Author Topic: Double Loop  (Read 2205 times)

xarax

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Double Loop
« on: September 03, 2014, 03:35:21 PM »
   New pictures of the most simple double loop presented in this Forum some time ago. It can be described as a two double-line overhand knots, or two overhand loops, tied with-a-bight, joined together.
« Last Edit: September 03, 2014, 03:36:38 PM by xarax »
This is not a knot.

xarax

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Re: Double Loop (2)
« Reply #1 on: September 03, 2014, 03:37:27 PM »
 Detail of the nub
This is not a knot.

Knutern

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Re: Double Loop
« Reply #2 on: September 04, 2014, 10:01:29 PM »
Is all those knots supposed to be possible to tie without access to the rope ends?

If yes it is possible, is there videos (or step by step pictures) somewhere viewing how to tie correctly?
I figured out the first one, but I had to use many fingers so maybe there is a better method?


Thanks
I'm aiming for knots that is secure, AND that is easy to untie.

xarax

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Re: Double Loop
« Reply #3 on: September 04, 2014, 11:15:30 PM »
how to tie (it) correctly?

   I guess you mean " to dress it correctly".
   As it happens with all knots tied with-a-bight ( so, knots where, along most or all of their rope-length, the lie is doubled ), there are many ways to dress it. That is due to the fact that the two lines twist around each other at the tips of the successive collars they form, and in each twist the one line can go "over" or 'under" the other. Therefore, at each turn along the path of this double line, the number of possible dressings is doubled. See, for example, the variations of the retraced fig.8 loop, at (1). I do not believe there will be  significant differences in strength between those variations, but one can not really tell without detailed tests.

1. http://igkt.net/sm/index.php?topic=2198
This is not a knot.

Dan_Lehman

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Re: Double Loop
« Reply #4 on: September 07, 2014, 06:42:02 PM »
Is all those knots supposed to be possible to tie without access to the rope ends?

If yes it is possible, is there videos (or step by step pictures) somewhere viewing how to tie correctly?
I figured out the first one, but I had to use many fingers so maybe there is a better method?

Firstly, there is not "all those knots" but just one,
shown in color and B&W and loose and tightly set.

And, yes, this knot is able to be --even expected to be--
tied without access to the tails ("TIB", "tied in the bight").

One might go a turn further, tucking each eye bight
around through its own turn and thereby forming
an overhand component in the knot --not sure
that this gains much, but maybe some stability.
(The general structure invites such playing around
with variations, altering parts one way or another,
and making extensions ... .)

For further reference, Ashley's ABOK #1088 & #1097
--and several others in this range-- are similar knots.
I was surprised upon discovering this knot that Ashley
didn't have it, esp. given #1097.


--dl*
====
« Last Edit: September 07, 2014, 07:06:14 PM by Dan_Lehman »

xarax

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Re: Double Loop
« Reply #5 on: September 07, 2014, 06:59:43 PM »
   TIB ? Of course. I believe any double loop used as harness in emergency situations, should be TIB.
   The possible advantage of this double loop is that is tiable with-a-bight ( TWB ? ) - AND that, although the procedure should be repeated twice, the knot to be tied with each bight each time, is the single overhand knot. I can not imagine many "simpler" symmetric double loops than this.
« Last Edit: September 07, 2014, 07:08:01 PM by xarax »
This is not a knot.

Knutern

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Re: Double Loop
« Reply #6 on: September 07, 2014, 09:27:02 PM »
One knot, many ways to dress it? See I have much to learn obviously.

Thanks a lot for describing pictures, xarax - now I too can tie this knot.
I'm aiming for knots that is secure, AND that is easy to untie.

xarax

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Re: Double Loop
« Reply #7 on: September 07, 2014, 10:25:15 PM »
One knot, many ways to dress it ?

  Yes - if by this "one knot" you mean what mathematicians mean...
  However, practical knots are not uniquely determined by their topology - topologically identical knots can be "tied" in more than one stable, geometrically different ways. It is a matter of nomenclature - in which there is no consensus, if we decide to say that those knots are "one" or "many", or that they are many different "dressings" of the same "knot".
   An example of two different geometrically knots / two completely different dressings of the same topologically knot, is shown at (1). 
   Is the "4-Rings bend" shown at (2) and at the attached picture a different dressing of the retraced fig.8 knot, or another knot ? I do not know...

1.  http://igkt.net/sm/index.php?topic=4201
2.  http://igkt.net/sm/index.php?topic=2198.msg16675#msg16675
« Last Edit: September 07, 2014, 10:25:48 PM by xarax »
This is not a knot.