Author Topic: How to Tie the Pop Lock Knot (An Innovative Bend) by TIAT  (Read 15005 times)

DerekSmith

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Re: How to Tie the Pop Lock Knot (An Innovative Bend) by TIAT
« Reply #15 on: March 14, 2012, 07:08:41 PM »
If this one bend do not fit the bill, use another bend. After all, there is a plethora to chose from.

Maybe there will come a bill to which this bend fits nicely. Until then, I suggest exploring its possibilities rather than what it's not suited for.

OK Wed,  good suggestion, so over to you.  What do you think its possibilities are?

Derek

Wed

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Re: How to Tie the Pop Lock Knot (An Innovative Bend) by TIAT
« Reply #16 on: March 14, 2012, 07:11:12 PM »
I can't see myself using this knot ... either. Which is why my post was short and concise. Nothing to add on my behalf

JD~TIAT

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Re: How to Tie the Pop Lock Knot (An Innovative Bend) by TIAT
« Reply #17 on: March 15, 2012, 03:31:18 AM »
Yeah... I've got nothing more to add here either.

With marginalizing statements like:

...his attempt to bring us a practical knot has exposed the limit of his practical experience,...

I'm not sure any further contribution I made to this discussion would even be heard.

Best to you all,

JD ~ TIAT

Explore, Discover, Innovate!

Dan_Lehman

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Re: How to Tie the Pop Lock Knot (An Innovative Bend) by TIAT
« Reply #18 on: March 15, 2012, 05:48:18 PM »
If this one bend do not fit the bill, use another bend.
After all, there is a plethora to choose from.

From Wed on Wed.(nesday), good to hear from you.
Spring is springing here on the Mid-Atlantic USA, 80^F   :D

Quote
Maybe there will come a bill to which this bend fits nicely.
Until then, I suggest exploring its possibilities rather than what it's not suited for.

One aspect that had bothered me about the PopLocker
is that the knots are left intact upon release --that could
be awkward, for subsequent use of the lines.  BUT, OTOH,
for some repeated opening/closing task, having tied the
knots once, then having them remain upon opening,
it could be a benefit to have those knots intact, waiting
to be slightly loosened for re-use (rather than having an
unknotted line which one would have to repeat the
not-so-easy knotting) --just insert the tails into their
respective gripping knots!

A use?  --perhaps some tie-off of a back-pack where
there would be (?) sufficient span to include the structure.

Still, on such a task, one might expect a compound
structure of an eye knot and then a releasable hitch
to it (such as a slipped beckt hitch ).  And these sorts
of tasks are with relatively light loads, well within the
scope of manual strength.

As a further test of this, I just tied the structure in 3/8"
nylon softish-laid non-new rope and gave it a good load
via my pulley.  I had no chance of *popping* it open
manually; putting the doubled-parts (nipped tails) into
the pulley to pull them open/apart did get movement,
and would've pulled out ONE --but not both(! nb)-- tail
(i.e., the opening was effected by movement in just one
tail, or so it seemed).


Another concern about opening this structure while
under load
is getting purchase between the tails,
so to grip and pull --that, too, suggests that practical
loads will need to be relatively small.


--dl*
====
« Last Edit: March 15, 2012, 06:27:41 PM by Dan_Lehman »

Dan_Lehman

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Re: How to Tie the Pop Lock Knot (An Innovative Bend) by TIAT
« Reply #19 on: March 16, 2012, 08:04:16 PM »
--some memory awakening, and further play:

Heinz Prohaska proposed a tie-in eye knot that was similar
to this, in being an anchor bend base through which one
would reeve the tail (to enter the knot from the opposite
side of its coil to where the tail exited).  He was trying to
redress a possible problem situation in which rockclimbers,
using the same rope for a climb, would tie in with a fig.8
eyeknot
and then untie, leaving a fig.8 (stopper base)
for the next user; and might someone only reeve the tail
in, to begin tying in and forget (by distraction) to finish?
It was a (wrong) rumor that world-class climber Lynn Hill
had done this with a fig.8 (but in fact it was a bowine
and the only reeeving she'd done was of the rope through
her harness --very fortunately, her long fall was broken by
some tree, etc., and she climbs still!).  One could even see
this as Heinz's path to the ProhGrip (aka "Blake's H."),
except I think that the chronology is well the other way.

I tried such a structure --essentially, JDT's PopLocker with
differently reeved tails-- now in 3/8" laid rope, again.  It holds,
but requires some effort to release, UNtensioned.  AND, I found
that the bulge of a whipped tail can frustrate complete release.

I should note that there was ample room between the nipped
tails' span to gain purchase on them to pull apart (but there
was no give, to my manual pulling, when under tension).


--dl*
====

X1

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Re: How to Tie the Pop Lock Knot (An Innovative Bend) by TIAT
« Reply #20 on: July 05, 2012, 01:40:07 PM »
Whenever a tensioned line penetrates a tight knot s nub, any tight knot s nub, it is nipped to a lesser or to greater degree. I do not believe that this has anything to do with the complexity of the chosen knot. A simple overhand knot, a double overhand, a fig.8, a fig. 9, any knot can squeeze a tensioned line that passes through it, irrespectively of its complexity - and the tighter the knot itself gets, the greater the friction force acting on the penetrating line becomes. The nipping knot shown in this thread is a double overhand knot - but a single overhand knot would also nip the penetrating line to a degree that may be adequately tight for some purposes ( when we expect a light loading only). See the attached pictures, for such a simple solution - in fact, the simplest possible one.
   There is yet another thing I would like to mention : In a more complex nipping knot, there are many possible paths through the knot s nub that the nipped line can follow. It is not easy to figure out in which one of those possible solutions the nipping knot will nip the penetrating line more effectively.
   Even in the case of the double overhand knot shown in this thread, the penetrating line can go through the knot s nub in a number of ways. See the attached picture for another similar solution, that nips the line very effectively.
   (Note : In order to dress this " double overhand nipping knot / penetrating line"  compound knot shown here properly, it is better to hold the (white) tail at a right angle (in relation to the standing end) while the knot s nub is tightened. If it is dressed like this, when it will be loaded, the knot will settle in the form shown in picture 2.)
« Last Edit: July 05, 2012, 02:28:50 PM by X1 »

knot4u

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Re: How to Tie the Pop Lock Knot (An Innovative Bend) by TIAT
« Reply #21 on: July 06, 2012, 12:43:48 AM »
J.D., I appreciate your work, the pics, the video, etc. You put a lot effort into them. I wish more people would do this. Regarding the Pop Lock Knot, it's intended to be used in practical applications. So, I'll just discuss things here from a practical application perspective.

I share the reservations mentioned above. I won't repeat them. If I needed to untie a bend under a load, I'd rather go with a Slipped Sheet Bend or Trigger Bend. Somebody mentioned a Slipped Zimmerman. That's a new one. I'll have to try that out.

By the way, I consider all these knots suitable for non-critical applications only. If the application is critical, I would not be using any of the bends. For a critical application, I'd use a tried-and-true bend, no matter how inconvenient, no matter if the bend needed to be untied under a load, too bad. If it's a critical application (e.g., the bend will keep a person alive), I will put 100% of the focus on the reliability of the hold.
« Last Edit: July 06, 2012, 12:58:07 AM by knot4u »