Author Topic: Half Hitch around-a-bight. ( ABoK#1821)  (Read 5380 times)

X1

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Half Hitch around-a-bight. ( ABoK#1821)
« on: June 25, 2012, 03:16:30 PM »
   There are many similar looking things that we use to call by the same name : "Half Hitch". When a "half hitch" is tied around the tip of the bight, we may call it "half hitch around-a-bight" - or something like that. Ashley shows a similar knot, a half hitch around-a-ring (ABoK#1821). In the case of the half hitch around-a-bight ( where the U shaped object around the tip of which we tie the half hitch ) is a rope, we have one of the most simple and secure ways to attach a loaded line.
   This configuration can be exploited ( in fact, it has been exploited already ) as an element of an  end-of-line loop, that enables us to attach the tail on a bight formed on the standing part. In a sense, the half hitch "around-a-bight" is a bowline s collar AND a bowline s nipping loop, merging together into some compound, yet simpler knot !  :) So, the fact that this most simple knot is sooo effective, should not surprise us...

DerekSmith

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Re: Half Hitch around-a-bight. ( ABoK#1821)
« Reply #1 on: June 27, 2012, 11:09:00 AM »
Hi X1,

They say simple things please simple minds.  This simple little overhand knot certainly pleases me, so perhaps it says a lot about the state of my mind...

It is just an OH knot made around some solid object, yet when loaded it forms a Carrick component and by the simple measure of passing the free end under the loaded carrick leg and creating a simple hitch component, the device locks up wonderfully.

I have had it fail a couple of times when I made it onto flexible insted of rigid loops, but it is still a lovely concept.

Derek

X1

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Re: Half Hitch around-a-bight. ( ABoK#1821)
« Reply #2 on: June 27, 2012, 02:52:13 PM »
Thank you, Derek,

It is just an OH knot made around some solid object,

I have had it fail a couple of times when I made it onto flexible instead of rigid loops, but it is still a lovely concept.

   That is exactly what I had tried to stress ; When this knot is tied around the tip of the bight of a rope, it is not just an OH knot made around some object.
   Right after they are loaded, the two legs of the bight start to squeeze the OH knot from both sides, so the OH knot will remain more tight tied and compact as long this loading remains in action. That is the big difference in mechanics that is not shown in the pictures, and makes the " half-hitch-around-a-ring" ( ABoK#1821), and the "half-hitch-around-a-bight" quite different things, indeed. The ring is a solid object, it can not be deformed - while, on the contrary, the bight of the rope is a flexible object. Its width shortens when it is loaded, so its two legs squeeze the OH knot, and enhance its ability to keep the tail squeezed in between the object and its nipping riding turn -i.e. it behaves as a sort of an opposing U s, or Versatackle s lock mechanism. A very effective lock/mechanism, comparable with the nipping loop+collar mechanism of the bowline.
  (Of course, if the solid ring is of a small enough diameter, I guess that the two knots will behave quite similarly.)

   I had tied and tried it a hundred times ( literally !), and I had not been able to make it fail , not even once ! Of course, I have dressed it properly AND loaded it only with a gradually increasing load. I have not submitted it to any alternating loading pattern.
    I will publish some pictures of the most simple end-of-line loop one can made out of it - shortly. When this OH is encircled from its upper side as well, ( as it happens inthe  loop I am referring to ), the danger of being accidentally untied is diminishing, I believe.
« Last Edit: June 27, 2012, 03:04:03 PM by X1 »

X1

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The " Half Hitch around-a-bight" utilized for a simple end-of-line loop.
« Reply #3 on: June 27, 2012, 09:12:11 PM »
   This is the most simple end-of-line loop I can imagine, that utilizes a "half hitch around-a-bight" ( ABoK#1821 tied around a bight of a rope ) in order to attach the eye-leg-of-the-bight on the standing part.
   On the first sight, we would describe this loop as yet another crossing knot loop : there is, indeed, an S shaped crossing knot-looking structure tied on the standing part. However, the main task of this " crossing knot"  here is only to provide the needed bight ( an anchor the half hitch around-a-bight would be attached on ), and not to nip the tail ! The tail is nipped by the half hitch itself, which presses it firmly on the tip of the bight.
   The fact that we do not have a solid object here, as we had in ABoK#1821, means that, as the bight is loaded, its legs can move inwards, and squeeze the half hitch/overhand knot. This squeeze, by its turn, forces this knot to remain more compact and more tightly and securely tied around the tip of the bight, than it would have been if it was tied around an a inflexible ring.
   We can replace this S shaped form tied on the standing part with any other knot that would provide a bight - yet all the other possible solutions would be much more complex, and much less economical in rope consumption.

   See the attached picture for a KnotMaker (1) 2D drawing of this loop, and some pictures of the knot s nub.
« Last Edit: June 27, 2012, 09:13:14 PM by X1 »

X1

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Re: Half Hitch around-a-bight. ( ABoK#1821)
« Reply #4 on: June 28, 2012, 02:22:18 AM »
Here is a second example of the same theme : there are more such end-of-line loops that utilize the "S shaped standing part + half hitch "around-a-bight"" way of attaching the eye leg of the bight on the standing part, because there are many different ways the S shaped segment of the standing part can be interwoven with such a half hitch. I have chosen those two I present in this thread as the most stable and seemingly most secure of all. However, the interested reader should better investigate all the combinations by himself, and test them under heavy loading ( I did not) and with the variety of ropes he has in his disposal.


( Seec the attached KnotMaker drawing and pictures of the knot s nub.)