Author Topic: Janus Bowline or an equivalent secure bowline for climbing/rescue purposes  (Read 153934 times)

Dan_Lehman

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Re: Janus Bowline or an equivalent secure bowline for climbing/rescue purposes
« Reply #105 on: February 01, 2009, 10:53:43 PM »
>>> I will tie all the knots such as the ones in this thread, [e.g.]

Here is a secure knot re-formed:  to form the Locktight I  from this,
push the extra turn of the S.Part (lower, in image) back up around
its beginning, rather Blood-knot/Grapevine-like.  The wrap(s --one
or two more can be practical, YMMV) will bind down upon the
S.Part and, well, "lock tight" upon it; but the upper collar etc. is the
*backdoor* to loosening & untying it, easily.

 :)

[edit in bold part:  "will not" => "will"]
« Last Edit: February 02, 2009, 06:42:47 AM by Dan_Lehman »

DerekSmith

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Re: Janus Bowline or an equivalent secure bowline for climbing/rescue purposes
« Reply #106 on: February 01, 2009, 11:54:00 PM »
Here is a secure knot re-formed:  to form the Locktight I  from this,
push the extra turn of the S.Part (lower, in image) back up around
its beginning, rather Blood-knot/Grapevine-like.  The wrap(s --one
or two more can be practical, YMMV) will not bind down upon the
S.Part and, well, "lock tight" upon it; but the upper collar etc. is the
*backdoor* to loosening & untying it, easily.

 :)

Pardon ??

Dan_Lehman

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Re: Janus Bowline or an equivalent secure bowline for climbing/rescue purposes
« Reply #107 on: February 02, 2009, 03:35:30 AM »
Oops, make that "WILL bind down" on top of the S.Part and bind it.

Take your right hand, grasp knot at bottom, and with right thumb
press that part coming up from the coil (into S.Part-side eye-leg)
right-back-around the nub,  until it is fully seated above the S.Part's
beginning wrapping--all wraps now going around/over the S.Part.
(Then orient the end a bit leftwards under the end-side eye-leg
so that the S.Part makes its hard impression into the end and
draws it clockwise around, cushion against the end-side eye-leg.)

--dl*
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DerekSmith

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Re: Janus Bowline or an equivalent secure bowline for climbing/rescue purposes
« Reply #108 on: February 02, 2009, 08:21:52 AM »
Are you saying Dan, that just by riding the two coils up over themselves, so the SPart comes down inside them and out the bottom, starting the wraps from the bottom up, that this knot then becomes the Locktight-1 ?  (do you have any pictures or diagrams of the Locktight-1?).

When I allow the knot to naturally dress itself, it takes on the form in the climbing rope picture - I have attempted to diagram it in the LHS diagram attached.  But if I force the dressing into the configuration you (I think) described, then it takes on the form in the RHS diagram.

In moderate loading of the RHS version (Locktight-1) the SPart first wrap - marked in red - jams into the coils above it and as you aptly named it - LOCKS.  While the naturally dressed version shown in the climbing rope picture does not jam in my limited selection of test cord, is nicely secure and offers an SPart path which should be slightly less drastic a load shedding geometry than the standard Bwl.  It's also a doddle to tie and easy to remember.

Derek

Dan_Lehman

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Re: Janus Bowline or an equivalent secure bowline for climbing/rescue purposes
« Reply #109 on: February 02, 2009, 05:47:12 PM »
Are you saying Dan, that, just by riding the two coils up over themselves,
so the SPart comes down inside them and out the bottom,
starting the wraps from the bottom up,
tthis knot then becomes the Locktight-1 ?
Bingo!
There used to be images of this on Dan Britton's Knot Knowledge  site,
but that is now defunct.  But you have it (or the 1st of the series, varied by
wraps).  There are some variations on this that seem better for stiffer rope,
as well as more secure vs. ring-loading--where the end, after making the
collar, enters amid the coils.

Quote
In moderate loading of the RHS version (Locktight-1) the SPart first wrap - marked in red -
jams into the coils above it and as you aptly named it - LOCKS.  While the naturally dressed
version shown in the climbing rope picture does not jam in my limited selection of test cord,
is nicely secure and offers an SPart path which should be slightly less drastic a load shedding
geometry than the standard Bwl.  It's also a doddle to tie and easy to remember.

Which is the point:  to lock--security.  Which locking is only of the knot from
general loosening, as the collar offers quite easy untying otherwise.  It is a
structure better suited to slick rope, which will see early movement of the
wraps and better distribution of the tension.  The reddened part is a critical
area, and prone to a hard bend; this can be mitigated by dressing so that
it bears upon the end and draws it with it.  But, again, at issue in such ropes
is security more than strength.

There IS some concern about such knots where movement comes in the
critical, SPart-bending area:  at high, dynamic loading, will friction generate
heat too much.  Dave Merchant alleged that this phenomenon gave the Fig.9
eyeknot varied results, whereas the Overhand eyeknot was more constant
between slow-pull & rapid-loading tests.  So, the freedom of movement in
the knot you present nicely in photograph, as well as in bowlines, might have
its drawbacks; another instance is not in severe but rather cyclical/repeated
loading, where chafing might occur with the change in tension.

--dl*
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alpineer

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Re: Janus Bowline or an equivalent secure bowline for climbing/rescue purposes
« Reply #110 on: February 03, 2009, 08:40:22 AM »
I cannot believe that Derek is using real rope or has his eyes anywhere but
embedded in FCB lines:  for the bowline abomination he suggests is just that,
worse than the gratuitous tucking indulged by Agent_Smith & Alpineer!? In
the target domain (rockclimbing & caving/SAR (& canyoneering)) or kermantle
cordage, it's a non-starter; frankly, it's awkward in thinner, more flexible stuff, too.

The EBDB works because the end-binding goes around 3 diameters, which
is an effective approximation of a circle.  Trying to achieve such binding around
just two diameters suffers from their modeling an oval  space; repeating such
a wrapping only provides a second not well snug binding.  The single Bowline
can provide a 3rd diameter by having the wrap take in the end-side eye-leg,
but the geometry of this just doesn't equal that of the Double Bowline base.

All this conjecture about the coils having some "friction hitch" effect is silly:
they are untensioned; they don't begin to have a chance in the cordage of
issue (where one insists on smaller cordage hitching to thicker--not equal
diameters, as in some arborist cordage with Blake's/ProhGrip hitch.
(Which, we might note, doesn't have "the force bear[ing] down on the coils.")
One could try to impart force into the coils by making the binding wraps
on the end's entry  into the nipping loop; but this will just aggravate
the friction with the S.Part.  (From my stressing, the--what I call--"Bowl-in-a- Bowl"
(with a Single Bowline and one such binding wrap) doesn't deliver much force
into the coils, surprisingly (it must do so at high loads, else we'd never hear
of bowlines jamming/cinching!).  (To put this in terms Derek will appreciate:
this is the Myrtling of the Bowline! ))

 :)

Dan,
Firstly, there is no GRATUITOUS TUCKING in any of the knots being offered up here for comment. They serve to change the balance of a knot's properties.
Secondly, re the "coils having some friction hitch effect" as being silly, my comment to Derek's was in the context of allowing for some obscure (to me) action involving a dynamic high loading scenario.
Thirdly, per Reply #97, this is NOT a Yosemite finish (which as you know takes a turn around the Bight Side Eye Leg). After taking the last tuck through the Nipping Loop, the Tail simply heads STRAIGHT NORTH and through the Collar.
Finally, I do this Northward tuck not to clear the Eye, but to position the Tail where it may be better seen. There may be other reasons re security/stability in stiffer line.       
« Last Edit: December 08, 2012, 06:50:33 PM by alpineer »

Dan_Lehman

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Re: Janus Bowline or an equivalent secure bowline for climbing/rescue purposes
« Reply #111 on: February 04, 2009, 07:13:15 AM »
The EBDB works because the end-binding goes around 3 diameters, which
is an effective approximation of a circle.  Trying to achieve such binding around
just two diameters suffers from their modeling an oval  space; repeating such
a wrapping only provides a second not well snug binding.  The single Bowline
can provide a 3rd diameter by having the wrap take in the end-side eye-leg,
but the geometry of this just doesn't equal that of the Double Bowline base.

Dan,
Firstly, there is no GRATUITOUS TUCKING in any of the knots being offered up
here for comment.  They serve to change the balance of a knots properties.

IMO, there are several gratuitous tuckings.  As I explained above, putting
the end-binding on a Single Bowline does not give good security in the
target domain of cordage--I'm looking at considerable open space between
the wrapping and wrapped two strands, after considerable effort to set,
in 11mm dynamic rope.  And I've just been to a shop and felt the various
skinnier ropes (and even played around with one loose end of one) now
in vogue, and they equally resist 1-diameter bending.  And the tucks added
by Agent_Smith through an end-binding also are gratuitous IMO--much
fiddling for little or no return.

In contrast, the EBDB can be set tight.  It needs to be, for, on loading,
the two turns of the S.Part will shrink with extension, and likely some gap
will open between them & end-binding; but on relaxation, the binding should
come into effect again.

Quote
Thirdly, per Reply #97, this is NOT a Yosemite finish ...
Yes, well, it is the part of it that runs back through the collar, which was
all I meant to indicate.

--dl*
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alpineer

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Hey agent smith,

WHERE ARE YOU? please touch base and let us know you're still alive.
I'd like to offer some thoughts re secure bowlines. There are 2 extended versions of the SINGLE Cowboy Bowline which give a turn around 3 rope diameters ("Nip and Eye Legs"), then a tuck through the Nipping Loop and then directly through the Collar (no Yosemite) with the Tail running parallel to the S Part. One version tucks the Tail through the Nipping Loop and on the OUTSIDE of the Collar (preferred?), the other version tucks the Tail through the space intersected by the Nipping Loop and the Collar. IMO tucking the Tail back through the Collar is MANDATORY for maximum security (no backup knot necessary), and also allows the knot to be tied loosely and then drawn up tight with greater ease.
Let me say that I have NOT tied these extensions in stiff, slick line as I do not have easy access to this stuff. I respectfully defer to Dan Lehman on this matter, if he would care to comment. This is a rather long thread and I haven't read everyone's post, so please accept my apologies if I am waxing redundant here.

Cheers,
alpineer

     
« Last Edit: March 09, 2009, 03:36:37 PM by alpineer »

Dan_Lehman

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Hey agent smith,

WHERE ARE YOU? please touch base and let us know you're still alive.
DITTO!  --glad someonElse said it, too!
Meanwhile, a dead logic board (I must've been trying to both do & not do something :-)
has reduced my e-time and I've been so busy in borrowed (library) time researching the
replacement that I've not gotten around to these parts since whenever.  Okay, new
machine en route, and here I am.

  :-\

alpineer

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However, if you want a Bwl. that is secure and STRONG, then I am working on a structure that will make your eyes water.  Now, I am not saying it will be through laughter or crying in horror, but the brute should definitely get a response from you.

Derek

Hey Derek,
Any updates, please and thank you. :)

agent_smith

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Just letting you all know that I am alive and kicking!

Have been away traveling (for work) a fair bit this year - and been totally bogged down with work commitments (and earning money to survive).

Will endeavor to get back on track with my knot testing as soon as time permits...

I'm sure Dan has been wondering what the heck I've done with the specimen knots and photos...


agent smith

Dan_Lehman

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Good to hear from you, at (lonnnnnng) last!
Yes, as the posts indicate, we've been keenly awaiting further data
(AND PHOTOS).

Got an eyeful of lobster rope over Mother's Day: several miles of
new, sinking groundline, to try to prevent Right whales from
entangling themselves in it as they open-mouth feed.

(-;

agent_smith

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Firstly, I would like to apologise to Dan and Derek (and others) for delaying on this project and basically dropping off the radar screen.

After the economic woes...I too fell into some scary times and had to focus on other matters to keep my business running.

I admit that I have lost touch with, and lost focus on my knot testing project.

I still have all the sample bags containing the destroyed knots (pulled to failure) - and I still have the tools and equipment to press on.

Its just that I've lost my way...

I need to regain my drive and motivation again.

Sorry.

agent smith

Dan_Lehman

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Agent_Smith, good to hear again from you, and that you are among the
steadfast if challenged among us.  I'm sure I speak for all in wishing you
well, et cetera.

I admit that I have lost touch with, and lost focus on my knot testing project.
...
Its just that I've lost my way...
I need to regain my drive and motivation again.
On this, I'll recommend that you simply enjoy some time looking back
over your so-far work, re-familiarize yourself with it, and remember that
your step-by-step progress through the testing was putting out some
quite interesting, useful data.  (Even without the urged photographs
-- of whatever quality!).  We had, recall, at lonnnnnng last -- after some
centuries of ignorance or silence -- nearer indications of where certain
knots actually broke.  And, with photos of the pre-rupture tautness to
complement, we'll have further insight to the behavior of cordage at
the high-load point.  (Though we might need to temper enthusiasm
for this being key to much, as  --ideally-- one should hope that usual
practice doesn't put rope to such extremes.)

Pardon if I'm reaching here --not sure of what's entailed-- ,
but you might re-post/re-URLink your latest pdf of images for those
here to refresh their memories, and for newer-reading members to
get a first glance into some of what you've been crafting.  (We have
results contained above.)
 [Note to self:  for that matter, I could perhaps help out by posting
 my own photos (make & post, i.e.) of knots you're testing!]   ::)

So, all that should be both satisfying and reassuring.  And your example
can help others to do similarly -- to not merely pull things apart and
record some numbers from a device reading, but to have noted by
photograph and by material marking how the knots are transformed
through the tensioning cycle.

 :)

Cheers,
--dl* (and, I suspect, the rest of the IGKT Forum)
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Dan_Lehman

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Re: Janus Bowline or an equivalent secure bowline for climbing/rescue purposes
« Reply #119 on: November 06, 2009, 08:42:19 PM »
I'm apprehensive about engaging in verbal imaging with you again,
but from the Slip Knot or --otherwise loaded-- Overhand Noose, one
gets either of the two collared Bowlines & Eskimo Bowlines, and that's
four right there; I see no Tugboat Bowline, even barring the counting.

And while I know how to insert the bight through the loop for the above,
I can't imagine what you mean by "the bight has passed through the loop
for a second time"
-- a double bight thrust into the loop (which begs
the question about the span of the bight), or ... what?!

Photos / images would be great help, here -- either specially produced
and shown, or URLinked or otherwise referred to.

--dl*
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