Author Topic: The Strongest Knot?  (Read 13926 times)

DerekSmith

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The Strongest Knot?
« on: June 24, 2007, 12:01:02 AM »
Following on from the previous post regarding knot breaking strength and theories.

Is this possibly the strongest of loop knots?

If you think it might be -- discuss.


SS369

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Re: The Strongest Knot?
« Reply #1 on: June 26, 2007, 01:08:50 AM »
Hello Mr. Smith,
it is a beautiful thing no matter if it is the strongest knot or knot. Would it be no stronger than perhaps another knot since any knot is only as strong as it's most load bearing crossing? ie either the entrance of the standing part into this knot's braid or where it returns into the braid at the loop. I hope you don't think I am knotpicking here.  How do we test it?
Scott

DerekSmith

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Re: The Strongest Knot?
« Reply #2 on: June 26, 2007, 10:22:04 PM »
Hello Mr. Smith,
it is a beautiful thing no matter if it is the strongest knot or knot. Would it be no stronger than perhaps another knot since any knot is only as strong as it's most load bearing crossing? ie either the entrance of the standing part into this knot's braid or where it returns into the braid at the loop. I hope you don't think I am knotpicking here.  How do we test it?
Scott

Thanks for starting off the discussion Scott,

Yes it is a pretty little loop knot, but like most of our knots, this is just the face that it presents to the world of knot tiers.  But some (most) knots have a business side, their working side, and when they go to work they tend to take on a totally different structure --  this is also true for this little knot.

Load the knot up to +80% of line breaking strain and its shape changes into this :--



The tension on the line tends to make it want to stay straight.  This forces the adjacent lines to take a longer path and thereby expands them.  In turn the adjacent lines press back against the loaded line.

As the loaded line enters the plait, through the first loop, there is virtually no squeezing force, only a gently sideways pressure causing some tension to be fed to the next crossovers and adjacent plait lines.  Some of the tension is transfered into the two white lines.  The loaded line continues virtually straight through the knot, passing load into the two white line by friction (there are no bends, so only friction can be at work) right up to the last turns, when so much of the line tension has been shared with the white lines that the red line starts to bend and follow the same curvature as the white lines.  By the time the red line emerges, it has shed 50% of the load into the white lines, through a series of 16 encounters of either lateral pressure or scissor grips, that is sixteen steps on average each of ca 3% transfer.

Of course, neither the emerging red, not the returning white are likely to break, because they only carry 50% of breaking strain load, and as they enter the knot without any fierce bend or constriction, they are highly unlikely to break at 50% load.

So, should we expect this knot to exhibit at least ca 97% strength?

SS369

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Re: The Strongest Knot?
« Reply #3 on: June 26, 2007, 11:07:55 PM »
Hi Derek,
Now that I see it in a different position what you write makes sense. It is of the "Chinese finger handcuff" style.
My guess is that were the line to break it would be at the return of the white line into the plait from the loop at the first crossing.
But as for 97%?, we would have to test that if anyone ever decides what the best course of action to do that is.
Scott

DerekSmith

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Re: The Strongest Knot?
« Reply #4 on: June 26, 2007, 11:25:26 PM »
Hi Scott,

Here is a closeup of the loop cords re-entering the plait.



When each one is only carrying 50% of the load and both are nearly straight, why should either break?

Derek

SS369

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Re: The Strongest Knot?
« Reply #5 on: June 26, 2007, 11:31:48 PM »
Hi again Derek,
Looks like it shouldn't break at all. You are quick with the camera! You take those especially just for little old me?
Have you the tying directions for this cute number handy?
Scott

DerekSmith

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Re: The Strongest Knot?
« Reply #6 on: June 26, 2007, 11:49:22 PM »

SS369

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Re: The Strongest Knot?
« Reply #7 on: June 27, 2007, 12:33:40 AM »
Many thanks Derek !

TheTreeSpyder

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Re: The Strongest Knot?
« Reply #8 on: July 03, 2007, 04:23:24 AM »
in my imagery this is a 'loose splice' type of knot.  The idea is to maintain inline force i think (as you say); with little/Zer0 deformation; especially of the fully loaded parts.  Here the deformation of Standing is on the eye side, where it only receives 50% of the loading, not the Standing Part end of same; that receives 100% loading.  But; i'd say that pull split into 50; comes from the eye 100% as equal and opposite of the Standing End 100%; not that the Standing Part force broke down to that 50?  And that the white tensions were really fed by the eye 100% split; and there wasn't enough force remaining to bend the Standing Part /red at start of lacing at 100% force.  But has enough force in white closer to it's full 50% load to deform red of equal 50% force.

The eye should be pulled inline with Standing; not spread across perpendicular to Standing; as spreading force would change to less inline bends/more perpendicular force to weaken and also work against the security of the lacing too i'd think.

This form should also impart some dynamic absorption?

DerekSmith

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Re: The Strongest Knot?
« Reply #9 on: October 07, 2007, 09:38:05 PM »
Well, I tested it and it beat the toughest knot on the list - The Blakes Hitch.

Can it be beaten?

knudeNoggin

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Re: The Strongest Knot?
« Reply #10 on: October 08, 2007, 06:12:54 PM »

Well, I tested it and it beat the toughest knot on the list - The Blakes Hitch.
What if you give Blake's hitch even 3/4 of the material consumed by this other
hitch?  Blake's should be taken as a general schema and not merely as a precise
order.  Add some more turns both over the tucked end and away from it.  Maybe
help "cascade" the far-reaching part around those "away" turns a little, around
them (which is sometimes a natural effect).

*knudeNoggin*

Stoatstail

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Re: The Strongest Knot?
« Reply #11 on: October 16, 2007, 11:01:35 AM »
Derek

What material did you use to test the knot ?

DerekSmith

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Re: The Strongest Knot?
« Reply #12 on: October 16, 2007, 11:30:53 PM »
Derek

What material did you use to test the knot ?

2mm cored 16 strand polyester braid  - ref R20C from English Braids www.englishbraids.com

Tensile strength 910N

Derek

Stoatstail

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Re: The Strongest Knot?
« Reply #13 on: October 17, 2007, 08:56:18 AM »
Its called an Aussie Briad in the fishing world and, like the Bimini Twist, is credited as a 100% knot.

Are you interested in testing this in mono ?, this being the material it is most commonly used in.
 

DerekSmith

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Re: The Strongest Knot?
« Reply #14 on: October 17, 2007, 11:30:35 AM »
Its called an Aussie Briad in the fishing world and, like the Bimini Twist, is credited as a 100% knot.

Are you interested in testing this in mono ?, this being the material it is most commonly used in.
 

The illustrations athttp://www.thaifishingguide.com/fishtechequip/techniques/knots/plaiting_a_double_steps.html are published by the Australian Fishing Network in the "Complete book of Knots and Rigs" by Geoff Wilson.  Geoff calls it a plaited double, for some reason in Oz a loop seems to be called a double ??  Still, half a world away names seem to vary with ease.  Geoff illustrates the lovely Centauri Knot which turns out to be the simple slipped double Strangle  AKA the treble OH -- still, a rose by any other name....

Re testing in mono - yes I think that mono should be one of the cords used in the overall testing schema.  Perhaps those who use it could agree between themselves what specific line should be chosen for the tests.  I personally do not use mono, so could not comment one way or another as to which would generate the most usable information.

Derek
« Last Edit: October 17, 2007, 12:15:00 PM by DerekSmith »