Knotsaver,
Made some amendments per your suggestions.
(- p.2 l.4 " ' " is missing: "whats in a name").Unsure what this comment was actually referring to??
Hope all is okay now?
This is still a work in progress…
Mark Gommers
(- page2 line4 (the Contents page): " ’ " is missing: “what’s in a name”)
I noticed it…
Ciao,
s.
I’m unsure of “neutral” : “middle-of-possible-rotational-range” is what
that one is --and it allows rotation opposite to what you chose for the
2nd orientation. IMO, show all three ; let viewers see the whiter rope
making the loop, then the “neutral”/“middle” state where both ropes
go away from viewer, up into knot, then a less in-your-face(large) and
equal image of the other end of the range, where now the blue rope
loops to the white rope’s “arc” (my terms).
Respectively of this trio of states, tails come AT viewer, run to left,
or go AWAY from viewer. --all from the “same knot”, one might think!
Are you still in support of a rotation to induce a chocking effect to trap and crush the tails of #1410?Absent any much testing of this, still, I'm yet leery of the middle orientation vs. either of the ones w/a loop in them, yes. But that's a continued position devoid of further testing to support ..., not one that comes WITH such further support. (Hoping that interested parties to this thread might test their own materials with some kind of slow-loading or bouncing/shock loading in variously tied/tightened knots.
Recent testing has demonstrated that ... the tails do not mysteriously slip.I don't know what recent testing this is, but I can be pretty certain that it hardly covered the myriad possible combinations of ropes that might be joined for abseil --varied in firmness, bending resistance, slick/frictive surface, sizes, & elasticities!
Now, you persist in putting up a strawman --or, at least
a weak substitute to what has been advanced to you by
me in this thread-- for attacking the “EDK-backed EDK”
(as colloquial/common parlance might put it) :: it is very
much a desirable tool in the knots kit on occasion that
all the important just-tie-it-right points cannot be done,
as is quite reasonable to anticipate via fatigue and other
stressful circumstances (and user error (my ‘usERror’ in fusion)!
And noting that this “back-up” EDK is loaded differently,
qua stopper, and more assuredly effective/safe thus,
and thereby ensuring ultimate security of the base knot.
As for “larger footprint”, that, too, exaggerates likely effect
of the more material :: the 2 overhands will fit through
a slot about as likely as one, and the 2nd shouldn’t affect the
offset qualities of the first in pulling down. (Beyond this one
can note some reports of lonnnnnnnnnng uses of only the
grapevine w/o all the troubles alleged of non-offset
knots.)
–dl*
QuoteRecent testing has demonstrated that ... the tails do not mysteriously slip.I don’t know what recent testing this is, but I can be pretty
certain that it hardly covered the myriad possible combinations
of ropes that might be joined for abseil --varied in firmness,
bending resistance, slick/frictive surface, sizes, & elasticities!
And this refers to my personal testing both in a test bench/lab environment and in actual field use.
I have just returned from a week long climbing trip to Mt Arapiles (Australia) where I had an opportunity to use #1410 (offset overhand bend) in a number of typical EN892 dynamic climbing ropes (different brands, different diameters, different sheath characteristics, some slick and some not so slick, etc) - in retrievable abseil systems.
NOTE: I use a modified #1410 - with an additional turn of one strand to bind and lock the structure.
I made approximately 10 multi-pitch abseil descents (as a means of descending to the ground after completing a route).
There were up to 4 climbers in my group - all descending one after-the-after.
There was no observable tail displacement or ‘slippage’ of tails at any stage.
I ensured that the tails were tied to identical lengths and then checked again at each intermediate belay ledge and then again upon reaching the ground. I could not discern any appreciable difference in tail lengths.
The point here is that if #1410 is properly and diligently cinched and dressed - with the nominal loading of a single person (100kg average) - you are simply not going to see any tail movement of statistical significance.
Keep in mind that in a typical double rope retrievable abseil configuration, the end-to-end joining knot (ie #1410) will only have 50% loading.
Now, you persist in putting up a strawman --or, at least a weak substitute to what has been advanced to you by me in this thread-- for attacking the "EDK-backed EDK" (as colloquial/common parlance might put it) :: it is very much a desirable *tool* in the knots kit on occasion that all the important just-tie-it-right points cannot be done, as is quite reasonable to anticipate via fatigue and other stressful circumstances (and user error (my 'usERror' in fusion)! And noting that this "back-up" EDK is loaded differently, qua stopper, and more assuredly effective/safe thus, and thereby ensuring ultimate security of the base knot.As for “larger footprint”, that, too, exaggerates likely effect
of the more material :: the 2 overhands will fit through
a slot about as likely as one, and the 2nd shouldn’t affect the
offset qualities of the first in pulling down. (Beyond this one
can note some reports of lonnnnnnnnnng uses of only the
grapevine w/o all the troubles alleged of non-offset
knots.)–dl*
My counter-point is that duplication of #1410 is simply an attempt to add security where none is required in the first instance (per certain conditions which I will try to elaborate).
Your proposition is one that is often quoted…ie; “tired”, “mentally fatigued”, “cant think straight”, “oxygen starved”, blah blah blah…) is your justification for knot duplication.
The list of things that could go wrong in the hands of mentally fatigued climbers is long..and is not just confined to knot tying errors.
Climbers (by definition) are conditioned to certain routine behaviours - like putting one foot in-front-of-the-other. Like coiling a rope - it is a conditioned behaviour.
The conscious act of climbing a big/long route means that they would have knowledge ahead of time that an abseil descent is a likely consequence of getting down safely. In other words, they would be aware ahead of time that joining 2 ropes together is a likely task. Such an act is not haphazard - they would already have a procedure in mind. Risk mitigation is something that many climbers takes seriously, so the act of joining 2 ropes together would not be a random/haphazard process. There would be a rehearsed or well practiced procedure - it would not be made up on-the-spot using a random tangle. So their minds are prepared…even in a stress situation, the process would be automatic/routine - like soldiers/paramedics/firefighters who train and practice for stressful events - skills become automatic, and appropriate decision making (in the ‘fog of war’) is still possible.
…
If you tie #1410 and then duplicate it by tying another #1410 (in a stacked configuration) which now creates a composite structure - you have increased the footprint of the original joining knot (which is obvious…and it should be obvious to you). Logically, the larger the footprint of a knot, the more likely that it might foul somewhere. Even if it is unlikely that any knot will foul - it is the principal of the matter…in that it is logical to keep things small and compact (the opposite view would be; makes things larger and less compact).
The central tenet of your argument is based on the premise that a fatigued climber could make a fatal error in joining 2 ropes together using #1410 by virtue of the fact that they do not have full use of their mental capacity. #1410 is the simplest way of uniting 2 ropes. This knot was even found on the ‘iceman’ (some 5000 years ago) - and this humanoid likely had less mental processing power than modern humans. Even if there is a slight dressing misalignment - provided that all 4 rope segments are tightly cinched - there is little chance of anything going south (remember that the joining knot only has 50% loading).
Based on such an argument, we can perhaps see different classes of user groups of #1410.
Examples (not exhaustive):
User group A: Not mentally fatigued, not hypothermic, not starved of oxygen
User group B: Mentally fatigued, hypothermic, starved of oxygen
Your argument appears to require certain pre-existing conditions - for example, those conditions experienced by group ‘B’.
Does this mean that group ‘A’ must also duplicate #1410 into a larger composite structure, regardless of conditions?
The other argument often touted in internet forums etc, is that duplication of #1410 by adding another #1410 in a stacked composite structure guards against potential tail slippage.
This argument has little real-world testing that proves #1410 is prone to failure (ie that #1410 is inherently insecure by virtue of tail slippage). This is largely a myth that is passed on by word-of-mouth. Also, there is a the fear-factor…such as when standing near the precipice of a massive cliff and about to put absolute trust in #1410… and then step backwards into the void and abseil down. Some may gain a psychological boost from a duplicated #1410?
I have personally used #1410 and its ‘locked’ variant (extra binding turn) for 30 years with many different ropes. Evidently I am still alive (because I am writing this post).
Those that have ran into trouble seem to have made a mistake..that is, they did not properly cinch and dress the knot. Now, this is a basic requirement of any mission critical knot - and not just confined to #1410. Eg…a tie-in knot to a harness for lead climbing.
Mistakes might also have been the miss-tying of #1410 into some other knot species…eg #1411 in its ‘offset’ form.
A miss-tied harness tie-in knot can be just as fatal as a miss-tied end-to-end joining knot.
Mark G
[Grammar edits…]
New update has been uploaded…
Link to knots page: http://www.paci.com.au/knots.php
Now VER 1.2
Major updates to pages 14+15 (effect of rotation)
Also revised page 16 (tying duplicate #1410 as a ‘backup’)
Page 17 is a work in progress…
Mark G
NB : then you missed the point of my remark.
Especially, I’m thinking of cold or wet ropes,
where stiffness might keep too loose the knot
and make slippage possible (or a smaller, more
flexible-slick strand).
Keep in mind that in a typical double rope retrievable abseil configuration, the end-to-end joining knot (ie #1410) will only have 50% loading.And keep in mind that the cyclical ratcheting slippage observed by Tom Moyer and a corresponder to his tests found slippage [u]only[/u] under relatively light loads!
Now, you persist in putting up a strawman --or, at least a weak substitute to what has been advanced to you by me in this thread-- for attacking the "EDK-backed EDK" (as colloquial/common parlance might put it) :: [b]it is very much a desirable *tool* in the knots kit on occasion that all the important just-tie-it-right points cannot be done,[/b] as is quite reasonable to anticipate ...–dl*
Climbers (by definition) are conditioned to certain routine behaviours
And doing again immediately what one just did
in this conditioned state is a much surer thing
to ask be learned than making one of our more
efficient, well-intentioned improvements.
[failures have come because...] that is, they did not properly cinch and dress the knot.Again, to my point about removing most vulnerabilities.
Does this mean that group 'A' must also duplicate #1410 into a larger composite structure, regardless of conditions?You seem to be hearing me as advancing an *either or* choice, vs. promoting a should-be-known tool for use.
If you tie #1410 and then duplicate it by tying another #1410 (in a stacked configuration) which now creates a composite structure - you have increased the footprint of the original joining knot (which is obvious...and it should be obvious to you).IMO, a *footprint* is much a 2-dimensional thing, a matter of area, presence --not so much so volume. And the issues regarding knots being hung up during abseil-ropes pull down is one of rope-movement impediment (the rationale for "offset" knots!), and sometimes crack-filling stoppage (stopper effect). In neither case does a back-up [i]OWK[/i] IMO pose adding much risk --as noted, if the base knot can fit through the crack, it can bring the other along with it (the line won't be running through [i]holes[/i] after all!).
Even if there is a slight dressing misalignment - provided that all 4 rope segments are tightly cinched - there is little chance of anything going south (remember that the joining knot only has 50% loading).This is a tough thing to test : "... misalignment" being just a "NOT " wide open, broad designation; and on that, one is advised IMO to feel some doubt! The best I can come up with re testing the challenged knot of our debate would be to actively strive to form badly aligned/dressed knots, thinking that such structures lie farther from [i]good[/i] than anything better done. AND, I think that the debated knot will survive; this makes it commendable to be known.
–dl*
New update has been uploaded…
Link to knots page: http://www.paci.com.au/knots.php
Now VER 1.2a
Corrected error on page 15 (references to image ‘C’ was incorrect)
Minor revision to page 16 (primary knot is under maximum tension but duplicate ‘backup’ is not under tension and simply tails along)
Page 17 is a work in progress…
Dan, my response to duplication of #1410 (to create a ‘backup’) is that the primary #1410 knot is under maximal load. However, the duplicate #1410 is not under maximum tension. The primary #1410 always has a tendency to self-align and translate over an edge. My concern is that the tailing duplicate #1410 backup is increasing the overall footprint and could conceivably cause issues downstream (it does not self-align in the same manner as the primary knot).
…
Since you appear to be a strong advocate for duplicating #1410, I would like to include commentary in the analysis paper supporting your view.
I can pull quotes directly from your posts in this thread or you could write some supporting argument. Please advise…
…
Also, I have significantly improved pages 14+15 (re orientation)…I am reaching the limits of what a photo can convey - camera angles are tricky to get right. Any further comments?
Mark G
New update has been uploaded…
Link to knots page: http://www.paci.com.au/knots.php (at #3 in the table)
Now VER 1.2b
Page 17 (long tails) has been updated.
Mark G
It concerns me that you posit stability --as though something
needing minding-- to the trio of extreme/center orientations
of the offset water knot :: IMO, we just don’t know enough
about their influence; but we do want to make their existence
known!
(There might be something to the conjecture (mine,
on this writing) that by having two “pry-up” “arcs” in the
SParts, the mid-range orientation raises greatest vulnerability
to capsizing; the orientations with a “loop” (+ arc in opp.SPart,
of course) have this bit of resistance !?
)
(FYI, I go further in dressing & setting the owc : I pull
the choking line’s tail up into the expected curve of the
SParts, anticipating their draw on this important part by
setting it most in opposition/distance from where the draw
will rotate it --so, e.g., one would see NO slit of gap/space
at knot nub center as one can see in your mid-range image.
)
Dan, my response to duplication of #1410 (to create a 'backup') is that the primary #1410 knot is under maximal load. However, the duplicate #1410 is not under maximum tension. The primary #1410 always has a tendency to self-align and translate over an edge. My concern is that the tailing duplicate #1410 backup is increasing the overall footprint and could conceivably cause issues downstream (it does not self-align in the same manner as the primary knot)."Leaving long tails" --which is the commonly given advice-- can invite my challenge : "Rather, DO something with them (with all that "left" material)!" Because the common advice is given in anticipation of some sort of capsizing/"rolling", and I'm not comfortable with asserting that that will be limited and so within some unknown though believed length of tails.
In any case, one can imagine somehow that dangling tails
get slipped into mischief? --never heard of such, though.
I don’t think that the knotted bulk (vs plain length of ropes)
invites anything bad; it won’t need to “self-align”, as it won’t
be so oriented to snag (as the aligned base knot will lead to
the back-up from its top, away from edge/surface).
Since you appear to be a strong advocate for duplicating #1410,Maybe esp. in cases of stiff ropes and mitten'd hands, though perhaps in such an alpine situation there'd be less advantage to offset aspects!? (Tom Moyer also suggested by his limited testing that the [i]grapevine[/i] can be poorly tied but yet work; tensioning the knot IS presumed, at least. Forming an [i]offset water knot[/i] and then with tails OR with SParts forming a 2nd, and setting to reasonable tightness & closeness I'm surmising is a measure surer than tying many things; the [i]grapevine's[/i] ability to be tied in halves (each rope [i]strangle-[/i]ing the other) remotely/clearly apart (un-interfering; not requiring intricate interlacing) is a good attribute similarly. )
I am reaching the limits of what a photo can convey - camera angles are tricky to get right. Any further comments?
I was looking at some of those top-/tails-down views
and thinking "my, this can show how a thicker rope in the
choking position (bad) has a lot of material half way to
coming out around the thinner --which if in the choking
position might not be visible from under its thicker twin!?
Hmmm, some of us should perhaps go out into the wilds
and do a batch of drop-tests --can we muster up some
weight about 50-100# (noting as you do that the knot
is usually taking half a climber+pack’s weight) !?
–do some shock-loading short drops;
–do some mild, like-during-abseil “bounces” to see if
anything worrisome appears to be happening (under
this relatively light, but cyclical loading)!?
–in a mixture of ropes (not only likely offset-knot users),
and tying goodness.
Maybe a quick-&-dirty batch of tests so done would at least
point to some orientation as indeed looking worse, as taking
a step farther from desired snugness & so on!?
Thanks,
–dl*
It concerns me that you posit stability --as though something needing minding-- to the trio of extreme/center orientations of the offset water knot :: IMO, we just don't know enough about their influence; but we do want to make their existence known!
Ahhh a paradox! I am getting into a ‘catch 22’ situation. Damned if I do, and damned if I don’t.
I can add wording to the effect that further testing/investigation is needed. I posit that the mid-rotation state does have a vulnerability to capsizing…indeed, this rotation state would appear to be the orientation most often tested (testers are not aware of this - they just orient the knot in this way by way of automatic, in-grained behaviour).
(FYI, I go further in dressing & setting the owc : I pull the choking line's tail *up into* the expected curve of the SParts, anticipating their draw on this important part by setting it most in opposition/distance from where the draw will rotate it --so, e.g., one would see NO slit of gap/space at knot nub center as one can see in your mid-range image.
Dan, virtually all of the photos in this ‘analysis’ paper are loosely tied, and with deliberate short tails. Part of the reason for this is trying to get all of the knot to fit within the narrow field-of-view of the macro camera lens. The other reason is to show details. So the slit/gap you refer to is a deliberate act on my behalf (sort of my attempt at creating an ‘X-ray view’).
I will add remarks to this effect to further emphasize these salient points.
I re-assert that I am reaching the limits of what can be done with a camera. I am not a professional photographer - I am an amateur - and working with a very limited budget. Be that as it may, I want to get this right and I am very motivated in this regard.
"Leaving long tails" --which is the commonly given advice-- can invite my challenge : "Rather, DO something with them (with all that "left" material)!" Because the common advice is given in anticipation of some sort of capsizing/"rolling", and I'm not comfortable with asserting that that will be limited and so within some unknown though believed length of tails.
I concur here. I am not an advocate of long tails. It is largely providing a psychological boost (picture oneself standing on the edge of a very high cliff - about to step backwards into the void…add wind to that mix and you have all the sphincter valve-heart rate-breathing elevated inducements!
You say - ‘Do something with those darn tails’!
I say, why have long tails in the first instance?
.....[OP comment...per duplication of #1410]... Maybe esp. in cases of stiff ropes and mitten'd hands, though perhaps in such an alpine situation there'd be less advantage to offset aspects!?
I am happy to add any personal commentary from you regarding your ‘official’ position re adding a duplicate #1410 to serve as a ‘backup’. I just need some relevant words to that effect and I can insert it into the paper.
I would like to hear some well considered argument to support the duplication of #1410 - and I am sure any potential readers would also be interested.
Hmmm, some of us should perhaps go out into the wilds and do a batch of drop-tests --can we muster up some weight about 50-100# (noting as you do that the knot is usually taking half a climber+pack's weight) !?–do some shock-loading short drops;
–do some mild, like-during-abseil “bounces” to see if
anything worrisome appears to be happening (under
this relatively light, but cyclical loading)!?
–in a mixture of ropes (not only likely offset-knot users),
and tying goodness.Maybe a quick-&-dirty batch of tests so done would at least
point to some orientation as indeed looking worse!?
Indeed.
I am a huge fan of well thought out testing. As long as it isn’t just the usual mind numbing MBL yield/break testing. The spacial orientation of the knot per inducing a choking effect should be near the top of the test criteria. And different diameter ropes - to investigate the effect of altering the relative positions of the different diameters.
In addition:
instability threshold/range
jamming threshold
icy ropes
very stiff ropes versus supple ropes
Maybe that fine fellow who responded re the ‘Prusik Hitch tests’ (ITRS symposium)?
Mark G
New update has been uploaded…
Link to knots page: http://www.paci.com.au/knots.php (at #3 in the table)
Now VER 1.2c (15 OCT 2017)
Password to open pdf document = thankyou
[Yes, I do believe this is necessary…a lot of time and effort goes into producing these documents…and you never seem to get much thanks).
added note about loose tying (X-ray view)
added commentary about long tails
added commentary about follow up testing of the different states of orientation
added some ‘grim reaper’ toon images (most people recognize this as a bad omen)
…
Dan, I need some feedback to advance this paper further.
Now is your chance!
Mark G
Well, you went further than anything I see as a basis
in making what appears to be your worst rating of
the 3rd-shown orientation (in which the white rope
makes the loop) --it gets a nasty thumb vs. a note
of dubiousness, whereas my current thinking (noting
w/o a firm basis) is that mid-range is likely worst.
It IS something to note any seeming preponderance
of an orientation; beyond this, those Australian Bush
Walkers asserted a point re direction of tails --and
wanted just this mid-range one for its aligning the
tails w/axis of tension! Not that I’ve checked on
what a preponderance of orientation is, which should
indicate the most common tying method (with some
alteration via setting perhaps).
"Leaving long tails" --which is the commonly given advice-- can invite my challenge : "Rather, DO something with them (with all that "left" material)!" Because the common advice is given in anticipation of some sort of capsizing/"rolling", and I'm not comfortable with asserting that that will be limited and so within some unknown though believed length of tails.I concur here. I am not an advocate of long tails. It is largely providing a psychological boost (picture oneself standing on the edge of a very high cliff - about to step backwards into the void…add wind to that mix and you have all the sphincter valve-heart rate-breathing elevated inducements!
You say - ‘Do something with those darn tails’!
I say, why have long tails in the first instance?
IIRC, while there haven’t been reports of the owk failing
–beyond the old one w/“Karen” the victim–,
there have been some climbers citing “shorter tails”
upon completion of abseil, suggesting that there had
been some “rolling” of the knot --and that’s their
grounds for the advice. (Along with testing that shows
this, albeit typically at higher than expected forces.)
–dl*
New update has been uploaded…
Link to knots page: http://www.paci.com.au/knots.php (at #3 in the table)
Now VER 1.2d (17 OCT 2017)
Password to open pdf document = thankyou
[Yes, I do believe this is necessary…a lot of time and effort goes into producing these documents…and you never seem to get much thanks).
amended page 15 per Dan Lehman feedback (Dan - please check and confirm if this is now acceptable?)
enhanced page 19 with further commentary re loading profile (compression up against anchor)
…
There is still time for interested parties to add commentary / feedback (but please be quick because I am starting to run out-of-time for this project).
What is needed now is some testing to investigate some of the concepts in the paper.
Mark G
THANKYOU 謝謝
alanlee 謝謝
New version has been uploaded…
Link to knots page: http://www.paci.com.au/knots.php (at #3 in the table)
Now VER 1.3 (01 NOV 2017)
Password to open pdf document = thankyou
[Yes, I do believe this is necessary…a lot of time and effort goes into producing these documents…and you never seem to get much thanks).
Changelog:
new content on page 9 (photos and text about inherent tendency of offset knots to roll during retrieval process)
amended text content on page 15 (bottom of page)
…
Hoping Alan Lee can test the different orientation states of #1410 to see what affect this has on stability 
Once I have these tests results (here’s hoping) - they would be published in the paper…
Mark G
If I can, I’ll offer some re-wording for the EKD-backed-EDK
presentation, which is still underwhelming on its benefit.
(hint : the “2nd” knot --which could be first-tied!-- isn’t
there for back-up but stopp(er)ing : it stifles any
pull-through.)
Steve Reid of NeedleSports introduced the knot upon some
unfortunate experience w/an offset fig.8 --a knot that
seems to yet retain or is it regain favor w/French, now?!
He thinks it was over a decade back.
Searching RC.com (now a slow-acting, largely ignored place)
for “knudeNoggin” --that sage commenter–, I see threads
remarking at the above presentation (presumably --citing
Steve R., at least, & site) in July 2006. Andy Kirkpatrick
has further remarks at
The Ultimate Abseil Knot?
and most notably a testimony to near failure --arrested
manually!!-- of the offset water knot (in thin wet ropes)!
THAT is why … ! (tying w/gloves on, likely --& preferably!)
–dl*
New version has been uploaded…
Link to knots page: http://www.paci.com.au/knots.php (at #3 in the table)
Now VER 1.4 (02 NOV 2017)
Password to open pdf document = thankyou
[Yes, I do believe this is necessary…a lot of time and effort goes into producing these documents…and you never seem to get much thanks).
Changelog:
page 17: amended and new content added… reference to Dan Lehman proposition that adding a duplicate #1410 (ie backup) acts to retard any risk of tail slippage
page 27: revised the conclusion and added some images
Dan, if you want specific changes/amendments - you will need to write and submit content. Please make it very clear as to precisely what you want changed/amended… I am starting to run out of time and energy on this particular paper. Need to draw it to a rapid close
Mark G
In a bit of squeezed time (I feel your pain), here is what I’ve
just tossed together, which I think is an improvement in overall
thrust re the information, though writing-wise less smoothly put
than I’d like. AND yet devoid of some further quick’n’dirty drop
testing of small masses to see how a well a sloppily tied “EDK=
backed-EDK” performs.
SUGGESTED TEXT FOR MARK -------------------------------------- Circa 2006, Steve Reid of Needle Sports reacted to the report of another presumed failing of the [i]offset figure 8[/i] knot by introducing what he then called the [i]"double overhand knot" [/i]and which is better named, per its construction, the [i]"offset water knot with stopper(knot)"[/i] --and in the common parlance among rockclimbers, [i]"EDK-backed-EDK"[/i] will be an even clearer communication of the knot. In short, the fundamental [i]offset water knot[/i] which will take the main force has its tails --both-- tied in a 2nd [i]overhand knot[/i]; this 2nd, "back-up" knot will not be offset loaded but loaded as a "stopper" knot as its drawn to abut [edit : 'by'=>'but'] the main knot --and arrests any potential slippage of tails out of that knot. The current [2017-11] reference for the NeedleSports article (dated 2015, w/Lyon's test data) that presents this knot is: www.needlesports.com/content/abseil-knots.aspxHere is Steve’s sage advice given in the aforementioned article:
"Of course we all know that knots shouldn't be tied sloppily, and that long tails should be left, but as we said before, you're cold/wet/tired/frightened/distracted, the weather has turned gnarly/you've run out of daylight/ you've bitten off more than you can chew etc, or maybe you've just been distracted by the attractive girl/boy sharing a stance with you. Whatever the reason, we all tie our knots less than perfectly on occasions, so it makes sense to use the safest knot available."While adding a 2nd, like knot to stopper the first increases the knotted
bulk, it does so in a way that ought not to be any problem in general,
as this added knot will fit through slots and bounce over/around
impediments along with the main knot. Moreover, it is a better thing
to do with the recommended "long tail’s --i.e., to knot them-- than
merely have long tails. At this point, it should be noted that the
two knot halves of this compound knot can be tied in either order :
once can tie a knot “with long tails” which then are used to make
the 2nd knot as a stopper, or if the tails come out not so long,
tie the 2nd knot in front of the first --two ways to the same result.Considering the more material-efficient knots recommended by
this paper, one realizes that their aptness often comes with making
a particular tying decision. If one gets this wrong, results are not
necessarily good. Consider the warnings about tying correctness
given above, pp. 13-16 (Vers. 1.4):
"Correct Dressing is Critical " (cf. Vers. 1.4 p.13);
“It is critically important to position the thinner rope underneath the thicker rope” (cf. Vers. 1.4 p.14);
And the uncertainty about the effects of radial orientation of the knot to the plane it is offset from (cf. Vers. 1.4 p.15/16).
But to Steve’s note above, indeed, it seems that one can violate many of the
preferred tying recommendations of dressing and orientation with this doubled
knot and the structure will still hold! That is no small commendation for it,
at least under certain circumstances! It is a knot that should be known,
and sometimes used.
And “suggested text” is better taken as "some more words to
consider incorporating, as supplements or replacements (or
amendments).
Also, I find “Lehman posits that … <the stopper knot will in
fact work qua stopper knot!>” pretty lame :: OF COURSE it
will, that should be pretty much w/o question, no? (Okay,
some no in a case of a really loosely tied 2nd overhand
stopper, but … .) AND it can be noted that Moyer (et al.?)
have noted that the capsizing/flyping seen in the offset
water knot is rather apt of the colloquial “rolling” whereas
that in the offset fig.8 is more of a “jump” --a bigger flip
which consumes more rope. So, stoppering the former
should be well assured, but perhaps an offset fig.8 could
partly capsize around a stopper knot (and then who
knows what transpires further)?!
–dl*
The other evening I was sitting fiddling with the
offset water knot tied in 8mm low-elongation,
“accessory cord” & 11(ish)mm low-elongation (“static”)
kernmantles and a moderately well dressed & set
knot, under continual stressing & relaxing,
by hand (so, maybe 30# force?),
saw choking line ratcheted out of the knot!!
(And this is why you want even-length tails,
to make this imbalanced slippage evident.)
Whoa & wow!
Now, I’ve repeated this light loading a few times,
and not always with such dramatic, eye-opening
results. And note that this was bit-by-bit upon
each surge of force, after relaxing (kinda like the
intermittent loading that can come from some
abseils), and so not the sort of continuous
slippage asserted by the famous Karen Turk
fall or the one posted to Andy Kirkpatrick’s site
posted above (and elsewhere, to ukclimbing,
I think, too).
.:. strange things can happen!
–dl*
New version has been uploaded…
Link to knots page: http://www.paci.com.au/knots.php (at #3 in the table)
Now VER 1.5 (23 NOV 2017)
Password to open pdf document = thankyou
Changelog:
page 17 + 18: complete re-write (added commentary from Dan Lehman)
page 28 + 29: new content added to conclusion
- a few minor tweaks and enhancements here and there…
…
This is likely the last update for 2017 - and most likely for some months into 2018 - unless something is glaringly wrong or a crucial update is required.
Comments/feedback is always welcome
Mark Gommers