Two pairs of pet TIB twin eyeknots

[X1]

   5. The "last" bight through the "first" one.

[SS369]

I only wish we had more like this one > http://www.youtube.com/watch?v=s3fHYGY3YTo !

How often does anything like this occur in real-world use, especially with the size of rope shown?

Good day roo.

Perhaps if this was done more often, the testing mind you, we would have something else to talk about besides conjecture and opinion.
I believe that the testing as shown (youtube link) would be applicable to smaller sized ropes of similar construction not just the 10.5mm used for rescue work and could benefit knot tyers worldwide.

I can think of quite a few instances where the breaking strength of ropes/cords/webbing  is approached. Regardless of the safety warnings people will use what they have sometimes. So, it would be nice to gather more knowledge of the mechanism of destruction within the knot(s).

If you are not interested, then by all means please ignore the links or further data.

SS

[roo]

I can think of quite a few instances where the breaking strength of ropes/cords/webbing  is approached. Regardless of the safety warnings people will use what they have sometimes. So, it would be nice to gather more knowledge of the mechanism of destruction within the knot(s).

I'm thinking that the intersection of people who disregard safety warnings and destroy big expensive ropes rather than use the right size and will also review these links is going to be pretty small.   

It might yield data or insights for smaller, disposable stuff where rupture is a more common event.  With smaller rope, they'd could afford to do more tests.

[SS369]

Sorry for drifting off topic X1. Just thought the link showed testing that the IGKT should do or be aware of.

SS

[Ruby]

I think it's easy to get the 5th pic's stage

after your 5th step,  I think I'd push the leg of the main loop with left thumb
to change the position with the other leg, before the final inserting.


as 1049,  if just do the final inserting without twist the main loop,
the two legs (yellow parts) need additional dressing.


maybe change the two yellow parts position after inserting?
maybe no need to change?


anyway, now it changes from a difficult knot to a pretty easy one.


interesting.

[X1]

maybe no need to change?

Precisely. As with the Span loop. I forgot to tell you, in my previous post, that you have only to flip the main bight over the tangle, and insert it into the half-reeved "last" bight from the 'back" side - no need to twist it before you reeve it ( as you show at your picture with the red arrow). You can always dress it afterwards, when you will pull the tail to tighten the knot you will be holding with your left hand by the standing end.

I think it's easy to get the 5th pic's stage

   Of course, but there is a purpose in my suggestion to follow this sequence if steps, and arrive at the mirror symmetric 3 rd stage...Notice that you can not twist your wrists ( well, you can not twist them easily, as I say...) the wrong way...so you do not run the danger to twist them the other, wrong way. Also, it is also easier, it comes more natural, if you twist your wrists in a mirror symmetric way - so you do not run the danger to tie two congruent , not mirror-symmetric bights.

   If you tie all the possible pet TIB loops that I have presented in this thread, you will see that they are not difficult : they are based on the simplest crossing-knot nipping loop, then the working part / returning eye leg first penetrates this crossing-knot loop and then turns around both eye legs ( makes the "lower" collar ) in every possible way, and then it goes through both the standing part s and the returning eye leg s "hooks" ( first curves ), so it is secured there, as a tail, in the most effective way. Understanding a knot makes any apparent "difficulty" disappear at once ! I have not tied those knots in "random" , as roo advocates ( and I will not be surprised if he believes this, too !  ). I had tied them by just following the straightforward reasoning I have described, which, if it is retraced, reveals that those knots are most "natural", and the simplest possible- so they are not difficult at all. Of course, there are people who are not able to understand this, and they will probably never be... For myself I can tell that I am not able to play a decent table tennis game ( among MANY other things I am not able to do...), although I have tried for many years !  However, I do not feel any inferiority complex about that !   

[Ruby]

You can always dress it afterwards.

ok.

they are based on the simplest crossing-knot nipping loop, then
the working part / returning eye leg first penetrates this crossing-knot loop
and then turns around both eye legs
and then it goes through both the standing part s and the returning eye leg s "hooks"...

ok , I think I get it.

now keeping these instructions in mind,
I think I can tie this pet loop with one end.
and I did. it's just like tying a  bowline. (so it's really PET)

things get more interesting.

[X1]

   Notice that the pet TIB B can be tied in a more secure form, if the path of the tail ( in relation to the standing part s and the eye leg s "hooks"/ first curves ) is similar to the path followed in pet TIB A ( i.e., if the tail is "locked" securely in between them ). I have chosen to present it in this less satisfactory form only because I wished to show it only as a "twin" to the pet TIB A, to complete the two "pairs" presentation - and in the other, more secure form, it was looking more "different" than the pet TIB A. Anyway, I think that the pet TIB A is the most easily tied one, while it retains all the useful characteristics of the two "pairs" set.
   Unfortunately, in the country I live most docks available to small fishing boats and sailboats have rings, not bollards - so I guess I will not be able to "show" the pet loop as often as my inferiority complexes dictate ! 

[Ruby]

I  just tried to tie it as a PET bowline. see if it's right:

1
the working end first penetrates the nip loop. this is same first step as tying a common bowline


2
then turns around both eye legs (make a colloar at lower,  unlike a common bowline  )


3
note the "hook" made by  first curve and eye leg
I see this structure many times in this forum,  ( seems called "two U shape lock"??)



4
pull the tail throughthe "hook".
done.

[Ruby]

acturally I think this is bowline like method is  more easier than that span loop like method, if right.

and,

seems that structure is called "opposed-bights nipping?？

I think I saw it in that TackleClamp hitch.

[X1]

see if it's right:

Nooope !  Start from a crossing-knot based nipping structure / loop, not the single nipping loop of the "common bowline !
All those 4 (5) knots are base on the same crossing knot s initial nipping loop.

[Ruby]

Nooope ! 

are you sure?

I checked again, and I think it's just the knot. where's wrong?

[X1]

is this structure called "opposed-bights nipping?？
I think I saw it in that TackleClamp hitch.

   It bears some resemblance, yes, but we can not say that is the same mechanism.
   In the oppose-bights nipping, ( that can secure the trucker s hitch tail, for example (1) ) all the four limbs of the two opposed bights are loaded at about the same degree - that is not the case here, because the two bights, although they are "opposed" , are "buried" inside the knot s nub, so their limbs are in touch with other segments, and dissipate much of the tensile forces running through them there.
   The thing one should always seek when he tries to prevent slippage, is to arrange the segments of a knot so they meet each other at the right angles, the right angle ! When segments of rope are squeezed upon each other while they form a right angle, they "bite" each other hard, so the friction forces are greatly enhanced. Doing this for the tail of a knot, is the most effective way to secure it.

1. http://igkt.net/sm/index.php?topic=1870.msg17364#msg17364

[X1]

it's just the knot. where's wrong?

   Nothing is wrong with the knot !  It is wrong with the tying method : it is not the tying method I had described, that starts from a crossing knot s nipping loop ! Tying the knot like you did, the crossing knot structure is hidden, and it is revealed only after the last tuck. THIS is exactly what makes the knot seems "difficult", as you said ! I do not believe that knots should be tied as "puzzles"( see the way sailors used to tie the sheepshank, for example, the "parlor" method, ABoK#1162, or the way the Farmer s loop ( ABoK#1054) is tied in ABoK ), because that makes them look like some kind of "magic", of a magicians play, while they are just rope-made mechanisms, and their structures can be very easily understood - IFF we wish them to be so ! 
   In short : those are not common-bowline-like loops based on the "common" bowline s single nipping loop, but crossing knot loops based on the nipping structure of a crossing knot loop. I believe it is better if the tying method reveals this right from the start, and does not involve the common bowline image. For other crossing knot loops, see (1).

1.  http://igkt.net/sm/index.php?topic=3467.msg24483#msg24483

[Ruby]

"Nothing is wrong with the knot ! "

I think this is enough.

I think it's just a simple tying method, for me at least.


tying a span loop is just like tying a farmer's loop, seems easy, yet hard to dress.

this method is easy to tie, and easy to dress.


so , as someone said, different tying method maks different knot, even the structure is the same?