Another Bend for Dyneema

New Knot Investigations
41

I don’t think balancing the legs is a concern in Dyneema. There’s enough slippage during draw-up that they tend to balance themselves.

...so what about two (pseudo-)Zeppelin in a #1454 version?

The two configurations that I tried were analogous to ABoK 1454 and 1455. Both fared the same (the Bowlines capsized and all the components needed tools to untie). For what it’s worth, the capsized Bowline appears to be stronger than the normal geometry.

or what about the use of the #1459-1460 structure with Bowlines instead of seizings? and #1457? :)

What leads you to think that the round-turns and half-hitches (1457), Whatknot (1459), or Whatknot and half-hitches (1460) would make a better central structure than a reef knot? In my previous tests, two Bowlines eye-hitched (reef-knotted) together was unreliable. Sometimes it held and sometimes it slipped.

Regards,
Eric

42

After speculating that:

[ol]- a Granny Knot might be easier to untie after loading than others, and

  • given that I’m loading the knot on both ends, there’s no difference between the Granny and the Whatknot,[/ol]
    I decided to try out a central Granny with Bowlines on each end.

In both forms (like ABoK 1454 and 1455), the Bowlines slipped a little, capsized, and then slipped the rest of the way. At that point, the bend held. It was possible, but not easy, to untie the capsized Bowlines and Granny Knots. Pliers were necessary.

That got me to wondering about why the Bowlines capsized on the Zeppelin and Granny, but not the Reef and Carrick structures. So, I experimented some more, and discovered that Bowlines can capsize on the other bends too. The propensity to capsize seems to be related to how close one dresses the knots initially. If the Bowlines have little distance to migrate, they have less opportunity to capsize.

I do not, however, trust knots whos properties change depending on how closely or snugly you dress them – especially in high-load applications (like you’d use Dyneema for). Therefore, I’m no longer enamored of the bends in replies 34 and 35, unless something can be done to prevent the Bowlines from capsizing.

The Overhand and Collar I showed before, and the Angler’s Loop do not capsize under load – but they both jam. The Overhand and Collar (does it have a name?) can be untied with pliers, but the Angler’s Loop defies me. Is there a Bowline variant that resists capsizing yet remains easy to untie?

Regards,
Eric

43

Good for you. I’ve eyed this structure’s appearance
when loaded --i.p., how the apex turn is over space
(between the crossed ends)-- and thought that it should
work well thus!

The propensity to capsize seems to be related to how close one dresses the knots initially. If the Bowlines have little distance to migrate, they have less opportunity to capsize.

I do not, however, trust knots whose properties change depending on how closely or snugly you dress them
– especially in high-load applications (like you’d use Dyneema for).
[Except that unless you can show us actual loads at which
you’re working, here, one might reply that knots don’t
come up to adequate for benefiting from HMPE’s strength!]
Therefore, I’m no longer enamored of the bends in replies 34 and 35, unless something can be done to prevent the Bowlines from capsizing.

The Overhand and Collar I showed before, and the Angler’s Loop do not capsize under load – but they both jam. The Overhand and Collar (does it have a name?) can be untied with pliers, but the Angler’s Loop defies me. Is there a Bowline variant that resists capsizing yet remains easy to untie?
[/quote]
I’ll suggest (a) using the “left-handed” bowline
or (b) putting in a complementary collar (extend
the common knot by having the tail collar the “outgoing
eye leg” (i.e., the continuation from nipping turn)).
ALSO, one could putting the eye knots close to the
center knot and running the tails through the center
and tucked out through the opposite eye knot’s body
(nipping turn) !? This gives 3 vs 2 diameters in the
nipping loops of the eye knots, and clamps a 2nd time
(opp. eye) and 3rd (center knot) on the tails.
–though sometimes it seems that such stuffing of
a part for further nipping comes with a downside
of lessening the nip effect given the now increased
number of parts nipped there.

–dl*

44

I tried the Cowboy Bowline - ABoK 1034 1/2 (* see note below). It also capsized. What about its structure made you think it was resistant to capsizing?

  • I generally choose to use Ahsley’s names for knots but I dislike the moniker “left-handed bowline”. There are right- and left-handed versions of the actual Bowline (ABoK 1010); and right- and left-handed versions of the “left-handed bowline” for that matter. Ashley’s name for this knot seems awkward and confusing (dare I say "gauche"?).

Regards,
Eric

45

Consider the knot in the image below.

http://igkt.net/sm/index.php?action=dlattach;topic=5935.0;attach=21715;image

It is a Reef Knot (tied left-handed) with Bowlines (tied right-handed) on each end; and with the tails tucked through the center of the Reef Knot and then through the nipping turn of the opposite Bowline. The knot was tied in 3mm Amsteel Blue (Dyneema SK75).

Because each turn in the Reef Knot and the nipping turns in each Bowline now encompass 3 strands instead of 2, I expected that:

[ol]- the bend would be stronger, and

  • the bend would be less secure[/ol]

than the untucked version I had tried previously. Given that the previous bend had occasionally slipped, I anticipated that this bend would slip too.

Well, I tried it twice. The first time, one Bowline drew up tight and the other not quite snug. When the standing end on the not snug side started to break (strands fracturing) I stopped pulling and inspected the bend. Both Bowlines had partially capsized. The nipping turns had migrated into the knots, but had not pulled through the collars and so did not fully invert. The location of the partial breakage was at the entry to the collar, not at the nipping turn as is the typical failure point for a Bowline. The central reef knot was not nearly as tight as the untucked version. I was able to untie both bowlines and the reef knot by hand (no tools) without much difficulty.

On my second try, both Bowlines drew up snug to the Reef Knot. One of my end loops (an Angler’s Loop) broke first. This photo shows the bend after loading.

http://igkt.net/sm/index.php?action=dlattach;topic=5935.0;attach=21717;image

Both Bowlines had partially capsized, just like the first try. I had left fairly long tails on the bend, but it didn’t swallow much of them when tensioned. Again, I untied the entire bend by hand (no tools needed) without difficulty.

This bend is a bit bulky and complicated, but it did hold and - unlike all previous attempts - could be readily untied after hard loading. That is something I began to doubt was possible with Dyneema.

Regards,
Eric

TuckedReefAndBowlines.jpg

46

Hi Eric,

Do you really see Whatknot there? I only see nipping loops! :wink:

About your last post, do you think a Surgeon Bend will perform better than the Reef?
But above all, please try tying these variations (look at the attached pictures). They are based on a 3 nubs structure, two Standard Bowlines and the central part is formed by a 2 bights locking mechanism that bites/locks the 2 ends (after that we could retuck the ends through the nipping loops but perhaps the bend becomes too bulky…). We can tie the internal hitches close to the nipping loop of their loop, or close to the nipping loop of the other loop. I don’t know which will perform better in Dyneema…
Here the 4 variations.
If the bends are not in tension the ends could not be so stable, we could add other turns (as in ABoK#523) or we could tuck the ends through the nipping loops or through the collars…
Ciao,
s.

Dyneema_2Bwl-2Bights-2Hitch_3.jpg
Dyneema_2Bwl-2Bights-2Hitch_3.jpg1000×625 86.5 KB

47

Yes. If you pull the two nipping loops of ABoK 1459 together (as will happen in Dyneema), then you get a Whatknot. In fact, in the description, Ashley says “mechanically the knot is the exact duplicate of the Whatknot…”.

About your last post, do you think a Surgeon Bend will perform better than the Reef?

No. I previously tried the Granny / Whatknot as the central structure, hoping it would be easy to untie, but that idea didn’t pan out. The Reef Knot, however, is easy to untie. One can either pull the end bights apart (just like rolling the collar of a Bowline), or capsize the knot by tugging an end back. A Ligature (Surgeon’s) Knot would put a bulkier, asymmetric structure in the center of the bend. It should still untie easily by capsizing but I generally prefer symmetric bends to asymmetric ones.

But above all, please try tying these variations (look at the attached pictures).

Please don’t take this the wrong way. I really appreciate your interest and suggestions, but I can’t try out every possible bend. In addition to the time spent, each test takes about two dollars worth of Amsteel Blue, and I don’t have a limitless supply. I’m happy to conduct trials provided there’s something to be learned, but I can’t justify the expense otherwise.

Each of the bends you’ve pictured have nothing to prevent the Bowlines from capsizing, and they have nothing to secure the tails’ tucks until the Bowlines are drawn together. Those attributes make me highly doubtful that any of them will yield practical bends. Given that, what do you hope to learn from testing them?

Sincerely,
Eric

48

Eric, if the ends are seized, to my mind, the knot (the knot structure) works differently! But maybe I miss the point and I really don’t know how the Dyneema rope works.

Thinking about ABoK# 1454 and #1459 I tied the bend in the attached picture, surely it is a known knot and you can find other similar bends by searching the forum (for instance at
http://igkt.net/sm/index.php?topic=2871.0 )

I tied another bend based on ABoK #523, but it is a little bit bulky and I think it is untiable! maybe I will post in another occasion about fishing bends! :slight_smile:

Sorry, here I meant a symmetric Surgeon, that is to say, double Half Overhand down and up.

I wrote “please try tying…” (not “please try testing”) :wink: , so if you consider them interesting you can test or not (it’s up to you obviously)…oh I’m only curious and because I appreciate the power of the 2 bights locking mechanism I think the structures I showed could perform very well. About the instability of the ends if there isn’t tension, we could tie the loops very short ( for instance just 2 rope diameters) and maybe we could only put the ends through the 2 bights without the internal hitches (maybe) …

I don’t know the Dyneema rope behaviour (I repeat) and so I don’t know why the Bowline capsizes, but a well dressed knot is of fundamental importance…I think you will agree with me.

Happy tying.
Ciao,
s.

49

The knot pictured raised an interesting question: if the tail is tucked through the opposing Bowline’s nipping turn, do you need the central structure at all – or are the Bowlines themselves sufficient to back each other up? I thought that was worth trying, so I tied the bend (like ABoK 1454 but with mirror-image Bowline structures and with the tails passed through each other’s nipping turn) and put it on the winch. I tested it and under moderate load, the bend rolled apart. Afterwards, I realized that I hadn’t looked to see if the Bowlines had capsized, so I tried again. The Bowlines did not capsize, but they rolled. Thinking back, I recall much higher tension on the line at the point where Bowlines capsized.

I tied another bend based on ABoK #523, but it is a little bit bulky and I think it is untiable! maybe I will post in another occasion about fishing bends! :)
I look forward to seeing it. I too was trying to evolve bends that involved each working end taking nipping turns around both its own and the opposite standing end. Then I tried the 6-nips (3 Water Knots?) which worked and is much simpler.
I don't know the Dyneema rope behaviour (I repeat) and so I don't know why the Bowline capsizes, but a well dressed knot is of fundamental importance...I think you will agree with me.

Lol, I don’t understand Dyneema rope behavior either. I certainly agree that proper dressing is important, but I’ve also found that Dyneema can easily re-dress a knot for you, no matter how carefully and firmly it is set up. The Double-Dragon Loop, for example (even when dressed and pulled as tight as I could get), capsized and failed at relatively low load when tied in Dyneema. The Angler’s (Perfection) Loop, on the other hand, has drawn up tight and secure to the same geometry (swallowing very little tail) every time I’ve tied it in Dyneema. I’ve used it for the end loops in attaching to my test rig many times, so I’ve certainly exceeded the sample size needed for statistical confidence. I feel that a knot must be “self-dressing” (that is, it must draw up consistently to the same geometry on its own) in order to be trustworthy in Dyneema.

Regards,
Eric

50

Indeed, I was about to say the same thing. Much of
what is put forwards here is just stupid --e.g., MY idea
for the further-tucked bowline should not have passed
“the smell test,” in that --THINK, THINK, THINK!–
the SPart has 100% tension and multiple parts coming
out of the nub imply a split of tension further than the
50-50% normal for two eye legs, and THAT requires
more offloading via friction in the nipping turn than
one can expect w/HMPE (which has been shown to just
flow out through even the dble. turn of the double bowline
in one Brion Toss testing!). BTW, a sort of water bowline
but w/cow vs. clove as the compound nipping structure
DID hold, to break (at what Brion thought was not great force,
but w/o calibration read-out to confirm).

So, one must first have a reasonable expectation that
the candidate knot brings something to the table not
seen in the many failures.

Now, the bowline variation where the nipping turn
is the cloverhand IS something new, in that it makes
a doubling of nipping structure in a way different than the
slipping dbl.bwl and maybe more sure like the holding
water(-like) bowline !?

And I’ve found --and will soon post-- an image to go with that
extended fisherman’s knot I described, and which was tested
but MAYBE not quite in desired form?! That knot brought to
the table the tucking of tail at U-turn of SPart --presumably
a heavily loaded nipping point.

–dl*

51

Well, I’m willing to try ideas that may seem stupid as long as I can learn something from it. After all, my experiments so far have disproved several of my own hypotheses about what makes a knot secure in Dyneema, and I’m sure that my current understanding is still flawed. I can’t explain why some knots roll under moderate load while others that look less secure hold at much higher tension. High nip is not the answer. Neither is complication (extra tucks), nor reversal (u-turns). Jamming (backing up one knot with another) apparently plays an important role, but cannot be the sole factor. I have a feeling that there at multiple interacting variables and that the real answer is too complex for conventional wisdom to explain.

I can see how tucking a tail through the center of a Reef Knot, and through the nipping turn of a Bowline might make them stronger, but it seemed strange to think that it might increase security. I fully expected such tucking to make the Bowline less secure, and almost didn’t test it. But then I admitted to myself that I didn’t really know the answer and tried it out. The result surprised me.

Regards,
Eric

52

We should be advancing a rationale for WhyTestThis? and
what we think will happen. That’s a good way to put into
contrast the reality --so far as we can know it-- with the
beliefs. --and a boon to learning from the efforts.

Attached are images for that extended fisherman’s knot
discussed (& tested, like it shows?) above.

NB : The white rope stands in a mirroring orientation
to the illustration; the orange-to-black is in like orientation.
(And in both cases they are less helpful than the drawing.)

motto :: “HMPE, Abandon All Hope ye who try knotting this!”

Cheers,
–dl*

knots-fishermans_knot_retucked-M800-3.jpg
knots-fishermans_knot_retucked-M800-3.jpg600×800 63 KB

53

I finally figured out how to tie a “Cloverhand Bowline”. I was looking at the Water Bowline (which is like a Double Bowline except that the nipping turns form a Clove Hitch) and didn’t like how pull on the eye tends to separate the nipping turns. In looking for a similar structure that pulled the turns together instead, I inadvertently came up with a knot that I recognized as a Cloverhand with a Collar, i.e. the “Cloverhand Bowline”. My previous efforts failed because I was tying the Cloverhand as shown in Ashley’s diagram (running left-to-right, or downwards) when I needed to tie it reversely (right-to-left, or upwards). With the standing end exiting from the bottom and the working end from the top, the Cloverhand does make a stable platform for a collar.

See the first image below. It shows both sides of the “Cloverhand Bowline” (left and center). The knot seemed to be crying out to have the working end tucked up through the collar (as shown on the right). I doubt that the extra tuck has much (if any) effect on the strength or security of the knot, but it fills a gap in the collar and looks nice.

The second image below is the Double Bowline (front, back, and with the working end tucked through the collar) for comparison. The two knots have a very similar appearance, but look closely and you’ll see that the “Cloverhand Bowline” has an additional part on the side of the nipping turns.

I put “Cloverhand Bowline” in quotes because a purist might argue that this knot does not belong in the Bowline family. It is not “Post-Eye-Tieable” (PET).

Anyway, I tried both the Double Bowline and the “Cloverhand Bowline” (with and without the collar tuck) in 3mm Amsteel Blue. Both eye knots held (with little slippage during draw-up) in both configurations to their breaking points, which seemed similar. I was able to untie them all without tools after loading. The Double Bowline untied easily whereas the Cloverhand took some wiggling to let go.

Twin Double Bowlines (untucked) tied in the form of ABoK 1454 drew together under load and then jammed. I was unable to untie them.

Twin Double Bowlines (untucked) tied in the form of ABoK 1455 with the eyes hitched (Reef Knotted) held without drawing together. The nipping turns did not capsize, but one of them did pull through its collar, and I couldn’t untie it. When tied with the running end tucked through the collar, the knot seemed more resistant to pull-through. I didn’t perform enough tests to be confident, but in the few I did, the Double Bowline retained its dressed geometry.

Twin “Cloverhand Bowlines” (tucked or untucked) tied in the form of ABoK 1455 with eyes hitched (Reef Knotted) held without drawing together and seemed quite resistant to changing geometry.

From a security/strength standpoint, the hitched twin “Cloverhand Bowline” bend seems the best so far, but the hitched twin collar-tucked Double Bowline bend is very close and is significantly easier to tie (the Double Bowline being PET) and to untie. As an aside, the collar-tucked Double Bowline is also tiable in the bight (TIB).

I’ve come to the opinion that holding without drawing together under load is preferable. You don’t want a bend that starts moving once it reaches a certain tension, even if that movement is still secure. First off, the bend may be somewhere you can’t inspect it (like at the top of a mast), and secondly, movement may cause undesirable loss of tension (like in a halyard). Therefore, I prefer these bends to my previous eye-hitched twin Bowlines with ends tucked bend. All of them, however, take a fair amount of line to tie. Given enough line, an end-to-end splice would be superior in every way. I’d only tie a bend in Dyneema if something kept me from making a splice.

I hope that makes sense,
Eric

DoubleBowline.jpg

54

It’s worth pointing out that this video is of a dbl.bwl.
NOT holding, but feeding material out into its SPart
(and with the tail stoppered against slippage) :
www.youtube.com/watch?v=ZFRQcExLA34

So, beware attaching behavior to a knot vs. to some
knotted line !

–dl*

ps : Did your interpretation of my tying guidance
for the re-tucked single fisherman’s knot match
my later-posted images? (I sob, if so, for it means
that that knot slipped.) :frowning:

55

Here’s yet another attempt,
though it I suppose falls into the set of those knots
with simply extra nipping zones,
which this hard-to-knot material has been shedding.
Still, what I’ve tried to do in this knot is put in many
rather hard U-turns, in hopes that not only pressure
of constriction but also resistance in bending will get
the slippage arrested (eventually)!?

NB: The tied/photo’d knot is what is only described
in my notes --i.e., the tails take that guidance to cross
over opposite SParts, unlike what I’ve sketched in ink.

–dl*

end2end_201707xxbxx-m480-2.jpg
end2end_201707xxbxx-m480-2.jpg480×480 41.9 KB

56

Hi! Iike to try this one, maybe retucked. It’s like a bloodknot, but with nipping loops in the middle.
No dyneema available..

57

NO, it’s not like that --except by many of the quite
misguided images that float around, ignorant of what
the blood knot should be! And I don’t think
that your knot has much hope in HMPE, and maybe
not so much for even traditional rope, without some
careful setting.

I like the idea (presumably) :: of incorporating some
gripping coils for distributed nip and presumably good
strength; I’ve done similar things (but without testing
basis for really showing that they can work). Tying it
now in some marine polypropylene monofilament kernmantle,
I find that I can get more of a hitch in that one side
will grip the other leaving the other side’s coils quite
loose --the first side’s nipping turn & coils are gripping.
So there is this sort of “race condition” to deal with
in setting the knot, to try to achieve balanced loading.

Note that, contrary the true (angler’s) blood knot,
your knot’s coils coil away from compressing the
center tuck area. Working in fishing line, one can
tie the knot with the coiling in either direction, as the
setting will convert away coils (Barnes called them
“outcoils” or at least the “outcoil method”, IIRC) to *to" coils.
But in rope, they can remain away and as such will tend
to have enough grip to pull apart (from each other, and
the center tucks) rather than clamp tight on the center
tail-tucks!

Now, for rope, this away behavior is consistent with the
goal described first, above; but it likely will take some
careful tight dressing and then setting so that the coils
take load immediately, in hopes of building grip before
some almost inevitable SPart slip --and once slippage
occurs, I think it then reigns as far as denying the
coils that hoped-for gripping benefit.
YMMV per material?

But in my quick testing of this ? 5/16" (8mm) line,
I’m seeing coil-to gripping, as for a rolling hitch.
???

(Btw, regarding HMPE, I’ve come to suspect that frictional
heating --high pressure-- might lead to slippage by making
surface melt, and lead to rupture otherwise!? --in some
cases, anyway.)

–dl*