Here is a not I developed for climbing and mountain rescue.
I would appreciate any feedback.
http://www.milesgear.com/BowlineCinch/BowlineCinch.html
Thanks,
Dave
Dave,
I’m another newbie. Your post is the first time I have seen a Yosemite bowline. I think I’ll use this in place of my regular bowline.
Thanks,
Mike
Hello David and welcome to the forum.
I’ve tied this just a few moments ago in small accessory cord (3mm) and while I think it is neat and ingenious, I am wondering about the necessity of it and what are characteristics make this better than let’s say the Y-Bowline and just thread through the open loop instead of threading through the nipping areas?
The captured rope seems to be under more abrasive stresses and possibly weaken the knot(?) when more advanced angles are encountered.
Aside from the leg of the sling being captured I am unsure of the need of tying complexity. (Not all that complex, but more so than just passing the end through the loop.)
I’d love to know more about the tests you ran and where the examples failed.
Thank you for sharing this.
SS
Mike,
The Yosemite bowline is very nice since the end is tucked neatly and secure. It is used in climbing to secure the climbing rope directly to the harness. Very compact and secure. A substitute for the figure 8 follow-though.
SS,
I’m not sure I follow your comment. The whole idea of this is to form a loop of rope where the end is captured. Is the end captured after you thread it through the Y-bowline? Do you have a picture? You can tie this loop at home and not have to re-tie on the rock. We do this with prusik loops and webbing runners.
The testing was a pull of 1 sample on a Instron. Broke on one of the tightest nips in the bowline.
Thanks,
Dave
I’ve been disappointed by the security of the Yosemite add-on. There are more secure bowline variations, such as the intuitive Water Bowline, and the less intuitive Janus variation, although the Janus variation has some possible evil impostor issues if the wrong leg gets the extra wrap.
I’m not sure of all the particular demands of your application, but could a Slippery 8 Loop be adapted to do the same thing?:
Hi Dave.
No I don’t have any pictures at present. Didn’t think my passing the end through the open loop needed graphics.
I haven’t needed a set up like this during my climbs though I can see a potential use of being able to adjust the length of a Prusiking sling at infrequent times, etc.
I’m not dissing your set up, far from it, I am trying to see the or any advantage to it for my own use.
And just doing the feedback thing as requested.
Did you capture any pictures of the Instron test? I would love to see which nipping coil the break occurred. And any other testing/pictures you care to share.
Thanks.
SS
There’s only one that’s under any real strain --that would be it.
Though, if one adheres to “AllAboutKnots” article about where the
break occurs, you’ll be amazed that it indeed occurs in the loop
and not the “stem”!
Dave, welcome to the scene! 
Regarding this knotted structure, I’m not happy with a few things
about it:
I find the tuck of the structure’s tail to be insecure
(yes, so it held to break in a test, but, still, I don’t like it’s
too simple pass-through in this knot (bowline )).
And I’m not happy with how the reeved tail loads the knot.
As I understand your desired structure, you want a small eye
at one end and an adjustable eye (essentially) for the remainder.
And you want the structure to be self-locking (as opposed to there
being a tie-off step).
It occurs to me that one could use a bowline-terminated end
but then bring the “tail” (of the structure --the S.Part of the
bowline, as you show) up through a larkshead/Girth Hitch
through the 'biner and back down through (so, twice through
the larkshead); the tail will now be twice-nipped by both of
the two loops of the larkshead. This seems to slip a bit as
tension is built and the loops tighten.
I know of a (what I call) “symmetric Fig.9” eyeknot in which
this pass-through of a tail seems to be well nipped if loaded qua
eyeknot (and not end-2-end loaded or ringloaded).
And the structure that Roo gives as a “Slippery 8” would suit this
task better if the tail is reeved through in the opposite direction
(which I name “Quick8”), AND you make the Fig.8 a Fig.8 eyeknot
to start with (replacing your YoBowl). This seems well secure and
easily adjusted and reasonably easily untied, I think, given the
extra strand running through the knot.
And one could try the same thing but with the tail run up around
the ‘biner and then brought back into the knot (nice the the Fig.8
is the same "comin’ as going’", for this). It seems that this should
be slightly stronger, but … --you’re not going to be breaking ropes.
Btw, is that Bonati 'biner (w/orange (& red-taped?) gate)?
–looks similar but differently stamped to an OLD 3_000kg fat
one I have.
Cheers,
–dl*
Roo,
I like the Slippery 8 Loop. It’s a little to harder to adjust than the one I posted. Very important to be able to do with one hand while climbing and not require a lot of effort. This one does require that both strands of the loop are loaded the same. This is done by the biner. Do you know the break strength % for the Slippery 8 Loop? I have other applications for it.
Dan,
I know that it does not look like it would hold that one strand as well as it does. I was actually very surprised by the strength. I was hoping for 1500 lbs in 8mm cord. This would be similar to another surprising knot I made 3 years ago. I called it the secure bowstring. It is a bowstring knot formed with a double overhand knot instead of a single overhand. This prevents it from traveling down the rope. We use this on our rescue stretcher now. It will slip at 1500 lbs until it reaches the stopper knot and then hold full strength (8mm cord). In fact, out of the 3 samples shown here for testing, one broke at the figure 8 on the bight first!
http://www.milesgear.com/SecureBowstring.jpg
I really appreciate everyone’s feedback on this. My friends are tired of me showing them knots.
Dave
Break strength percentages for knots in rope are fairly irrelevant, in that if you’re even close to approaching the breaking point of the knotted rope, you’re doing something horribly wrong. A rope loaded too heavily can rupture if it encounters a tight curvature from passing over miscellaneous objects even if you had huge, gentle-curvature knots employed at all other points.
Having said that, it’s a good estimate that no knot will reduce the strength of the rope by more than 50%. For a given knot there are a range of breaking strengths based on how the knot is drawn up, the rope material, construction, etc. I actually prefer to assume a 50% reduction simply because it’s hard to be confident of the bell-curve boundaries of knot breaking strengths when only a few dozen tests are conducted in a limited selection of rope, with a limited range of knot dressings, as is typically the case.
I’m finding that this mechanism slips too easily from imbalance in the legs. In the real world such imbalances will regularly occur from swinging and other similar motion.
Roo,
Yes, the legs must have near equal loads. Have you tried clipping in with a harness and hanging on it.
That was my first test in the garage. Swinging and bouncing get get a little slip and re-adjust, but it’s stable.
I you just pull on the loop with you hand, it’s easy to get it to slip. However, I do want it to be easy to adjust with one hand.
Thanks,
Dave
And the reversal of that that I suggested?
I was hoping for 1500 lbs in 8mm cord.
What is the strength of the cord? (nylon?)
#3000?
Btw, on your URLinked page in the OP, you say that the bowline
is good for 3-way loading and thus other connections can be
clipped into its eye (or, that was my take of what you said):
I wouldn’t do this, as the bowline is very poor on ringloading
–i.e., pulling the eye apart–, though the Yosemite finish will
help.
I called it the secure bowstring. http://www.milesgear.com/SecureBowstring.jpg
A s for your 2nd-linked-to knot, I’d love to have seen what shape
it took when the Fig.8 failed (or simply at any high load) --assuming
that that was a high break strength–, for Fig.8 eyeknots generally
are the survivors. (You dressed yours one way of various ways.)
AND, I suggest that you send the tail from the would-be double
overhand out where you have the stoppered tail finishing (which,
yeah, means that you in fact have but a single overhand in the
mainline), and run the tail through both turns of the (had been)
double overhand --you should be able to visualize this from the
photos of the knot, just swapping positions/connections.
What this does is give the central knot the form of a sort of
minimal ProhGrip (Blake’s hitch) gripping the tail.
(And I’d otherwise have run the tail through the full round turn
of the double overhand (which it can be said is loaded partly
like the Anchor Bend ).)
–dl*
Dan,
I haven’t tried the Quick 8 you mentioned yet. I’m kind of pressed for time since every MRA team in CA is getting together tomorrow to do our Rock Recertification. I will be out for a day or two. Plus my side business of making bivy sacks limits my knot play right now. I will be playing with this knot at our recert and should have some notes when I get home.
Is there a better way to dress that figure 8 on a bight? We use interlocking Bowline with long tails to attach our main and belay lines to the stretcher. They are much better for ring loading than a figure 8 on a bight. With rescue we also have to face the challenge of everyone on every team being able to recognize and check you knots. This makes it difficult to introduce new knots. This is very important since the knots never break. Failure occurs from mistakes or bad edge protection for the rope. KISS principle definitely applies in the cold night rescue.
Secure Bowstring
Don’t remember the cord strength, but the last sling with a grapevine knot broke at 6500 lbs. I have the old broken samples and will try to scare up a picture or two next week. Is there a better way to dress that figure 8 on a bight?
Haven’t tried the other suggestions yet. I’ll get back to you.
Thanks again,
Dave
Which is the “Slippery 8” Roo linked to but with the tail reeved
through the 8 in the opposite direction; it could be used as you
have done with a YoBowl, and I think is better for that (now this
would be with a Fig.8 eyeknot not mere Fig.8, to be reeved into
by the adjustable-length tail).
I'm kind of pressed for time since every MRA team in CA is getting together tomorrow ... .
Hey, let us know of any developments in thinking on knots
and of cordage in use. Though, as you say, SAR tends to be
conservative. --but some things such as Sterling’s “HTP” super
static main ropes (polyester w/little stretch), and infiltration of
HMPE (Dyneema/Spectra) into things (also Technora, esp. in
sheaths and firefighter use) such as slings & river rescue rope,
can require innovation to the new materials.
Is there a better way to dress that [i]figure 8 on a bight?[/i]
Fig.8s get dressed in various ways. I consider what you show
to be the “perfect form” in “weak form”, based on some hints of
strength given long ago, which I’m not so sure of, really. Dressed
the same but loading the other end would be the “strong form”,
in my jargon. Dave Merchant’s Life on a Line recommends a
rather awkward symmetric dressing of the Fig.8 and says that
it can be 10% stronger, and easier to untie.
We use interlocking [i]Bowline[/i] with long tails to attach our main and belay lines to the stretcher. [b]They are much better for ring loading than[/b] a [i]figure 8 on a bight.[/i]
No: the bowline will fail on ring-loading --the tail pulls out
(this is the common bowline w/o any securing extension)!
You can’t be worse than that. Maybe a Fig.8 eyeknot (or
offset end-2-end knot) will flype (“roll”) on such loading,
but that’s not a guarantee and not so sure as with the bowline’s
slipping (it can hold in some cases, yes). Tom Moyer’s testing
of offset Fig.8 & water knots did have some Fig.8s going to
rupture, afterall.)
I think that you are referring to some different sort of loading
on the bowline; by “ring-loading”, I mean the pulling the eye
apart and essentially treating the knot qua end-2-end joint
–which puts the common bowline as a wrong-formed Lapp
bend (and the “left-handed bowline” as a (correct) Lapp bend ).
With rescue we also have to face the challenge of [u]everyone on every team being able to recognize and check you knots.[/u] [b]This makes it difficult to introduce new knots. [/b] KISS principle definitely applies in the cold night rescue.
Is there any way innovations can be made? Is there some
governing body (or might there be, or convened collection
of SAR organizations) who might help vet innovations,
including knots? --for which as you imply there might be
some steep hurtle of first establishing the need for! (If all
is fine w/current knots set --and how bad can it be?–, why
bother with anything else? (IIRC, Tom Moyer made some
contact --he, also in an SAR organization-- with a guide group
who then recommended the offset Fig.8 end-2-end joint,
to advise them of what his testing shows about its vulnerability
to flype; they were not receptive, at the time, to his advice.)
It’s quite a tricky issue, as you note. But there should be
some broader recognition & understanding of knots beyond
the KISS set used, for that might be necessary in order to
deal with what is found in the resuce tied by others --the
victims, i.e.. (There was a rumor that someone hooked into
a climber’s tie-in bowline and learned --or at least showed–
the dangers of ring-loading with tragedy.)
So, one might stipulate a limited set, but teach a broader
set for knots-knowledge.
This is very important since the knots never break. Failure occurs from mistakes or bad edge protection for the rope.
Here I urge circumspection; consider my note above about
conveying any new directions in cordage use. New cordage
can behave quite differently from traditional cordage in knots.
I try to remind myself et al. of not thinking in terms of knots
but of knotted material when evaluating knots. To see
a double bowline just slide down its collapsing eye when knotted
in bare HMPE is an eye opener. I don’t see this rope used in SAR
knotting, but it can slip in in core material, and might have some
unexpected behaviors there. E.g., some canyoneering main ropes
include it; I’m not sure how much testing has been done to see
its effects on any falls --the very low elongation (4% or so at
rupture force, so maybe 1.5% on possible in-use loadings).
You are probably aware that some cordage makers recommend
a double grapevine (writing “triple fish.”) for joining ends
of HMPE-cored cord. (One of Moyer’s old misc. test results was
of a grapevine (non-dbl) breaking its nylon core and seeing the
Technora core pull free like snake from its skin!)
The infamous “cordelette” was introduced into rockclimbing with
celebrity flair and only recently tested by Sterling in help with
John Long’s revised Climbing Anchors, 2nd ed., and found to
be wanting in terms of any equalization, esp. tied in HMPE.