Greetings, my search for the identity of a knot has led me to find this website and I’d like to fish in the pool of knowledge here if I may.
Some quick background. I am a caver and have been involved with some testing of various double loop knots recently. One of the most commonly used knots in caving is the Bowline on the Bight, its two loops making equalised rigging from a pair of bolts easy.
We have been using a version of the Bowline on the Bight for some testing and have called it the Double Bowline on the Bight as it seems to follow the standard convention of naming that the Bowline and Double Bowline follow.
It has been brought to my attention that a Double Bowline on the Bight already exists, a 4 loop version similar to a Double French Bowline.
I think that the knot we are using should be called the Double Bowline on the Bight but I’d like to see if it has a correct name.
A bit of a detour: I’m hesitant to go down this path. Double loops tend to use an huge amount of line (especially in this case), don’t get much testing, and due to their complexity they often tend to have hidden vulnerabilities.
A cleaner, more reliable route would be using a separate line for your two anchors and in the middle of this line a clove hitch can be made over a carabiner to equalize as needed. A Pile Hitch may be used as a more jam resistant alternative to the Clove.
The pool of knots we use are well tested. I had this one on a drop test rig last week.
Cave rigging tends to follow a line of anchors (traverse) along to a pair of bolts at a pitch head which we call a y-hang. The rigging would follow the bolts from the start of the line to the y-hang and on down the pitch giving an abseil line. The use of multiple strands of rope of this would introduce too many weaknesses. There are dozens of ways for me to rig traverse lines and pitch heads but the Bowline on the Bight is the most appropriate knot for its simplicity, ease of tying and adjustment and shock absorbing ability when a bolt fails. The Double Bowline on the Bight has shown to be better as absorbing shock loads over and over again.
Thanks for the ideas but I’m really only looking to see if this ‘DBotB’ has a true name.
What do you mean by size the rope? I’m not following your explanation sorry, long day.
I’m probably not explaining myself well. The continuous path of the rope, without break or the introduction of extra components, is integral to the safety chain of the system. The exception being using karabiners to attach the rope to the bolts in the rock.
Ahh, I’m with you now hopefully. The karabiners or maillons are stronger than the 9mm semi-static rope that we generally use so no worries there. It is also much faster to use them instead of rethreading the rope through the bolts, something I can do but is very slow and not very user friendly.
The testing is a comparative set of tests not designed to give a statistical certainty but an indication of mentionable differences in performance, which it did. The variables do not matter here, there will be little difference in real world usage.
Why have you been testing double-eye knots recently?
–i.e., what of the de rigeur ones used for caving has moved
you to look further?
And what sort of testing are you doing. You mention making
a drop test (so, strength in dynamic, worst-case loading);
were there other sorts of tests?
(Okay, wrote the above prior to browsing the lonnnng
thread on UKCaving. Still, a summary might help, here.)
One of the most commonly used knots in caving is the Bowline on the Bight, its two loops making equalised rigging from a pair of bolts easy.
My concern with some various double-eye bowlines is that
if the eye that leads directly to the loaded end is not itself
loaded --say, if its bolt fails--, the unloaded eye can collapse,
which entails perhaps too much frictional heat/abrasion,
and an extra dynamic of additional extension. (This could
be prevented by joining the two ends of the dbl.-eye knot
into a single-eye knot such as the [i]bowline[/i] --maybe
tucking the tail through the dbl.-eye knot for security.)
It has been brought to my attention that a [i]Double Bowline on the Bight[/i] already exists,
a 4-[eye] version similar to a [i]Double French Bowline.[/i]
I think that the knot we are using should be called the Double Bowline on the Bight but I'd like to see if it has a correct name.
Is there a citation for who calls this other knot that,
where? --can't say that the moniker has surfaced
to my awareness (and I see one caving forum from
time to time).
And for anyone who is interested the context of the enquiry: http://www.peakinstruction.com/blog/ & http://ukcaving.com/board/index.php?topic=14602.0
Thanks for looking and your help is appreciated.
Ahhhh, good to have some knots reading (though again
and again one sees the same confusions …), thanks!
The karabiners or maillons are stronger than ...
And take to the contact with the bolt hangers much
more kindly than will rope!
Thanks for taking the time to reply, sadly I dont have any myself for a proper response.
I coined the name for our Bowline varient, the name Double Bowline on the Bight fitted with the Bowline/Double Bowline naming convention I had observed already.
We came to using and testing this knot because the French Caving School advised against the use of the knot we would normally use in this position (Bowline on the Bight). We have done some ‘scratch the surface’ type testing to show comparativew strengths between the other well known appropriate double loop knots. More will need to be done but we have an indication of the Double Bowline on the Bight’s suitability.
Forget worrying about the name : what you did, as you
note, followed a reasonable nomenclature rule
–which is more than one can say for Ashley! (There
are plenty of contradictions in ABOK.)
(“bight” itself is an adventure.)
Btw, I think you’d be a bit better with using the
“water bowline” for a solution --doing the usual BotBbackflip of the twin-eyes bight to finish–
as the 2nd turn I think will give a better lock than
in the dbl.bwl structure. (The water bowline
has a clove hitch base, so to speak, into which
the eyes bight would be reeved.)
Hi Pete K,
Your naming convention has good merit and I would continue using it.
The knot in the photo is a Double Bowline On The Bight having the nipping loop closest to the collar simply pulled open to form the two extra loops.
Thanks for that. I’m playing with Water Bowlines now. A little harder to tie than the dbl.bwl and botb but I will do some experimenting. They may provide another option for caving use.
I have another option for you which is but a simple variation of the DBoB’s nipping structure and tying procedure. I’ll explain how to make the nipping structure in terms of it’s Double Bowline single loop counterpart…
Stack two loops, each of opposite handedness, and such that the Standing Part is sandwiched between the coils of the two loops. That’s it. This is the most efficient nipping structure that I’ve come across for the Bowline and renders it very secure and very stable.
Tell me : is it customary (or even not advised against)
to ring-load a knot, as is what the French video
shows being the failure mode?
(For those not seeing the French video, they show the bowline on a bight with eyes splayed near and far
(to the viewer), AND the short tail tied at a seemingly
perpendicular-to-axis-of-loading angle (eyes are apart
at, what, the fairly extreme angle of 140degrees (!!?)
upwards; THEN one eye is clipped into with a 100kg
weighted runner (!), and … w h o o o oooossshhHH …
the entire long, hanging SPart is sucked up through
& out the knot as the weight “decks” !!)
Now, my first thought was "huh, how is that rigging
reasonable (the tying off of the tail, especially), and
then “WHOA, who ring-loads an eye??”! ???
Ring loading in the way the French show in there film is not recommended and it is the practice of caving instructors like myself to teach clipping a cowstail/safety connection through both eyes/loops. Although still ring loading the knot is secure in this use. The additional benefit of using a 2 loop knot is that clipping into both loops creates a central attachment point for hoisting and belaying if required.
Clipping a single loop as the French film shows is a mistake of the uninformed and probably common. It has however, never led to a published incident, injury or rescue.
The tail in the video simulates the line forming the BotB coming from a bolt as part of a traverse line rigged to get a caver safely to the pitch head.
That’s another knot for me to play with alpineer ta. The ideal 2 loop/eye knot in our eyes must be: Easy to learn and tie, easy to untie after load, easy to adjust, intuitive to use. Sipping in normal operation is not desired but a small degree of slippage is beneficial for shock absorbtion if a bolt were to fail with the active line loaded.
You are correct, the Fusion is a Karesh, I will change my paperwork and reports eventually to reflect this but I wrote most of it before the true name came out.
I’d add a few requirements: It should be easy to check and be rope efficient.
Which brings us back to using a separate short rope to act as a V shape with your anchors at the tops of the V and the main rope at the bottom of the V.
If you don’t want to use a carabiner at the bottom of the V with a clove or pile hitch (the easiest option for checking), you could use your main rope to form a friction hitch (like Blake’s Hitch) around the bottom of the V. Now that’s easy equalizing and it will save you yards of rope in comparison to a double loop.
Ah, I see now in some older correspondence that some
sort of clipping-to-eyes is done (and I didn’t question this,
then). Okay. Given this, though, I’d want a structure
that could endure the single-eye ring-loading --even though
that is an ill-advised practice (who can say when things go
wrong : perhaps just as one in reaching to make the 2nd
clip!).
Although still ring loading the knot is secure in this use. The additional benefit
of using a 2 loop knot is that clipping into both loops creates a central attachment
point for hoisting and belaying if required.
And not to tie into the dropped line?
The ideal 2 loop/eye knot in our eyes must be:
Easy to learn and tie,
easy to untie after load,
easy to adjust,
intuitive to use.
Sipping in normal operation is not desired but a small degree
of slippage is beneficial for shock absorbtion if a bolt were to fail
with the active line loaded.
How about a combination of knots? Use some guard
knot such as a symmetric fig.9and then the BotB?
The purpose of the “guard” is to thwart this potential slippage,
leaving the commonly used two-eye knot to work as desired.
Then, again, if the Karash knot proves to meet needs w/o
further precaution, it’s a simple solution worth choosing.
You are correct, the Fusion is a Karesh,
I will change my paperwork and reports eventually to reflect this
but I wrote most of it before the true name came out.
–just to note the typo : “a” is the only vowel (twice).
I don’t know of the French origination, but do know of the
Karash origination circa 2000. (“fusion” is a vision from one
perspective; “Karash” is ad hominen :: “What’s in a name? …” )
There were some very interesting double loops presented recently in this forum, by IPAtch, Luca and Alan Lee ( Eric22 ). Perhaps they might be of some interest to you. See
Alpineer - I am unable to reply to PMs yet so thank you for the message, a very nice little trick I’d not seen before. Cheers.
X1 - I will have a read, ta.
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