Analysis of Bowlines paper uploaded for review and comment (PACI website)

[xarax]

@knoeud post:91

this compact knot, its ease of tying, and ease of visual inspection,
I have adopted this knot as my tie-in knot for everyday climbing.

Compact, easy to tie and inspect, it is, indeed - but not much else, I am afraid. This “vertically” oriented round turn around the two rims of the double nipping loop does not look secure enough to my eye - except if you are prepared to accept a really looong tail - and do not forget to check its length, from time to time ! Those single turns, loaded from their one only end, unwind easier and sooner than you think. You should not suppose that the double nipping loop will be loaded ( and grip the round turn ) all the time ! A secure bowline should be able to remain in its initial state even if/after it is loaded unfavourably, and through any combination of its three limbs.

@xarax post:115

When you pull the second leg of the collar… upwards, you see that this “round turn” rotates as a whole around its axis, and unwinds rather easily. This happens because the “two” points/segments of the tail where it is “nipped twice”, move like one piece : if the first segment is forced to be set in motion towards one direction, the second can follow it and move towards the same direction, without having to overcome any additional friction force. This is the reason we never use a naked “round turn” as a final means to secure a tail…

The other thing those parallel to the axis of loading turns may suffer, is that, squeezed by an external agent, they may clinch around themselves, and become difficult to untie. A corresponding bend, on which the one link is a double and the other a single round turn, was presented some time ago by JP, at (1)( with REAL tests, not just trials ). For a slightly different idea, where the round turn takes place before the collar ( so, it contributes much more to the stability and the integrity of the nipping structure ), see the 8 variations of the Link bowline, at (2). The single-nipping-loop version of what you show was shown by DDK, at (3).
It seems to me that you were too fast to fall in love and adopt one bowline - which may be good for the bowline, but not for you…

1. http://igkt.net/sm/index.php?topic=4150.15
2. http://igkt.net/sm/index.php?topic=4314.15
3. http://igkt.net/sm/index.php?topic=19.msg20960#msg20960
   http://igkt.net/sm/index.php?topic=19.msg20961#msg20961

P.S. I do not believe that this single round turn counts as a second collar ; it is a sort of an anchor, a way of securing the Tail End ( like the infamous not-so-clever overhand knot tied on the eye leg… ), but a second collar, it is not. That may be the main reason I do not believe this is a “secure” bowline, and I do not like it - as I had said many times, IMHO, a really “secure” bowline may include a double nipping structure, or not, but it should include a double collar structure.