A better way to tie-in to the middle of a climbing rope

[bushrag]

With your #1074 double tie-in, how did you manage to do this on the bight? It looks fishy.

[Dan_Lehman]

What do you think of the alpine butterfly water knot combo?
Seems practical and doesn?t reinvent the wheel.

The last criterion is on target (using common knowledge)!
But I think that this is overly consumptive or rope.

How about alpine butterfly with the [eye] reeved back
through the heart then finished by using the bight to tie
a barrel around the loops.

This scores a win, but maybe with some other
finish.  (Clipping a 'biner makes sense in this,
as a sure-lock vs. slippage.)
Your later, OH-stoppered structure seems apt,
and with obvious clipping point.

I even figured ways to --get this--
incorporate the tie-in loop into the butterfly,
but that had the hallmarks of impracticality
-if not impracticability--, awkwardness, and
looney tunes.  (But it was kinda neat.     )


--dl*
====

[agent_smith]

per bushrag:

With your #1074 double tie-in, how did you manage to do this on the bight? It looks fishy.

The only thing that is 'fishy' is your apparent dislike of #1074 Bowline with a bight.

Keep in mind that this website is the IGKT - and by definition, it is aimed at knotting enthusiasts, prolific knot tyers, decorative knot tyers and other roping/knot technicians.
It is intended for deeper dives into the art and science of knotting - including experimental knots and exploration of knotting concepts.

Now - with that in mind...

Issue at hand: A party of 3 all wanting to tie-in to a climbing rope...
According to known laws of physics, a rope only has 2 ends.
This means 2 climbers can access and use both ends.
The poor old 3rd climber will have no ends to work with - and must seek a way to attach to the climbing rope without access to either end (so called 'tying-in-the-bight').

#1053 Butterfly has always been the default thinking.

How would Elon Musk view this matter?

Elon would say... "I'm going to revolutionize this process and come up with a method that is much simpler and more efficient".

Using #1053 is same old same old same old same old same old thinking...

Those who subscribe to the old way of thinking usually throw in a locking carabiner (or two) - to attach the eye of the Butterfly to their harness.

What you are doing is using the same old #1053 Butterfly... but, trying to attach without the use of carabiners.

So you are now faced with having to use a composite structure.

Elon would say:
"Dude, if its too complex or takes too long - then its wrong".

I think Elon is correct.

Loading profiles:
What is the underlying reason for having a party of 3 on one rope?
Arguably, the principal reason is for glacier travel.
And here the loading profile is in the horizontal axis (ie 'x axis').
If the middle climber (attached mid-rope) falls into a crevasse, it is more likely than not, that load will be injected from one end.
It is less likely (but not impossible), that load will be equally injected from both ends simultaneously.

What typically happens is that the rope will 'saw' into the lip/edge of the crevasse.
The 2 climbers at each opposite end of the rope will dig-in and plant their ice axe in response.
Now - it is inevitable that one will sustain more load than the other - human reaction time is not measured in milli seconds... it is measured in maybe half or one second increments.
It is highly improbable that both climbers at each end will dig-in and arrest at precisely the same instant in time.
One must also factor in terrain and slope.
If walking up a slope or incline, the lead climber will more likely take the brunt of the initial load, and the tailing climber will less likely to take any significant load.
Most of this is obvious if you think about it.

Another scenario is on vertical rock.
And here the loading profile will be nominally in the vertical (y axis) direction.
Again, one has to ask, why would a third climber attempt to tie-in to the middle of a rope?
It wouldn't be out of a planned choice.
A planned climbing trip with a party of 3 would normally require two EN892 ropes (not one).

So we are likely thinking in terms of some kind of emergency or perhaps, mountaineers trying to make do with just one rope while using a 'simul-belay' technique over easier ground (for speed).
In both scenarios, the loading profile is nominally in the vertical (y axis) direction. Which means the brunt of the load will come from the direction of the lead climber. If the middle climber fell, it is hedging bets that the lead climber will react fast enough to plant an ice axe to arrest the fall! If moving over rock, this makes it very difficult for lead climber to arrest with an ice axe!

Glacier travel involves potential for horizontal loading profile (x axis)...but, if the middle climber falls down into a crevasse, its actually mostly translated into vertical loading profile. Again, one end of the rope will sustain greater loading than the other. It is unlikely that both ends will have perfect equal loading.

[Dan_Lehman]

It looks fishy.

Apparently it's not (all) aquatic,
but smells musky!

The insight is that the initially straight line is brought
through the tie-in loop as a (rather long) bight,
but as the goal here is not one knot but two,
AND THEN
that bight amoeba-like subdivides into two too (in your tutu)!
And then you double your tying by doing two knots
instead of one, and get extra fun, and sooooon
... "to the MOON" (... Alice) !!

Let's measure rope consumption and security of these
candydate mid-rope tie-ins, eh?!


 

[agent_smith]

per Dan Lehman:

Apparently it's not (all) aquatic,
but smells musky!

At least Musk doesn't smell fishy.
But i do like his paradigm..."If its too complex and take too long - then its wrong"

The insight is that the initially straight line is brought
through the tie-in loop as a (rather long) bight,
but as the coal here is not one knot but two,
AND THEN
that bight amoeba--like subdivides into two too (in your tutu)!
And then you double your tying by doing two knots
instead of one,

Yes - cell division is a humorous analogy.
It is double-duty and a composite mess of cell divided amoeba.

Let's measure rope consumption and security of these
candidate mid-rope tie-ins, eh?!

A useful metric for knot efficiency is the amount of material consumed to form the knot structure.
The #1053 composite approach fails in this metric.

And Xarax would no doubt point out that when untying from this composite mess, a remnant knot is still left in the line - and this too must still be untied.
There is a lot to be said for using one Post Eye Tiable (PET) tie-in knot... that leaves no remnant knot when untying.

[Dan_Lehman]

per Dan Lehman:

Let's measure rope consumption and security of these
candidate mid-rope tie-ins, eh?!

A useful metric for knot efficiency is the amount of material consumed to form the knot structure.
The #1053 composite approach fails in this metric.

I'll reckon --yet to measure-- that the butterfly
with eye reeved back through it (where it can then
be simply clipped, having adequate nip from the
knot) will come out ahead --and is certainly more
easily tied.  (And required no new knot to learn.)

And Xarax would no doubt point out that when untying
from this composite mess, a remnant knot is still left in the line -
and this too must still be untied.
There is a lot to be said for using one Post Eye Tiable (PET) tie-in knot
... that leaves no remnant knot when untying.

Thankfully, one need not heed X's fancies.
There are two knots to untie in your double-BWL
solution, and just one with the butterfly
--which in some circumstance one might prefer
to leave available for future use!?
--or just untie it, which just might be on the mind!

--dl*
====

[agent_smith]

per Dan Lehman:

I'll reckon --yet to measure-- that the butterfly
with eye reeved back through it (where it can then
be simply clipped, having adequate nip from the
knot) will come out ahead

Luckily I have measured the difference...

[ ] #1053 Butterfly in combination with #1046 (derived) requires 1880mm

[ ] #1074 Bowline with a bight - secured with Yosemite finish requires 1150mm

Difference = approx 700mm

Note: There is no need to tie dual #1074 Bowlines... a singular #1074 is sufficient in the majority of cases.
I originally showed dual #1074 Bowlines purely as a novelty - to show that if one wanted to, one could do it.

Thankfully, one need not heed X's fancies.

Xarax has some really profound ideas...he was (and is) ahead of his time.
Leaving a remnant knot which must also be untied is an important concept.

There are two knots to untie in your double-BWL
solution, and just one with the butterfly

As stated, there is no pressing need to tie-in with dual #1074 Bowlines...I simply showed it as a novelty - and even so, if one wanted to, it is not that difficult.

So your contention could be flawed - because you appear to presume that dual #1074 Bowlines are required? One could also reach a conclusion that you are simply ignoring the fact that it is perfectly safe to tie-in with a singular #1074 Bowline (with a suitable locking maneuver), and instead choosing the dual #1074 tie-in because it supports your contention??

I would also point out that no carabiners are required when using #1074 Bowline.
If a carabiner is a necessary ingredient - this implies that is a conditional method which further suggests that it is less efficient.

The overall length of rope consumed to tie a knot is not the sole determinant of 'efficiency'. Other metrics also must be considered. Jamming is certainly another issue.

I would remind you that #1053 Butterfly is vulnerable to jamming when eye loaded.
Surely you know this?

[Dan_Lehman]

I would remind you that #1053 Butterfly is vulnerable to jamming when eye loaded.
Surely you know this?

Omit "would" : you did.
(And another word you want is "single", not "singular".)

And I'll remind you that we are talking about a different
knot* here, one that surrounds more diameters.
(And if I tie it, it won'd be the same dam ill-formed
and parroted butterfly but Wright&Maggowan's beauty
anyway!  --or, maybe the OH+Fig.8 same-rotation version.)


--dl*
====

[agent_smith]

Omit "would" : you did.

?

(And another word you want is "single", not "singular".)

I intended to use the word 'singular'.

And I'll remind you that we are talking about a different
knot* here, one that surrounds more diameters.

Only in the sense that 4 rope diameters are now fed through the #1053 Butterfly structure - but its still #1053 Butterfly.
But - I concur that having 4 rope diameters in #1053 Butterfly may boost jam resistance during eye loading.
Although i would point out that no one has positively tested this - it remains in the realm of theory.

The reason I previously mentioned #1046 (derived) overhand loop as a composite with #1053 is because it was suggested by bushrag - and it avoided adding a carabiner to the mix. the amount of rope consumed is about the same as what you had suggested...

I would point out that your notional concept of feeding the bight back through #1053 and then stoppering in some fashion is actually creating a noose to the climbers harness. And you had suggested using a carabiner as part of the procedure.

I would suggest to you that this whole concept is messy and inefficient.

Using #1074 Bowline is simple and efficient - and leaves no remnant knot in the rope once untied  - and its also PET (Post Eye Tiable).
#1074 Bowline on-the-bight is also jam resistant and uses much less rope material to create the tie-in.
Furthermore, it requires no carabiner!

[Dan_Lehman]

[] your notional concept of feeding the bight back through #1053
and then stoppering in some fashion
is actually creating a noose to the climber's harness.

?!  No, the OH of the butterfly seizes/grips the
stoppered bight tail and that's a fixed loop.
Adding a 'biner to surely clip off the bight tail is
not the problem you make of it --simple enough.
(Now, if clipping that 'biner and they suspending
oneself thusly, then there is the (butterfly) noose
--but to the harness, not the body.

Btw, a PETiable solution --and by this I mean
"it can work at some at least small forces--
is to reeve the bight through the harness
loop en route to making that final tuck
of the knot !!  (Then you might really want
the 'biner toggle!)

--dl*
====

[agent_smith]

?!  No, the OH of the butterfly seizes/grips the
stoppered bight tail and that's a fixed loop.

True - only if the stoppered end is in fact fixed/attached to the Butterfly core knot in some way.
I thought you meant that the enlarged eye of the Butterfly was simply fed back through the core and then a simple overhand knot tied at the end. In which case, the doubled eye thus created to the users harness would not be a fixed eye - the only thing stopping catastrophic failure being the stopper knot to prevent it trying to work its way back through the core of the Butterfly.

In any case, it is still a convoluted concept.

Btw, a PETiable solution --and by this I mean
"it can work at some at least small forces--
is to reeve the bight through the harness
loop en route to making that final tuck
of the knot !!  (Then you might really want
the 'biner toggle!)

#1074 is a PET solution.

Any method that requires an initial #1053 Butterfly as a first stage of the process isn't PET.
And any method that further requires a carabiner to achieve security is inefficient.

Not sure where you are going with your line of argument?
Presumably you are in favor of a composite tie-in method that is built upon a #1053 Butterfly?
If this is your contention - you are perfectly entitled to form such a view.

There are no laws or on-the-spot fines for tying-in to a climbing harness using a non approved method.
Technically, a climber can choose any tie-in method s/he desires - provided it doesn't result in tragedy (unless the climber is willfully careless and reckless).

[Dan_Lehman]

?!  No, the OH of the butterfly seizes/grips the
stoppered bight tail and that's a fixed loop.

True - only if the stoppered end is in fact fixed/attached to the Butterfly core knot in some way.

I thought you meant that the enlarged eye of the Butterfly was simply fed back through the core and then a simple overhand knot tied at the end. In which case, the doubled eye thus created to the users harness would not be a fixed eye - the only thing stopping catastrophic failure being the stopper knot to prevent it trying to work its way back through the core of the Butterfly.

No, the knot is fixed by the frictional nipping of
the bight-legs  by the overhand component of the knot
--whichever one is loaded, or both.  --think sheepshank
(not the happiest thought, agreed).  The stopper is an
added assurance vs. slippage.

Btw, a PETiable solution --and by this I mean
"it can work at some at least small forces--
is to reeve the bight through the harness
loop en route to making that final tuck
of the knot !!  (Then you might really want
the 'biner toggle!)

Any method that requires an initial #1053 Butterfly as a first stage of the process isn't PET.

In my case -2 B clear--, the PET aspect comes in forming
the butterfly, in which the en-route-to-tucking
eye bight captures the harness loop(s).


--dl*
====

[Dan_Lehman]

Follow the load strand and you can see it would induce torsion
on the tie-in points and leave you in a strange body position if,for example, you were the middle man and you fall into a crevasse.

Per your nice photo, I see a problem in that if
the loaded SPart is the one on viewer's RIGHT
side, then the knot body will be pulled INTO
the harness loops, maybe not all so happily.

(Whereas the two-knot cleverness avoids this,
as well as the simple reeve-the-eye in/out ones.)

(aside :: Agent_Smith's photo of his dual-knot
solution IMO is a good demonstration of the better
perspective to view the bowline --the image
on the right side makes it easy to see where parts
run through the knot, while that on the left leaves
esp. SPart crossing(s) hidden and ambiguous.)

Btw, a 'biner clipped into the bight-end of the
(any) solution is hardly much "inefficiency"
and potentially a ready means to effecting
a pulley to lift a fallen person up out of the
hole.

--dl*
====

[agent_smith]

per Dan Lehman:

Per your nice photo, I see a problem in that if
the loaded SPart is the one on viewer's RIGHT
side, then the knot body will be pulled INTO
the harness loops, maybe not all so happily.

As I have already pointed out in detail, loading will never be along a perfect horizontal direction (x axis).
The middle person in a party of 3 (one rope linking all 3 climbers) is something that might occur for glacier travel.
If the middle guy falls down into a crevasse, load on the harness will actually be directed in the vertical (y axis) direction.
Also, load will never be distributed evenly from both sides. Load will always be biased on one side or the other.

For vertical rock climbing, it would be a rare event to have a 3rd person tie-in to the middle of a singular climbing rope. It just isn't done.
IF it was done (for some kind of obscure emergency scenario) - loading will be in the vertical (y axis) direction.

In any case, as i had pointed out, it is trivial to tie a second #1074 Bowline if there really was some concern for bi-directional loading. But, I accept that IF a second #1074 Bowline was tied, this would consume more rope. For the sake of absolute safety in a party of 3 crossing a glacier, a dual #1074 tie-in would be perfectly fit for purpose.

Btw, a 'biner clipped into the bight-end of the
(any) solution is hardly much "inefficiency"
and potentially a ready means to effecting
a pulley to lift a fallen person up out of the
hole.

It depends on how you wish to define 'efficiency'.
From a purely technical viewpoint, minimalist wins that argument. In that, if a tie-in requires additional equipment, how could that be more 'efficient' than the method that requires no extra equipment (just the rope by itself).
Be that as it may, using a single carabiner to clip to something to boost safety is not a deal-breaker either.
But, it might be in an emergency where the middle climber simply has no additional (or spare) gear.
I should remind you that in a normal tie-in situation for lead climbing at the end of a rope - nobody uses a carabiner! Its just the rope by itself - and the rope is tied directly to the climbers harness.

Well Dan, where to from here?
I know that if i were faced with the prospect of tying-in to the middle of a climbing rope - I would choose #1074 Bowline - the virtues of which i had already pointed out in detail.
And i presume that you would choose a composite with the first stage being a #1053 Butterfly...?
There's a lot going on with a composite tie-in method - and it needs to be properly managed since it relies on multiple steps. And at the end of that sequence, maybe further counter-measures need to be taken by adding a carabiner.

[Dan_Lehman]

Omit "would" : you did.

?

(And another word you want is "single", not "singular".)

I intended to use the word 'singular'.

Why?
Which in your phrase
dual #1074 Bowlines... a singular #1074 is sufficient
is obviously quite wrong : the question is number,
not any esoteric aspect, and "single" opposes "dual".
(which I focused on because I'd hastily read and thought
it was your solution).

--dl*
====