Author Topic: Adjustable Loops  (Read 43842 times)

agent_smith

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Re: Bowline "knot wars"
« Reply #30 on: June 09, 2015, 08:42:20 AM »
Hi Alan,

Have you got a photo of the above knot with it tied loosely?
I am getting ready to take some more photos of your ingenious knot creations - and I have limited time - so just want to make it easier if I can quickly find all the info here in one place (yes, I am being lazy).

If you cant find it Alan - I know Luca is one of the worlds best blood hounds as he can sniff out any obscure piece of information from miles away :)

Mark G

Mobius

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Re: Load testing of various Bowline structures
« Reply #31 on: June 09, 2015, 08:43:40 AM »
Hello mobius, I have added more key stroking content to my post at reply #14.

Would be good if you could also consider changing the title of this thread from 'Knot wars' to 'Load testing of various Bowline structures' (or something with a more scientific bent).

Mark G
I will change the thread to your suggested name, though I am not sure how 'scientific' I can actually do trials though. It might take more than a couple of weeks to try and get material and methodology as good as I can for a home trialling situation.

One thing that occurred to me was that I often hear rope fibres start to break prior to complete knot failure. If I stopped the test at that juncture I could potentially mark the entry points into the nub carefully, cut the nub apart carefully and see where the rupture actually started. Was it the inside of the curve, or the outside of the curve, and where on the curve rupture actually started. This idea sounds alright in theory, but doing so in practice might prove really difficult.

Cheers,

mobius


agent_smith

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Re: Load testing of various Bowline structures
« Reply #32 on: June 09, 2015, 08:55:08 AM »
Quote
If I stopped the test at that juncture I could potentially mark the entry points into the nub carefully, cut the nub apart carefully and see where the rupture actually started.

Hello mobius,

Might have to defer to the 'big guns' of the IGKT for a clear-cut answer to that question. It might actually be an engineering question - so perhaps Derek Smith could weigh in (although Derek 'the dunny man' has been absent from this forum for some time I think?).

My spider senses tell me that cutting open a compressed knot structure will immediately release tension and therefore alter what you are seeing. Also, stopping the test before knot failure might also alter the heat flow/friction contribution to knot rupture.

I have no clear-cut answer...sorry.

Mark G

alanleeknots

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Re: Bowline "knot wars"
« Reply #33 on: June 09, 2015, 09:36:41 AM »
Hi Alan,

Have you got a photo of the above knot with it tied loosely?
I am getting ready to take some more photos of your ingenious knot creations - and I have limited time - so just want to make it easier if I can quickly find all the info here in one place (yes, I am being lazy).

If you cant find it Alan - I know Luca is one of the worlds best blood hounds as he can sniff out any obscure piece of information from miles away :)

Mark G

Hi Mark,
            Here is all my knots in here.  Thanks you.

            謝謝 alan lee   

alanleeknots

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Re: Load testing of various Bowline structures
« Reply #34 on: June 09, 2015, 09:39:19 AM »
more picture

alanleeknots

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Re: Load testing of various Bowline structures
« Reply #35 on: June 09, 2015, 09:47:32 AM »
more knots

" Lee Eskimo 8 bowline (A)" can't support heavy load, and will jam, I think we should abundone this loop.
   Hi Mark  I have one more loop posted in Reply #55  please have a look.
   (Edit date june-9-2015)
« Last Edit: June 10, 2015, 07:18:53 AM by eric22 »

xarax

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Re: Load testing of various Bowline structures
« Reply #36 on: June 09, 2015, 02:22:30 PM »
   There are many TIB variations of the Alpineer s bowline. Read :
   http://igkt.net/sm/index.php?topic=4697.0

   After the trials by Alan Lee, I came to believe that this bowline will become difficult to untie after heavy loading, and I had abandoned it. The "link" around the rim of the nipping loop "closes" around itself too tightly - and this may happen in all "Link bowlines" .
This is not a knot.

alpineer

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Re: Load testing of various Bowline structures
« Reply #37 on: June 09, 2015, 04:36:50 PM »


   After the trials by Alan Lee, I came to believe that this bowline will become difficult to untie after heavy loading,...

Heavy loading, in what material?  I don't climb on what appears - in his images - to be soft laid frictive trolley cord, a material that would challenge many a knot's untiability. My particular interest in this knot is as a secure harness tie-in. As is the case with any knot, extreme differences in the cordage material can change a knot's performance characteristics.
« Last Edit: June 09, 2015, 04:45:49 PM by alpineer »

xarax

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Re: Load testing of various Bowline structures
« Reply #38 on: June 09, 2015, 05:07:26 PM »
   Heavy loading, in what material ? 

  What I use to all "heavy", I guess that it should be a significant percentage of the MBS of the knot, or even of the line - say, 25%, 33,3%, or 50%. We have to define what we mean by this term - and it would be great if we could establish some benchmark loading percentages, and test our ropes in all of them.
  My own experience comes from kernmantle ropes, like those used in climbing, canyoning and rescue. I prefer them because they are stiff ( so they do not like sharp turns, and this makes me, too, to tie knots with wide, smooth curves ), they are not very compressible ( so they can not be flattened too much, and fill the voids in between the segments within the knot, turning it into a compact, massive and rigid ball which can not be un-knotted easily ), and they can retain an almost circular cross section ( so the contact area between two adjacent segments is not very extended ). I think that, in such material, the properties of the "knot" itself ( the geometry ) will manifest themselves more clearly, and the properties of the particular rope ( the material ) will play a secondary only role. I also tie knots in marine ropes, but I do not judge them by how they behave there - marine ropes are usually braided, and softer ( and less slippery ) than kernmantle ropes.
   Alan Lee has tried this bowline on such a climbing rope :
   http://igkt.net/sm/index.php?topic=4851.0
   He is much more creative in tying eyeknots, and experienced in trying them, than me - so, when he is not satisfied, I, too, am not !
This is not a knot.

roo

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Re: Load testing of various Bowline structures
« Reply #39 on: June 09, 2015, 06:29:22 PM »
   He is much more creative in tying eyeknots, and experienced in trying them, than me - so, when he is not satisfied, I, too, am not !
And yet when he reports that a Zeppelin Loop can be untied after taking twice (!) the safe working load of the rope, you apparently don't believe him (or anyone else, for that matter):

      Just to make sure to have more accurate reading, again I carefully tested the Zepplin loop,
       for soft rope after loaded 1200 lbs. is manageable to untie

the soft rope is 3000 lbs. breaking strength  and 300 lbs. safe working load.
If you take 1/5 of the 3000 lb as the safe working load, it'd yield 600 lb.  So it seems all the loops you're testing recently are performing well.
« Last Edit: June 09, 2015, 06:34:19 PM by roo »
If you wish to add a troll to your ignore list, click "Profile" then "Buddies/Ignore List".


xarax

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Re: Load testing of various Bowline structures
« Reply #40 on: June 09, 2015, 07:17:25 PM »
  a Zeppelin Loop can be untied after taking twice (!) the safe working load of the rope

  The satisfaction of tying a pathetic knot that can only be untied when it is loaded by the "Working load" ( that is, a small fraction of the MBS...), can be all yours ! Because, evidently, you have not anything else...
  What a knot tyer can invent ( other than a decent knot, of course...- it seems that this is not so easy for some people ), in order to defend a frog-knot... If a knot is not a prince-knot, I am not interested in it - and I do not believe that frogs can be turned into princes with such cheap tricks.
   However, this particular frog has many more ugly characteristics ! It "closes" around itself not only too tightly, but also prematurely, leaving half of the knot loose, and so redundant... And it is not PET. AND it is a disgrace for the genuine Zeppelin knot, the Zeppelin bend ( provided one has managed to understand how a Zeppelin-like knot "works", and why it is easy to untie...- if he does not, it is a hymn !  :) ).

   ( However, if you share the marlinspike Dan Lehman uses for the Lehman8, you CAN untie the so-called "Zeppelin loop", indeed - which is NOT a Zeppelin-like knot, but I guess you will never be sincere/brave enough to accept it...)

Zeppelin loop is the worst one among all ,
 besides the name "Zeppelin", it really has no much to offer.
« Last Edit: June 09, 2015, 08:20:05 PM by xarax »
This is not a knot.

roo

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Re: Load testing of various Bowline structures
« Reply #41 on: June 09, 2015, 07:40:59 PM »
  a Zeppelin Loop can be untied after taking twice (!) the safe working load of the rope

  The satisfaction of tying a pathetic knot that can only be untied when it is loaded by the "Working load" ( that is, a small fraction of the MBS...), can all yours ![

I guess you missed the "twice (!)".  That's grossly exceeding the working load limit.  Is Alan is on your hit list now?  What a quick turnaround.
Quote
Because, evidently, you have not anything else...
Trolling again. ::) 

 
Quote
the so-called "Zeppelin knot", indeed - which is NOT a Zeppelin-like knot, but I guess you will never be sincere/brave enough to accept it...)
I know this is supposed to be an insult, but your mistyping makes it funny.   ;)   But seriously, I'm not interested in accepting your bizarre terminology.
If you wish to add a troll to your ignore list, click "Profile" then "Buddies/Ignore List".


xarax

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Re: Load testing of various Bowline structures
« Reply #42 on: June 09, 2015, 07:47:21 PM »
I guess you missed the "twice (!)". 

  No, YOU had not managed to divide 7663 by 1400... :)  :)

   Trolling again. ::)

  Fishing clients again !
   Is your knot-selling business going OK ? Because if it does, you will be truly satisfied, and you will not need this lamentable myth of the so-called "Zeppelin loop" ...

   How people who tell others to put trolls in their "ignore list", and offer detailed instructions for that, and who try to persuade themselves for 6 (six !) years now that I am a troll, do read my posts, is a MYSTERY !  :) :) :)
« Last Edit: June 09, 2015, 07:51:25 PM by xarax »
This is not a knot.

xarax

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Re: Load testing of various Bowline structures
« Reply #43 on: June 09, 2015, 07:59:52 PM »
  Oh, I did miss that  !
 
  Is Alan is on your hit list now?  What a quick turnaround.

   Poor roo... You try to divide and conquer  :), - when you can not even divide 7663 by 1400...  :)

   I can safely conclude that the ratio of the British Empire, which divided and conquered, to you, is the same as the ratio of the genuine Zeppelin knot, the Zeppelin bend, to your fake, so-called "Zeppelin loop".  :) :)   
« Last Edit: June 09, 2015, 08:29:52 PM by xarax »
This is not a knot.

SS369

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Re: Bowline "knot wars"
« Reply #44 on: June 09, 2015, 08:20:11 PM »
Quote

Your honesty and integrity were never in doubt by me, SS.

Of course, all aspects of material nature - including dimensions - determine a knot's performance. But do they explain per se the use of pliers and spike to untie the knot in your case?

Thank you Alpineer for not doubting my honesty and integrity. That is what I will always strive for in evaluating an offering. I may be wrong, but I will be honest.  ;D

The use of the round nose pliers was needed for both those samples I tied due to small diameter ratios to finger size and materials. I can only suspect that if the loads were great enough on the larger diameter ropes the results would be accordingly similar. I have not tried them. I'll certainly take your report/results as honest at the loads you've subjected the knot to. NP.

SS