Author Topic: Adjustable Loops  (Read 43165 times)

Dan_Lehman

  • Sr. Member
  • *****
  • Posts: 3930
Re: Adjustable Loops
« Reply #150 on: January 06, 2016, 05:34:11 PM »
Hi All,
       Happy New Year
Yes, thank you --and may it be so!
(but rumblings all over this world are worrying)

Quote
... this loop is well secure and easy to untie,
and the tail of this loop was nipped by the top collar with full force, make it little more secure.

Hmmmm, the severe curves in the S.Part worry me,
and it stands thus in sharp contrast to a somewhat
similar-looking "locktight" eye knot --and one that
Alpineer also formed, naming it "...tresse...".  Although
the knots I present here

http://igkt.net/sm/index.php?topic=4476.msg29741#msg29741

show a pretty sharp U-turn for the S.Part, so too does the
blood knot which nevertheless seems to fare well
in nylon monofilament --and breaks, per Barnes, not at
those turns but in the center where S.Parts pass on either
side of the nipped tails (!).

(One of those locktights has a broader collar for the sake
of stiff, low-elongation ropes (I think I was fiddling with some
well-used Bluewater II, which resists bending!).'  I like to put
the tail so that IT is what the severe turn of the S.Part bites
into (as the tail lacks tension and so can deform under such
pressure, which I presume is beneficial to the SPart).
)


--dl*
====

Mobius

  • Sr. Member
  • *****
  • Posts: 338
Re: Adjustable Loops
« Reply #151 on: January 26, 2016, 07:48:00 AM »

Perhaps if the additional loop around the SPart is made
away from the eye --so that it will press into the other--,
jamming will not occur (or as much) ?!


--dl*
====

I think the first image below is one way to revise the double collar knot I showed a few posts ago. A good suggestion from DL I believe, I will trial this revised knot in due course. I like the way I feed the tail through the nipping turn, but there may be better ways to do it. I don't think this knot will jam as I show it.

Image number two is a PET eye knot that to my mind can still be called 'adjustable'. A moot point perhaps. I have trialled this knot in a  preliminary fashion and it does hold at 200Kg in dynamic rope so far. The collar around the eye can be left loose, the knot appears to be secure regardless.

Image three is both PET and TIB. It holds at 200Kg in dynamic rope as well. Note that for TIB to be a significant attribute, I believe an easy TIB tying method also needs to be available. Easy to me means: the knot can be held in your hands and tied in total darkness in less than 30 secs (eye knot). 30 secs is probably generous, but I hope you get the idea of what i mean by 'easy'.

None of these images I claim as new.... Alan Lee (in particular)  has a lot of knots out there, some of which I recollect as at least being similar :)

Cheers,

mobius
« Last Edit: January 26, 2016, 07:56:34 AM by mobius »

Mobius

  • Sr. Member
  • *****
  • Posts: 338
Re: Adjustable Loops
« Reply #152 on: February 20, 2016, 08:38:35 AM »
(I think my camera is playing up, nothing I do achieves focus... sigh)

The first left-hand image is the one Alan first proposed. The second right-hand one is a variation that may also have been shown by Alan Lee. Regardless of where the knot version started I thought I would share with you that the image on the right is probably better to use.

I have used this style of adjustable knot a lot on my rig.  The knot on the left has jammed under 200-400 kg load in dynamic rope while the version on the right has always behaved itself to date. Possibly jamming was an aberration, however I am not in a hurry to waste good rope finding out for sure.

From a practical user's perspective, I only use the right-hand version now.

Cheers,

Ian
« Last Edit: February 20, 2016, 08:40:53 AM by mobius »

alpineer

  • Sr. Member
  • *****
  • Posts: 507
Re: Adjustable Loops
« Reply #153 on: February 20, 2016, 09:44:25 AM »
(I think my camera is playing up, nothing I do achieves focus... sigh)

Pull the batteries for a bit, then re-install to reset camera.

Mobius

  • Sr. Member
  • *****
  • Posts: 338
Re: Adjustable Loops
« Reply #154 on: February 21, 2016, 05:38:29 AM »
(I think my camera is playing up, nothing I do achieves focus... sigh)

Pull the batteries for a bit, then re-install to reset camera.

Thanks for the advice, though it did not work for me (see image in my 'offset' post). Maybe I just need an idiot-proof camera ;)

With that in mind, I asked for an early birthday present and my wife is getting me a new Nikon Coolpix 840. Good? I don't know, however it has to be better than what I have been struggling with to date, a 10 year old Sony 5.1 3X Cyber-shot.

Cheers,

Ian
« Last Edit: February 21, 2016, 08:07:00 AM by mobius »

alanleeknots

  • Sr. Member
  • *****
  • Posts: 544
Re: Adjustable Loops
« Reply #155 on: February 21, 2016, 08:39:19 AM »
Hi All,
       Mobius ,I have put together a few pictures here, you will find which one have a better collar near the standing part.
       A loop will jam or not, most of the time is govern by how the main collar set up (if there is the only collar with the loop).

       Fourth picture is TIB Adjustable loop, it can be tie in one continuous motion like the "Quick tie TIB Scott's locked bowline", 
       with half a step less effort.  This loop may find little hard to tie it with PET method.
       I only test it with medium load and it perform very well, I think it will do well with heavy load.
       Related links, Reply #31 and Reply #34  http://igkt.net/sm/index.php?topic=5444.msg37446#msg37446
                             Reply #13  http://igkt.net/sm/index.php?topic=5322.0
                             https://www.youtube.com/watch?v=cfgN2EPfxH8
       This loop also can transform to Quick tie TIB Scott's locked bowline.
        謝謝  alan lee.
« Last Edit: February 21, 2016, 09:12:06 AM by eric22 »

Mobius

  • Sr. Member
  • *****
  • Posts: 338
Re: Adjustable Loops
« Reply #156 on: February 21, 2016, 09:04:53 AM »
Memory has played tricks on me it seems. Alan came up with the version that does not appear to jam, whereas the other one might have more problems (and maybe the one I came up with, lol).

I will try xarax's version sometime soon.

Is there a simple PET (post eye tiable) adjustable knot? We were shown one somewhere I think (that does not fall apart). If not, I will work on one.

Cheers,

Ian.
« Last Edit: February 21, 2016, 09:06:55 AM by mobius »

Dan_Lehman

  • Sr. Member
  • *****
  • Posts: 3930
Re: Adjustable Loops
« Reply #157 on: February 23, 2016, 06:54:20 PM »
Is there a simple PET (post eye tiable) adjustable knot?
One can see this, conceptually, at least, in two knots:
the venerable "midshipman's loop" --which is a noose
hitch (hoped to be non-sliding, though) formed by
tying the tail to the structure's S.Part with some
variation of rolling hitch;
then one could put a Prusik hitch coil in the S.Part
and reeve the tail through this (surety could come
by tying off the tail further (stopper, e.g.) after
adjusting the size of the eye (which in a sense
is indefinitely adjustable given that the overall
knotted structure is PET and so can await the
rough sizing of the eye to do anything tying-wise).

In the books already is something called "the crabber's eye
knot"
in which a (I might be mistaken in recall here!)
marlinespike hitch --or similar-- is formed with the tail
around the S.Part and only set into secure form upon
reaching the desired eye size.  (The harsh bending of
the S.Part doesn't appeal to me.)


--dl*
====