Author Topic: Simple load test on Alpineer s TIB bowline  (Read 5791 times)

alanleeknots

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Simple load test on Alpineer s TIB bowline
« on: March 29, 2014, 06:20:24 AM »
 
     Hi All,
      Here are some broken knots for Xarax favorite loop. This loop have some problem with it compactness and
      to untie.

      Photo A show how I try to maintain the compactness of the loop and as well as manageable to untie.
      For stiff rope I tie as hard as I can, then give the final tuck and tighten the rest of it. 
      For the softer rope tie it just lightly tie, then give the final tuck and tighten it just snug.

      Photos X and Y with stiff rope, I tie the loop as Photo A, and loaded with approximately 2500lbs, she only pick up 1/4"
      slack from the tail side. at this stage the Aux loop just tight, but not jam, there is nothing for you to
      grape here, because two loops are lock together.
      To untie, It is reasonable easy to loosen the collar, and now you have to draw some line out of the
      standing part, and with just some effort, you can push it loose.
             
      For softer rope as the way I tie, when it loaded, the Aux loop just tight not jam. but the rope is too soft
      to push, need more effort to move the Aux loop back and fore and in meantime push on the standing part to
      loosen it, is manageable.

      Photo Z no much you can do to the loose tail.

      謝謝  alan lee
« Last Edit: March 29, 2014, 07:08:59 AM by eric22 »

alanleeknots

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Re: Simplle load test on Alpineer s TIB bowline
« Reply #1 on: March 29, 2014, 06:43:08 AM »

     More Photos

alanleeknots

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Re: Simplle load test on Alpineer s TIB bowline
« Reply #2 on: March 29, 2014, 06:45:22 AM »

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alanleeknots

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Re: Simplle load test on Alpineer s TIB bowline
« Reply #3 on: March 29, 2014, 06:46:54 AM »

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alanleeknots

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Re: Simplle load test on Alpineer s TIB bowline
« Reply #4 on: March 29, 2014, 06:48:35 AM »

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alanleeknots

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Re: Simplle load test on Alpineer s TIB bowline
« Reply #5 on: March 29, 2014, 06:50:08 AM »

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alanleeknots

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Re: Simplle load test on Alpineer s TIB bowline
« Reply #6 on: March 29, 2014, 06:51:21 AM »

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alanleeknots

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Re: Simplle load test on Alpineer s TIB bowline
« Reply #7 on: March 29, 2014, 06:52:37 AM »

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xarax

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Re: Simple load test on Alpineer s TIB bowline
« Reply #8 on: March 29, 2014, 09:54:25 PM »
   Are you saying that it "locks" too early, and, because of this, even under / after heavy loading, the last part of the Tail End remains slack - meaning that the last tuck through the collar-around-the-Standing-End is more or less redundant ? That would be a disadvantage, indeed. In an "ideal" practical knot, we would had wished that each and every part of the whole would contribute to its security and strength to an equivalent degree - that is, we would had wished that the tensile forces would be dissipated / absorbed by the whole nub. Of course, this can not be achieved 100% in any real knot - but that does not mean we should be satisfied by not-compact knots, with parts which remain slack and "decorative" !  :)  I have also expressed the opinion that the last line of defence against slippage, the one that blocks the movement of the last part of the Tail, should be utilized more than the other parts, because, in this way, the loaded knot would be always self-dressed in a compact form :  such a Standing Part, where no segment would be allowed to remain much less tensioned or even slack, will always force the whole nub to "fold" in a compact form.
   With soft ropes, it is true that it is always more difficult to push a particular segment, and feed more rope length into a "locked" area of the nub, in order to release the tension. If there is no available "handle" to grasp a bight and be able to pull some rope length out of this area, untying the knot would be more difficult, indeed. I have never tied and loaded so heavily as you did this knot on a soft rope, so I do not have a "feeling" of the difficulty you describe, but I think I can understand it.
   What can I say ? You tie a simple knot, and you worry because the Tail can slip. You tie a just one tuck more complex one, and you worry because now the same Tail does not slip at all, and remains slack !  :) Catch 22 !  :)
   
This is not a knot.

alanleeknots

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Re: Simple load test on Alpineer s TIB bowline
« Reply #9 on: March 31, 2014, 07:41:10 AM »
     Hi All,
       Photo #1  For softer rope at this stage if you dress it little hard, there is problem to untie it already,
       if you loaded it will be lots harder to untie.

       photo #2  Like I said before when you load the loop, the collar will push the tail up ward and make the tail loose.
 
       Just base on this two points, I may have to said no to this loop.

       Photo #3  If you want a Aux loop around the cross over of the nipping loop, I prefer this ugly loop here.
       she is simple very well secure and compact, easy to dress it tight, and easy to untie.
       Seem like quiet simple, I guess there must have some one already tie it before.

       謝謝  alan lee

« Last Edit: March 31, 2014, 07:43:07 AM by eric22 »

xarax

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Re: Simple load test on Alpineer s TIB bowline
« Reply #10 on: March 31, 2014, 01:09:24 PM »
I guess there must have been some one who already had tied it before.

  It is a variation of the left-handed Fontus bowline, so yes, I had tied it, but I had not considered it any better or easier to remember how to tie, or to tie, than the right-handed Fontus bowline I had presented. ( See this variation, and the right-handed Fontus bowline, at the attached pictures ). There are some more such loops, where the tail follows a different over-under path, in relation to the two opposite segments of the nipping loop s rim, on the one hand, and two legs of the collar which penetrate this nipping loop, on the other. However, I had not loaded any of them with such high loads you did, so I can not be sure about their final form.
   After a while, one gets tired with tying and trying all those equivalent, regarding complexity and security, two collar ( Janus-like ) bowlines, and starts to demand something more. Perhaps that was the reason I had paid more attention to secure, two-collars bowlines-like ( PET) eyeknots, which have another property, regardless if it will be utilized often or not : be TIB as well. Searching for such loops, I had arrived at the Alpineer s bowline, without even recognizing it as the bowline that was already tied and presented by Alpineer and Mark Gommers some time ago ! Now, if it turns out that the second line of defence against slippage of this loop is not utilized, and the knot "locks" too early, so the last part of the tail runs the danger to remain slack, I guess we have to abandon it, and turn our attention elsewhere...
   So, what about the Eskimo-like Janus TIB bowlines presented at (1) ? Have a look at them, and tell us if they are worth their complexity.

   1.   http://igkt.net/sm/index.php?topic=4703
« Last Edit: March 31, 2014, 01:10:26 PM by xarax »
This is not a knot.

Mobius

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Re: Simple load test on Alpineer s TIB bowline
« Reply #11 on: April 11, 2015, 07:10:40 AM »
   Are you saying that it "locks" too early, and, because of this, even under / after heavy loading, the last part of the Tail End remains slack - meaning that the last tuck through the collar-around-the-Standing-End is more or less redundant ? That would be a disadvantage, indeed.

....

   What can I say ? You tie a simple knot, and you worry because the Tail can slip. You tie a just one tuck more complex one, and you worry because now the same Tail does not slip at all, and remains slack !  :) Catch 22 !  :)
 

It might not be a bad idea to have a knot that seemingly has a 'redundant' last tuck, especially if that helps the knot achieve the TIB ability. Another aspect of an extra 'decorative' tuck is that it may be deemed a 'belt and braces'  approach. Feeling safe about a knot is an indeterminate quality, however if one extra tuck makes a group of users happier about using that already safe knot then so be it. Thirdly, maybe in one rope material the final tuck does not do much, however in HMPE ropes that final tuck might make all the difference to knot security.

Just to be clear, I am not advocating tucking for tucking sake. For example, a bowline that is more than 2 nips and 3 collars is probably an overkill and inefficient knot. Some would argue for less structure than that as being overkill, I'm sure  :P

Cheers,

mobius