1. security,
2. jamming,
3. unintended misuse
1. You must be joking ! It is more secure than it should
( meaning, this convoluted collar structure is an overkill ).
2. Perhaps. ( Although "jamming" is a very vague concept - I prefer the simple "difficult to untie", which is enough ! We want bowlines easy to untie - otherwise we do not need bowlines at all ! )
When you see a "closed" knot tied on the Standing Part before, or even
after the eye ( for example, an
overhand knot, a
fig.8 knot, etc - here the knot tied on the returning eyeleg is even
worse !
), you should be cautious... Under really heavy loading, even the returning eye leg will be pulled hard, and the knot tied on its continuation, the "collar structure", may "close" around itself too tightly.
Now, there is a basic distinction we should make here : This "closed" knot can be tied
before or
after the tip of the "higher" collar, and this makes a great difference. If it is tied
before the tip of this collar, it will absorb the full tension coming from the returning eyeleg ( that is, about 50% of the total load ), and then it will become difficult to untie, that is for sure. However, if it is tied
after the tip of the "higher" collar, as it happens here, the situation may be less dangerous. At the U-turn of the collar, the direct continuation of the returning eyeleg "uploads" a significant portion of the tension which runs through it ( because of the capstan effect - the collar is not a pulley, it can not
revolve freely around the Standing End ! ), so the tension which "comes down" is much less that the tension which was "going up". With less tension, there is less danger of a too tight closing of the "collar structure".
Alan Lee has tied many bowline-like eyeknots with
overhand knots or
fig.8 knots tied on the returning eyeleg ( on the Standing Part after the eye ) - but, on most of them, they are tied after the "higher" first collar, so there is less danger of them being "closed" around themselves too tightly. Myself, I prefer to follow the rule of thumb, and avoid ANY such knot - so the eyeknots I now tie are PET-2, and they are less prone to jamming / untying difficulties.
3. I do not understand what you mean by this "
unintended misuse"... This eyeknot is meant to be loaded mainly as a bowline ( that is, from the "yellow" end - the nipping loop is the yellow one ). If it will be loaded by the other, "blue" end, its "blue" "nipping structure" will be too complex, and its "yellow" "collar structure" will be too simple !
HOWEVER, there IS the issue of
unintended dressing !
This eyknot can be dressed in a number of different ways, just as it happens with all the "retraced" knots which have parts traced with double lines - the
fig.8 bend and
fig.8 loop included. In other words, this knot is not self-dressing in one and the optimum way - and, judging from the fact that generations of climbers had not even
suspected how many different dressings the
fig.8 loop they use can have
, I think that we should not expect that the average knot tyer would be able to distinguish, and to care, about the different dressings of this knot either. A badly / not-uniformly dressed knot can not be inspected easily, and can even become less strong than a properly dressed one - I think that the twistings and the other irregularities of the flow of the double line, especially around turns, will become the weak links of the nub.
Read what, by coincidence, I had written just a few hours ago ;
the double line is fine when it runs along straight segments, but poses problems when it makes O- and U-turns. Exactly as it happens in all such "retraced" knots ( meaning knots which can be tied in-the-end by retracing the path of the first line with a second line ) - the fig.8 bend and fig.8 loop, for example. In each turn, each of the two lines can follow the inner or the outer track, and so the knot can be dressed in many ways, and the most regular, streamlined dressing of them requires attention from the knot tyer. That is the reason I had abandoned the "shrunk", single-eye version of this loop : too many dressing forms mean that the knot is not self-dressing, and it can settle in a not-optimal form .
