Author Topic: Non slipping bend in Dyneema  (Read 67127 times)

Dan_Lehman

  • Sr. Member
  • *****
  • Posts: 3748
Re: Non slipping bend in Dyneema
« Reply #90 on: January 29, 2014, 01:40:59 AM »
One factor which should be considered, and which may be critical, indeed, is the force with which we pull the Tail ends during the set-up and the dressing of a knot - because any practical knot will be disentangled, if it will be tensioned when it is still just a very loose arrangement of lines in space, ...

I don't think in this case there is much lattitude for
transformation, though I remarked about it above.
But angling knots designed for the then-new, slippery
nylon monofilament are often given with prescribed
setting that not only loads various ends but does so
frequently at relatively high loads!

HMPE takes such high loads as to preclude this.

--dl*
====
« Last Edit: February 05, 2014, 06:18:06 AM by Dan_Lehman »

allene

  • Full Member
  • ***
  • Posts: 89
Re: Non slipping bend in Dyneema
« Reply #91 on: January 29, 2014, 01:48:34 AM »
In terms of what slips.  On the latest pulls I have done the knot doesn't so much slip as explode.  I have taken to taping them to the test line so that I don't have to search all over for the test sample.  On the ones that did slip, that didn't explode, they just pulled apart as I cranked on the winch.  They did not capsize.  But these were the stronger knots, like my first knot against the variation, or against the last knot.  I can't really say for sure which ones explodes and which slipped but the last one I remember testing was my knot against a triple fisherman's and the fisherman's exploded. By that I mean that it seemed to break but then looking at the remains, it has slipped.  By the way, I don't think there is an uglier knot than the last knot I did.  And the first knot with variation stips at a higher load than the last knot broke at.  So not slipping is not the total end all.

Allen

allene

  • Full Member
  • ***
  • Posts: 89
Re: Non slipping bend in Dyneema
« Reply #92 on: January 29, 2014, 01:51:48 AM »
   Allen, those are fine pictures, for KnotGod s sake ! Beautiful, clear pictures, that show the tying of this knot in a step-by-step, unambiguous way ! I would be happy if I was able to tie such knots, and test them, and take such pictures, at the very start of my knot tying pass-time ! 

    P.S. Two more old pictures of the Oyster bend. I do not have anything else in my files - if you wish, I can take new, decent pictures, but I have to wait the sun - which now is on your neck of the woods !

There are only two steps in your step by step pictures.  Step one: tie the knot.  Step two: tighten it up.  Did you see the nine steps I posted for tying my first knot?  That is what I call step by step.  Does that make it more clear what I am trying to say?

Allen

allene

  • Full Member
  • ***
  • Posts: 89
Re: Non slipping bend in Dyneema
« Reply #93 on: January 29, 2014, 02:01:18 AM »
Again, I will test your knot if you show me how to tie it.  Here is one thing that came up in my search for the Oyster Knot.  It is not your knot but it is a good example of what instructions on tying a knot look like http://www.animatedknots.com/ashleystopper/index.php?LogoImage=LogoGrog..

allene

  • Full Member
  • ***
  • Posts: 89
Re: Non slipping bend in Dyneema
« Reply #94 on: January 29, 2014, 02:27:56 AM »
^^ I understand what you are saying.  Therefore, I am not testing that knot.

Cheers,

Allen

allene

  • Full Member
  • ***
  • Posts: 89
Re: Non slipping bend in Dyneema
« Reply #95 on: January 29, 2014, 02:48:32 AM »
^^ I just want you to understand that the reason I am not testing the knot is that I could not figure out how to tie it. I cannot test it if I cannot tie it.  I am not being stubborn.

Allen

xarax

  • Sr. Member
  • *****
  • Posts: 2781
Re: Non slipping bend in Dyneema
« Reply #96 on: January 29, 2014, 03:08:39 AM »
   OK. Here is the Ashley s method.  ( I can not show the picture of p.125 of Miles for the B5, because his book is only 20 years old ! ) :)
   One can try it with any number of turns he wishes - as long as they are three ! ( The simpler ABoK#776 / B4 = 2-fold / 2 strand Matthew Walker knot is a very unstable knot...)
« Last Edit: January 29, 2014, 03:17:13 AM by xarax »
This is not a knot.

allene

  • Full Member
  • ***
  • Posts: 89
Re: Non slipping bend in Dyneema
« Reply #97 on: January 29, 2014, 04:30:53 AM »
Sorry, not good enough.  I tried.  Three turns and tied what I thought I was seeing and what I got looks nothing like the Oyster Bend.  It doesn't even look like a bend.

Allen

xarax

  • Sr. Member
  • *****
  • Posts: 2781
Re: Non slipping bend in Dyneema
« Reply #98 on: January 29, 2014, 05:05:22 AM »
   More pictures of the 88 bend, to see how the strands are interweaved within the nub.
   The good thing with the pictures is that they offer the impression of a 3D "object", which the tying diagrams do not.
« Last Edit: January 30, 2014, 04:04:58 AM by xarax »
This is not a knot.

allene

  • Full Member
  • ***
  • Posts: 89
Re: Non slipping bend in Dyneema
« Reply #99 on: January 29, 2014, 05:18:07 AM »
Let's stick to your best shot and not switch knots.  I don't think the picture is correct.  Please clarify.


xarax

  • Sr. Member
  • *****
  • Posts: 2781
Re: Non slipping bend in Dyneema
« Reply #100 on: January 29, 2014, 05:24:59 AM »
   Bingo ! You have spotted the mistake at a glance ! That proves my conjecture that symmetric bends are always easier to inspect ! I wish I would be able to see DL s bicycling in 8-shaped rims of wheels right now ! :)
  Follow the other pictures - never tie asymmetric bends, at least when you are not asleep !   :)

  ( Of course, it is not "my best shot:). There is no silver bullet in the KnotLand ! Personally, I have tried to tie possible replacements of the triple Fisherman s knot only once, in the thread you have read, with the retraced convoluted stoppers. I remember that the one I thought it was more balanced was the retraced fig.9 bend. All the bends I show to you in this thread have been tied and tried for and on climbing ropes - I just pick the ones which I believe they can offer us some valuable information about the behaviour of this peculiar material...)
« Last Edit: January 29, 2014, 05:39:08 AM by xarax »
This is not a knot.

allene

  • Full Member
  • ***
  • Posts: 89
Re: Non slipping bend in Dyneema
« Reply #101 on: January 29, 2014, 05:27:35 AM »
"Other" is such an all inclusive word.  The other picture I am looking at seems to have the same characteristic.  I think this this is a good demonstration of the need for some instructions.  But barring that, which is correct, under both or between?

xarax

  • Sr. Member
  • *****
  • Posts: 2781
Re: Non slipping bend in Dyneema
« Reply #102 on: January 29, 2014, 05:37:24 AM »
The other picture I am looking at seems to have the same characteristic.

  No, no other picture has the same characteristic. The Standing Parts do not go in between the bights of the "8' shaped links, in any of them. That is why the Tail ends end up at this angle, in relation to the Standing ends.

   Here is the correct picture for this bend. When it is 6.30 in the morning, without sleep, you can show asymmetric bends !
« Last Edit: January 29, 2014, 05:43:21 AM by xarax »
This is not a knot.

allene

  • Full Member
  • ***
  • Posts: 89
Re: Non slipping bend in Dyneema
« Reply #103 on: January 29, 2014, 06:20:08 AM »
I tied this knot http://l-36.com/oyster_bend.php and pulled it against the variation of my knot shown here http://l-36.com/no_slip_knot.php.  In Lash It, neither knot slipped.  The Oyster Bend broke first.  I am unable to gain more data than that.  I do not find it simpler to tie but that may be because I am familiar with tying carrick bends.  Finally we got one that did not slip and it was fairly strong.

As I said to Estar, I cannot tell if knots do not slip.  I can only tell if they slip.  There are knots such as the ones I submitted, that do not slip in Lash It but do slip in larger line.


Allen

xarax

  • Sr. Member
  • *****
  • Posts: 2781
Re: Non slipping bend in Dyneema
« Reply #104 on: January 29, 2014, 01:04:04 PM »
  You "First" bend is nothing but a symmetrically ( = good ! ) re-tucked through the central opening ( = not so good, I am afraid...) Carrick bend. It is a very unstable, regarding its dressing, knot, which, although symmetric, is difficult to remain in a symmetric form while it is tensioned all the way - but I am talking only about the knot been tied on ordinary materials. Anyway, not an interesting knot - it should have been tied many times, but, evidently, it did nt survive the test of time.
  Your "variation" / "Last" bend ( I hope that it will not remain so... :)), is an asymmetric variation of the side-by-side Pretzel bends I had shown to you many times. If this holds, a more symmetric variation will probably hold as well - and it will probably be stronger, too, because the distribution of forces within the knot s nub would be more even, and the loads will be spread over larger areas.
 
  Mr. Find has unearthed that quotation, which proves that an experienced knot tyer never speaks about re-tucking a Carrick mat through the central opening this way :


 I find it beneficial to re-tuck the tails through the interlocked SPart turns to obtain the interlocked-overhands knot Ashley's bend #1408 !  (Or to re-tuck them and get Harry Asher's "shakehands bend" (cf. #1031).
With variations on this theme, one can discover the superior Ashely's bend #1452 & #1453 as well.
And if one is fortunate enough to seek such benefits with the inferior version of the carrick bend, one will be rewarded with the superior Ashley's #1452!

  If you wish to see all the possible single re-tuckings of a particular Carrick mat, pay a visit at  :
  http://igkt.net/sm/index.php?topic=3086.msg18601#msg18601
  Re-tucking through the central opening ( C stands for central ) so we get a stable, re. its dressed forms, knot, is shown at the attached pictures and at :
  http://igkt.net/sm/index.php?topic=3086.msg18725#msg18725

« Last Edit: January 30, 2014, 04:07:33 AM by xarax »
This is not a knot.