International Guild of Knot Tyers Forum

General => Chit Chat => Topic started by: DerekSmith on June 24, 2007, 12:01:02 AM

Title: The Strongest Knot?
Post by: DerekSmith 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.

Title: Re: The Strongest Knot?
Post by: SS369 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
Title: Re: The Strongest Knot?
Post by: DerekSmith 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 :--

(http://knotbox1.pbwiki.com/f/strongloop03sml.jpg)

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?
Title: Re: The Strongest Knot?
Post by: SS369 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
Title: Re: The Strongest Knot?
Post by: DerekSmith on June 26, 2007, 11:25:26 PM
Hi Scott,

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

(http://knotbox1.pbwiki.com/f/strongloop04.jpg)

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

Derek
Title: Re: The Strongest Knot?
Post by: SS369 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
Title: Re: The Strongest Knot?
Post by: DerekSmith on June 26, 2007, 11:49:22 PM
Sure,

I found it here  http://www.thaifishingguide.com/fishtechequip/techniques/knots/plaiting_a_double_steps.html

Derek
Title: Re: The Strongest Knot?
Post by: SS369 on June 27, 2007, 12:33:40 AM
Many thanks Derek !
Title: Re: The Strongest Knot?
Post by: TheTreeSpyder 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?
Title: Re: The Strongest Knot?
Post by: DerekSmith 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?
Title: Re: The Strongest Knot?
Post by: knudeNoggin 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*
Title: Re: The Strongest Knot?
Post by: Stoatstail on October 16, 2007, 11:01:35 AM
Derek

What material did you use to test the knot ?
Title: Re: The Strongest Knot?
Post by: DerekSmith 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 (http://www.englishbraids.com)

Tensile strength 910N

Derek
Title: Re: The Strongest Knot?
Post by: Stoatstail 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.
 
Title: Re: The Strongest Knot?
Post by: DerekSmith 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 (http://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
Title: Re: The Strongest Knot?
Post by: Stoatstail on October 17, 2007, 01:11:38 PM
Aussie Braid, Aussie Plait, Braided Double.... all the same :)

Six commercially available brands of monfilament at 16-20lb published breaking strain. In lightweight monos true BS is most often less than that claimed, in heavier weight it is more. So, each line would have to be tested sufficiently to find a statistically acceptable true BS, then each knot the same.

Lots of work, still interested ?.

 
Title: Re: The Strongest Knot?
Post by: DerekSmith on October 17, 2007, 07:23:03 PM
Aussie Braid, Aussie Plait, Braided Double.... all the same :)

Six commercially available brands of monfilament at 16-20lb published breaking strain. In lightweight monos true BS is most often less than that claimed, in heavier weight it is more. So, each line would have to be tested sufficiently to find a statistically acceptable true BS, then each knot the same.

Lots of work, still interested ?.

 

Yes indeed lots of work -- in fact much too much for one individual to contemplate -- this has to be a group task if it is to succeed, many hands make lite work.  That is why the proposed test rig has been set up to be low cost and very easy to set up, so as not to put off members from becoming testers.

So far we have a test rig and an outline protocol and a proposal for the first test cord (R20C).  It has been proposed that eventually we consider a number of cords (obviously mono included), and when they have been set, then it is probable that the protocol will need amending to reflect the characteristics of the cords involved.

My guess (and hope) is that those with a vested interest (i.e. anglers in mono) will take up the project in those particular materials so that we might even have a number of cords under test at any one moment.

So, it's lots of work -- interested ??

Derek
Title: Re: The Strongest Knot?
Post by: Stoatstail on October 17, 2007, 08:19:54 PM
Definitely. :) 
Title: Re: The Strongest Knot?
Post by: Dan_Lehman on October 19, 2007, 04:09:52 AM
One might want to read the Sport Fishing (I think that's the title) articles on testing
of various knots in August's (September's?) issue.  There were a great many test cases
--lots of lines, lots of repetition--, and some interesting results.  The magazine escaped me
before I got a good look at it (hesitating at the $5 initially), so I don't know more; but I
did see that the results for the same knot ranged broadly, and there was some suggestion
that knotted line could be stronger than unknotted, odd as that seems (to me this suggests
some issue with the anchoring, but I don't know the details).
I think that the recent testing done here was in conventional mono & braid, and that done
a year or so ago was in the hi-mod "gel-spun" HMPE stuff.

--dl*
====
Title: Re: The Strongest Knot?
Post by: paulj on October 19, 2007, 06:48:47 AM
I didn't find anything about knot tests at 'Sport Fishing' online, but followed a few links to Stren Super Knot Mono, a line designed to take knots, and reduce breakage at the knot.  The product blurbs talk about abrasion resistance and internal lubrication.

http://bassbuzz.outdoorsfanmedia.com/br_news_article.asp?thecat=3&id=87
Title: Re: The Strongest Knot?
Post by: Dan_Lehman on October 19, 2007, 02:26:06 PM
I didn't find anything about knot tests at 'Sport Fishing' online, but followed a few links

Following links is dangerous, esp. for a knotty person and a fishing site--one could get hooked!

I found (newly) both a nice forum section (and noted some doubters questioning editor-in-chief
Doug Olander (aka Top Shot) about his assertions/findings of a (mere) 10-/12-turn Bimini Twist
vs. those w/say 40..06 turns) and the link to the very article cited--to wit:
www.sportfishingmag.com/techniques/tips/staying-power-53427.html (http://www.sportfishingmag.com/techniques/tips/staying-power-53427.html)

& another:

www.sportfishingmag.com/article.jsp?ID=43558 (http://www.sportfishingmag.com/article.jsp?ID=43558)

(FYI, as I seem to recall having some similar problem from a different computer with
slightly different browsing--of the Bimini-in-gelspun article--, I got browser error on chasing
the 2nd embedded (bimini tests) link?!   If others find such troubles, might be worth
sending an alert to SportFishing about it.)

--dl*
====

ps/edit-add#2:  This link is to an article in which selected fishing pros give recommendations on knot tying:
www.sportfishingmag.com/techniques/natural-baits-and-terminal-rigs/thoughts-on-knots-from-some-real-pros-21722.html (http://www.sportfishingmag.com/techniques/natural-baits-and-terminal-rigs/thoughts-on-knots-from-some-real-pros-21722.html)