Riggers / Hunters / Smithunter end to end joining knot -transformed

[agent_smith]

Some time ago, I asked X1 to tie tie a whole new range of end-to-end joining knots including variations on the Smithunter.
Here: http://igkt.net/sm/index.php?topic=3251.msg19749#msg19749

A question that I never got around to asking or finding out a satisfactory explanation to was how a Smithhunter can be transformed with one simple manipulation into a non-jamming structure. In its original form, the Smithunter (aka riggers bend) jams under load. By manipulating the tails so that overlap, the Smithunter is now transformed into a structure that resists jamming.

My question to all you great IGKT knotting minds is this; - Why? What is the mechanism involved? How is it that repositioning the tail positions can transform the knot into something that does not jam?

I think that the answer to this question may help us understand how the Zeppelin end-to-end joining knot actually operates to resist jamming and at the same time - maintain its stability and security. I know that X1 has described the Zeppelin as a 'rope made hinge', although I am not sure if this concept was fully explained...

What do all knot structures that resist jamming have in common? What do all knot structures that jam have in common?

Perhaps Dan, Roo, ss369, X1, or some other interested person can give clear and succinct answers here?
This subject really interests me.

I have attached 2 photos of the Smithunter end-to-end joining knot - the original form that jams and the transformed version which is jam resistant. Also 1 photo of the Zeppelin for comparison.

Mark

[roo]

Each knot is a different machine that operates according to the variances of its geometry.  That makes it hard to create blanket statements that will cover every knot satisfactorily.

Generally speaking, knots jam because something about their geometry stores up a great deal of spring energy without there being some easy method of relief.  Sometimes the easy means of relief is blocked by another part of the knot and sometimes the part than needs to be moved is the very part storing the spring energy in the form of tension, making it difficult to overcome the frictional forces.

Knots that resist jamming either never store up of this spring energy, or they store up spring energy, but it's just in a way that can be released.

Even if you did an exhaustive analysis of all the interaction of forces in a specific knot, such that you can figure out why that knot resists jamming, all you'd have to do is change the material to make you have to re-evaluate the possible outcome.  It's not an easy question.

[Dan_Lehman]

By manipulating the tails so that overlap, the SmitHunter is now transformed into a structure that resists jamming.

My question to all you great IGKT knotting minds is this; - Why?
What is the mechanism involved?  How is it that repositioning the tail
positions can transform the knot into something that does not jam?

Your image doesn't so well show it, but look at that by
X1 @ http://igkt.net/sm/index.php?topic=4201.0 in Reply #1,
3rd image, which shows the knot from a bit to its front.
The collars partly embrace the opposite tail and this
impeded their otherwise tight constriction around the
knot to potentially jam.  (Similarly, Ashley's bend #1452 can
be oriented to get or resist jamming by how its tails are
crossed, which enables or precludes the collars from
binding tightly around the nub.)

Beware : you've spoken about jamming as though it's
a quality/attribute of a *knot* --by implication, those
cordage-joining schemas that are manifest in the actual
tangible things-- : but material will play a role in whether
something jams.  At least, in one eye knot I'd loaded by
my 5:1(-ish) pulley to heavy loads in some traditional
cordage w/o jamming, I found that in Dyneema it got
jammed in a break test --much higher load both in
%-age & absolutely (2 tons), but, still, I think that
traditional cordage simply wouldn't enable the fluid
tightening that HMPE did.  (I've not tried to unjam
it w/tools, yet, as the specimen stands for analysis.))


--dl*
====

[X1]

Why? What is the mechanism involved? How is it that repositioning the tail positions can transform the knot into something that does not jam

  Good question ! The only thing I can say is : " I wish I knew ..."

 "Jamming" is not a well-defined characteristic of knots, I believe. One day it may well turn out that it was one word that described many different things.
  Geometry matters in many ways : a more "jammed" knot may be less difficult to untie than a less "jammed" one, because the shape of the fully tightened knot provides ways, "handles", using which we can pull, push or twist parts of the knot, loosen it, and untie it. The apparent difficulty or easiness with which we can untie a knot may convey the impression of a more or a less "jammed" knot, without any relation to the amount of the accumulated tensile forces within the knot s nub.

   When I tie a new-to-me knot, I have a very efficient way with which I manage to make it be strong, and do not jam : I keep my fingers crossed !