Author Topic: Two by Four knot (or what knot is this)  (Read 33857 times)

James Petersen

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Two by Four knot (or what knot is this)
« on: December 04, 2012, 06:18:28 PM »
        While experimenting with ways of tying a bowline I somehow ended up with a loop tied with a whatknot -- ABOK 1406. This simply seems to be a round turn around a round turn. I doubled the knot and dubbed it the two by four (2x4) -- two round turns around two round turns.

        It a handsome knot to my eye. It seems very secure, even in small monofilament, although very difficult to impossible to untie after loading. I hope to do some controlled load tests to check on its strength, used as a bend as well as a loop. I would expect it to be fairly strong since each set of loops pass
es completely around three diameters of the opposite cord.

        Has anyone seen this knot described or tied anywhere?

        Thanks, and best regards.
« Last Edit: December 04, 2012, 06:23:38 PM by James Petersen »

Sweeney

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Re: Two by Four knot (or what knot is this)
« Reply #1 on: December 04, 2012, 06:41:44 PM »
Welcome to the Forum James. What you have tied is in effect what is known as the anchor hitch variant (sometimes anchor bend variant) where the first round turn is tied around a ring or pole and the second round turn applied as you have done. This is sometimes used by tree surgeons (arborists) as a harness tie in knot  and having something inserted into the first round turn makes it less jam prone. This knot uses the working end of a single rope rather than 2 ropes and is a hitch (despite being called a bend by some) - no doubt it works as a bend without a ring etc but being so difficult to undo limits its use.

Barry

SS369

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Re: Two by Four knot (or what knot is this)
« Reply #2 on: December 04, 2012, 06:47:56 PM »
Hello James and welcome. Thank you for sharing.

I have finagled some cord as you have with this, but only in an eye-loop form. I have to say that when loaded it is a true bear to untie. I had to use a spike and round nose pliers! I tied it using 6mm accessory cord that has a fairly smooth sheath and is of a firm construction.
I can only imagine the difficulty of disassembling it in soft frictive rope.

It is a little bulky, but that is not a drawback to me.

It lends itself to a more "permanent use", whether loop or bend, imo.

I will try it with other cords and ropes I have, especially the 5mm Titan Dyneema.

SS

Dan_Lehman

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Re: Two by Four knot (or what knot is this)
« Reply #3 on: December 04, 2012, 08:49:31 PM »
Greetings, James !   :)

The knot that you show is interesting, in being symmetric
whether loaded A-v-1 or A-v-2 (where the joined ends are
named by A-B & 1-2, B/2 being the unloaded tails in what
you show --only clearly indicated in the topmost image).

For an eye knot, I'd prefer to enter the "rabbit hole" nipping
loop from the opposite side to that in which the tail enters
for the bowline --i.e., to be reeving the tail in the opposite
direction.  And thus I call such eye knots "anti-bowlines".
The basic one(s) do show up in actual use, from time to time.

Trying your knot in some slippery small shopping-bag cord
(yes, I salvage that, occasionally), I see more rotational
movement upon tightening than is comfortable to me;
maybe it will eventually --tails long enough-- come to a
jammed conclusion and the knot hold, but I'd rather not
guess at that!  Apparently you've gotten it to hold to breaking
in nylon monofilament fishline?

(I don't see this as all so directly connected to the extended
fisherman's /anchor bend although I see the matching wraps,
but note also the quite different loading of these structures.
And, as for Ashley's urged nomenclature re "bend", I decline
--too much going against that, as Day noted.)
 ;)


--dl*
====

X1

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Re: Two by Four knot (or what knot is this)
« Reply #4 on: December 04, 2012, 11:28:25 PM »
   What a difference a tuck can make !
   I had tried all the possible hitch-to-hitch ( so to speak ) bends, but I have never tried this two-round-turns to two-round turns most simple one... :)
   Why ? Possibly because the two round turns are not sufficient to offer the gripping power of a hitch - so they are not considered as a knot, "a hitch",  at all. However, when those two very weak hitches work in tandem, the one enhancing the gripping power of the other, the two round turns turn out to be more than enough ! Moreover, at the same time, the tails of those two hitches are efficiently encircled and secured.   
   In a curious way that I can not predict in advance or explain, at some of those hitch-to-hitch bends, when they settle in their most compact form, the two standing ends are parallel / aligned to each other, and at some other they are perpendicular to each other. I think that, at the hitches where the standing ends are perpendicular to each other, their forced subsequent alignment will generate sharp first turns - and this may be a disadvantage.
   See the attached picture for two forms of a Strange-to-Strangle bend. At the first, the Standing ends ( and the tails )of the compact knot are perpendicular to each other - like it happens in the Two-round-turns bend presented in this thread - while at the second they are parallel / aligned.

X1

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Re: Two by Four knot (or what knot is this)
« Reply #5 on: December 04, 2012, 11:41:24 PM »
   Two more hitch-to-hitch bends : The Clove bend, where the standing ends of the compact knot are perpendicular to each other, and the Trefoil bend, where they are parallel / aligned to each other.
   Now, if it turns out that the Two-round-turns bend is sufficiently secure, and we do not care about jamming and untying, it will serve as a very useful, easy to remember and to tie permanent bend. 

P.S. I have tried this bend with many different ropes. It works fine with the soft ones, it does not work at all with the stiff ones, but the main problem is that I could not predict in advance if it was going to work with something in between...It is too much material-depended. Also, on material of intermediate stiffness, it will work, but only after a careful dressing, where all fingers are needed - and then some !  :) So, I conclude that, if I am to tie something like this, it will cost only a few seconds more to tie the Strangle bend - and then sleep like a baby.
« Last Edit: December 05, 2012, 02:02:23 AM by X1 »

James Petersen

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Re: Two by Four knot (or what knot is this)
« Reply #6 on: December 05, 2012, 05:12:33 AM »
  ...   Now, if it turns out that the Two-round-turns bend is sufficiently secure, and we do not care about jamming and untying, it will serve as a very useful, easy to remember and to tie permanent bend. 
Actually the simplicity of the 2x4 is what initially pleased me when I tried it out. It is virtually impossible to forget.

Quote
...
P.S. I have tried this bend with many different ropes. It works fine with the soft ones, it does not work at all with the stiff ones, but the main problem is that I could not predict in advance if it was going to work with something in between...It is too much material-depended. Also, on material of intermediate stiffness, it will work, but only after a careful dressing, where all fingers are needed - and then some !  :) So, I conclude that, if I am to tie something like this, it will cost only a few seconds more to tie the Strangle bend - and then sleep like a baby.

I have to agree. I find the strangle on strangle you posted extremely handsome, especially the version with standing and working ends parallel. It looks very much like a two-strand Matthew Walker. It would make a very nice lanyard knot. I also like the naming potential for a strangle-on-strangle knot, the "SOS" knot.

As I mentioned, I have done some simple tests on 6# test fishing monofilament with the 2x4. When carefully drawn up, it hasn't slipped and seems quite strong.

X1

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Re: Two by Four knot (or what knot is this)
« Reply #7 on: December 05, 2012, 06:01:12 AM »
It looks very much like a two-strand Matthew Walker.

 :) You solved half of the puzzle...(1) ( See the attached pictures )

1. http://igkt.net/sm/index.php?topic=1919.msg16859#msg16859

Sweeney

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Re: Two by Four knot (or what knot is this)
« Reply #8 on: December 05, 2012, 12:58:40 PM »
Not quite as easy to tie, the strangle bend with ends parallel to the standing parts might be used instead of the double fisherman's eg in permanent (or at least semi-permanent) slings - it's shorter and a little fatter but neat. I tried the original form with 30lb monofilament but it wouldn't hold - it might need extra round turns something like the Jansik Special. The strangle version would no doubt be better but also very fiddly to tie in fishing line unfortunately. I'll try again when I have some time.

Barry

X1

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Re: Two by Four knot (or what knot is this)
« Reply #9 on: December 05, 2012, 02:40:15 PM »
the strangle bend with ends parallel to the standing parts might be used instead of the double fisherman's

   Here comes the question :
   The Strangle bend and the double fisherman s knot (=bend) are made by the "same" kind of links - the double overhand knots -, interlinked in two different ways. In this sense, these two bends are "similar" knots.
   Now, let us suppose that we tie them on one material, where the Strangle bend is proved to slip less / be more secure than the double fisherman s ( or vice versa). If we tie them on a second, different material, will this continue to happen ? If the A bend slip less / is more secure than a "similar" B bend when both are tied on one material, will it slip less / be more secure when both will be tied on any other material ? In other words, is the form, the structure of two " similar"  knots the only thing that determines their relative security, or the material can also play the decisive first role ?
   If the Strangle bend does not hold when tied on a 30lb monofilament, but the double fisherman s does, this might imply that it will also be less secure / slip more than the double fishermsn s bend when tied on any other slippery material. Is this what is happening ? If it is, indeed, I suppose we should dismiss it altogether right away - why we should use a particular knot, when a very similar one will always do the same job much better ? As it might happen to us to have to join two ropes we meet / use for the first time, it is possible that we will not know, in advance, if those ropes are more or less slippery,- so I guess we should not take any chances.
« Last Edit: December 05, 2012, 02:42:41 PM by X1 »

Sweeney

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Re: Two by Four knot (or what knot is this)
« Reply #10 on: December 05, 2012, 03:24:08 PM »

If the Strangle bend does not hold when tied on a 30lb monofilament, but the double fisherman s does, this might imply that it will also be less secure / slip more than the double fishermsn s bend when tied on any other slippery material. Is this what is happening ? If it is, indeed, I suppose we should dismiss it altogether right away - why we should use a particular knot, when a very similar one will always do the same job much better ? As it might happen to us to have to join two ropes we meet / use for the first time, it is possible that we will not know, in advance, if those ropes are more or less slippery,- so I guess we should not take any chances.

I haven't tried the Strangle bend in monofilament (only the OP's bend) and it is not a knot which appeals for this material because of the difficulty of tying. However monofilament is an extreme case - it is so stiff and slippery that few rope or cordage knots will hold  but at the same time most knots tied in monofilament will not be effective in rope or cord as they rely on the extreme slippery nature of the material especially hitches for attaching hooks etc which need to be lubricated to make sure they slide into place. The sort of material I had in mind for considering the Strangle bend against the Double Fisherman's is accessory cord which although stiff is not particularly slippery. In any case there is certainly no guarantee that a Double Fisherman's will always be secure enough - hence the use of the Triple Fisherman's.

Barry

X1

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Re: Two by Four knot (or what knot is this)
« Reply #11 on: December 05, 2012, 04:24:26 PM »
I haven't tried the Strangle bend in monofilament ... it is not a knot which appeals for this material because of the difficulty of tying.

  Come on !  :) The Strangle bend is but two double overhand knots, interlinked to each other with the most simple way they could possibly be interlinked !  :) I could argue that, in fact, it is easier in tying than the double fisherman s knot(=bend) - but it suffices to say that it has the same number of turns and tucks, and a much simpler interlocking mechanism of the two links. ( I had called the Strangle bend as a two simply interlinked overhand knots bend, and the double fisherman s knot a two interpenetrating overhand knots bend. )
   The Trefoil bend has an added tuck, indeed ( the Working end goes through the central opening two times -, so, in a sense, it is more complex than a double overhand knot ), but one can not say, even for the Trefoil bend, that " it is difficult in tying". In fact, the pattern of tying it is even simpler than the Strangle and the double fisherman s bends : each time you form a round turn of each link, you pass the working end through the central opening of this link.
« Last Edit: December 05, 2012, 04:25:34 PM by X1 »

James Petersen

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Re: Two by Four knot (or what knot is this)
« Reply #12 on: December 05, 2012, 05:17:10 PM »
I haven't tried the Strangle bend in monofilament (only the OP's bend) and it is not a knot which appeals for this material because of the difficulty of tying. However monofilament is an extreme case - it is so stiff and slippery that few rope or cordage knots will hold  but at the same time most knots tied in monofilament will not be effective in rope or cord as they rely on the extreme slippery nature of the material especially hitches for attaching hooks etc which need to be lubricated to make sure they slide into place. ...
Barry
I like to test knots that I might use in slippery materials. Two  other extreme cases are tying knots in shock cord (bungee cord) and in rubber bands. Again, with several quick tests, the 2x4 holds very well in 1/8" shock cord, and can hold well in rubber bands (my rubber bands are made from natural rubber and are approximately 8" when cut) when very carefully drawn up. The strangle bend also holds like a champ in my 1/8" shock cord. I haven't tried it in rubber band -- tying the 2x4 in the rubber bands was fiddly enough, as simple as the knot is.

X1

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Re: Two by Four knot (or what knot is this)
« Reply #13 on: December 05, 2012, 06:26:04 PM »
tying knots in shock cord (bungee cord) and in rubber bands.

   I do not know anything about knots on those elastic materials - and I even doubt that a "knot" tied on such very elastic material belong to what I have tried to define as a "knot" (1). If we allow the deformation of very elastic material to all dimensions, we end up with knotted membranes, knotted amorphous masses, knotted amoebae s pseudopodia, and all that... :)

1. http://igkt.net/sm/index.php?topic=3610.0

Sweeney

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Re: Two by Four knot (or what knot is this)
« Reply #14 on: December 05, 2012, 07:21:01 PM »
I haven't tried the Strangle bend in monofilament ... it is not a knot which appeals for this material because of the difficulty of tying.
  Come on !  :) The Strangle bend is but two double overhand knots, interlinked to each other with the most simple way they could possibly be interlinked !  :) I could argue that, in fact, it is easier in tying than the double fisherman s knot(=bend) - but it suffices to say that it has the same number of turns and tucks, and a much simpler interlocking mechanism of the two links. ( I had called the Strangle bend as a two simply interlinked overhand knots bend, and the double fisherman s knot a two interpenetrating overhand knots bend. )
 

Have you tried tying a Fisherman's Knot or Strangle Bend in monofilament fishing line? Neither are knots I would use in this material which has its own set of knots with generally a lot more wraps. Incidentally the Grinner Knot used in fishing line is not the same as the Double Fisherman's Knot even though the name "Grinner Knot" is used to describe the Double Fisherman's in rope/cord.

Barry