Author Topic: A 'Better' Loop Knot ?  (Read 20400 times)

DerekSmith

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A 'Better' Loop Knot ?
« on: December 03, 2006, 09:28:04 PM »
For general purpose work, I use 8mm three core laid Polypropylene rope - the really cheap blue stuff that every hardware store now stocks in abundance.  It's tough and its cheap but it is a real pig to hold a knot.  Tie a Bowline in it at your peril, the first time the tension slackens and the knot flies open, never to be seen again.  You don't need to shake test knots in this stuff, just let go and the knot springs open in your hand, at least, if not in your hand, then as soon as you turn your back on it.  I am so wary of tying terminal loop knots in it that I had got into the habit of lashing the free ends in place with a Constrictor or Strangle knot using a bit of thin stuff or simply taping the end to the SP with Ducktape (messy but it does the job).

Around the garden, I use this cheap cord in lighter weight and use the Slippery Hitch to great effect (ABOK 82).  This uses the goosneck component principle, trapping the cord behind itself around some other object.

Having experimented recently with the Bowstring Knot, the 8mm Polyprop was one of the cords I tested it on.  Perhaps not surprisingly, as soon as the tension came off the knot it started to spring open - this was not going to be a usable end loop knot, strong or not.  Just about the only knots which I would consider as reasonably stable in this stuff are the Strangles and Constrictors (but being a laid rope they must be tied the right way round).

But the Strangle is nothing more than a double overhand, so I went back to the Bowstring Knot and used the strangle instead of a single OH.  It worked much better than the OH version, but there was a tendency for the end loop to work its way into and through the strangle.  So instead of taking the end back through the middle of the knot, I simply passed it under itself in a goosneck configuration - and it works !!

I have made this knot in the 8mm PP rope and set it with only moderate force, then put it to the shake test.  Once the Strangle has gripped the goosneck in place - nothing moves.  Over 150 vigorous shakes, wet or dry and so far it stays put.

The knot is super easy to tie using the two wraps and pass the end through method, then draw up the strangle before setting the loop size.  Finally, pass the end around the SP and back under itself - then tighten the knot to draw the goosneck tight against the strangle.

Perhaps fellow cord shakers could try tying this little end loop knot into some of their most problematic cords and let us know how it performed.

With ends reversed, this is the Poachers Knot (ABOK #409)


Then make a goosneck with the end and draw up tight (front and back views)


Does this make it the Strangle Loop ?

But I have saved the best to last.  It can be untied !!  Because one component is the goosneck, simply bend the back loop of the goosneck away from the strangle and the goosneck loop is forced open.  Once the gooseneck is gone, bend the two back wraps of the Strangle away from one another and again you can force open the body of the Strangle provided it has not been set with too much load.

How strong is it?  I don't know yet, but I will give it a work out and see how it performs.

Does this pass muster as a good knot?

Derek

Dan_Lehman

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Re: A 'Better' Loop Knot ?
« Reply #1 on: December 03, 2006, 10:38:46 PM »
Tie a Bowline in it at your peril, the first time the tension slackens and the knot flies open, never to be seen again.  You don't need to shake test knots in this stuff, just let go and the knot springs open in your hand, at least, if not in your hand, then as soon as you turn your back on it.  I am so wary of tying terminal loop knots in it that I had got into the habit of lashing the free ends in place with a Constrictor or Strangle knot using a bit of thin stuff or simply taping the end to the SP with Ducktape (messy but it does the job).
...
Having experimented recently with the Bowstring Knot, ...
Gee, sounds like you wanted to Secure the Bowline--as in http://igkt.net/sm/index.php?topic=341.0.
--or was it, rather, Reinvent the Wheel?   ;D

epigram:  A few weeks in the laboratory can often save hours in the library.

--dl*
====

DerekSmith

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Re: A 'Better' Loop Knot ?
« Reply #2 on: December 03, 2006, 11:28:53 PM »

Gee, sounds like you wanted to Secure the Bowline--as in http://igkt.net/sm/index.php?topic=341.0.
--or was it, rather, Reinvent the Wheel?   ;D

epigram:  A few weeks in the laboratory can often save hours in the library.

--dl*
====

LOL,  Thanks Dan.

But seriously, I never warmed to any of those contortions to make the BL safe(ish), other than the one I used for climbing that I called the Double BL which was totally safe.  Even in this 8mm Polyprop it doesn't budge.

The reason for taping the ends was that it was just so easy and did not create a clunking great knot which held itself.

This new? little knot is ultra easy to remember and to tie, seems to hold tight to itself in real nasty cord, can be untied, and has a lineage which hold the promise of this possibly being a strong knot.

If this knot continues to hold up well, I would have no reason to ever go back to the BL, in any of its 'Secure' contortions.

I fly stunt kites, and the lines made from Spectra and Dyneema are particularly hard to secure into termination loops.  Guess what !! this little baby has held perfectly with only one criticism - I don't think I will ever be able to untie them.

Derek

roo

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Re: A 'Better' Loop Knot ?
« Reply #3 on: December 04, 2006, 12:41:25 AM »

The knot is super easy to tie using the two wraps and pass the end through method, then draw up the strangle before setting the loop size.  Finally, pass the end around the SP and back under itself - then tighten the knot to draw the goosneck tight against the strangle.

Perhaps fellow cord shakers could try tying this little end loop knot into some of their most problematic cords and let us know how it performed.

...

Does this pass muster as a good knot?

Derek

I feel like it's April Fool's Day.  I took one look at your diagram and thought to myself, "a jam waiting to happen".  But I tried it anyway just in case I was wrong, and although the red part came undone, the other part jammed hard, as expected.  Folks, let's pull these knots hard in various rope types before claiming they don't jam.   If you're using medium to large size rope, arm and leg strength will not cut it.

Although it's possible I tied it slightly wrong, I kinda doubt it.   I will now take another 20 months off from testing the jamming tendencies of knots so that my fingers can recover.
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DerekSmith

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Re: A 'Better' Loop Knot ?
« Reply #4 on: December 04, 2006, 01:14:02 AM »
Roo,

As ever - what did you tie it in?

Derek

Dan_Lehman

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Re: A 'Better' Loop Knot ?
« Reply #5 on: December 04, 2006, 07:33:18 AM »
But seriously, I never warmed to any of those contortions to make the BL safe(ish),
other than the one I used for climbing that I called the Double BL which was totally safe.
Why didn't your fingers warm up ... ?  "Contortions" doesn't help the understanding much;
one can see this "new" knot as a greater contortion/distortion, for that matter (of the Bwl).
One ties a knot, or another knot; what it might be like need not be part of the picture.
(Incidentally, I just saw that the Janus Bwl (my name) was disclosed in 1928, and the
mechanics for the EBDB were also present in that article, though not directly so.)
My Locktight loopknots have exactly the overwraps of the Strangle knot but
with a bowlinesque back-door collar for easy untying; why do these not heat
your fingers?

Quote
This ..., seems to hold tight to itself in real nasty cord, can be untied,
and has a lineage which hold the promise of this possibly being a strong knot.
In that "lineage" comes simply holding--as in jamming, as Roo remarks.  And it
can at lesser loads loosen, too, which isn't all so bad sometimes for the Strangle
part itself, but could lead to the end's Half-hitch coming untied.  The Strangle can
be a double/triple strangle to overcome such problems.

Quote
If this knot continues to hold up well,
... against further usage & testing, or all this hot e-air?!   :D

Quote
I would have no reason to ever go back to the [Bwl], in any of its 'Secure' contortions.
Except in cases of needing to not have to preform some part of the knot in advance of sizing
and closing the eye--a strong selling point for the Bwl, afterall (in many variations of it).

Quote
I fly stunt kites, and the lines made from Spectra and Dyneema are particularly hard to secure into termination loops.
Guess what !! this little baby has held perfectly with only one criticism - I don't think I will ever be able to untie them.
Perfectly to what?  I.e., do you think it will go to rupture w/o the end slipping untied?
--have you tried some iterative shocking of it (as I think comes in kite usage, yes?)?
I'd think that a Strangle would not provide sufficient grip on the end ESP. OF HMPE(!)
to stem slippage, and the simple HH not enough hold at what force would pass that
gauntlet.
(FYI, one can tie the Blood knot in a loop; though I recall the Blood knot (bend) being
considered weak in HMPE fishline.)

--dl*
====
« Last Edit: December 05, 2006, 05:31:05 PM by Dan_Lehman »

Dan_Lehman

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Re: A 'Better' Loop Knot ?
« Reply #6 on: December 04, 2006, 07:41:07 PM »
A version of this loopknot that perhaps redresses the problem of jamming,
as well as yielding a TIB (Tied In Bight) knot--which might be a nice aspect in
some cases--, is to have the end's path (red part in Derek's photos) be to go
OVER its own AND the parallel (white) part to be tucked back under both
(between them & SPart).  I've just tried this in 8mm nylon kernmantle (climbing
accessory cord, pretty flexible & slick) and loaded it with myself and a bit of
bounce.  Actually, I used a double Strangle.  The exit of the end is reminiscent
of the Blood knot; indeed, this can be seen as a minimal Blood loopknot.

--dl*
====
« Last Edit: December 05, 2006, 05:38:09 PM by Dan_Lehman »

DerekSmith

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Re: A 'Better' Loop Knot ?
« Reply #7 on: December 06, 2006, 12:46:21 PM »
A version of this loopknot that perhaps redresses the problem of jamming,
as well as yielding a TIB (Tied In Bight) knot--which might be a nice aspect in
some cases--, is to have the end's path (red part in Derek's photos) be to go
OVER its own AND the parallel (white) part to be tucked back under both
(between them & SPart).  I've just tried this in 8mm nylon kernmantle (climbing
accessory cord, pretty flexible & slick) and loaded it with myself and a bit of
bounce.  Actually, I used a double Strangle.  The exit of the end is reminiscent
of the Blood knot; indeed, this can be seen as a minimal Blood loopknot.

--dl*
====

I haven't understood your description of the TIB variant (would you give it a second, more detailed explanation please).

But I did tie the knot in your proposed double strangle variant and from a purely intuitive perspective I like it.  The extra turn increases the length of the three loaded lines as they pass in through the body of the knot before they start load shedding turns and all the nip points seem relatively gentle.

I think this one (despite the fact that it will undoubtedly lock in a number of cords) is well worth closer inspection and testing for strength, especially because of its close relation to the Bowstring knot and your observed comparison with the Blood Knot, another knot recognised for its strength



This then presumably would be the "Double-Strangle  Loop"?

Derek

roo

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Re: A 'Better' Loop Knot ?
« Reply #8 on: December 06, 2006, 06:07:13 PM »
... Tie a Bowline in it at your peril, the first time the tension slackens and the knot flies open, never to be seen again.?  You don't need to shake test knots in this stuff, just let go and the knot springs open in your hand, at least, if not in your hand, then as soon as you turn your back on it.?  I am so wary of tying terminal loop knots in it that I had got into the habit of lashing the free ends in place with a Constrictor or Strangle knot using a bit of thin stuff or simply taping the end to the SP with Ducktape (messy but it does the job).

...

Have you tried this?:
http://notableknotindex.webs.com/zeppelinloop.html

P.S.  To answer your other question, I was using 100% nylon kernmantle, about 1/4 inch.  I'm pretty sure I could get the same effect with other rope and materials, though.

« Last Edit: October 28, 2009, 05:11:59 PM by roo »
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DerekSmith

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Re: A 'Better' Loop Knot ?
« Reply #9 on: December 06, 2006, 09:03:33 PM »

I feel like it's April Fool's Day.  I took one look at your diagram and thought to myself, "a jam waiting to happen".  But I tried it anyway just in case I was wrong, and although the red part came undone, the other part jammed hard, as expected.  Folks, let's pull these knots hard in various rope types before claiming they don't jam.   If you're using medium to large size rope, arm and leg strength will not cut it.

Although it's possible I tied it slightly wrong, I kinda doubt it.   I will now take another 20 months off from testing the jamming tendencies of knots so that my fingers can recover.

Hi Roo,

I had not intended to imply that this was an unjamable knot.  I think anything that can hold itself fast in 8mm laid Poly Prop. is likely to have a vicious grip that will make it prone to lock in more 'grippy' media.  A knot that holds well in one material - such as the BWL in my Kernmantle climbing rope - will fall apart in slippery, springy media such as the Poly Prop rope I was having a problem with.

So, no, it was no April Fool on you nor intended to make a fool out of myself - the knot will jam in certain media and I said as much in the comment about tying it in stunt kite lines (which were hard jammed).

The reason for making the untie comment related to the structure of the knot which because of the 'hinge like' components of the gooseneck and the two wraps of the strangle, it is possible (in some media) to open those 'hinges' and thereby have access to a mechanism of releasing this potentially very tight knot.

Having said that, I feel your warning is appropriate, that folks should not tie this knot in cordage that is going to get a heavy load, that normally grips well and which they fully intend to untie - But, if you want to tie an end loop in problematic cord (like 8mm Polyprop) then by all means give this knot a try and let us know what you thought of it.

Derek

Dan_Lehman

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Re: A 'Better' Loop Knot ?
« Reply #10 on: December 06, 2006, 09:43:40 PM »
I haven't understood your description of the TIB variant (would you give it a second, more detailed explanation please).
Sure.  It's pretty easily seen via the upper of your two just-posted images, so I'll reference
that.  Have the (red) end cross Over/behind itself (opp. to shown, i.e.), and then be tucked
down between the two SParts of the Strangle component.  (So, to TIBight, one would make
the Strangle up to that point, then lay the free end into that position, and continue with the
bight to make a final turn & tuck out to both form/close the Strangle and produce the eye.)

Now, it takes a bit of care in dressing this structure:  one wants the twin eye legs to
oppose the loopknot's SPart vis-a-vis the tucked end, and it helps that the eye legs have
this orientation (planar) all the way out (or even curving a little), as the strong draw of the
SPart is going to un-twist/-curve them (i.e. pull the end's leg) a quarter-half turn or so,
depending on the dressing/set & loading.  It's a less compact & slack-secure knot if
the eye legs AND SPart are more nearly co-planar and the end thus more tucked between
SPart & nearer leg, if you get the idea.  AS YOU HAVE IT in the image, by my terms, your
end-leg (reddened) is WELL set against the SPart's draw; I think that this positioning might
be harder to assume/set with the finish/tuck I describe, hence I alert one to strive for it.

I've now done several body-weight bounces on 8mm kernmantle & some other rope(s)
and it unties pretty easily; it LOOSENS at the SPart-end easily, but torsion makes it a
little difficult to move that looseness to the tightened eye-end of the knot to slacken the
SPart.  And this knot looks relatively compact compared with the Fig.8 loopknot, which
is the standard climber's tie-in knot (and which is not easy to untie after a hard fall).

--dl*
====

DerekSmith

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Re: A 'Better' Loop Knot ?
« Reply #11 on: December 07, 2006, 12:48:35 AM »
Thanks Dan for trying, 

Unfortunately I am showing my ignorance here, because I do not have sufficient understanding to be able to follow your instructions or indeed understand the terminology when I can't picture the knot or the moves.

Where to from here?

Derek

Fairlead

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Re: A 'Better' Loop Knot ?
« Reply #12 on: December 07, 2006, 09:00:46 AM »
I think I will stick to the Swami Loop

Gordon

Znex

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Re: A 'Better' Loop Knot ?
« Reply #13 on: December 07, 2006, 03:33:44 PM »
In trying to tie what Derek initially had done, It kept coming out as shown below when some of the windings were moved over. I found that this way of tying made a reversed, well holding, adjustable knot and was also somewhat easy to untie. Is this a known knot? I can't find any reference to it in either ABOK or on the WWW.



Dan_Lehman

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Re: A 'Better' Loop Knot ?
« Reply #14 on: December 07, 2006, 06:27:46 PM »
Derek:  Where do you get lost?  It can't be that hard to follow words!
Your finish takes the end under itself in a Half-hitch; my revision takes it over
itself ("over"~="outside, away from core") then back under, BUT in this case
I say to include the parallel strand of the knot (the twin of the two eye legs)
in what is cross over/outside, and to then tuck under both, or "between"
those twin parts and the SPart.

NB:  Tried this knot in a supple smooth slick multi-fil PES or PP (or mixture?)
and the knot got too tight for favor!  So my earlier assessments of ease of
untying likely fall to Roo's chary eye re jamming at greater loads (don't have
my 5-to-1 pulley set up at the moment).  --retreat!  (to a different and double
tucking, hopefully)

Gordon, the Swami Loop is better tied--for the sake of UNtying, at least--by
bringing the end back into the initial Overhand from the opposite side.  Ref.
http://www.rescuedynamics.ca/articles/knots/Knots.htm  image
0) consider the top diagram, arrow showing end's entry through Oh. as
 from 3o'clock to 9o'clock, crossing Over-Under;
1) replace this with end entering at 12o'clock to 6o'clock (just for the tying)
 and crossing Under-Over-Over.
.:.  the Oh thus assumes a form w/collar for easier loosening--ABOK#1185 vs 1183.
There might also be less force transmitted through it to the tie-off (dbl) Strangle H.

NB RE THIS SITE'S IMAGE FOR THE FISHERMAN'S KNOT:  the orientation of
the Overhand components in the upper image (before back-ups) shows them with
ends-wrapping-SParts asymmetric geometry; this is a naturally acheived form
from heavy loading, and is generally what I've found in Commercial Fishing Knotting;
the orientation of the tie-off/back-up Oh.s is ends-&-SParts-twist symmetric
orientation, which is harder to maintain (given that the SPart only is loaded).
Frankly, it would make more sense in the climbing application to REVERSE these,
wanting the better jamming asymmetric form for the tie-off, and hoping that the
presence of these tie-off Oh.s enable the symmetric Oh. main components to
hold that orientation, which might be both stronger a bit and easier to loosen!?
Then, again, stiffish kernmantle climbing rope might not accede to taking the
jamming form so agreeably.

Znex:  You can't figure to dress your multi-Overhand into the crossing-w-wraps form
of the Strangle/Grapvevine?  --btw, this seems to me to be a real question/issue with
anglers knots (the Uniknot, i.p.) as to what's expected:  they typically SHOW the
1-end-wraps-SPart form, but in instructions for setting this knot, imply or even
indicate that the transformation to the other form is expected--the image of the
tied knot though is an ambiguous scribble (nicely, e.g., Des Pawson's book had
magnified photos of such knots).  In any case, see the URLink above for how to
tie Derek's form, which is presented there for the tie-off to the Swami, and also
for the Grapevine Bend; adding extra turns should be easily understood.
In any case, I recently saw someone replace the Grapevine bend with knots in
your Anchor-Hitch orientation, presumably to yield a more easily untied bend.
It should work well enough.  Note that this orientation is asymmetrick, and so
could be done the other way 'round, SPart running through structure to coil
back before exiting as an eye leg.

NB:  If you bring your end (blue) out BETWEEN the SPart's initial turnn and
the tuck of it out through the coil(s)--i.e., last crossing of blue part/end w/black
is blue going OVER & done, you have made a good friction-gripping knot onto
the end, and have an adjustable, tensionable eye (knot form is Blake's Hitch-like).
As with friction hitches in general (also other knots, more or less), YMMV depending
upon cordage.

--dl*
====