KnoLikely's initial proposition (way back in earlier post) is that it was the
collar that got snagged.
This has now been morphed into something of an entirely different character.
Snagging a
collar to cause core disruption isn't within the realm of possibility.
The
initial test conditions created in roos so called Eureka test were off nominal - and therefore invalid.
He would have to run the test again - using an eye set to 100mm and with EN892 rope.
If setting a loose initial dressing state - this would only serve as the 'control group' for the test.
The ongoing eye-leg part of the nipping loop,
The nipping loop is the nipping loop.
The outgoing eye leg is the outgoing eye leg.
The outgoing eye leg begins at the point where it exists from the knot core.
per KnotLikely:
This is what the knot looks like when I am done with a single top-rope gym climb. It does not stay extremely tightly set, though it maintains its shape and does not fall apart.
?
I would suggest that you have not properly dressed and cinched your tie-in knot.
In the past 10 years of extensive lead and top rope climbing with Scotts locked Bowline (see image for 'my preferred' version) - I have never had a loosening event (ever).
There is initial friction to overcome, but once the nipping loop starts to feed through (as shown in this video) there is nothing to stop it.
One wonders
how the initial friction is overcome while in the act of climbing.
You must have commenced climbing with an improperly dressed and cinched knot.
Its simply not possible to loosen by itself - there has to be
causality.
It is resistant to slack shaking and cyclic loading.
Yes, I am discussing slack in the standing line while lead climbing.
There is something rather peculiar going on - in terms of how the purported failure mode can actually get started and then propagate. Direction of loading is key here...
If you were
lead climbing, the knot nominally lies in an inverted orientation in your harness - such that the SPart is pointing
downwards.
If you were top rope climbing, the knot lies in its upright orientation - such that the SPart is pointing
upwards.
This alleged 'snag' could not actually occur while in the act of climbing
upwards.
Any purported snag of the
eye of the knot would immediately cause alarm - and result in halting upward progress.
It would be quite a feat for any snag to catch a 100mm eye.
If the lead climber was being lowered back to the ground - the knot would lie in its upright orientation - with the SPart pointing upwards.
Again, while being lowered to the ground, the 100mm size eye would somehow have to catch upon a snag.
This is another feat to accomplish.
I just spent another entire weekend rock climbing (both lead and top rope) using Scotts locked Bowline.
I tried to catch snags in the 100mm size eye - with no luck.
I actually took 2 free-falls on a bolted sport route - and I found it impossible to scrape the front of my body down the rock surface while I was falling.
I would have injured myself in the process - so I simply could not get my body close enough to the rock to catch any 'snags' while free-falling.
i did not climb a slab route. I'll try that next time - but again, I would have to scrape the front of my body down the rock surface - which would cause personal injuries. So its a difficult test objective in real-world climbing - in that the climbers body has to be in very close proximity to the rock surface - which is remote (ie highly unlikely).
I also ran a load test to expand the eye of Scotts locked Bowline and reached 5.2kN peak load.
I detected no core failure or enlargement of the eye - other than that caused by normal stretch under load.
EDIT NOTE 1: Image should be of reasonable quality now.
EDIT NOTE 2:Scotts locked Bowline actually has 4 different geometries (I have only shown 3 - don't have 4th image as yet).
Scott actually drew my attention to this fact many years ago, pointing out that there are in fact 4 different geometries.
My personal favorite version is the first image - with the
tail outside configuration.
The reason for this is that when the
eye is circumferentially loaded (ie hoop stress) - the core takes on the
characteristics of a
#1431 Sheet bend and resists slippage.
There is
nothing wrong with the tail inside versions - all versions are
inherently secure.
Part of my confidence in the tail outside variation is that I have extensive real-world climbing experience with it. I have climbed something in the order of 500 single and multi-pitch routes in the past decade using this version and never had an issue with it (that includes free-falling).
