Break Testing

[Brion]

[ QUOTE ]

Re weakness in compression for HMPE, don't the numbers really suggest
that it's about equally strong there, and just super strong in tension?
I.e., nylon or polyester will be (in force terms) no stronger; but they have
much lesser tensile strength, so percentage-wise they look better.
Which still leaves the point about sacrificing this strength via knots, for hi-mods.

[/ QUOTE ]
It seems that, if HM fibers were stronger in compression, relative to their tensile strength, they would not be weakened as much by knots. It is the relative efficiency of knots vs splices, in various materials, that concerns me.
[ QUOTE ]
FYI, HMPE "dental floss" slings for climbers have apparently been tested
in Clove hitches (no more than that!) on 'biners and shown good strength,
not slippage (!! -- my surprise), breaking the 'biner if tied in twin strand
(i.e., tying the sling vs. just one side of it ("sling" here = circle of material)).

[/ QUOTE ]
Source?

[ QUOTE ]
Okay, Yes, I tested the Bowlines you describe,


[/ QUOTE ]
!! Haven't seen hint of these from anywhere. I confess to some skepticism
given that you aren't seeing clear in at least the capsized bowlines case.

[/ QUOTE ]
If I am not seeing clear, perhaps it is because I am misinterpreting the photographs; any chance that you might send clearer ones, to remove ambiguity? I've looked repeatedly at the attachments, and just don't see the capsize mechanism. I have, however, repeatedly seen people tie what I believe is the knot you picture, both in classes I have taught, and in the field. It is a simple matter of taking the end around the wrong part after passing it through the loop. The knot is know variously as an Eskimo Bowline and a Sideways Bowline. This is a far simpler, and therefore far more likely explanation for what you are seeing than some manner of capsize. But again, it is possible that I am misinterpreting the pictures.
You "confess to some skepticism" about my tests on the Bowline variations. Why?

[ QUOTE ]
I will post further shots. The point of which, btw, is that these commonly
known knots have shown transformations likely not expected, and one
can only wonder how loosely tied they were or if in fact it's a matter of
usage forces working this change. AND whether similar such changes
occurred in some of the testing referred to above, which might escape
notice.

[/ QUOTE ]
Seems farfetched, doesn't it, that widely separated lab workers would fail to notice, in repeated testing, that their Bowlines have somehow capsized into something else? I appreciate that this is a possibility, but it's hard to think of a more remote one. Tell you what, next week I'll be breaking some pieces of HM as part of a course we are teaching for Coast Guard inspectors. The idea is to demonstrate the danger that knots in HM can pose for charter vessels. I'll see if we can photograph the tests, and forward the results.

[ QUOTE ]
The "Figure 9" is, I believe, just a Stevedore's Knot, made as a loop.


[/ QUOTE ]
In some books, yes; but the Stevedore should have an extra half twist and
by this numerical naming be "Fig.10" (Lyon so tested it -- marginally better
than F.9).

[/ QUOTE ]
In what material(s)? To what results?

[ QUOTE ]
I have no doubt that people tie lousy knots at times, or loose ones, or sideways ones, but I fail to see why you are bringing those up in this discussion.

[/ QUOTE ]
Because those people can run tests, too. Because at the great loads put
by a break test, things happen that might be mostly unseen otherwise,
where what seemed a "good" knot was that -- good enough, then.

[/ QUOTE ]

If your argument has merit, I believe that it cannot be demonstrated simply by impugning the competence of others. Show us that what you say happens, happens. Please, show us, instead, that your postulates are valid.


[ QUOTE ]
As for the Sheet Bend, neither "half" of this "asymmetrical knot" will break; the break occurs outside the knot, as the internal deformations manifest in the apparently full-strength standing part.

[/ QUOTE ]
Firstly, I don't buy this breakage point. Yes, I HAVE some broken knots,
and one can find a point of hard compression/pressure near an entry point;
otherwise, you have quite a task to explain how weakness in compression
results in rupture where there is none.
E.g., consider the broken line in the video presented above: that pop of
material certainly manifest itself outside, but I think you can locate its
start right at the bend into the Clove, hard against the crossing part.

[/ QUOTE ]
I have no such task. The weakest point, by definition, is the one that gives way first, and in this case it happens to be just outside the knot. The rupture didn't "start" in the knot; it was related to forces occurring within the knot. This is not mere semantics. As opposed to mere knot semantics.
[ QUOTE ]
But in either case, the question remains: in which of the ropes joined in
a Sheet Bend --the bight-formed or hitching one-- does the break occur
(wherever posited)? This knot is recommended often for diff-sized ropes;
the data that's published is however for same-diameter ropes: if one joins
3/8" rope to a bight of 1/2" rope, will one get better than (say) 55%
of the 3/8" line (assuming that's the usual strength in like-dia ropes)?
(As there's some torsion in the hitching rope, I'm suspecting that it's the
one more weakened; but in thick-thin working, a thicker line on that half
just doesn't work well.)

[/ QUOTE ]
I'd love to know. Care to report on this?
Fair leads,
Brion Toss

 

[allmark]

When the rope breaks like in my video it would be my first thought this is due in part to the lack of fibers ability to stretch on the knot side.The fibers in between the anchored points still have the ability to stretch.
With a splice there is also more stretch allowed.
Is this true?

 

[Brion]

[ QUOTE ]
When the rope breaks like in my video it would be my first thought this is due in part to the lack of fibers ability to stretch on the knot side.The fibers in between the anchored points still have the ability to stretch.
With a splice there is also more stretch allowed.
Is this true?

[/ QUOTE ]
I don't know. A splice or knot will typically not fail at the eye, because the legs share the load, and are thus stronger than the standing part. And they typically do not fail internally, because there is simply more mass there, and this compensates for deformation, as I understand it. But in a splice the transition to the standing part is, ideally, gradual, so everything can take the load -- and perhaps stretch -- more or less in unison. But in a knot there's an abrupt transition -- a stress riser -- with less load on the knot side, and thus less stretch than on the standing part side. How or why this might contribute to the break I don't know, but it seems a variable worth considering.
Fair leads,
Brion Toss

 

[knudeNoggin]

[ QUOTE ]
When the rope breaks like in my video it would be my first thought this is due in part to the lack of fibers ability to stretch on the knot side.

[/ QUOTE ]
I think you could have confirmed that the particular fibers that broke
in your rope were those at the inside (concave side) of the bend of the
Clove hitch as the mainline was deflected against the cross part. They
suffered not only the tension felt in fibers generally, but also the greatest
pressure against the fibers of the cross part -- they were strained and
had much of the rest of the high-tensioned strand bearing into them.

Look and see where that initial puff-burst of broken fibers comes.

*kN*

 

[knudeNoggin]

[ QUOTE ]
Tell you what, next week I'll be breaking some pieces of HM as part of a course we are teaching for Coast Guard inspectors. The idea is to demonstrate the danger that knots in HM can pose for charter vessels. I'll see if we can photograph the tests, and forward the results.

[/ QUOTE ]

This will be great! Photos I hope will show the knots at some point of
serious load prior to breaking, to get an idea of the geometry in effect.

And the "HM" will be ... ? (various?)

Attached is a photo of particular "Janus" Bowline with a good-looking
geometry for bending the standing part. One can only do so much re
this, and given the reported break strengths just getting up into the 40%s
without slipping would stand as an advance. Note that the base pre-tucking
the extra time is a "Left-handed" bowline, which is often disparage; I think
it offers benefits over the usual.

The photo shows grey Spectra 12-strand line with the knot under some
slight load and in a perspective to try to highlight the nice curvature; the
front side of the knot is shown in exploded form in half-inch Sta-set.

*kN*

 

[knudeNoggin]

A second eyeknot to test is a sort of derivative of Ashley's #1425 bend,
where the interlocked Overhands of that bend are seen as abbreviated
symmetric "fig.9" knots (stopper #525 being the whole magilla).

Photo'd here is one such not that has had substantial loading (on the right)
and one in loose form to show its structure. Note that this knot is easily
tiable in the bight (a little less so, by reeving). While the knot can be set
fairly tight against untensioned/jostled loosening (though it can be looser),
it remains non-jamming.

(Photo shows eye legs going up, standing part (mainline) down, and
the end running rightwards from both knots.)

*kN*

 

[Jamin_Mayer]

[ QUOTE ]
Nifty idea. Hard to duplicate in the lab, or to bring the lab to the trees.

[/ QUOTE ]

Na. You just need to be creative.

How about bringing in many different diameter log sections with enough length to choke off one end with a very large choker (that will not break under the testing) and the other end with what ever you want to test?

Then, the text book answers may show to be true or false.

I believe, that a running bowline and a half hitch, around a log, will yield a much different result than a simple bowline around a pole.

(See illustration)

 

[Brion]

Hi again,
Bummer, it turns out that the tension gauge we have the use of is not rated for break tests. We've done some preliminary security tests with it, though. Normal Bowlines, in Amsteel, start crawling at about 10% of rated strength. They crawl right down to the Figure-8 stoppers in the end, and then, very weirdly, the Figure-8's start crawling apart. Tomorrow we'll repeat, with a variety of "Locked" Bowlines.
kN, I would like to try some of the knots you've described, but am unable to figure them out reliably from the photo's; any chance you could either send clearer photo's, or actual samples? Whatever we don't accomplish here I will be glad to have done at a ropemaker's lab later.
Fair leads,
Brion Toss

 

[knudeNoggin]

[ QUOTE ]
Normal Bowlines, in Amsteel, start crawling at about 10% of rated strength. They crawl right down to the Figure-8 stoppers in the end, and then, very weirdly, the Figure-8's start crawling apart.

[/ QUOTE ]
Wow, this is very hard to believe! Pardon, indeed, but there is after all
testing done as noted by some Oregon? U. for forestry use where stoppers
(overhands, I think) held through rupture.
THINK about what you're seeing!? You say "above 10%", and I'll give you
15-20%; that is on the S.Part/mainline. On the flip side of the knot is the
eye -- TWO legs/strands --, which have then each less than 10% force,
and the end which runs through the knot's central nip, u-turns around
the S.Part, AND THEN BACK THROUGH the nip into a Fig.8 stopper has,
what, 2%? At uppergrade pulley efficiency, even, how much load could
be reaching this Fig.8 stopper knot? -- to pull it loose?!
(And sounds like the stopper should be set up against the bowline, not
down the line like a good-luck charm; this is a reason for NOT using the
Fig.8 but using an Overhand stopper -- it can be set pretty snug to the
stopping point.
And esp. as a Fig.8 in stopper loading really doesn't much favor pulling
itself loose, as the flow just isn't there so well.
.:. I'd sure like to see video of this in action!

[ QUOTE ]
Tomorrow we'll repeat, with a variety of "Locked" Bowlines.
kN, I would like to try some of the knots you've described, but am unable to figure them out reliably from the photo's;

[/ QUOTE ]
Whoa: the photo two posts above, of a "Janus" bowline (file name is
"knot_JanusCBowline_L1000.jpg", (msg.#--898?), is about as clear as can be?
What don't you see? The eye runs down out of the photo, the single S.Part
runs up. The knot is about as basic as can be, Ashley's #1034.5 (kinda an
afterthought by him?!), with the end then taken (in my photo's orientation)
left behind the eye legs and then around front to be tucked down through
the central nip between the end-bight legs. (which renders a perfectly
symmetric knot structure: could fuse end w/S.Part and cut eye and have
same knot, e.g.)
The same knot is tied in that grey 12-strand Spectra to the right of it and
given some tension, but is turned a little to show the S.Part's curvature.

(The knot above this one is something I think should show best strength
in hi-mod, but is material-consuming and likely to jam and ... begs the
question Why not splice? loudly (lack of tools in emergency, might be
the only answer). That cannot be so easily explained; it's a sort of active
working of the anglers' Bimini Twist -- "active" in that the twin eye legs
will impart twist to the S.Part, whereas in the Bim.Tw. a long twist is
simply passively held by a counterwrap.)

[ QUOTE ]
any chance you could either send clearer photo's, or actual samples? Whatever we don't accomplish here I will be glad to have done at a ropemaker's lab later.

[/ QUOTE ]
I see that somehow there was no attachment photo to my 2nd eyeknot,
in post following the aforementioned one!? -- huh, I thought I saw that it
uploaded ..., but ... EDIT and it should be there now. Again, Ashley's #525
shows the fundamental structure that is used here; #1425 shows it used
qua bend and abbreviated from essentially a symmetric Fig.9 to Overhands.
But 525 should guide if any is needed.

Here, too, the image seems pretty clear.
The eye here is UP out of photo, the S.Part hangs down.
Look at left, exploded knot (right is under tension).
Form an "overhand"? loop -- turn clockwise and cross OVER S.Part;
(tying in bight, nb) form bight and lay end up within the just-formed loop
(in photo, this end runs right behind tensioned knot's eye and into manila);

then turn bight back around (thumb or -- will tuck inside this turn...) and
through S.Part's loop (back-right-forward, re view of photo);
and turn now down around base of this bight
and up through bight's just-formed loop.

To work tight, pull the S.Part's u-turn beside end's exit -- points at right
of knot as shown-- to draw the twin wraps snug; then pull S.Part. Also
easy to do these parallel parts separately, and a tug or two on eye can
assist. For strength in HiMod I'm guessing a snugger vs. open knot will
be better; for some use where easy untying was wanted, this knot could
be left well loose; there would be more initial deflection at entry, then.

- - - - - - - - - - -

[ QUOTE ]
a variety of "Locked" Bowlines

[/ QUOTE ]
HERE, in this post, another such knot. (I am unimpressed by those so far
shown in popular press.) This knot takes what is sometimes referred to
as the "Water Bowline" and shown with a Clove Hitch base (I think that this
might be mistaken of historical origins) but uses instead a Cow Hitch base,
which I think works better; it also lends credence to the name "Mirrored
Bowlines" -- a marketing consideration. (-;

But in addition to the usual "down-thru-hole-around-tree-back-in-hole"
reeving, REPEAT that movement a half run further -- i.e., treat the S.Part's
eye leg as a S.Part and go around it and back ... . This adds a third diameter
of material through the nipping turns, and if oriented well, I think will give
some boost to strength; of course, it makes a further two nips of the end
(and for rockclimbers, points the end downwards, for gravity assist in
staying in place).

In my photo in grey Spectra I show the basic knot w/o final tuck; frankly,
Left-handed (here) or Right-handed orientation doesn't matter so much.
But do follow the left-hand side's shown completion, putting the the end
-- which I substitute a white cotton cord for, to illustrate position --
as shown behind/below the other two parts. This makes I think the best
triangular (3 dia.s) geometry for the the S.Part to heavily load, glancing
around the loaded left red part, then turning heavily into the white end
and wrapping up around the right red part to complete its turn.

The "mirrored" turn not only puts in another nip, but should stem the
reported walking-down of this turn (your SAIL report), as now both of
these turns would have to walk the walk. If the very low friction of the
material isn't aiding the off-loading of force in the first turn, this 2nd
one should help.

whew!

As for sending samples, hmmm, that would be nice, of the to-be-tested
material. But I'm JustAGuy(tm), not a rope shop. I'd have to order ... .

*kN*

 

[knudeNoggin]

Testing note:
It should be possible to STITCH INTO TEST SPECIMEN some thin bright
thread to mark position, which can help to document (via observation
and preferably photos / video) rope deformation/movement/rupture point.
For this purpose, it probably makes sense to stitch just around some
surface fibers -- rather than through rope, which risks then the thread
being drawn in two directions. And even in reference to one marker,
other points can be roughly determined.

Now, here is a quick Fig.8 knot, just loaded substantially in the grey Spectra
(no slippage), and shown in exploded form in red yachting rope with the end
being shown in the small white cotton cord to highlight that. Frankly, in
most cordage, this seems to hold (with my pulley strains, at least) without
the final tuck down between eye legs; but I'll take the extra tuck for both
security and strength boost (?) for hi-mods.

*kN*

 

[Brion]

Hello,
We had just a few minutes today to test some knots. First, we repeated the test with simple Bowlines, and observed them crawling at about 10% of rated break (certainly not 15 or 20%). They crawled right down to the shackle pin, then began untying.
We then tied them with stoppers, and worked the stoppers down as tight as we could. This time the stoppers were crawling, but more slowly than the knot. They also had rather long ends (3"); the knot broke before the stopper could unwind completely.
Tomorrow morning I'll steal some time to test the locked variations for slippage.
The most recent photo's from kN are clearer, but my eyes glazed over at the descriptions.
As for future tests, yes this stuff is expensive, so I hope to have the ropemaker contribute materials as well as tests. If you, kN, are interested, PM me for a shipping address. I'll forward the ropemaker's requirements -- basically eye size and specimen l.o.a. -- to you. Here's your chance to test your theory. If you are right, we'll have a new tool to use. And in any event we'll have useful information.
Fair leads,
Brion Toss

 

[knudeNoggin]

[ QUOTE ]
We had just a few minutes today to test some knots. First, we repeated the test with simple Bowlines, and observed them crawling at about 10% of rated break (certainly not 15 or 20%). They crawled right down to the shackle pin, then began untying.

[/ QUOTE ]

Firstly, is anyone TAKING PHOTOS OF THIS BEHAVIOR?

Otherwise, it is hard to understand exactly.

If the END is slipping out, then the EYE WOULD ENLARGE,
but you in fact report the shrinkage of the eye to zilch,
and the knot becomes some kind of noose-hitch to the pin.

This seriously suggests the sort of deformation of partial
capsizing which I have already photographed and presented here.
I would like the same documentation of this Nth to the thousands
of tests, to try to make a half step towards comprehending the
mechanics involved. Simply, if the S.Part were rotating around
the end bight of the bowline, there'd be no need for any stopper
on the end -- it would dangle. And the eye would shrink by this
rotation into the S.Part.

But the stopper IS engaged,
AND the eye is shrinking. Although in latest report you say that
the knots "crawled right down to the shackle pin" : with
how much tail in place to start and to finish? -- I mean, it wasn't
that, UNstoppered, the ends pulled out; but the knots crawled ... .

Frankly, I can only conceive the reported behavior coming by the
sort of capsizing deformation presented above, where the loop
of the S.Part opens into a bit of a spiral, and doing so does
pull on the end (esp. of the #1010 bowline, LESS SO of #1034.5,
"Left-Handed" ("Cowboy") bowline), as well as ease the slippage
of the now near Pile-Hitch noose down to the pin.

TRY THE LEFT-HANDED BOWLINE.
But I've shown better: Left-handed with the end wrap & tuck, above.
Surely all of the knots I've shown in this thread are clearly enough
presented to enable one to tie them. (It's not like we're dealing with
N-bight / M-lead Turk's Heads variants!

WHAT MATERIAL IS BEING TESTED? (diameter, construction, chemistry)

*kN*

 

[Brion]

Hi again,
I took a brief video of one of the locked Bowlines crawling, and will upload it as soon as I figure out how (I am a confirmed Techanderthal). Meanwhile, I undertand your puzzlement about the mechanism of the crawling; it is a very weird thing to watch. But I can assure you that the knot does not capsize, even partially. Instead, the end stays put, the knot stays stable, and the loop diminishes until the knot reaches the pin. At that point, if there is no stopper the end pulls out. If there is a stopper, sometimes it will fetch up and stall at the knot, in which case we proceed to break, and sometimes the Figure-8 unties itself, and then the end pulls out. Creepy.
Fair leads,
Brion Toss

 

[Jamin_Mayer]

Sweet. I'm interested in the videos.

 

[knudeNoggin]

[ QUOTE ]
Hi again,
I took a brief video of one of the locked Bowlines crawling, and will upload it as soon as I figure out how (I am a confirmed Techanderthal).

[/ QUOTE ]
Bravo!
I feel your pain. Getting photos up, at last (this is 2009, eh?), I count as
my personal breakthrough.

[ QUOTE ]
Meanwhile, I undertand your puzzlement about the mechanism of the crawling; it is a very weird thing to watch. But I can assure you that the knot does not capsize, even partially. Instead, the end stays put, the knot stays stable, and the loop diminishes until the knot reaches the pin. At that point, if there is no stopper the end pulls out.

[/ QUOTE ]
Ah, I see: the END slipping out is NOT an issue, until abutting the pin.

Okay, then it's something to do with the too-little-friction, and the offloading
of 50% from the S.Part to the S.Part-side eye leg (i.e., the emanating parts
from the "rabbit hole") just doesn't happen -- and so some 55-65% or
whatever is going into that leg, pulling around the pin, and bringing down
the *knot*.

For THIS behavior, really, the extra-tucked Left-handed bowline above
should NOT help -- in fact, its 3dia (fatter by 1) wrapping rabbit hole might
rotate all the easier.
But the "Mirrored Bowline" -- the one with a 2nd rabbit hole, so to speak --
should work. This is where you can begin by forming a Cow Hitch, and then
tying a bowline finish into to it both coming & going . That was clearly
shown in the red double braid rope; and it should have the extra finishing
tuck of end, to boot. While that Cow hitch base need not be closely formed,
I'd make it rather snug in this stuff, to keep the two rabbit holes abutting.

And the Quick8 and Semi-Symmetric Fig.9 eye knots should both hold,
though it sounds like one's battling the Devil's cordage.

[ QUOTE ]
... and sometimes the Figure-8 unties itself, and then the end pulls out. Creepy.
Fair leads,
Brion Toss

[/ QUOTE ]

And what type/size rope is this?

*kN*

 

[Mark Chisholm]

This thread is a great experience. Thank you all for contributing!

 

[Brion]

Okay,
Here is an attempt at sending a brief video:
http://www.youtube.com/watch?v=ZFRQcExLA34
The knot is the "locked" Bowline variation in which the end is taken twice around the standing part before it goes down through the loop to finish. The line is 3/16" Amsteel. For this one we tied a Figure-8 up close to the knot at the start, just to shorten the throw on the machine, to get a break (not shown). Watch and you'll see the line crawling through the knot. If this upload works, I'll try to get back into the facility on Tuesday to try some of the knots that have been suggested. Meanwhile know that the same thing happens with a couple of other "locked" variations. Again, if this works -- and if there is time before my flight out -- I'll show pictures, including loose knots. If I can't get to this before I leave, it'll have to be some time in the future.
Fair leads,
Brion Toss

 

[knudeNoggin]

[ QUOTE ]
Okay,
Here is an attempt at sending a brief video:

[/ QUOTE ]
... a successful attempt -- great!

[ QUOTE ]
The knot is the "locked" Bowline variation in which the end is taken twice around the standing part before it goes down through the loop to finish.

[/ QUOTE ]
NO! Sorry, but this is a regular ol' "Double Bowline"* aka "Round-turn Bowline"
(Pawson, et al.), Ashley #1013. The movement of TWO turns of S.Part are
clearly visible; there is just a simple/usual bight collar, no extra turn there
(which would've made it Asher's "Enhanced" (& I think he later/earlier had
"Birmingham") bowline). Hmmm, I still think that the Mirrored Bowlin I've
shown will help; but seeing the double turn rotate lessens the amount of
bet I'd put on that call!. (*There is no way a Dbl.Bwl<=>Enhanced Bwl, btw.)

NB: The parts that are tightly nipped -- the end bight -- are not slipping
out of the nip, here, at least (report of Fig.8 crawling suggests ... later).
Rather, it is the nipping round turn, which itself doesn't really see any nip
upon it.

[ QUOTE ]
The line is 3/16" Amsteel.

[/ QUOTE ]
Hmmm, okay --THINNER by 1/8th" than the grey Spectra stuff I show. And
if it's much like that, similar 12-strand, its cross section compresses a lot (UNfirm, fluid).

[ QUOTE ]
Meanwhile know that the same thing happens with a couple of other "locked" variations.

[/ QUOTE ]
It all depends what "locked variations" amount to. Given the description of the
behavior in your prior post, anything just fiddling with the end could be seen
to be of no help here (e.g., the "Janus" bowline re-tucking above). What is
needed is some fiddling with the S.Part! (E.g., the Water Bowline (#1012) or
better the Mirrored Bowline above.) Such as what you tried here, the Dbl.Bwl,
and that shows the cordage to be made by the Devil indeed! I think that
the Clove or Cow bases should give more resistance than the mere 2nd turn
of the Double; they will have a different angle of impact to the turns given
the separation of them.

The Quick8 & Semi-Sym.Fig.9 have entirely different and should-be secure
geometries.
In order of guesstimated success (no slippage; break strength),
I'll rank:
Semi-Symmetric Fig.9;
Quick8;
False Bowline 8 (attached).
(The Lehman8 would be another; Quick8 might be stronger --similar nipping.)

The attached eye knot which I'll name "False Bowline 8" has a form of the
Fig.8 as a base (yes, sort of the mid-"flype" Fig.8 form -- manipulate the
red rope's form and you'll see a common Fig.8 geometry appears);
but whereas the Bowline's nipping turn flows into one eye leg,
this "False..." one (my reason for this qualifier/name, btw) flows
into a collar around the eye legs, and then back through the knot,
where it makes a 2nd nipping turn (loaded by one eye leg);
the finish is trad. bowlinesque tucked bight. And, yes, I now worry about
THAT slipping, but, heck, it'll be an *improvement* so far; and really there
is going to (should) be now a LOT of nipping pressure on the end and its
eye leg.

re attch knot photo
The red cord shows mid-flype Fig.8 base; white cap is the "X" marking the
spot for tucking in end, bowline style (bunny hole, i.e.).
The grey Spectra holds this form with the orange 6mm kernmantle highlighting
the end's tuck -- the rabbit's path.
The white Sta-set (in focus, at last) shows the strength/security aspect of
the combined nipping turns, and the fore&aft collars holding things in
place. (NB: The end could be brought in through the eye-side collar,
an after thought I had after stressing the grey Spectra and examining the
points of compression/wrinkle -- was there too much on S.Part-side eye leg?)

I have one other such false bowline, and another with the mid-flype 8 as
the base which is very similar.

*kN*

 

[knudeNoggin]

Here's a different, briefer version of a false bowline in Fig.8 mid-flype base.
In this knot, though briefer, the end makes some compression upon itself
(a sort of Half-hitch locking), which along with the strong nip of the
mainline's (S.Part's) turn into the collar around the eye legs, and the
other eye leg's corresponding nip, should hold the end in place.
-- even in the Devil's cordage?!

In this photo, I've used twin/double 6mm kernmantle to be of near equal
visual presence to the half-inch Sta-set in showing the reentry of the end
to finish the knot. The eyes (both loose & tensioned knots shown) run right;
the main line /S.Part is from the left (and little shown, short, in picture).
One might want to work the collar around the eye legs a bit snug in
dressing & setting the knot; it won't get much help during loading.

*kN*

 

[Brion]

Hello again,
Tested a few more Bowline variations in something of a hurry yesterday. You'll find a video of one of the tests at:
http://www.youtube.com/watch?v=fpt6nxgAOEI
This one came near the end of the series, with everything except the last of kN's "Figure 8" knots slipping at very low loads. So I put one of those at the lower end, and a "Mirror" Bowline at the top. This latter is a Locked Bowline variation in which the end emerges from and reenters a Ring Hitch structure, instead of a simple loop.
So the Mirror starts taking up, and then stops slipping, and then I notice that the much-vaunted "Enhanced" variation is crawling right out. I stopped the video before the end pulled free. For the last test (not shown) I put two Mirrors on the sample and pulled. Again, considerable settling, but then none, followed by a break.
So first, the mushy term "Enhanced Bowline" really means, in this context, "Extremely-complex-to-tie-but-with-no-advantages-Bowline".
Next, the Mirror from the video'd test was jammed solid, even though it was under a relatively low load. Not a good field knot, then.
Finally, this test was only for security; every test I've made for knot strength in HM has shown a reduction in strength of 60 to 70%. So at best I think we have a dire emergency secure variant, but one that cannot be untied, and which weakens the rope tremendously.
Fair leads,
Brion Toss