Author Topic: Janus Bowline or an equivalent secure bowline for climbing/rescue purposes  (Read 148589 times)

Dan_Lehman

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Re: Janus Bowline or an equivalent secure bowline for climbing/rescue purposes
« Reply #45 on: December 26, 2008, 06:03:21 AM »
Version 1.5 is up...Merry Christmas!

A fine present, no doubt, but I'm not able to download this, at the moment;
I'll read your notes on its changes.

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Added a clove bowline with yosemite finish (I think I have yosemite on the brain).
I am also considering adding a yosemite finish to the EBDB (p8, fig 22) and photographing it - hope that won't offend!

People have been drawn & quartered for less.  Yes, you do have --for whatever? reason--
"Yosemitis", which is a serious brain affliction.  Get rid of it.

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Does anyone have any historical and technical data on any of these variations to the original #1010 bowline?

Beyond what has been discussed above?

1. One needs to drive home the point that "technical data" is very seldom attached
to a well-specified knot structure:  use the case of the Fig.8 eyeknot in which it is
seldom indicated which of the two ends bears the load from the knot--a simple,
obvious, fundamental point, ... ignored.

2. Beyond that, one can show that knots behave sometimes differently in different ropes.
(On this forum, years ago but I think in the present archive, one fellow reported finding
the Butterfly eyeknot noticeably weaker than the bowline; but Dave Richards's tests
(the URLink given previously, above) show things much the other way 'round:  and
--to emphasize my initial point here-- neither case specifies the exact geometry of the Butterfly,
or which of its potential SParts (it's an asymmetric knot) was loaded.

3. The only "data" one is likely to find (aside from the implicit sort of some considerably
useage w/o cited problems, as Roo remarked) for knots is slow-pull testing of break
strength; this data is not directly applicable to in-use conditions; Dave Merchant has
pointed out that testing he did showed differences for some knots between slow and
rapid loading for strength.  We don't know of a test for security.

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Will take one or two more photos tomorrow (time permitting) and then upload.

I should have returned to HQ by then and be ready to receive ... .   ;)

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Will need to do some serious think tank over next few days and make a few bold statements
about which variation is the better candidate.  By 'better', I mean a knot that has the 'easy to untie'
property of a bowline but also has the security and stability of a figure 8 eye knot (now I'm calling it an eye knot).

Note that the Fig.8 is not all so stable on ring-loading.  (Note that "the Fig.8 ..." glosses over
the fact that there are VARIOUS actual geometries carrying that moniker and presented in
the literature and tied in practice!!)  (Note that there are some who will debate this knot(-set)'s
need for a "safety/back-up" knot, too!)

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Dan, do you have any issues with the so-called 'yosemite bowline' (page 4, figure 6).

I sure do.  This knot requires the end to make a 1-diameter turn, and many kernmantle ropes
--the particular domain of interest to the OP--resist bending so sharply.  The making of this turn
and the setting of the knot can displace the curved tail from its most favorable into dubious
positions (witness that misformation on the Ch.3 cover page of the original On Rope.
The tucking through the collar is a weaker means to security than other extensions.
In short, I don't find the YoBowl doing a good job for what it is tasked to do.
And, although Craig Connally (Mountaineering Handbook) is all agaggle gung-ho
for the YoBowl, claiming it to be stronger than the Fig.8 eyeknot, I remain skeptical
that the extension can do anything much for strength (for what that's worth),
and must question his basis for assertion.


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Also, how do I tie this?

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Oh, yes, Clove Bwl.  A beauty of this and --better, IMO-- Cow Bwl are the "mirrored"
variations in which you "collar" both ends of the loop-making parts, "coming & going"

You do as it says--make the same "collar" on the eyeside of the central loop(s) as done
just prior for the SPart side (it is as though, at the point in the "rabbit...hole" tying riddle
you reset the riddle to "comes out of the hole" as it has just "gone back into the hole"
from forming the SPart's collar.  "Mirror" has sense, here.
I was verbose, on the 8th post of this thread (p.1), my 2nd.

I might wonder, here, why none of the many Constrictor afficianadoes has suggested
replacing the Clove H. in the Clove Bwl with the Constrictor, for greater security?!
Yeah, one could do this, too.  --not clear that it really helps, FYI, there it is.

Or, we could merge Roo's preference for the Water vs. Dbl. Bwl by doing BOTH:
form a Rolling Bowline (Rolling H. vice Clove, dbl turns in the SPart).  Well, yeah,
another possibility.  The list goes on & on.

But simplicity sells, here.  And so I've repeatedly urged an easily formed variation
of "Janus" bowline, from maybe best a Cowboy Bwl (1034.5) start.  This also suits
your seeming insistance on the end pointing SPartwards or at least being "outside"
of the eye.

-----------

I'll reiterate (voluntarily):  if you are really faced with some committee to hear your
use-the-bowline case, present the "partially tied Fig.8" as an eye-knot candidate,
and show the finish to form the Fig.8 as an "extension" to that--one that most
folks take so much for granted that they don't consider the briefer knot complete.
THEN cast the extension(s) to the Bowline as similar, and challenge them to why
they should treat it differently!

--dl*
====

agent_smith

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Re: Janus Bowline or an equivalent secure bowline for climbing/rescue purposes
« Reply #46 on: December 26, 2008, 10:49:37 AM »
On a roll here..ver 1.6 is uploaded.

Same link as before.

Added a constrictor bowline (p6, Fig 16), but lighting conditions were poor so the image is not ideal. Will try to improve image quality another time.

Added yosemite finish to Dan Lehman's EBDB which should bring a smile :) - see p8, fig 24. I actually like this variant...and believe it has some merit.

I acknowledge DL's points re the inherent difficulties with adding a yosemite finish but dont these issues also occur with a standard figure 8 eye knot (ABoK #1047)?

Quote
Quote
Also, how do I tie this?

Quote
Oh, yes, Clove Bwl.  A beauty of this and --better, IMO-- Cow Bwl are the "mirrored"
variations in which you "collar" both ends of the loop-making parts, "coming & going"

You do as it says--make the same "collar" on the eyeside of the central loop(s) as done
just prior for the SPart side (it is as though, at the point in the "rabbit...hole" tying riddle
you reset the riddle to "comes out of the hole" as it has just "gone back into the hole"
from forming the SPart's collar.  "Mirror" has sense, here.
I was verbose, on the 8th post of this thread (p.1), my 2nd.


Sorry Dan, I'm lost here.

You might need to hold my hand a bit and walk me through once more please... or it could be a touch of inebriation on my behalf due to xmas spirits..no pun intended!

Overall, this is still a work in progress but its certainly adding to my toolbox of knowledge... the permutations/variations on #1010 are seemingly endless.

Again, which variation is the holy grail? Maybe there is no holy grail and I'm on a wild goose chase? But I do like the EBDB with yosemite finish....

agent smith

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Re: Janus Bowline or an equivalent secure bowline for climbing/rescue purposes
« Reply #47 on: December 27, 2008, 09:51:59 AM »
Still going strong...VER 1.7 is uploaded.

Go grab it here: www.paci.com.au/IGKT/Bowlines.pdf

Okay, I've made some improvements to the images and added a few new ones.

I think I had a eureka moment with figure 26 & 27 on page 9.

I felt a cold shiver and broke out into a sweat (what does this mean?).

I tied what I am calling an End Bound Single Bowline (EBSB) and then added a Yosemite finish (ha!).

Now I like this form because:
1. The base structure is a standard ABoK #1010 bowline that most of earths population are familiar with
2. It has three rope diameters inside the loop (like the EBDB from Dan Lehman)
3. It dresses well and has a reasonably compact form
4. The eye is clear - due to the infamous 'yosemite' finish (I am not convinced about any potential issues caused by the tail taking a tight turn around the eye leg and then through the collar).
5. It seems relatively easy to tie and remember
6. It may well be stronger than the original bowline (ABoK #1010) - due to the 3 rope diameters inside the loop - by stronger I mean % MBL remaining relative to an unknotted rope of same type.

Dan/Roo/DerekSmith, I am very interested to have some feedback/opinion here... eg has this particular form been tied and tried before, and if so what performance data exists?

I also added what I hope is the correct depiction of the Janus variant that Dan Lehman was referring to. It took a few attempts...but I hope that I got it right!?? I'm sure Dan will point out any issues if I erred.

Anyhow, its still a work in progress but I feel I AM closing in on my holy grail of discovering the ultimate Bowline (for mission critical applications in a life support role).


agent smith

SS369

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Re: Janus Bowline or an equivalent secure bowline for climbing/rescue purposes
« Reply #48 on: December 27, 2008, 02:53:06 PM »
Just because I feel the need to ask: Is this, when it is potentially settled, going to be any better, in any way, than the much used fig.8 tie in? Seems to me the fig8 has done a reliable job for a while now. Pretty compact, easy to tie, relatively easy to untie, been secure.
Just asking.
Scott

DerekSmith

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Re: Janus Bowline or an equivalent secure bowline for climbing/rescue purposes
« Reply #49 on: December 27, 2008, 07:11:40 PM »
OK,

Although I dislike the Bowline for anything other than non critical work, here are three you might find interesting.

The first is a tiny variant on the basic Bowline - take the WE back up the outside of the knot, alongside itself in the bight, then pass it between the bight and the SP



This end is now clamped by the bight which is clamped by the HH which is now clamped by this returned end.  The knot is now self holding.

The second one is another clamping variant of the basic Bowline - take the WE left and back around the eye, then bring it back up the RHS and pass it between the legs of the eye, up the back of the knot and pass it through the primary bight loop alongside the SP.



A similar self locking effect is achieved, but it is susceptible to rocking.

Finally the variant I climbed with for many years after I saw a basic Bowline simply fall open.

Take a long bight in the end of the rope and use it to tie a basic Bowline.  Pass the two loops formed through the small eye in the WE.  Draw up the WE loop until it is snug and dress the Bowline.

For me this variant had a number of advantages whilst still being easy to untie -
  • The WE being a loop was now trapped by the working loops (eyes)
  • The new WE was orders of magnitude more secure
  • The knot was slightly stronger in that it now had a larger radius at the load point
  • It gave me two loops at the belt either of which are loadable independently

It suffers the 'Sin' of requiring to be clipped to my harness via a bina instead of tying right into the belt.  However, I use a DMM locked screwgate bina for this job because I prefer to be able to unclip from the climbing rope rather than have to untie, and as the rest of my protection relies on the use of binas I do not consider it to be an undue risk.

I liked the security of this knot and only moved to the '8' because of the undue strain the Bowline imposes on the rope if the need comes to load it heavily.

Regarding your last question - "is any bowline going to be preferred to the '8'?", not by me it  won't and that is down to security and strength (but I still clip my '8' eye to my belt with a  bina)

BUT, you have moved from simply exploring the world of Bowlines into the search for the Grail and that is an altogether different question...

Derek

DerekSmith

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In Search of the Grail...
« Reply #50 on: December 27, 2008, 09:01:57 PM »
What do I want it to be?

  • Easy to tie
  • Easy to remember
  • Hard to get wrong in the cold or the dark
  • Easy to untie even after extreme loading
  • Secure
  • Strong

The bowline fails on the last two and even the more secure variants fail on the last one and start to loose out on the first three.  Even my preferred bight method failed on the last requirement.

The '8' fails on the first four, especially the fourth.

So, take a step back, pick up your climbing rope, make a bight in the end (or in the mid if you prefer).

Are you ready?

OK, tie a nice fat slipped overhand knot.  Now you have two options - first, bend the single bight loop down alongside the two slipped loops and clip all three loops together, or,  option two, pass the two slipped loops through the bight loop, dress the OH and set the bight loop snugly against the SP('s), then clip the two loops together.

  • Easy to tie  --  very
  • Easy to remember  -- the OH is probably programmed into our DNA
  • Hard to get wrong in the cold or dark  --  even with your hands behind your back
  • Easy to untie even after extreme loading  -- try it, the OH has a 'hinge' on both sides and the slipped double has plenty of meat to allow it to move, plus the 2/3 loops seriously spread the load on the loop side of the OH
  • Secure -- the end is either secured against the SP('s) or is one of the holding loops, there is nothing that can slip out or go anywhere
  • Strong  -- leaving the best to last - it has the long diagonal load shifting structure of the '8' and a lot more meat to 'give' in the case of shock loading.
  • ..and did I mention that you can tie it midline?

OK, you cannot reasonably tie it though your harness ring, but then no one has stated that need yet, and as I mentioned earlier, it is my preference to clip to my harness/belt anyway.

Immediate reactions - no way, it's only a flimsy little old OH - it can't be any good - but before anyone jumps off in that direction give it a try in climbing rope, you might just be surprised - this simplest of knots really has an awful lot going for it !!

Derek

agent_smith

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Re: Janus Bowline or an equivalent secure bowline for climbing/rescue purposes
« Reply #51 on: December 28, 2008, 02:56:26 AM »
Firstly thanks for the feedback/comments.

First to SS369:

Quote
Just because I feel the need to ask: Is this, when it is potentially settled, going to be any better, in any way, than the much used fig.8 tie in? Seems to me the fig8 has done a reliable job for a while now. Pretty compact, easy to tie, relatively easy to untie, been secure.
Just asking.
Scott

Response: In the world of climbing, dynamic (EN 892) ropes are getting thinner and crucially - lighter in weight. Hardly anyone lead climbs with 11.0mm diameter ropes anymore. The sweet spot is now in the 9.1 - 10.2mm range. For example, Beal make a 9.1mm diameter rope called a 'joker'. It is certified in all 3 categories or single, half and twin.

Thinner ropes cinch up tighter after lead falls (ie potentially hard falls). The figure 8 eye knot becomes quite difficult to untie after repeated hard falls (as happens when you are working a new route or climbing at your limit).

In top rope climbing, 11.0mm diameter ropes are still popular and obviously you dont take long hard falls in top rope climbing (unless the belay person has failed in his basic duty of care and dropped you). Therefore, you will tend to find that figure 8 eye knots are a popular tie-in method in this context.

So the issue... modern climbing ropes are getting thinner. 11mm ropes are no longer the norm. Figure 8 eye knots are definitely harder to untie after repeated lead falls. Consider also that the climber would have tired hands - from all the hard cranking on tiny pockets and holds with forearms 'pumped'. I know that after some hard climbing I couldn't even squeeze an orange to save my life...imagine trying to untie a stubborn knot in this scenario. Also, consider extreme cold and numb fingers in alpine environments.

I agree that a figure 8 eye knot (ABoK #1047) is easy to tie and learn - but it still requires a 2 stage tying process. Anchoring your rope to a sturdy tree can be slow and cumbersome (for inexperienced persons). They would first need to form a simple 8 and then go round the tree and then re-thread the rope back through this pre-formed knot to complete the process.

A bowline avoids this tedious process...

Consider also that the ability to tie a rope directly through the harness to make a direct rope-to-harness connection is of paramount importance (see my rant below). Again, the bowline avoids the tedious 2 stage tying process of securing the rope to your harness.

There is also the needs of vertical rescue teams - in a patient/stretcher/medic scenario there could be loadings of up to 250kg at the knot interface with the stretcher. Again, the knot needs to be secure, stable and strong (and easy to untie after high loading). And Bowlines seem to be the norm in the USA with SAR teams... can anyone explain this? The 2 forms of Bowline that are in common use in the USA include the Yosemite bowline and what I will call a long tail bowline (a standard #1010 but with super long tails). The long tails are used to make a backup tie in for the medic and the patient (if the patient is wearing a harness in the stretcher).


To DerekSmith:

Thanks for the drawings. I tied the first variant - yes its simple but I don't think it adds anything remarkable to the subject. Its not blowing any wind up my skirt! It is a contribution - but I don't think it is the equal of say Dan Lehman's End Bound Double Bowline (EBDB) or my variant the EBSB with yosemite finish. There could be issues with novices tying this form and not leaving enough tail protruding or perhaps too much tail and getting confused (we call it 'house-keeping' in Australia). In that, too much tail can become a trip/snag hazard or can interfere with attempts to clip into a carabiner (tail gets in the way). I prefer the yosemite finish because it places the tail on a parallel exit path with the standing part - thereby allowing users to tie a backup double overhand knot to finish (if they wish). It also keeps the tail out of the way which is a good thing.

As for the second drawing - I can't understand it - is there an error with it? - The red line is broken/disjointed from the blue line... Can we also agree on some terminology - you use the the term Working End (WE) instead of tail..any reason for this? I would like to establish common ground for defining the anatomy of a knot.

I have one other major issue - and that is the notion of using a clip-in method of securing a rope to a climbers harness (ie the carabiner forms the interface between the users harness and the eye knot). This is DANGEROUS!

Why is it dangerous. In a word; cyclic loading.

Cyclic loading causes the carabiner to rotate into a sideways (ie cross-loading) configuration.

The weakest part of a carabiner is the gate. The last thing you want to do is direct the force of a fall across the gate of a carabiner - this is simply a bad idea.

I will point out a landmark case here in Australia known as the 'Jade Francis case'.

Jade Francis was 15 yrs old when she became a paraplegic in an indoor climbing gym accident.

The owner/proprietor of the climbing gym was convicted of an offense under the Occupation Health & Safety (OHS) Act for failing to provide a safe and healthy workplace and safe system of work.

It was held that using a clip-in method (with carabiner) was inherently risky on account of cyclic loading which leads to rotation and misalignment of a carabiner.

There was a public outcry and the State Government responded by enacting legislation to prevent clip-in attachment methods at artificial climbing surfaces and other fixed sites such a challenge ropes courses.

Both the manufacturer of the carabiner and harness and the supplier gave opinion evidence in the court that cyclic loading leads to carabiner misalignment. They testified that tying the rope directly into the harness was the only way to eliminate the risk of cross-loading a carabiner (that is, remove the carabiner from the equation).

...

Now I can tell you from my climbing experience (which is considerable), carabiners do rotate in your harness. I see it happen virtually all the time. It is a particular problem in abseiling - as you make your way to the edge you get cyclic loading events and it is not uncommon to see the locking carabiner rotate into a cross-loaded configuration with the descending device bearing on the gate. I see many abseilers almost subconsciously looking down and monitoring their carabiners and giving it a bump with their hand to re-align it. But, it only takes one momentary lapse of concentration and you have unacceptable risk.

Edit: It is also a common occurrence while belaying a climber - the locking carabiner in the harness is subject to cyclic loading events which cause the carabiner to rotate and become misaligned. Again, if you watch a belayer in action, you'll see that they (the belayers) regularly look down and monitor their carabiner alignment and give it a bump with their hand to straighten it out (so the load is directed along the spine and not across the gate). The reason they look down is that they know (like an unconscious competence) that carabiner misalignment while belaying is common... it tends to be more of a problem while belaying a lead climber than a top rope climber - but it can also happen easily in a top rope scenario.

I would argue that if this is the way you have been attaching a rope to you harness - you have been LUCKY! Its a numbers game... one day you'll get caught out just like poor Jade Francis.

Anyhow, I am still keen for feedback/opinion on the EBSB with yosemite finish..



agent smith


EDIT: Added important fact that ropes are getting thinner, but more importantly, they are also getting lighter in weight (weight per meter is a crucial factor when climbing long hard routes).
« Last Edit: December 29, 2008, 02:53:18 AM by agent_smith »

agent_smith

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Re: Janus Bowline or an equivalent secure bowline for climbing/rescue purposes
« Reply #52 on: December 28, 2008, 05:12:31 AM »
Okay, just completed a quick field test of the EBSB with yosemite finish. Please refer to figures 26 & 27 on p9 of my Bowline analysis paper VER 1.7.

I took a 1.0m lead climbing fall on to a Beal Joker 9.1mm diameter dynamic (EN 892) kernmantel rope.

I'm still alive, which is a good sign. The EBSB was easy to untie and held its structure and form after the shock load.

I repeated the fall using a figure 8 eye knot (#1047). This knot was very hard to untie...in that it took some working to loosen it.

I weigh 100kg.

I am reluctant to take bigger falls at this stage - mainly because I'm a coward and secondly, it stresses and strains my gear (and my nice new Joker rope).

I also did some static hangs in my garage where I suspended myself from a bolt using a length of my Joker rope - and did a few aggressive bounces up and down to stress and load the EBSB.

Again, the knot performed well in that it held its shape and form and was easy to untie after loading. I repeated this bounce test using a Butterfly knot and a Figure 8 eye knot to anchor the Joker rope to a bolt. The Butterfly knot was very difficult to untie - took quite some effort before I eventually managed to loosen it. The figure 8 was also a little difficult to untie, but not as hard as the Butterfly.

Am still waiting for some considered feedback/opinion on this End Bound Bowline variant... I don't think it has been published before and I can find nothing in any texts anywhere recommending its use.

Dan, what say you?

I imagine you might have played with this variant while devising your EBDB, but did you publish it anywhere? Is it reported anywhere by anyone as a possible life support knot?

I am somewhat excited about the structure of this knot - it borrows from Dan Lehman's EBDB masterpiece but simplifies it... I know you are not a yosemite supporter, but creating such a finish sets the tail on a parallel path with the Spart thereby mimicking the form of #1047 - which has some spin-off benefits...eg, some users are adamant about using a double overhand knot to secure and finish the bowline. It also keeps the tail well clear of the eye (which I think has merit).


EDIT: Did a google search and found this link: http://www.ukclimbing.com/articles/page.php?id=4

Has anyone ever heard of an Edwards Bowline? (attributed to Rowland Edwards)

I tried it but I am not a big fan...however it does place 3 rope diameters into the nipping loop but the methodology is a little contrived for me... I prefer the EBSB with yosemite finish (but I am biased).


agent smith
« Last Edit: December 28, 2008, 08:52:45 AM by agent_smith »

DerekSmith

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Re: Janus Bowline or an equivalent secure bowline for climbing/rescue purposes
« Reply #53 on: December 28, 2008, 04:02:47 PM »
Wow, you bite !!

Nomenclature --  WE working end - the end you are working with to tie the knot - it isn't a tail until you have finished with it and as I was continuing the knot, it was still the WE.

First variant -- indeed it does not have the mass of rolls and tucks you seem to think confers security.  Instead it utilises the principle of self holding, the three functional holding parts of the knot each hold one another, much like the constrictor holds itself.  Follow the functional gripping parts around and you will see how each holds the next like a snake eating its own tail.  It is the foundation of a stable knot and should not be confused with tangles that rely on mass friction to imbue stability.

Second variant, sorry, missed out the curve which shows the old WE taking the new red path (this one is pretty, but not as good as the first) - no wind up your knickers here.

Re clipping in.  I did make the point that I use the DMM Belay Master



After locking the screwgate, the clamp is closed creating an 8 configuration.  This design stops cross loading and prevents accidental opening of the screwgate.  It also nicely isolates my harness from the climbing/belay rope and equipment.  I was not aware that your legislature had stepped in and made such attachments illegal.  That is sad, because the law is always a blunt and ignorant tool and can never be appropriate for all occasions, but will be applied so none the less.  Luckily, you have to live with it and not me.

As to your assertion that climbing is a numbers game, you are Oh so right, and that is why it is critical to have the thinking brain in gear all the time and always consider overall system functionality.  I had been climbing for over four years before I saw a bowline slide open.  Pretty new shiny climbing rope, a class of beginners had been roped up and checked and were about to make their first assents of a nice 'Nursery slab', then before my eyes, a properly tied dressed and set bowline simply untied itself and the climbing rope hung open ended through climbers harness.  Once in four years, but that number was 'up', only by luck that the situation was not perilous.

I tried a couple of security tie outs, but finished up tying the bight back lock method described in variant three.  Little did I know at the time, it was also giving me considerable protection against the greatest failing of the bowline - its fundamental design flaw - it is designed to be just about the weakest knot possible.  Fine for mass tiedown, non critical applications but how on earth did it ever become the primary link between a climber and their lifeline?  Probably no one gave it much thought ??

Take the Sheetbend - a half hitch around a bight(Becket).

Easy to tie and release, only secure if the load is constant and can flick open if the load evaporates, but strength wise this little knot is surprisingly good.  The half hitch (or 'simple hitch') is used as a self holding load shedding fixing.  The load is shed frictionally through a two diameter round turn, and the end is clamped by the sheet load.  The more load, the more the end is clamped and the more the frictional load can be generated into the two Becket lines.  The load transfer geometries of this knot are extreemly good and hence its surprising strength.

But the Bowline is the same structure, a half hitch to a bight, where then did the strength go?  The answer comes from a total misuse of the half hitch.  Instead of simply being a self gripping structure, in the Bowline the HH becomes a critical load transfer point with almost the worst possible geometry.

To break a cord by hand, you make two interconnected loops in the hand and snatch load one end.  The load is focussed on a single diameter 180 degree turn - maximum compression on the inner face and maximum elongation on the outer face and the cord snaps at the junction of the loops.  The Bowline has almost an identical construction in its primary load path, created by loading both sides of the HH.  The cord makes a 90 degree turn about itself (single diameter), so as the load force enters this critical point it immediately meets the restraining force from one side of the load loop.  This is the weak spot of the Bowline and cannot be designed out without it becoming no longer a Bowline.

The Bowline is great for quick, bulk, non critical fixings.  It is arguably the last knot you would use in a life critical application.

"It is a numbers game", yes and the greater the complexity and the higher the frequency, the harder it becomes to ensure the numbers are low enough to 'take the risk'.  Ropes are changing - getting thinner, lighter and stronger.  But thinner means smaller and therefore tighter one diameter turns and this is making the critical weakness of the Bowline ever more relevant.  Enhancements like the double turn and the Edee Bedee are good, but they do not focus on the critical weakness of the Bowline, while changes in rope may well focus so heavily on this weakness that it might push the numbers game into another actual event.

So I repeat, safety is about "having the thinking brain in gear all the time and always consider overall system functionality".  It is not about blindly following the law, it is not about blindly believing that new rope design does not bring with it its own issues and it is not about deliberately choosing a knot known to have a fundamental strength flaw.  Go figure.

Is it starting to feel chilly around the knickers yet?

Let me know if you want to discuss the Bowlines G spot further (in this case, G is for grief).

Derek

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Re: Janus Bowline or an equivalent secure bowline for climbing/rescue purposes
« Reply #54 on: December 28, 2008, 06:01:22 PM »

EDIT: Did a google search and found this link: http://www.ukclimbing.com/articles/page.php?id=4

Has anyone ever heard of an Edwards Bowline? (attributed to Rowland Edwards)

I tried it but I am not a big fan...however it does place 3 rope diameters into the nipping loop but the methodology is a little contrived for me... I prefer the EBSB with yosemite finish (but I am biased).


agent smith

This is a variant of the second alternative I showed before, except it only collars one of the loop (eye) lines and adds yet another 8-esque end tuck.  Yet more attempts to prevent that falling apart which is natural for the basic Bowline.

But look in detail at the structure.


image courtesy of UKClimbing.com

The loaded HH (simple hitch) structure is there in its full glory (even though there are three diameters in the nipping loop there is still a 90 degree single diameter load transfer 'G' spot).  But I guess the author does not worry about this because he claims the Bowline has the same strength as the fig 8 and the only reason people are taught the 8 is because it is so easy ???

It also has the credit of having been posted on UKClimbing, so it must be right - mustn't it?

Stuff like this sends the shivers through me, loads of faux security yet the 'G' spot sits there in full view and it's even given the accolade of being as strong as the '8'.

Derek
« Last Edit: December 29, 2008, 12:02:19 AM by DerekSmith »

DerekSmith

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Re: Janus Bowline or an equivalent secure bowline for climbing/rescue purposes
« Reply #55 on: December 28, 2008, 07:03:54 PM »
Okay, just completed a quick field test of the EBSB with yosemite finish. Please refer to figures 26 & 27 on p9 of my Bowline analysis paper VER 1.7.

I took a 1.0m lead climbing fall on to a Beal Joker 9.1mm diameter dynamic (EN 892) kernmantel rope.

agent smith

I just took a look at the spec for Joker.  37% extension !!  are you sure you are not climbing on bungee cord?

You stated that you took a 1m fall - could I ask what Fall Factor was involved?

Derek

Dan_Lehman

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Re: Janus Bowline or an equivalent secure bowline for climbing/rescue purposes
« Reply #56 on: December 29, 2008, 01:36:45 AM »
I could reply in msg.-per-msg., or try to limit that number; I'll attempt to limit the posts,
but there are many things to respond to between Agent_Smith & Derek!

Firstly, thanks to A_S for the good work in updating ... ;
but no thanks for the Yosemite-finish predilection--the Yo-disease is one to contain.

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I acknowledge DL's points re the inherent difficulties with adding a yosemite finish
but don't these issues also occur with a standard figure 8 eye knot (ABoK #1047)?

No:  turns are 2-diameter, and there's no simple "(Half)Hitch"/"loop" structure so readily loosened.
Nor can the Fig.8 be misformed in setting, as can the YoBowl.
Also, we're trying to improve on that, not copy it.  (Well, okay, the Lehman8 does both.)

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Quote
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Oh, yes, Clove Bwl.  A beauty of this and --better, IMO-- Cow Bwl are the "mirrored"
variations in which you "collar" both ends of the loop-making parts, "coming & going"

Sorry Dan, I'm lost here.  You might need to hold my hand a bit and walk me through once more please...

Fine, but I want to see your *work* first--following the steps given in post#8 up until you are lost.
It just isn't that difficult (esp. in that, as with the Fig.8, there are several workable exact knots indicated).

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Again, which variation is the holy grail?  . . .  for mission-critical applications in a life-support role.

I remarked above about the intended user domain--pointing to dffering needs & materials
between SAR/caving & rockclimbing, e.g..  One knot might not fit all as best.  I sense that your
explorations have been accompanied, physically, by only a limited (maybe just one) rope set;
in maybe stiffer ropes in which I'm trying these variations, many just don't feel good at all.

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[re Derek's 1st-shown Bowline extension (shown in Rigger's Apprentice and elsewhere) of tucking
the end back perpendicularly between SPart & collar]
This end is now clamped by the bight
which is clamped by the HH
which is now clamped by this returned end.    .:.  The knot is now self holding.

I don't find the HH so well clamped by this tucking, esp. in firm rope, which as has been pointed
out repeatedly above--the collar is not snug around the SPart and things loosen here.
Moreover, the end is given a hard/1dia turn en route to the tuck.

---------
In Derek's 2nd secured Bowline, well, that's interesting but a long-winded way to do less well
what I've described above as "Janus" variants--one of which Agent_Smith has sort of shown
in version #6 of his pdf ("sort of" in this sense:  the tail must be tensioned more, and the collar
around the eye legs drawn tight, not allowing that broad spread of the image (the goal is to
keep the SPart-side eye leg up snug to the nub, providing thus sufficient friction on the SPart
to prevent it from loosening into the central nipping HH/loop)).
There is a similar variation for the Common Bwl (#1010).

---------
The 3rd Bowline variation Derek presents--that of tying the knot with  a bight, and using the
nature of its "end" (i.e., its being a bight/loop/eye) to completely lock the knot.  This is a very good
knot to use vice the Fig.8 for TR (top-rope) anchors where the two ends are taken to separate
anchor points (redundancy); it can take a day's worth of climbing and be easily untied.  Also,
by some dressing of it (relatively obvious), BOTH potential SParts look to have beautiful paths
into the knot--look quite strong, to me:  they bend around **4** diameters of rope to compress.

A quite similar knot can be tied in the more usual method, by repeating the threading-rope-through-harness
and then the "rabbit-out-of-hole-&-around-tree-&-back-into-hole" collaring , and then, take the end
around under (re "front" view as freshly defined here in the pdf from Agent_Smith) all legs and have it
dive back down through the central nip (bing:  diameter #5) for a securing lock)--this, and some other
like finishes, look much better to me than what is now done by some climbers, which is to tie the usual
Bowline on a Bight in this "re-weaving" method (and wasting the end in forming a shadow "HH"/loop).

And re clipping in, geeesh.
1) "cyclic loading" isn't the issue:  it's UN- & RE-loading (with the emphasis on "un-", allowing the
'biner orientation to change).  Frankly, I think that the rockclimbers' lust for using locking 'biners
everywhere is unwarranted; using two non-locking 'biners, opposed , would be my choice.
2) the locking 'biner could be employed to simply clip off the bight-end after direct, through-the-harness
attachment with the rope bight (which, yes, looses Derek's ability for easy unclipping).  (On some
rockclimbing one can read the specious rationale against a 'biner as it being "another link in the
system, which increases chances of failure" --um, oh sure ... .)

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I liked the security of this knot and only moved to the '8' because of the undue strain the Bowline imposes on the rope if the need comes to load it heavily.

Regarding your last question - "is any bowline going to be preferred to the '8'?", not by me it  won't and that is down to security and strength

This makes little sense to me.  Strength of many knots--indeed, ANY knot--is adequate in the OP's use,
but maybe there's some wear'n'tear aspects of those-testing-weaker-on-slow-pull.  One can read all
sorts of data for the Fig.8 (which, need I reiterate, is never specifically oriented) and the Bowline (which
allows of various settings, and some variations).  And NONE for the Derek-used 4dia-crunching version,
which I'll guess tests stronger than most Fig.8s ("most actually tied like this/that" Fig.8s, per user, I mean).

The Bowlines with 3 diameters in the central nipping loop do not have a known test history.  (I have just
returned from the beach with some 400' of 7.x & 8.x mm marine kernmantle :  yes, far from ideal (although,
by golly, someone might need to knot just such material--and should that  act be guided by tests on
new  rope?!), but at least I hope it's stable enough (equally strong/weak overall) to shed some light
on knot mechanics (on that in frictive rope, anyway).

And these extensions of the Bowline, made initially to redress the vulnerability to loosen in some
materials, are going to be secure, and maybe more so than the Fig.8 (which can resist being set
tight (despite risking becoming "welded" tight upon heavy loading), although usually without much
risk of coming untied, OR with the loose knot being prone to capsizing--it isn't (it would only be
quite vulnerable to flyping on ring-loading, which loading might be completely unlikely).

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    * Easy to tie
    * Easy to remember
    * Hard to get wrong in the cold or the dark
    * Easy to untie even after extreme loading
    * Secure
    * Strong

The bowline fails on the last two
 and even the more secure variants fail on the last one and start to loose out on the first three.
 Even my preferred bight method failed on the last requirement.

The '8' fails on the first four, especially the fourth.

As argued above, these extended bowlines w/3-4-5 diameters within the nipping loop
should be strong.  Might they induce friction-heat on cyclical loading (such as mooring
a boat), I don't know, but the looseness inherent in the knot might come with this issue.
But I completely disagree with Derek's assertion here--and so should he, as these knots
don't fit his rationale of the sharp turn.  (Moreover, testing of the Bowline often shows it
to be rather strong, as noted.)  And these variations are secure--at least adequately so
for various uses.

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OK, tie a nice fat slipped overhand knot. ...

This topological structure can go into various forms--such as #1696, intended qua hitch
(and found by me in a net's anchoring to single bricks in a museum (Rock Hall, Maryland, USA))--;
the general tactic of inserting a bight end of an eye into the nub and then doing the "back-flip"
works in all sorts of knots--and the Honda knot would be my Overhand orientation of choice,
for ease of untying.  I do not believe this other one will be.

The ability to form the eyeknot easily in the end--not using a bight-tying method--should be
obvious for tying in, which is in the OP; and why start off with something limited in this regard?

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you use the the term Working End (WE) instead of tail  ... any reason for this?
I would like to establish common ground for defining the anatomy of a knot.
[VS]
Nomenclature --  WE working end - the end you are working with to tie the knot -
it isn't a tail until you have finished with it  and as I was continuing the knot, it was still the WE.

Yes and no:  Derek points to an aspect that I think applies also to the standard use of "[SPart]"
--i.e., an implicit state of the knot, either finished (re "tail") or being tied ("WE" & "SP").  Good to keep in mind.

But re WEnd, the fact is that in some knots the part that one is actually working  with is not
the end, or not the side that will become a "tail"--and ditto, of course, for SPart--, but I get the sense
that it's generally presumed that the matching exists (although there's not so well established a
term for my use of "SPart"--"live end", "mainline" are a couple I've seen.  Tricky aspect, and one,
yes, it will be helpful to get clearly articulated.

I also want a term to designate any/all of the parts of a knot that leave the "nub", which in the case
at hand are, in my terms:  SPart, end/tail, eye legs (SPart-side, end-side).

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I also did some static hangs in my garage where I suspended myself from a bolt using a length of my Joker rope
 - and did a few aggressive bounces up and down to stress and load the EBSB.

Although neither of these loadings should've been in doubt.  Rather, it is the jostling (& rubbing against rock!)
of the knot without tension that is of greatest concern for security.  (Except in, e.g., tying a Bowline in super-slick
HMPE (bare, not what climbers call "Spectra") or other material where it has been seen to slip by great tension.)

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I repeated this bounce test using a Butterfly knot and a Figure 8 eye knot to anchor the Joker rope to a bolt.
The Butterfly knot was very difficult to untie - took quite some effort before I eventually managed to loosen it.
The figure 8 was also a little difficult to untie, but not as hard as the Butterfly.

And I'd better remind readers that both of these knots can assume various orientations,
and that the Butterfly is Asymmetric, so varies depending on which *end* is loaded in opposition to the eye
(I'm assuming that you weren't talking about through-loading  this mid-line eyeknot.)

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Am still waiting for some considered feedback/opinion on this End Bound Bowline variant...[aka EBSB]
I don't think it has been published before and I can find nothing in any texts anywhere recommending its use.
Dan, what say you?

GRATUITOUSLY COMPLEX ;  TOO CLEVER BY HALF ! !
--especially regarding tying it:  the more tucking you require, the more of a pain in the ass
it is to do, and the people who will do it, and fewer times they do so!  And, not so effective re security.

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I imagine you might have played with this variant while devising your EBDB, but did you publish it anywhere?
Is it reported anywhere by anyone as a possible life support knot?

The EBDB's end-binding wrap doesn't work so well on a single Bowline, as it wraps around
just 2 diameters, which is a poor, non-circular-like bending.  One CAN orient the end so that
it wraps around the end-side eye-leg, and thus gains a diamter, and holds better.  But if one
is going to this trouble, I think it's worthwhile to use the EBDB, which should still hold better
(and itself allows for the inclusion of the eye-side eye-leg, but that I think goes into excess
bulkiness and diminished/dubious returns in behavior).

There are all sorts of knotting components , so to speak--the back-flipping of a bight-end,
the end-wrapping, the YoBowl-tucking, the "doubling" of some part, ... :  one can work out
a table of combinations and fall over from exhaustion at having to give each one consideration.
(It's best if the YoBowling is first to go, to ease this situation.)  And to this, you added this
"Eureaka" aspect of another tuck of the end beneath its very binding wrap!!  How do you
expect to tighten this wrap, which is loose 'til the end is stuck through it, and then ... ?
--leave sufficient end to have as a small bight's worth of material to tighten down and then
have to pull that excess out to dangle?  --quite wasteful of material & time & effort & memory.

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but creating ]b]such a finish sets the tail on a parallel path with the Spart[/b] thereby mimicking the form of #1047 [Fig.8]
- which has some spin-off benefits:  eg, some users are adamant about using a double overhand knot to secure and finish the bowline.
It also keeps the tail well clear of the eye (which I think has merit).

We keep going over this.  If you want an easy Strangle hitch tie-off, the Janus bowlines are good,
and they are very quickly tied.  All this "end out of the eye" business leaves me cold:  I've never much
found the end to actually  be IN the eye (the normal Bowline's SPart's draw on the end in fact
pulls it up to one side).  But I've pointed out ways to avoid this.  A simple step to do both is let those
who suffer this defect in desires tie off the end with the strangle from wherever it ends up.  The Janus
versions, incl. those with a "double Bowline" base, and the "mirrored" ones (which you need to take
ALL of you time spent fancying the Yo-ness into learning instead   :D  ) send the end SPartwards.

To MY mind, having the end going SPartwards implies that, for a LEAD climber, with a dangling eyeknot
tie-in, gravity is holding the end from easy loosening.  (Though I'm not implying a need for an "Up" and
a "Down" pair of knots!)

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Has anyone ever heard of an Edwards Bowline? (attributed to Rowland Edwards)
I tried it but I am not a big fan...however it does place 3 rope diameters into the nipping loop but the
method[ology] is a little contrived for me... I prefer the EBSB with yosemite finish (but I am biased).

Yes, it has been discussed, questioned.  "Too clever by half" I deem it, also.  --and seemingly with the same
fancy for YoBowling.  It's a messing structure entailing/allowing too much slop in formation, though it will
likely perform fine, all the material keeping things pretty well in place.  But it does so with less *directness*
and clarity than what I've presented here.

--dl*
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Dan_Lehman

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Re: Janus Bowline or an equivalent secure bowline for climbing/rescue purposes
« Reply #57 on: December 29, 2008, 01:47:27 AM »
[2nd half, split as over 20k characters!]

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Take the Sheetbend - a half hitch around a bight(Becket).
Easy to tie and release,
only secure if the load is constant and can flick open if the load evaporates,
but strength wise this little knot is surprisingly good.
The half hitch (or 'simple hitch') is used as a self holding load shedding fixing.
The load is shed frictionally through a two diameter round turn, and the end is clamped by the sheet load.
The more load, the more the end is clamped and the more the frictional load can be generated into the two Becket lines.
The load transfer geometries of this knot are extreemly good and hence its surprising strength.

But the Bowline is the same structure, a half hitch to a bight, where then did the strength go?
The answer comes from a total misuse of the half hitch.  Instead of simply being a self gripping structure,
in the Bowline the HH becomes a critical load transfer point with almost the worst possible geometry.
...
The Bowline has almost an identical construction in its primary load path,
...  and cannot be designed out without it becoming no longer a Bowline.

The Bowline is great for quick, bulk, non critical fixings.
It is arguably the last knot you would use in a life critical application.

Incredible!!!
Derek, was the URLink above to Dave Richards's testing not working for you?
Or, frankly, just about ANY / every data shown for some "sheet bend" and "bowline" ?!!!

Because in most if not all cases, the eyeknot is shown as stronger and often considerably stronger
than the bend.  And, i.p., and most relevant to the OP (the kernmantle) domain, Richards's testing
shows (1) much weaker bends, both single AND double, and (2) INsecure bends--which slip WHEN
loading is increased, hardly a testimony to greater "frictional load" and viability for such loading.
(Former forum poster Jimbo remarked that this is what he found in sheet bends he stressed.
Commercial fishers, perhaps gratuitously, usually take some means to secure the end.)
Richards notes, for 10.5mm dynamic rope:
  |  With 8" tail,  pulled to 912 lbs. resulting in 4" tails ;
  |  @ 1600 lbs.,  the knot pulled out.
Heckuva genius in knot structure you have there!!   :P

I think that your view of the Bowline's geometry is overly *flat*, 2-dimensional; there are indeed
ways--and shown here, in fact--to design  a better bowline SPart curvature:  starting by putting
in more material for the loop to compress--and orienting it just so--is exactly that!

As for "non-critical fixings", that will come as a big surprise to most of the maritime users,
who have a lot of history of its being so used.  Now, they have some new materials to use
as do others, and there will be some adjustment, but the Bowline persists.  (But in the
trawler mooring lines, darn, there are a bunch of other things--including the capsized bowline--
put to work, and I'm not sure how much of that is by design.)

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but I guess the [Edwards Bowline UKClimbing article] author does not worry about this because he claims the Bowline
has the same strength as the fig 8 and the only reason people are taught the 8 is because it is so easy  ...
Stuff like this sends the shivers through me, loads of faux security yet the 'G' spot sits there in full view
and it's even given the accolade of being as strong as the '8'
In full view !!!
Here's what another author has to say about these sorts of things, maybe also w/o worry:
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[Craig Connally, The Mountaineering Handbook (c) 2005 ; p. 139]
I've strength-tested rethreaded figure eights against Yosemite bowlines many times; it's an
easy test, fry, wet, or frozen.  Advantage:  bowline, but many knots area adequately strong
for tie-in--that's not what determines the best choice.  More important for mountaineers are
the ease of tying the knot quickly and correctly and the ease of untying it.

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Enhancements like the double turn and the [EBDB]  are good, but they do not focus on the critical weakness of the Bowline,
while changes in rope may well focus so heavily on this weakness that it might push the numbers game into another actual event.

 ???   The EBDB, and most of the extensions discussed here, exactly promote putting in an extra
rope diameter for the SPart to bend around, making it bend more gently (and there are further
dressing elements that go some way to ensuring a better vs. worse curvature--just having 3 strands
there isn't a guarantee of goodness, and this is something I have noticed), so the supposed increase
in bending abuse from smaller diameters is countered.  But I think of the bending as something that
scales--or that the individual multi-filament fibres are WAY far from being sharply bent--;
re the rope composite, it is the same measure in diameters, hawser to cordelette!
But you can check Richards's test results for 7mm accessory kernmantle vs. 12.7mm rope and see
if your assertion rings true for the Bowline:  in fact, by about 4 %-points, it doesn't.

So, your
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safety is about "having the thinking brain in gear all the time and always consider overall system functionality".
has to beg the question re history and what hard data we have readily at hand,
even seemingly cut to order, for this OP.
(Chisholm's "reasoning" on "Why the bowline breaks" meets with like challenges from reality.

--dl*
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agent_smith

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Re: Janus Bowline or an equivalent secure bowline for climbing/rescue purposes
« Reply #58 on: December 29, 2008, 02:16:36 AM »
Thanks for all of your considered feedback and critique DerekSmith.

I don't want this thread to divert to off-topic discussion - particularly on the legalities and intricacies of rope attachment methods for climbing. I will repeat my preference for direct tie-in methods (ie direct rope to harness interface) in contrast to carabiner clip-in methods. The DMM carabiner you refer to is not widely known or immediately familiar to all of the visitors to this forum (since many may not be climbers). What concerns me is that your words may be taken as advice since you might be perceived to be an expert on the subject. It is conceivable that some may try to emulate or try your clip-in technique using a standard locking carabiner with no captive pin, forged eye or retro-fitted device for rope containment.

However, very briefly, I should inform you that I am often called upon by Government authorities and Occupational Health and Safety inspectors to provide what is known as opinion evidence (ie expert witness testimony) in court proceedings in Australia involving height related accidents.

I would like to email you a court report I prepared for another incident involving the clip-in method (I have deleted the names of those involved for privacy reasons).

The carabiner had a captive pin to prevent cross-loading and other misalignments.

This did not stop a horrific accident involving a school boy who fell approximately 13m and sustained severe injuries. The failure mode will surprise you when you see my report...

Please confirm your email address (via private message) and I'll send it to you...

...

Back on topic.

There is another factor I ought to mention with regard to the search for the holy grail of a bowline variant that is suitable for life support applications (eg in climbing and rescue contexts).

And that is, the knot must appear to be secure. This is both a visual and a psychological factor - for example, when I momentarily peer down at my rope tie-in while executing a tricky sequence of moves on a difficult climbing route, I like to see that all is in order - dressed, compact, shape and form, etc.

Your first bowline variant has merit DerekSmith, but I just can't see it being adopted in mission critical life support applications - for the simple reason that it doesn't look secure! This is a tacit implication and one which is not easy to quantify.

I will have a play with the second knot and comment...

As for the Joker rope, I failed to mention that I climb with 'double ropes' - that is 2 x EN 892 category 'half' ropes. When the joker rope was released to public, I immediately adopted it as one of my double ropes. I try to clip the joker rope into protection in crux sections of a route - so in the event of a fall, it will be the joker 9.1mm rope that takes the initial impact. My other rope is a standard 9.0mm diameter 'half' rope.... double ropes offer many advantages over single rope systems but I wont go into detail here as it is off-topic...

..

The EBSB with yosemite finish does require a couple of tucks to finish but this is just conditioning in my view. It could be argued that all knots require a degree of concentration and attention to detail. This can be learned. Anyhow, I'm still on the hunt for my holy grail (remember, for life support applications of a mission critical nature). At this stage, the pendulum has swung in favour of the EBSB variant for me... but I am actively searching.

agent smith

EDIT: Jeesh... Just missed your post Dan - we must have crossed posted at the same time. I am taking time to carefully read and understand your considered feedback...
« Last Edit: December 29, 2008, 02:49:12 AM by agent_smith »

TheTreeSpyder

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Re: Janus Bowline or an equivalent secure bowline for climbing/rescue purposes
« Reply #59 on: December 29, 2008, 02:38:03 AM »
Our we saying the 'lock' in a SheetBend is a Half Hitch; even though all the force terminates on one side of this 'mechanical module'/no Tension in its Bitter End?  And Simple Hitch is a Half and not a Full Hitch?  Or would it be a Hitch if mounted to something else, but as a Bend, it is then a Half Hitch?

To me a SheetBend has a Hitch to a Bight, and a SheetBend to self to form eye is a Bowline, but also the Hitch has tension on both ends, so is now a Half (in a BowLine)?  Another difference, i call an eye a Becket(and SheetBend to Eye a Becket Hitch, and an Eye with Hitch around (but not thru); then Bight of Hitch leg pulled down thru eye and locked with rod a Toggled Becket).

i've used a DBY plenty to trust it in the correct lines; which are lines you are familiar with and that aren't too stiff (fishing line, tight doublebraids, others as pointed out).  i too think we keep looking for the Holy Grail hear.  But, keep coming back to nothing is perfect in all situations, line stiffnes-strength-elasticity-slipperyness, personal educations, age group, purposes, load ranges, impacts, other similar knots used in said field etc. all are part of the mix too, for choosing one over the other tailored to suit.

Nice lil'paper; but due to the above insights that Smith points out; it does of course need a disclaimer?


 

anything