Author Topic: Janus Bowline or an equivalent secure bowline for climbing/rescue purposes  (Read 153762 times)

agent_smith

  • Sr. Member
  • *****
  • Posts: 1470
Re: Janus Bowline or an equivalent secure bowline for climbing/rescue purposes
« Reply #75 on: December 31, 2008, 02:53:41 AM »
Okay, finally figured this variant out:

Quote
1) "Take the Cow /Girth Hitch as a base;
CHECK, YOU GOT THIS.  (I will note that in the COW base, unlike the CLOVE, one can reverse-orient ends.)

2) "do the bowline maneuvreing with the tail on both sides,"
BUT YOU DID >>>NOT<<< do this.  We see thus only the one, usual collar.   b o r i n g  .  --a Water Bowline-like knot.
You need this "on both sides":  recall the moniker, "MIRRORED"--that means as though
a mirror was the dividing plane across (perpendicular to) the mid-section of the nub,
bisecting the Cow/Girth hitch base.  The collars *reflect* each other (each around an
end of the Cow H.).  I guess we could say it's a Janus-ing of a Clove/Cow/... base, then!?
And the reflection naturally provides the third diameter through the loops
(which strictly speaking breaks pure *reflection*).

Thanks for SHOUTING the instructions at me - that did the trick!

Will photograph and upload in a few hours...

My initial impression is that these 'mirrored' bowlines are a technical exercise in knot tying but do not really impress upon me as offering anything elegant and simple in structure. Okay, they are seemingly secure and stable but I just can't see the masses adopting it into their daily repertoire.

I know you don't like me stating this but I would opt for my so-called EBSB with yosemite finish before considering a mirrored bowline (but tht's just me).

Am also still trying to fully understand the geometry and possible benefits of DerekSmith's crossing knot/munter variation of the bowline. Now I see that structure as being much simpler than the mirrored bowline.


EDIT: VER 2.0 is up. Go here; www.paci.com.au/IGKT/Bowlines.pdf

Added mirrored bowline and made a few other image enhancements.


agent smith
« Last Edit: December 31, 2008, 10:01:10 AM by agent_smith »

Dan_Lehman

  • Sr. Member
  • *****
  • Posts: 4278
Re: Janus Bowline or an equivalent secure bowline for climbing/rescue purposes
« Reply #76 on: December 31, 2008, 08:50:20 PM »
Okay, finally figured this variant out:
...
Will photograph and upload in a few hours...

Great, thanks!  (I leave open any exact *routing* of the tail on its near
stitching of the mirrored loops together--and that lack of (needed) specificity
is one of the beauties of the structure (but, again, again, we should recognize that
many of the commonly known knots have much the same vagueness to them
(with or without actual insignificance to behavior--it simply isn't noted & known!)).


Quote
My initial impression is that these 'mirrored' bowlines are a technical exercise in knot tying
but do not really impress upon me as offering anything elegant and simple in structure. Okay, they
are seemingly secure and stable but I just can't see the masses adopting it into their daily repertoire.

Bah, humbug, on this mistaken impression (IMO ! ).
Rather, you should see how nice it is to employ a well-know structure
 (I do think that the Girth/Cow hitch base is better than the Clove)
with also should-be-well-known tying method (the "rabbit in/out of hole" travel of the tail)
to get a robustly secure, amply loose & easily loosened, and likely strong--both from
gentler bends AND from some force absorption from all the *knotting* in the structure--
knot so easily.  Granted, the "rabbit" tying method isn't as handily quick as others,
but with the given base of the Cow (especially!), the tyer is unlikely to bring the end
through it from the wrong (anti-bowline) side of the now-mirrored central loop(s).
AND note that with the Cow base, doing so results in a workable interesting (and
(**NON**-bowline, like Derek's is non-) eyeknot. (Well, the knot I'm thinking of has
the "wrong side" entry, but then the tail must collar the "live" line / SPart, not an eye
leg.)  It seems a very good knot to deal with STIFF ROPE.  (I simply find it hard to
accept that the YoBowl and the ancient simple Overhand tie-off can work in it,
despite some now assertions to use of both in PMI Max-Wear & other stiff ropes.
I'm saying this upon my own tying it in 11mm (or 10.x, geesh) climbing rope and
some old low-elongation rope of unknown origin.)

And consider how much friction the reeved tail has in going back'n'forth parallel
to itself:  there is a lot of material contact there for movement to overcome, not
merely at the points of contact with the two loops.

Note that in the common bowline (#1010), when in use as a LEAD climber's tie-in,
the tail points upwards, and gravity can help pull it back down through the loop;
whereas the Janus variants point the tail SPart-wards/downwards, and have gravity
assist in keeping it so.  (Note that top-grade climbs have challenged this assertion
by having such severe overhangs that the knot might be in a horizontal plane!)

So, in some of these variants one can see that the tail must go in opposite directions
re gravity in order to come completely untied (and will reveal partial untying by having
a long flapping tail to be aware of, felt/seen).

Quote
with yosemite finish
And note my guidance on an alternative like finish, given previously, to nicely complement
the YoBowl's appearance on top-half of that page.  DO give this other path a presence.

Quote
Am also still trying to fully understand the geometry and possible benefits of DerekSmith's crossing knot/munter
variation of the bowline.  Now I see that structure as being much simpler than the mirrored bowline.

Again, don't call it a "bowline" and further the corruption of that knot-notion.

Please reflect on what "simple" constitutes:  doing an easy action many times
can build a maybe complicated-looking structure, but repetition itself is pretty simple.
(I have now a remaining 100' or so of simply grossly entangled conch-pot warp, just
salvaged from the beach, which had some duration of water-worked pot rotation to
build considerable wrapping & inter-bight knotting.  Patience, and some backward
unwrapping, and backing out ever-lengthening ends (and some uttering of oaths)
is bringing me nearer to success.  --hoping to put this rope to use in destructive
testing (yes, aware that it is of dubious uniformity and quality to be greatly indicative
as a model, but, hey, it's free and some results might shed insights ...).


Quote
Added mirrored bowline and made a few other image enhancements.

NOTE THAT THE MIRRORED BWL. SHOULD **NOT BE SO TIGHT** ON THE SPart!!
Wow, Derek's GeeSpot is throbbing, there!.  And in Janus cases, too:  although the
structure has symmetry of entanglement, the setting should be biased so that
it is the collar around the eye-leg getting pulled relatively tight, while that around
the SPart is not.

--dl*
====

ps:  How does 2009 look, so far (you early adopters!) ?
« Last Edit: January 02, 2009, 06:28:32 AM by Dan_Lehman »

roo

  • Sr. Member
  • *****
  • Posts: 1926
    • The Notable Knot Index
Re: Janus Bowline or an equivalent secure bowline for climbing/rescue purposes
« Reply #77 on: December 31, 2008, 11:46:59 PM »
Six pages.  I didn't think it'd go this far.

Agent Smith, have you come up with repeatable pass/fail security criteria for what loops would or would not be recommended by your group?  If so, it may stop a lot of wheel spinning in the form of multiplying permutations because you are not sure where to stop.
« Last Edit: June 28, 2010, 12:42:46 AM by roo »
If you wish to add a troll to your ignore list, click "Profile" then "Buddies/Ignore List".

Notable Knot Index

agent_smith

  • Sr. Member
  • *****
  • Posts: 1470
Re: Janus Bowline or an equivalent secure bowline for climbing/rescue purposes
« Reply #78 on: January 01, 2009, 03:04:50 AM »
Hello Roo, you've bounced back in...good to see the bouncy fella again.

I like spinning my wheels - it gives me time to think. And when I've had time to think, then I might stop spinning my wheels.

And its not my group, its but one class of roping technicians - but I would have thought by now that you would have appreciated that this forum (and thread) is much bigger than you or me. All of the posts (including yours) are a contribution to world knowledge. I can't really say with any certainty if such a concentrated effort has been made on the subject of bowlines before - can you?

As far as I can ascertain from all of these important posts, no-one has yet come forth with a declaration that any of the discussed knots is the holy grail (and such a thing may not exist).

And even if it turns out that this was all one big exercise in spinning my wheels...at least the journey was a fulfilling and rewarding experience. Its what the human spirit is all about.

Happy new year!


agent smith




roo

  • Sr. Member
  • *****
  • Posts: 1926
    • The Notable Knot Index
Re: Janus Bowline or an equivalent secure bowline for climbing/rescue purposes
« Reply #79 on: January 01, 2009, 05:20:18 AM »

I like spinning my wheels - it gives me time to think. And when I've had time to think, then I might stop spinning my wheels.


Exploring permutations is fine, but if you are interested to coming to a conclusion, you'll eventually have to start nailing down variables and eliminating false or superfluous leads.  If a person reading this thread or your report was interested in a good climbing/rescue alternative to the Figure of Eight Loop, they might leave confused or frustrated if your final report ended in 20 bowline variants, fuzzy criteria, and no conclusions. 

Cheers.

If you wish to add a troll to your ignore list, click "Profile" then "Buddies/Ignore List".

Notable Knot Index

agent_smith

  • Sr. Member
  • *****
  • Posts: 1470
Re: Janus Bowline or an equivalent secure bowline for climbing/rescue purposes
« Reply #80 on: January 01, 2009, 05:51:59 AM »
Roo, I am not quite ready to begin moving on to the next phase of this project...still have to tie and photograph a variant to the Yosemite bowline and maybe one other variant as suggested by Dan Lehman.

I want to make sure no significant bowline variant has been missed or escaped my attention. I think I am closing in on defining the limits of bowline variables that are of practical value, and not mere demonstrations of engineering elegance or simply art forms.

You must understand that this is a work in progress.

Also Roo, consider this:
1. I am doing this out of personal interest - not as paid work
2. I can only fit this into my spare time (which I have a bit up my sleeve at the moment due to my holiday period)
3. It is a self driven project - I am not working to anyones time line - only my own
4. Progress relies on contributions from other like minded individuals - who see value in making contributions to world knowledge (in particular, our knowledge of knots).
5. I can end this project at any time I choose - since I am its originator - as long as I see value in it, I'll continue.

...

Quote
--hoping to put this rope to use in destructive
testing (yes, aware that it is of dubious uniformity and quality to be greatly indicative
as a model, but, hey, it's free and some results might shed insights ...).

Dan, we must be on parallel thought patterns... I have geared up for destructive testing of a selected range of Bowlines. Shopping list of gadgets I have purchased thus far:

[ ] 5 ton Dynafor digital load cell (can be set to output kN or kg and can remember highest load achieved - 50ms sampling rate - will check this) - check
[ ] concrete driveway with screw-in eye bolts (love that word 'eye') - check
[ ] 4.0mm diameter kernmantel construction accessory cord (purchase tomorrow)
[ ] Safety glasses (check)
[ ] Hearing protection (check)
[ ] Winch (yet to purchase - might purchase a simple lever hoist or similar chain block setup that I can get for reasonable dollars) - perhaps a boat winch (hand crank variety)?


I am thinking that 4.0mm diameter accessory cord is workable for me - because I don't have to apply huge forces to break the cord and risk injury to myself or my load cell.

I'll consult with Dan and DerekSmith to make sure I get everything right...

Some things I know for sure already:
1. I'll test the ultimate breaking strength of the 4.0mm kernmantel cord first - maybe 3 breaks to obtain a mean value - MBL (will be interesting to compare it to manufacturers claims)
2. Care must be taken in tying and dressing the knot specimens
3. Need to take care to isolate the forces with respect to the knot - will need to use large D shackles to obtain reasonable diameters at end termination anchor points
4. Results obtained will be compared to unknotted MBL of accessory cord
5. Will need to perform 3 tests on each knot to obtain at least some form of statistically valid sample (bearing in mind cost factors involved for each length of cord I break which eats into budget)
6. Will pause test at various loads to photograph the progressive knot geometry - eg pause at 1kN, 2kN, 3kN, 4kN and maybe at a point momentarily before failure (without risking personal injury)

...

agent smith


EDIT:

Trying to tie this Yosemite Bowline variant...

Quote
A variation is more easily made by bringing the tail across UNDER itself (given the
"front" view), in which case it would bend around 2 rather than 1 diameter; this is also
an easier knot to tie and to tie as a Single Bowline in the Bight.  --something for your
blank pages, maybe.

Quote
And note my guidance on an alternative like finish, given previously, to nicely complement
the YoBowl's appearance on top-half of that page.  DO give this other path a presence.

Dan, have to admit (once again) that I am confused...(it IS the first day of the new year...). Would have liked to have started 2009 with completing any missing links in the Bowline genealogy.

Can you give me clearer instructions please!

« Last Edit: January 01, 2009, 07:23:18 AM by agent_smith »

Dan_Lehman

  • Sr. Member
  • *****
  • Posts: 4278
Re: Janus Bowline or an equivalent secure bowline for climbing/rescue purposes
« Reply #81 on: January 02, 2009, 07:07:02 AM »
Six pp., yes, with some actual deliberation!  (Yet a drop in the bucket compared with the
infamous seminal Equalette thread on RC.com; and likely w/better results, though one of
those anchors did make it into print of a prominent book.)

Quote
[ ] 5 ton Dynafor digital load cell (can be set to output kN or kg and can remember
highest load achieved - 50ms sampling rate - will check this) - check
Hmmm, a worthwhile NON-(competely)-destructive test is this:
drop-test (you can figure Fall Factor, aim for something common, for the point
is durability  and likely damage, if ...) a weight repeatedly, on a test specimen
comprising BOTH a Fig.8 & <some/various> Bowline eyeknots; check for abrasion
damage from whatever material movement there is.  Maybe between drops you
only give a glance and handle the material to feel for warmth, and then to some
detailed inspection of the material (looking for GeeSpot marking) after the full
sequence is run.  (One must still deal w/issue of dressing & setting options
--i.e., recognize that there might be much you've not tested.)

I have some suspicion that a knot like the bowline that stays unjammed might
be prone to chafing (though where the SPart moves the tail with it, there shouldn't
be any; for parts that do not move and the SPart moves around them, there could be).

(Here I'll remind myself that the accessory cord isn't so dynamic as the target rope.)
Quote
5. Will need to perform 3 tests on each knot to obtain at least some form of statistically valid sample
(bearing in mind cost factors involved for each length of cord I break which eats into budget)
6. Will pause test at various loads to photograph the progressive knot geometry - eg pause at
1kN, 2kN, 3kN, 4kN and maybe at a point momentarily before failure (without risking personal injury)

YEA!!! for the photography.  I should think that a break will give you a good idea of where
you have sure safety margin (and likely the breaking knot will leave the immediate region
in flying to opposite ends)--i.e., at what force you are well safe.  And you might see after
a test that a particular knot body doesn't much change after such&such force (so no real
need to photo that, other than to SHOW us that it hasn't changed, which is something
--something not needed for every test).

You might try to employ some *exploding-knot-&-parts*-dampening mechanism,
such as bungee cord or other cord tied to 2kg? sand bags, or draping rope in heavy
towel/cloth!?

To my mind, it makes good sense to test TWO eyeknots in each specimen:  you end up
(1) showing that TWO knots survived forces up to <break_force>, and can presume that
the survivor maybe gets some 4% higher grade (speculative statistics at work :o), AND
(2) you have a near-rupture-load knot to examine for its severely loaded state.

In order to determine WHERE THE BREAK OCCURS (so we can send Derek off ... :-),
I suggest stitching colored threads through the knot--things readily photographed.
The post-mortem can then count "5 threads on SPart end of break, 2 on other,
so that would place the break as seen in high-load state photo'd at about <X marks the spot> !
I think we can begin to home in on this.
(Btw, at this writing, I have no idea where a common Sheet Bend breaks EVEN AS TO WHICH
OF THE BIGHT OR LOOP rope breaks!  THAT is something we should know (or know that it's
variable, not consistently one or other) by now, centuries after the knot has been much used
--but we don't.
Possibly you could stitch in the threads after some initial loading (when you'll have a good
idea of what part of the cord/knot to mark).

----------------

Quote
Trying to tie this Yosemite Bowline variant...
Quote
A variation is more easily made by bringing the tail across UNDER itself (given the
"front" view)
, in which case it would bend around 2 rather than 1 diameter; this is also
an easier knot to tie and to tie as a Single Bowline in the Bight.  --something for your
blank pages, maybe.
that page.  DO give this other path a presence.

Dan, have to admit (once again) that I am confused....
Can you give me clearer instructions please![/quote]

I can *yell* in bold.  The YoBowl takes the end clockwise, say (whichever);
the indicated variation takes it the opposite way; thereafter, ... out through the collar.
How much simpler can this be (and still be doing anything) ?!  (The given start is
1010, then contrast w/YoBowl extension--i.e., all the new stuff (incl. YoBowl)
happens after <state_#1010>.)

(I don't want language to die.)

--dl*
====

Dan_Lehman

  • Sr. Member
  • *****
  • Posts: 4278
Re: Janus Bowline or an equivalent secure bowline for climbing/rescue purposes
« Reply #82 on: January 02, 2009, 10:43:19 PM »
Quote
Exploring permutations is fine, but if you are interested to coming to a conclusion,...

Conceivably, a version of this report can be used more to lay out the variations
than to recommend to any user group some one knot; or might point out some
seemly knots to each of a few user groups.

Anyway, it will be good to have test data on a variety of geometries irrespective
of their viability in practice just for the sake of gaining insight to rope mechanics
(though we might be pushing interpretation, with only so many results--a matter
of *resolution* of results, which are coming only by one means of loading, and so on).

------

Re my "Mirrored Bowlines":  I have a version in which the tying/form goes
like this, and looks pretty good--the mainline's side of the knot is tied as a
Cowboy Bowline, the eye-side's side as a common Bowline, and the final
tuck is taken sort of between/BELOW (from our "front" perspective) the first
two passes of the end, which seems to give a nice curvature to the SPart.
(But there are many ways of doing this, and the recommendation shouldn't
depend upon doing it just so and not ...--that would be risky.

--dl*
====

agent_smith

  • Sr. Member
  • *****
  • Posts: 1470
Re: Janus Bowline or an equivalent secure bowline for climbing/rescue purposes
« Reply #83 on: January 03, 2009, 10:08:37 AM »
Just uploaded VER 2.1... added the yosemite bowline variant that DL suggested earlier. I didn't realise it was that simple - I was looking for something more intriguing and another example of his engineering prowess (thats why I couldn't figure it out - because I was looking TOO hard!)....

I thought that was just about it...then I noticed another mirrored bowline from Dan Lehman.

Quote
Re my "Mirrored Bowlines":  I have a version in which the tying/form goes
like this, and looks pretty good--the mainline's side of the knot is tied as a
Cowboy Bowline, the eye-side's side as a common Bowline, and the final
tuck is taken sort of between/BELOW (from our "front" perspective) the first
two passes of the end, which seems to give a nice curvature to the SPart.
(But there are many ways of doing this, and the recommendation shouldn't
depend upon doing it just so and not ...--that would be risky.

Hmm, looks like I will have to take just ONE MORE photo!

Then that's it... time for testing.

In another thread on knot testing, I put up a short list of knots for testing.

I am not going to test every Bowline variation... too expensive and too time consuming.

I'm going to have to narrow my work to a well defined range.


agent smith
« Last Edit: January 03, 2009, 10:11:19 AM by agent_smith »

Dan_Lehman

  • Sr. Member
  • *****
  • Posts: 4278
Re: Janus Bowline or an equivalent secure bowline for climbing/rescue purposes
« Reply #84 on: January 03, 2009, 10:25:36 PM »
In another thread on knot testing, I put up a short list of knots for testing.

I am not going to test every Bowline variation... too expensive and too time consuming.

I'm going to have to narrow my work to a well defined range.

If you're getting read-outs of peak loading--or, better, a graph of loading--,
the Mirrored Bowline should be a good candidate for possibly yielding lesser
peak loads on repeated drop tests (non-destructive), which should interest
"sport climbers".
To my eye, the Cowboy Janus makes a nicer SPart curve than either W&M's or Prohaska's.

And, consider, the EBDB uses much less material than your variations on it that extend
the end to be tucked under the wrap and out through the collar.

--dl*
====

Bob Thrun

  • Full Member
  • ***
  • Posts: 82
Re: Janus Bowline or an equivalent secure bowline for climbing/rescue purposes
« Reply #85 on: January 05, 2009, 01:10:43 AM »
If any of you want to read Heinz Prohaska's two-page article where he discusses the Yosemite finish and the Janus bowline, I have scanned it and posted it in a message at http://forums.caves.org/viewtopic.php?f=5&t=7818&start=15

alpineer

  • Sr. Member
  • *****
  • Posts: 513
Re: Janus Bowline or an equivalent secure bowline for climbing/rescue purposes
« Reply #86 on: January 21, 2009, 09:39:54 AM »
May I respectfully suggest what I call the "Triple Tuck Bowline". It appears to me to be incredibly strong and secure, and no more difficult to tie than making two additional tucks of the tail through the cuckold (edit: nipping loop). However, it requires scrutinous testing to be considered a viable alternative for climbing/rescue applications.
« Last Edit: December 08, 2012, 05:44:32 PM by alpineer »

Dan_Lehman

  • Sr. Member
  • *****
  • Posts: 4278
Re: Janus Bowline or an equivalent secure bowline for climbing/rescue purposes
« Reply #87 on: January 22, 2009, 10:13:46 PM »
May I respectfully suggest what I call the "Triple Tuck Bowline". It appears to me to be incredibly strong and secure, and no more difficult to tie than simply adding two extra tucks in the cuckold (collar). However, it requires scrutinous testing to be considered a viable alternative for climbing/rescue applications.

As I posted in another forum thread, Have you read the associated pdf here?
There are Bowline variations w/added tucks.  Btw, "cuckold" is the central
nipping "loop"; "collar" is the bunny's path out of the "hole" (cuckold) "around
the tree (SPart) ... ".  "Incredibly strong" really benefits no one, though it's
such a compelling marketing gimmick (not even measured by means modelling
the intended use).  With the plain ol' bowline, we're seeing 70% or so, which
is good; with some of the 3-diameter-in-loop knots, we'll hope for 80%.  But
this difference will have effect only in understanding knot behavior and in print,
not in practice.

--dl*
====

[edit:  yeppers, "c." was not it--now it is (both places)!   ::)  )
« Last Edit: January 23, 2009, 07:25:02 AM by Dan_Lehman »

TheTreeSpyder

  • Exp. Member
  • ****
  • Posts: 152
Re: Janus Bowline or an equivalent secure bowline for climbing/rescue purposes
« Reply #88 on: January 23, 2009, 12:41:51 AM »
ummmm Is that "cuckold"?

We need to look at different categories IMLHO, like ease of tie, untie, return on effort, security etc. but a lot towards dividing between static and dynamic considerations, and if the dynamic considerations if the same properties are immediately re-accessible or not.

i've always looked at trying to relieve the first point of change/deformation in the Standing in the Bowline (and many others) for greatest strength (generally).  The eye loading is equal and opposite, and has more deformation; but is (equal and opposite) / 2legs (as opposed to Standing's matching loading on 1leg).  Points in between (primary deformation of equal and opposites Standing and Eye) are usually behind friction buffering(s).  They can store force (be tighter than rest of lacing, or tight when rest of line is relaxed etc.) and / be a stash of line to be (fairly) singular impact buffer (IMLHO).  Now drDan has pointed out in stiffer line, that 2nd story/Turn can work against ya to give more leverage to invert the works.  So, like anything else, these forces (the Round Turn device hear), can work for or against ye, or offer some of each, depending on the way the forces apply to the situation.   i won't use a Bowline in stiff dblBraid, huge diameter nor fishline etc. 

i think a 3rd Turn (making dblRound Turn) gives less 'return' for your 'investmeant' of time and line as far as lowering the impacts of change on the fully loaded single leg of the Standing (open to most immediate and impacting changes).  But, could give more rope 'stash' of distance to be drawn thru frictions to handle impactings.  Also, more compressions for same. 

In the Yosemite (Sam) tie off i think we can see more security than strength gain because of these factors.  And not any really dampening qualities either.  But as we add more 'tucks' we would then increase 'cockhold' diameter; which would give more secondary than primary relief to the primary deformation in Standing (static strength); but would give more compressible diameter ('compressible fluff') for more increase in dampening of dynamic forces than strength in handling nonDynamic / static forces/loadings.  So, to me any of these 'Bitter' tucks give security (but even that seems like it would have an inverse at some point), and secondary increae in static and dynamic properties iff inside of 'cuckold'.

i think the 2nd Turn of a dblBowline, also allows less of an impacting change, by giving the same deformation a longer path to occur.  Also, be more shock worthy because of the coils stash of 'distance' that has to be drawn thru frictions(mimicking somewhat braid construction strategies) to be accessed, adding another dampening strategy to the dampening properties (which include elasticity etc.).  But, like elastic 'hysterics' that doesn't immediately 'reset' itself (or never does like a 'damaged' permanent extension), the lacing might have to be retied or redressed to perform at this level after a significant loading.  Another point to strength tests vs. actual use and who is conducting the orchestration (and their personal habits) of events of either (actual use or testing).

The simple answer to the questions of this search for the holy grail; is perhaps that there are no  global, simple answers.  In real loadings and activities it is an orchestration of events in relation ship to their orchestration  of loadings; and also the same in the devices temporary constructions/ lacings (straight/inline and curved/leveraged portions of lines, and their frictions) and the permanent constructions(material, braid, diameter etc.).  Anything that can stand for you to your aid, can also have the binary switch flipped to use the same forces against ye (and equal and oppositely the reverse too).

i due appreciate the effort as a work in progress, a journey for us individually and collectively hear now.  Each gives (k)new reaches for the next like the coral.  Even in the dynamics inbetwixt; things are even spring boarded higher as the ping-pong back and forth.  Then in years coming, someone else will trump us all, not to lessen the contributions though.  All wee can due is give as much structure to the sum total as possible during our 'watch'.
« Last Edit: January 23, 2009, 01:56:47 AM by TheTreeSpyder »

alpineer

  • Sr. Member
  • *****
  • Posts: 513
Re: Janus Bowline or an equivalent secure bowline for climbing/rescue purposes
« Reply #89 on: January 23, 2009, 08:43:54 AM »
May I respectfully suggest what I call the "Triple Tuck Bowline". It appears to me to be incredibly strong and secure, and no more difficult to tie than simply adding two extra tucks in the cuckold (collar). However, it requires scrutinous testing to be considered a viable alternative for climbing/rescue applications.

As I posted in another forum thread, Have you read the associated pdf here?
There are Bowline variations w/added tucks.  Btw, "cuckold" is the central
nipping "loop"; "collar" is the bunny's path out of the "hole" (cuckold) "around
the tree (SPart) ... ".  "Incredibly strong" really benefits no one, though it's
such a compelling marketing gimmick (not even measured by means modelling
the intended use).  With the plain ol' bowline, we're seeing 70% or so, which
is good; with some of the 3-diameter-in-loop knots, we'll hope for 80%.  But
this difference will have effect only in understanding knot behavior and in print,
not in practice.

--dl*
====

[edit:  yeppers, "c." was not it--now it is (both places)!   ::)  )

Please excuse my rather "raw" knowledge of knot terminology. Definition of "cuckold" and "collar" noted.
As regards strength, still, I like the idea of wringing out every ounce of it (if only for psychological reasons). More practically, I would conjecture a knot of greater strength would impart less wear and tear on a rope, although your point may also apply here to a fair degree. Also, if I had to use a scary small diameter rope in an emergency situation... (scenario non positus, if my Greek is correct :D).
« Last Edit: January 23, 2009, 08:47:33 AM by alpineer »

 

anything