowlines MBS yield"?


Mark G

alanleeknots

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Re: Testing Lee's locked Yosemite Bowline
« Reply #2 on: November 01, 2017, 09:56:25 PM »
Hi All,
        Mark, no problem will get it test for you.
        謝謝  alan lee.

Dan_Lehman

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Re: Testing Lee's locked Yosemite Bowline
« Reply #3 on: November 01, 2017, 11:33:28 PM »
This is really good to see Alan :)

We really need to test Bowlines with 2 rope diameters inside the nipping loop to establish a baseline result.
Then, we need to test Bowlines with 3 rope diameters inside the nipping loop.

We need to answer this question:  "What effect does the number of rope diameters inside the nipping loop have on a Bowlines MBS yield"?[/b]
This is really beside the point : the point is not number
per se --rather, some implied & occasional effect of ...--
but geometry of the SPart --sharpness of curvature.
(or abruptness of the ultimate/later sharpness :: images
of an Inston test device show it using a decreasing-radius
curved attachment structure --voici:
[url]http://www.instron.co.hu/hu-hu/testing-solutions/by-material/composites/tension/aramid-fiber[url]
).

In short, I've played around with versions of a given
knot in looking at the per-manual-force (and sometimes
going to my pulley stresser --but that takes getting my
rear end off of the arm chair!) shaping of the SPart(s)
per various arrangements (maybe just dressings).
.:.  Citing mere diameters is simplistic, alas; it's how
 they're arranged.  (Though, if one ups to 4-5 dia., it's
likely that a significant --in shape-- softening is bound
to occur.)

(Consider that one can surround 2dia as -----> 8 or ----> oo.
The 2nd is 2 dia ['oo'] aligned w/axis of tension and so the
curvature is really just around 1dia; the 1st ('8') has
the 2dia at 90deg to first, but somewhat implies that
a 1dia curve obtains **briefly** and then eases from
the one part to the next (2 lefTurns vs 1 U-turn, so to
speak).  Actual shaping with pull of rope ('--->') going
to top & down of '8' yields that Instron-like gradual
turn '%' --softly over upper 'o' getting main pull,
then sharply around lower 'o' but after some force
is consumed in friction (and so YMMV per cordage). !?

 - - - - -

On Lee's examination of the surviving knot
 --and very nice to have the two knots in the test!--,
upon loosening it further for view, one can see on the
(viewer's) left by his wrist a tightly compressed part
of the bowline's nipping turn/loop.
(Now, possibly one could have stitched some marked
threads into both knots around the turn and gotten an
idea of where the break came.)

 - - - - -

I thought I saw some slippage of the nipping loop as tension
rose into a serious range (and then beyond that seemed to
stop) --something more than mere compression!?
  (on first look, this; maybe not so).


--dl*
====

agent_smith

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Re: Testing Lee's locked Yosemite Bowline
« Reply #4 on: November 02, 2017, 05:18:56 AM »
reply from Dan Lehman per number of rope diameters inside a nipping loop...

Quote
This is really beside the point : the point is not number
per se --rather, some implied & occasional effect of ...--
but geometry of the SPart --sharpness of curvature.
(or abruptness of the ultimate/later sharpness

The practicalities of doing testing in a home lab environment where 'padding out' the nipping loop to achieve some larger radius gives the tester limited options. Alan Lee is not testing in a purpose built multi-million dollar lab.

I see no reason in principal why Alan can't test 'Lees link Bowline' and 'Scotts locked Bowline' and just see what results he gets.
Mind you, I care not for testing just see what the MBS yield is. In this case, I am interested in Bowlines with 3 rope diameters inside the nipping loop - and how they respond to load...relative to Bowlines with 2 rope diameters inside the nipping loop. So the pull-to-failure mode is simply serving a purpose.

What else can Alan Lee do in his home lab?

He could try testing a 'slipped' #1010 common Bowline....or, he could just insert a separate cut length (ie a short piece) of rope (of the same diameter as the parent rope) into the nipping loop to pad it out into 3 rope diameters.

In any case, Lee's link Bowline and Scotts locked Bowline all have 3 rope diameters inside the nipping loop...so why not produce some baseline results for these eye knots?

I just hope that this doesn't bog down or fizzle out...

Mark G

agent_smith

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Re: Testing Lee's locked Yosemite Bowline
« Reply #5 on: November 24, 2017, 05:56:56 AM »
I was hoping this process wouldn't slow down or grind to a halt.

Alan, I hope you can continue to test knots - we need your data!

Mark G

alanleeknots

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Re: Testing Lee's locked Yosemite Bowline
« Reply #6 on: November 25, 2017, 03:02:07 AM »
 
            Mark, I will get it done the next few days.