Thank you Hrungrir,
I can't get this knot to hold at all in thin polyesterline (2mm). I'm able to pull the knot apart in one motion, even with super long tails. It's better in thicker polyester
I believe that the problem with the small diameter cord you use, is that you can not manipulate carefully the strands in their correct position relatively to each other, because fingers can not handle such small diameter objects with the precision required here. So, I guess that the root of the problem is not the material, but the scale. I use kermantle climbing ropes 9 - 12.5 mm thick, that I can handle easily ( and I can
see what exactly am I doing, without glasses
! )
Now, pay some attention to this, please. This is not a bend that works like most of the others we know, where some bight shrinks, and nips a strand that goes through it, and, beyond a certain point, the friction forces prevent the slippage of this strand and secure the tail completely. The mechanism of this bend is depending upon
shear more, rather than friction forces. So, if this bend is not set correctly at the first place, and taut in this place right from the beginning, it will not hold better at any time after this - because the pulling of the standing parts do not shrink any bight, to make the friction forces around a strand sufficiently strong to secure the tails. Pulling the standing parts further will make no difference, and an initialy incorrectly set bend - where the shear forces do not act properly as they should - will not hold at any time afterwards, however
super long are the tails !
I believe that this peculiar property is the most interesting thing, because this bend, as I said,
"is depending upon the properties of the knot tyer more than the upon the properties of the rope itself ". Read my lips : this bend works
"if set, dressed and tightened carefully and properly". Try larger diameter ropes, and make sure you put the tails in the correct position relatively to each other, so that shear forces would have the chance to act, right from the beginning.
Less is
more difficult !
( A fair price to pay). That is the nice thing with this bend :
if one does not understand it somewhat, he can not tie it at all ! In other words, a blessing from the Knotworld for the knot tier.
Try it with larger diameter ropes, make it hold before the final tightening, and you will see what I mean.
The structure is ... close to a fisherman's knot.
No, not at all. The fisherman knot works in another interesting way : the volume of a stopper can not penetrate through a small diameter bight, because it is larger, bulkier than the diameter of this bight. The two overhand knots serve as two simple stoppers, and, as the tail of the one link goes through the nub of the other, they can not penetrate through each other. The stoppers are depending upon their internal friction forces to remain bulky and not degenerate into a straight line, which could easily pass though. So, a fisherman knot will work, (although not with the same efficiency, of course) even if it is incorrectly tied, and we have only the tail of the one overhand knot going through the nub of the other. The fisherman knot is a
superb bend, one of the best we have, just one click below the Zeppelin bend. However, it consumes a lot of rope, in a degree that we can say it is not economical... On the contrary, the symmetric sheet bend is the most economical symmetric bend there is and could be. However, it should only be compared to the ABoK#1406 and the Sheet bend, not to more complex, overhand knot based bends, like the fisherman s knot. Most of the bends based upon interlocking overhand knots work in this easy way we are accustomed to, where you set the bend and you just pull the standing ends until some bights get small enough, and the friction forces upon the penetrating the bights tails get larger and larger, and, eventually, the tails are secured. In short, set it and forget it...With this bend, you have to tighten it first, make sure the tails are at the right place relatively to each other, only then forget it. Something similar happens to the closest relative of this bend, the ABoK#1406, and also, to a lesser degree, to the Sheet bend.