Author Topic: Technical paper: Riggers bend (#1425A)  (Read 564 times)

agent_smith

  • Sr. Member
  • *****
  • Posts: 1204
Technical paper: Riggers bend (#1425A)
« on: May 08, 2020, 01:33:20 AM »
I have written a new technical paper on the Riggers bend (#1425A).
It can be found here: http://www.paci.com.au/knots.php (at #6 in the table).
Version: 1.1a

Feedback from Dan Lehman:
Link from a post by Dan Lehman: https://igkt.net/sm/index.php?topic=6777.msg44589#msg44589

Quote
In the latter --SmitHunter's history--, you write
that "studieS" (plural) indicate a 4.0kN jamming threshold,
but don't specify which size rope --that CE standard covers
"A" & "B" ropes, and a broad size range for "A" --8.5-16mm(!!).
11mm.
When converting word.docx to Adobe pdf file format - part of the text got displaced.
Am fixing this...

Quote
You claim that the knot "fails to perform" in this case,
but if I'm reading data/specs right, the particular
figure you cite (for how many ropes tested?) is well
ABOVE the safe working load given for such ropes,
which IMO gives some reason to regard the knot
as at least half-decent!
Dan: #1425A Riggers bend jams.
Sad, but true.
I tested 11mm EN1891 ropes 6 times - the results were always within the same range.
Once load reached 4.0kN - beyond that point, the knot reaches its initial jamming state (meaning that hand/finger strength alone is not sufficient to untie the knot - no use of tools).
Maximal jamming occurs at a higher threshold - meaning that not even tools will untie the jammed knot.
I did not investigate maximal jamming threshold - for the simple reason that I needed my ropes again and I didn't have sufficient stock of rope to keep destroying.

Quote
As for "towing", YMMV per cordage used on that, methinks.
I'll only surmise that ropes that don't so much compress
& flatten as kernmantle ones can
will stay more-easily-loosen-able to higher loads.
And, as you note, the better version of the knot
("crossed tails") better resists jamming, perhaps
*entirely* --meaning, to rupture-- in some rope.
One can assume anything with 'towing a car'.
One thing is clear though - towing another car will stress the rope and any joins.
Shock loading is inevitable in towing - particularly if the cars get out of speed sync.

Yes - crossing the tails will boost the initial jamming threshold in Riggers bend.
But, the idea of crossing the tails hadn't materialized in circa 1978.

Be that as it may - I would not want to join any vehicular tow ropes with Riggers bend.
You are setting yourself up for jamming the knot. I would use a Zeppelin bend instead...

Quote
Let me contribute, here.
Firstly, where something is "derived" from is jumping
to a conclusion betraying a presumed history which
we cannot know --and for particular knots fiddlers,
the *derivation* such as it is might've gone in the
opposite direction.  I'm only aware of Harry Asher's
published play with such knots,

Not "jumping" to any conclusions.
Harry Asher is the earliest known source that I am aware of.
Do you have proof of an earlier source?
Please share if you do.

Ashley did not publish Riggers bend or Zeppelin bend or Butterfly bend.
I don't think he conceptualised these types of bends or the idea of crossing the tails.
It does appear that Asher was likely the first to explore this concept.
But, he only investigated the idea with the Zeppelin bend (not Riggers bend).

Quote
Which I DID, in coming around to it (so, fitting to your
flow of derivation) as my #19791203s09:15 knot.
You are making a claim here...
"#19791203s09:15" is Egyptian hieroglyphics to me.
I would need evidence to back this before citing your claim in my paper.

Quote
And re Why...,
it's because the tails when crossed will push out
the surrounding collars sufficiently to impede their
getting to a position to severely bind against
the SParts.
Interesting proposition - which requires further investigation to verify.

Quote
(And the cross also puts in some
bit of deflection in the SParts, which might boost
strength --my lone test of this had comparative
values for the two versions of 62% & 65%,
possibly just *noise* difference, but at least
consistent w/the crossed-tails version being stronger
Am not interested in 'strength' per se.
But the mechanisms of jamming do interest me.
Your 3% difference is not significant - could others reproduce your results?
How many tests did you conduct and was your sample size statistically large enough?

Quote
Btw, though **crossing** tails in the zeppelin knot
yields asymmetric knot, there IS a variation that
you currently don't recognize in which each side's
tucked tail is pushed/dressed-into-being towards
the opposite SPart, and held there by the draw
of the SParts;
This symmetry breaking effect caused by crossing the tails in the Zeppelin bend has not been fully investigated - eg whether it impacts upon the knots resistance to jamming.
However, you are straying to the Zeppelin bend - not Riggers bend.
I only showed Harry Ashers so called 'Eastern' Zeppelin bend tail crossing maneuver... I realized there were other geometries but did not explore further.
Maybe Xarax looked into it in detail?

Quote
And another
good interlocked-overhands knot to compare
with the z. is Ashley's #1408, which also gives
wide collars & easy untying (and more dramatic
difference in position of tails!).
I possibly could examine this further in a future update to that paper...
For now, it isn't a pressing matter.

I have commenced work on a #1053 Butterfly Knot Bio paper - which is diverting my current thoughts...

« Last Edit: May 08, 2020, 01:39:45 AM by agent_smith »

Dan_Lehman

  • Sr. Member
  • *****
  • Posts: 3947
Re: Technical paper: Riggers bend (#1425A)
« Reply #1 on: May 09, 2020, 12:05:03 AM »
[edit for paper :: 'Dr. Hunters claim' needs an apostrophe. ]


Feedback from Dan Lehman:
Link from a post by Dan Lehman: https://igkt.net/sm/index.php?topic=6777.msg44589#msg44589

Quote
In the latter --SmitHunter's history--, you write
that "studieS" (plural) indicate a 4.0kN jamming threshold,
but don't specify which size rope --that CE standard covers
"A" & "B" ropes, and a broad size range for "A" --8.5-16mm(!!).
11mm.
When converting word.docx to Adobe pdf file format - part of the text got displaced.
Am fixing this...
Here is where "singular" comes to play (as the
complement to "plural") : you say "studieS" : aside
from yours, what others?  (You might know of some,
but then sort them out from pointing to YOUR found
threshold force.)


Quote
Quote
You claim that the knot "fails to perform" in this case,
but if I'm reading data/specs right, the particular
figure you cite (for how many ropes tested?) is well
ABOVE the safe working load given for such ropes,
which IMO gives some reason to regard the knot
as at least half-decent!
Dan: #1425A Riggers bend jams.
Sad, but true.
I tested 11mm EN1891 ropes 6 times - the results were always within the same range.
Once load reached 4.0kN - beyond that point, the knot reaches its initial jamming state (meaning that hand/finger strength alone is not sufficient to untie the knot - no use of tools).
And my point was that this force has exceeded
the manufacturer's stated safe working load.
(Beyond which I might suggest that you hold
your SINGLE rope as too predictive of even that
brand of rope --thinking of a more stiff well-used
kin, not to mention others which might have some
difference of *hand* & firmness.
As the loaded-knot image suggests a factor is in
how the particular kernmantle flattens to spread
its contact --aiding the grip/jamming--,
and a firmer/rounder-under-load rope should
be less aggressively jammed.)


Quote
Yes - crossing the tails will boost the initial jamming threshold in Riggers bend.
But, the idea of crossing the tails hadn't materialized in circa 1978.
Not publicly, maybe --though what good did Phil's
book being published do, for most of us?--, but I
had it in 1979 (which is circa '78).

Quote
Quote
Let me contribute, here.
Firstly, where something is "derived" from is jumping
to a conclusion betraying a presumed history...

Not "jumping" to any conclusions.
Harry Asher is the earliest known source that I am aware of.
Do you have proof of an earlier source?
Please share if you do.
Oh, I've shared my own; and it WAS so derived,
indeed.

Quote
Ashley did not publish Riggers bend or Zeppelin bend or Butterfly bend.
I don't think he conceptualised these types of bends or the idea of crossing the tails.
?!  Ashley's #1408, 1425, & 1452 are just such joints
--interlocked overhands (and symmetric).  Also #1453,
but that's a challenge to dress & set symmetrically!
And these can be derived from some obvious adjustments
to the carrick bend (also shakehands).
But he was careless re some of the dressing options
vis-a-vis tails.  (Everyone's fawning over the Butterfly
bugs me : #1408 is much nicer, neat & symmetric
(and 1452 & 1425).

Quote
It does appear that Asher was likely the first to explore this concept.
But, he only investigated the idea with the Zeppelin bend (not Riggers bend).
As I have cited above, in published material, Asher
presented the *improved* version of #1425a in his
1986 2-vol work (as Fig.19).

Quote
Quote
Which I DID, in coming around to it (so, fitting to your
flow of derivation) as my #19791203s09:15 knot.
You are making a claim here...
"#19791203s09:15" is Egyptian hieroglyphics to me.
I would need evidence to back this before citing your claim in my paper.
Those hieroglyphics are my chosen ID method
most of the (all too numerous) time : date stamp,
and English day names of (lowercase) m-t-w-h-f-a-s,
starting with lundi, er, Monday (my weekEND days
come at the one *end* of the week (think "engagement
calendar"!)).


Quote
Quote
And re Why...,
it's because the tails when crossed will push out
the surrounding collars sufficiently to impede their
getting to a position to severely bind against
the SParts.
Interesting proposition --which requires further investigation to verify.
Investigation, yes, just l00k   ::)

It's sorta like #1452, which if the tails are
dressed one way (Ashley btw is non-committal)
and leaving generous collars, those collars
can wrap up around the body to to pinch the
SParts against the body (what I see the flattening
of your rope doing, but can happen otherwise);
dressed the opp. way, the collars don't.

Quote
Quote
(And the cross also puts in some
bit of deflection in the SParts, which might boost
strength --my lone test of this had comparative
values for the two versions of 62% & 65%,
possibly just *noise* difference, but at least
consistent w/the crossed-tails version being stronger
Am not interested in 'strength' per se.
Ah, no, but perhaps there is some thought
to "being kinder to the rope" in terms of
accrued wear?  (In taking falls, one would
have to compare knot *wear* vs, that of
general over-the-arresting-'biner wear
--esp. as the latter might be the greater,
no point to having my "kind" knots (for those
who might chop long climbing ropes' ends
to continue with the less-worn shorter length
--differences in strength having been shown
in this regard in a few tests of used ropes.)

Quote
Your 3% difference is not significant - could others reproduce your results?
How many tests did you conduct and was your sample size statistically large enough?
Goodness, no.  I thought I made it clear that it
was simply "consistent" albeit far from establishing
the point (and even re that, the mere difference as
you note is just not much).  PERHAPS one could, in
some rope, work it to be more so; but knots that
come with lists of To-Dos for use are not winning
adherents, generally.

Quote
Quote
Btw, though **crossing** tails in the zeppelin knot
yields asymmetric knot, there IS a variation that
you currently don't recognize
in which each side's
tucked tail is pushed/dressed-into-being towards
the opposite SPart, and held there by the draw
of the SParts;
This symmetry breaking effect caused by crossing the tails in the Zeppelin bend has not been fully investigated - eg whether it [affects (climbers should know what "impacts"
are : keep the word working for that!)] upon the knot's resistance to jamming.
However, you are straying to the Zeppelin bend - not Riggers bend.
I only showed Harry Asher's so-called 'Eastern' Zeppelin bend tail crossing maneuver... I realized there were other geometries but did not explore further.
Maybe Xarax looked into it in detail?
And I understand that sacrificing rope
isn't wanted; but you might take a gander
at the version I note, eyeballing the geometry
vs. the common one --a diff. maybe as much
and no more than those 1425a versions.

Quote
I have commenced work on a #1053 Butterfly Knot Bio paper - which is diverting my current thoughts...
I'd luv to find some bona fide "linemen" info
on this knot!  Have looked a bit, w/no luck.
OH, some LUCK (no photos) :: here a fellow posting
on a fishers' forum writes:
Quote
I like to use

a zeppelin bend to connect rope together.

Bowline at the buoy.

Double sheet bend at the pot.

Haven't lost one in 2 seasons.
clipped from 2nd pg? of
https://forums.outdoorsdirectory.com/forum/alaska-fishing-forums/alaska-saltwater-fishing/1323-shrimp-pot-rigging/page2


--dl*
====
« Last Edit: May 09, 2020, 01:46:35 AM by Dan_Lehman »

agent_smith

  • Sr. Member
  • *****
  • Posts: 1204
Re: Technical paper: Riggers bend (#1425A)
« Reply #2 on: May 10, 2020, 03:09:17 AM »
Thanks for your considered feedback Dan.

As you can probably imagine, writing technical papers on knots is no easy task.
One thing i have come to understand is that knots and knotting is rather like the proverbial iceberg, in that there is a lot going on under the surface.

In a fit of inspiration, I produced the Riggers bend paper in a one day time frame (which is a record for me).

I am now in the process of making improvements...
I am currently working on adding 2 pages about symmetry.

Also working on adding some further information about jamming in 8mm and 9mm diameter human rate ropes.

As per some of your comments:
Quote
my point was that this force has exceeded
the manufacturer's stated safe working load.
(Beyond which I might suggest that you hold
your SINGLE rope as too predictive of even that
brand of rope --thinking of a more stiff well-used
kin, not to mention others which might have some
difference of *hand* & firmness.
With specific regard to "your" and "single" - this isn't an accurate diagnosis of my observations.
I am confident in declaring that #1425A Riggers bend is not jam resistant.
I would challenge you to make the opposite declaration!
The question is.. what is the jamming threshold?
I am only going to concern myself with human rated rope.
I did run tests on 8mm, 9mm and 11mm diameter human rated ropes.
In all cases, the end result was jamming - but I did not proceed all the way to maximal jamming state (where not even tools will loosen and untie the jammed knot).
I will probe this soon - as I may have some more rope material to work with.
You know - you could easily run your own jam tests too! And why don't you do this and report your result?
Why rely only on others test results? Is there some reason in principal why you cant also run a series of jamming tests?
And if you do, and you also experience jamming - you could provide data points on the thresholds where initial and then maximal jamming occurred.

Quote
though what good did Phil's
book being published do, for most of us?--, but I
had it in 1979 (which is circa '78).
Regardless, the fact is that Phil did publish!
So it is a real historical record.
You state that "you had it in 1979"... can you provide proof in the form of historical notes and/or imagery?
I am not doubting your claim...rather, if you are suggesting that I include your claim in my paper - I need something more substantial from you.

Quote
Ashley's #1408, 1425, & 1452 are just such joints
--interlocked overhands (and symmetric).  Also #1453,
but that's a challenge to dress & set symmetrically!
?
Are you suggesting that Clifford Ashley did in fact publish the Riggers bend and Zeppelin bend in his book (ABoK) in 1944?
I simply stated that Ashley did not...but yes, he did publish other end-to-end joining knots...he was close, but no cigar.
I could add more content about Ashley and include some of his published end-to-end joining knots...but, I don't want to stray too far off topic.
Maybe you could write a paper about those bends?

Quote
As I have cited above, in published material, Asher
presented the *improved* version of #1425a in his
1986 2-vol work (as Fig.19).
I dont have a copy of this book or those illustrations.
Can you assist in providing them to me (ie the illustrations)?

Quote
Investigation, yes, just l00k   ::)

It's sorta like #1452, which if the tails are
dressed one way (Ashley btw is non-committal)
and leaving generous collars, those collars
can wrap up around the body to to pinch the
SParts against the body (what I see the flattening
of your rope doing, but can happen otherwise);
dressed the opp. way, the collars don't.
The subject of how and why some knots jam while others don't could fill an entire technical paper in its own right!
Have you written such a technical paper?
I'd like to see a copy please, because it would provide me with valuable source information - and save me from duplication and re-inventing the wheel.

Quote
Those hieroglyphics are my chosen ID method
most of the (all too numerous) time : date stamp,
and English day names of (lowercase) m-t-w-h-f-a-s,
starting with lundi, er, Monday (my weekEND days
come at the one *end* of the week (think "engagement
calendar"!)).
Nice... there was no way for me to accurately interpret your hieroglyphics - since it would only have meaning to the creator (yourself).

EDIT NOTE: I am working on an update/amendment but need some of your source material Dan.
« Last Edit: May 10, 2020, 09:06:07 AM by agent_smith »

agent_smith

  • Sr. Member
  • *****
  • Posts: 1204
Re: Technical paper: Riggers bend (#1425A)
« Reply #3 on: May 13, 2020, 03:54:22 AM »
VER 1.3 of the Riggers bend paper is now publicly available.
Password = copyright

agent_smith

  • Sr. Member
  • *****
  • Posts: 1204
Re: Technical paper: Riggers bend (#1425A)
« Reply #4 on: May 25, 2020, 07:43:08 AM »
VER 1.4f of the Riggers bend paper is now publicly available.
Password = copyright
Get it from this link: http://www.paci.com.au/knots.php

I would like to express my sincerest gratitude to Monsieur's Xarax and Lentini for their peer reviewing and critical feedback.
Without their assistance, the paper would never have reached its final form.

KC

  • Sr. Member
  • *****
  • Posts: 290
    • latest project
Re: Technical paper: Riggers bend (#1425A)
« Reply #5 on: May 29, 2020, 01:20:12 PM »
Very Nice, thanx!
.
In my imagery,
The 'Primary Hook' of SPart (primary, most loaded straight rope part as force input imposing load against the system)
+ 'Primary Arc' (primary, most loaded arc against SPart)
>>is most tensioned/rigid part of each competing/antagonistic rope/side
>>of the sudden node-deformity of the actual Bend in other wise straight line of force /straight rope line
>>that allows not termination , but continuation of straight line thru this 'node-deformity'
(Hitch would be only 1 such Primary Hook to host as termination of line)
.
To me, defines why Riggers is more likely to jam than Zepp
>>The most rigid, competing parts of each side is the Primary Hook of each.
>>each grip the BE's together as 1 pin/bitt in horse's mouth as host mount for Primary Hooks
The Rigger's is more of a straight line compressing this 'pin' w/rawest forces of most inline
>>pinching together on rest of rope parts pin(BE's) w/o relief and in full rigid  circle of also no relief(dbl.whammy)
>>the Hooks bend each to a side(before 180 half circle arc mark) to allow this alignment
While Zepp is a near miss of this alignment of the rawest forces,
>>side by side most rigid line parts of hooks not bent to side before primary 180 arc
(primary180 arc ends at point where rope running direction now matches parallel to input/imposed force of SPart)
>>rest of rope pinches hooks together and from sides, rather than hooks pinching BE's and inline directly/full force
>>giving softer open side of hook on each side rather than complete circle force around pin
>>this also gives more Cow/counter-torque finish
But, hook's shank/spine on opposite sides for Zepp
>>giving even slighter misalign-meant
>>AND no weak/open side as the False/Faux Zepp has
So full circle of protection and balance w/o shared open side and imbalanced pull to one side as well
.
The force lines from Rigger's are directly confronting and pinching/nip as one function(fn)
>>More of Equal & Opposite inline math w/o conversions to leverage
>>Zepp uses squish from sides as conversion/therefore reduced forces for reduced need of shearing inline raw force
as the Zepp 'hooks' are pinched together side by side by rest of rope fns
>>and BE's pin-nip is separate fn from rope pinch of hooks together
>>vs. Rigger's that delivers all raw unconverted forces more inline to pinch rest of rope BE's.
Simply flip 1 side of Rigger's to (open) B'fly to give non binding form of both weak sides of hooks now aligned
>>but still direct inline pressure on 'pin' of both BE's
>>this morph thus gives inline shear force + some releif/weak side
.
i think these force patterns continue into other knots
>>and once see; they give mnemonic to knot tying, checking, differentiation even dressing as 'tuning'
>>to correct mechanical logistics
In non-Binding knots of Hitch/Bend USAGE forces, i always define from the Hook
>>as most ruling, tensioned, therefore rigid rope part
>>critical point of conversion from straight line force to arc
>>that rest of 'knot carriage' just keep hook lined up to task
>>as give frictions that can be leveraged for final nip/BE to use to enforce ballast
to hold, knot carriage, thereby primary hooks to task
>>1 hook as termination of rope line force by conversion to arc and ballast
>>or a continuance of straight rope line past the node-defromity of knot with other hook(s)
edit:

.
Same raw forces, names and effects, with normal extra dressings:

Zeppelin:Strong, non-Jamming w/ full rigid SPart parts as side guards, equal to each side and balanced pulls
>> False/Faux Zeppelin allows conversion to side force to exit thru least guarded side/rollout, as unbalanced 1 sided pulls dump towards open side with side force
Rigger's so intense can jam, but cousin B'fly has 1 weak side as Faux-Zepp, but w/o side force in it's pure inline focus
>>so B'fly wants to stay inline from pulls, but has some force limiter/steam escape to side not pressing/rolling towards, 'cuz side force, breaks full recursive back in line 2nd compression.
« Last Edit: May 31, 2020, 01:06:59 AM by KC »
Rope-n-Saw Life
"Nature, to be commanded, must be obeyed" -Sir Francis Bacon
We now return you to the safety of normal thinking peoples.
~ Please excuse the interruption; thanx -the mgmt.~