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.