Author Topic: Operating limitations of knots  (Read 2550 times)

PhilBendy

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Operating limitations of knots
« on: May 25, 2020, 02:33:15 PM »
Hi everyone,

I wanted to check my line of thinking with you. Even though a knot may be described as suitable for a particular material, the diameter of that material can have a big impact on how effective that knot will be.

So, for example, a knot with lots of twists and turns to exert grip on a fairly flexible cord could reasonably be expected to struggle once the diameter increases and the cord or rope is harder to flex. Similarly, a knot that works well with really heavy and large diameter line, cord, or rope will not perform so well if it is used without modification on a material much thinner and slicker.

In my hobby, angling, it is common to read about knots being suitable for this material or that material up to line classes of such and such a strength. With mono-filament where you have some grip, most standard knots work well on the thinnest of lines up to some quite stout lines - no questions asked. I use really thin braided line (thickness of 2 lbs mono). To reach anywhere near the line's breaking strain in loop format, I have to put in a lot of wraps.

I watch various videos of contributors using braid clearly a lot thicker than mine and advocating the efficacy of some loop pattern or other. Yet, when I test it on my much thinner braid, it inevitably fails well below what I am expecting. Hence the question above. Is it simply because the knot pattern being described requires a certain thickness of line to begin operating properly?

Phil

SS369

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Re: Operating limitations of knots
« Reply #1 on: May 25, 2020, 04:14:51 PM »
Hi Phil.

Answers may depend on various things. So, are the the knots failing the media or is the media failing at knot entry or in the knot itself?
Braided media goes through a pretty good compression in the the knot and there is tension applied as well. IMO, there is friction generated in that locale that causes heat at a small initial spot which causes the start of failure and can domino effect the neighboring fibers leading to complete failure of the media.

Also, the larger media, same knot, will require increased load to fail in the similar way. Again, my opinion is that the larger media allows for the dissipation of the detrimental heat. So, it would take a bit longer to fail.

Depending of the "twists and turns" the media may shed or spread the load along the line to lessen the load at any final point.
Examples of the force applied would be "Finger handcuff", eye splice, Bimini twist and The Australian Braid (or Plait).

SS

PhilBendy

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Re: Operating limitations of knots
« Reply #2 on: May 25, 2020, 06:58:29 PM »
Hi SS,

Thanks for your stimulating and thoughtful answer. The affect of detrimental heat is most interesting and your opinion that the larger media might disperse it better than the thinner is new to me but makes a lot of sense.

It's a great explanation that  lets me understand this situation more clearly.

Cheers

Phil

Dan_Lehman

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Re: Operating limitations of knots
« Reply #3 on: May 25, 2020, 10:31:45 PM »
I use really thin braided line (thickness of 2 lbs mono). To reach anywhere near the line's breaking strain in loop format, I have to put in a lot of wraps.
Phil, what "loop format" knots have you tried?

There are a lot of unasnwered or answered-via-conjecture
questions about knotting.
I recall one fellow getting good-great-less-great results
as he increased twists in the Bimini --and my conjection
re that is that there came a point where torsion reared
its head (and, afterall, the bar was already WAY high!).

--dl*
====

PhilBendy

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Re: Operating limitations of knots
« Reply #4 on: May 26, 2020, 01:23:08 AM »
Hi Dan,

I liked both your responses to my posts and am posting these comments by way of information rather than contradiction:

1) CROCODILE - I have used it many times as an ancillary locking out knot. I have not had the chance to use it in anger as a loop knot. I have tied it a number of times in preparation for its inclusion in my Blog. What I have noticed, particularly if I have not tied it for a while, is that an even rhythm is required when laying down the hitches. If the first few hitches are laid down too tightly, they seem to create a 'bottleneck' which does not permit the following hitches to take up and spread the strain. If you can lay them down at an even pace and an even tension, then the knot can deliver. So, despite the knot's apparent simplicity of construction, a little practice is warranted

2) LIMITATIONS - a few years back, I bought two lots of braid that were SUPER in every way - super thin, super strong, super slippery, and SUPER difficult to form a loop knot on. The Internet provided little succour. I recall trying the Bimini three times with varying amounts of turns. Three times it slipped. I'm not saying that it couldn't be made to work, but suspect that the number of wraps would be so big it would become impractical! Naturally, I wanted an easy life, so investigated the various 'Non-slip Loop' types. True, they did not slip, nor were they particularly strong. I remember trying to boost the performance using a double line which helped a little but still nowhere near allowing me to realise the full potential of my line. The best standard loop knot I found for my thickness of line was the KING SLING - in fact, I tied it just yesterday with 35 outward turns and was rewarded with a value of 9.8 lbs (approx. 88% - 89%). So, pretty good going. The three loop knots I have in my armoury will all produce 10 lbs and more on an 11 lb b/s line when dry-tested. They vary in difficulty from easy to medium to fiddly if the braid is fine. They all require upwards of 30 turns. Like anyone, I like an easy life! If I could find a loop knot where I only had to make 5-10 wraps, I would jump at it! I suspect the laws of Physics are against me on this one. Even though I know far less wraps would be needed for the diameter of braid most anglers use, the high tariff in wraps that I have to advocate for my lines is off-putting to most. Without wishing to blow my own trumpet too much, I wish I had had at my disposal the knowledge I have acquired in the intervening years. It would have saved me a lot of time and frustration if I could have gone to some reference link and there was all the information I needed to get started!

Hope you still awake after such a long-winded answer. I must have caught this verbosity from an overuse of wraps!

Phil

Dan_Lehman

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Re: Operating limitations of knots
« Reply #5 on: May 28, 2020, 01:37:25 AM »
Phil, here's a verbal sketch of an eye knot for you to try.

The Bimini Twist apparently --hard to see actual-- twists the
SPart sufficiently around a partner part to get it to gradually
bend and off-load friction; this twist of 2 parts is held by
passive resistance of a counter-twisting overwrap of the tail.
One should expect that what happens with the twisted parts
at the SPart-side of the knot --where the SPart comes with
full force-- might change slightly going to the idealized
equal twisting later.  One might also wonder at the effects
of tying method vis-a-vis imparted torsion to the strands
(I surmise this might have lead to some greater-number'd
knots being weaker than lesser ones.)

Now, what I have sought to do is to replace the inner,
SPart twist vs. a partner part with TWO such parts,
and then
actively --not passively-- resist this with the two eye legs
counter-wrapping !!

.:.  Bright idea, but ... who knows how actual any magic is!?
(This is where Phil comes in handy!   ::)  )

TO TIE:
fold a bight back and twist it (leaving ample material
for counter-wrap & eye) with the SPart; and in light
of expected high SPart force vs. the two parts, one
might *bias* the twisting so that the SPart does more

--nearly "wrapping" the other parts.
THEN at some guess sufficiently extent of twising,
U-turn your bight and counter-wrap with it back to
tuck out through the SPart's U-turn.  Here, too, it
will likely take some play with the general structure
to come up with specifics; but I think one will find
that these overwraps will get pulled out into the
eye on loading, so don't skimp!

At the EYE end, the eye legs' 50% each of force
should dominate action there, and not passively
resisting the inner twist, they will actually actively
IMPARTwist to the core
,
which at the opposite end will see the SPart press
hard into its twisted partners, but at (we hope) some
price of effort so to suck up its force by time it comes
to the U-turn.

The tail, btw, is just clamped-nipped at the U-turn
aperture; yes, maybe that could do with some better
securing, which you can figure.  (me, I've typed enuff!   ;)  )

Setting I'll surmise takes some attention to the goals
guiding the structure and trying to have things neatly
in place, and snugging a bit, and ... adjusting per experience.


--dl*
====
« Last Edit: May 29, 2020, 01:02:01 AM by Dan_Lehman »

PhilBendy

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Re: Operating limitations of knots
« Reply #6 on: May 28, 2020, 10:46:26 AM »
Hi Dan,

Sounds a great idea for the Bimini. I followed you up to the 'Eye' stage, before losing my way a bit. I'm sure many Bimini aficionados will have followed what you are saying. As ever, testing is the true arbiter of effectiveness.

The efficacy of counter-winding is an interesting one. Sometimes, it seems to be hugely influential, sometimes it seems other factors are more important. My two TUNA-based knots are a case in point. In my TUNA LOOP KNOT, the amount of counter-wound wraps back to the 'Eye' does not seem to be nearly as important as the amount of outward wraps and the amount of completion tucks. In the case of my TUNA BEND KNOT, where you might be seeking to join two ultra-thin braids (2 lb mono dia. to 1.5 lb mono dia.), it seems like the counter-wound wraps are making a contribution. I know this because, keeping everything else the same in the knot pattern, there was a noticeable drop in performance when I tried to reduce the number of the counter-wound wraps. It kind of makes sense because you are in a situation where 'every little helps'. It might not matter so much with a more conventional braid>mono/fluoro union, but why change a good thing?

Phil

Dan_Lehman

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Re: Operating limitations of knots
« Reply #7 on: May 29, 2020, 01:22:01 AM »
Hi Dan,
Sounds a great idea for the Bimini. I followed you up to the 'Eye' stage,
before losing my way a bit.
Hmmm, "At the eye send" (edit to remove errant 's') ?

Consider this : a lonnnnnnnnnnng/wide 'Z', um, sorta flattened;
bottom is SPart coming from right, and then U-turning clockwise;
center AND top parallel parts are the folded-back working bight,

. . . which will do-si-do (twist) for part of the bight's length,

 . . . . then U-turn & counterwrap back over the twists to be

. . . . . tucked out through the SPart's U-turn collar-eye,
          to be the knot's eye.

(As you can see, the working bight is sort of taken
in thirds : the initial third twisting w/SPart,
and then backtracking that distance --though now
at great radius, in...-- for counterwraps,
and still have enough left over to be the eye.

(The BTwist begins with an eye twisted to smallness
then opened up to make the turned-to-perpendicular
tail make its (passively resisting) counterwraps.)

--dl*
====

PhilBendy

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Re: Operating limitations of knots
« Reply #8 on: May 29, 2020, 07:44:37 AM »
Hi Dan,

Thanks for taking the time to explain. I shall now probably make a fool of myself (not uncommon, I hasten to add!) by saying that possibly, just possibly, I think I am beginning to grasp what you are getting at.

If I am correct, we have dispensed with placing the line around something solid, making 20 -30 outward twists followed by a similar number of inward wraps to take us back to the loop which we have now released from its post. Conventional wisdom says that you make a half hitch to hold everything in place before taking the tag line to the top of the loop and wind back towards the base of the loop in the style of an ALBRIGHT Line-to-line knot, where you tuck it. I think that you are suggesting that after making that half hitch, you carry on wrapping up to the top of the loop before counter-wrapping back in the style of an ALBERTO Line-to-line knot before making the tuck.

If I am on the money, there is certainly latent potential here. The ALBERTO configuration is said to be stronger than the ALBRIGHT but seeing as I never had much luck cinching the ALBERTO, I cannot comment! I do, however, believe that counter-wrapping does add to the strength of knots and that it is no accident that both my Line-to-line Knots, HORNET in single-line format, TUNA BEND in double-line format, both use this method.

I am hedging my bets here, but if this is not what you are describing, I certainly think it would be worth testing. You know, it's often something subtle like this that can make the difference between merely a good knot and a true classic - although, that said, the Bimini has long been recognised as that. But could it be that El Classico could get even better?

Phil

Dan_Lehman

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Re: Operating limitations of knots
« Reply #9 on: May 29, 2020, 11:18:31 PM »
I think I am beginning to grasp what you are getting at.
I can only help if I know where you go wrong.
But this is really darn simple.  (Precise dressing
maybe will reveal challenges, but conceptually
the knot structure should be perspicuous.)

THESE '|' (bars) are material making a turn!  [artist's rendering]

My flattened "Z" structure:

   v----: tail
    ________________________________________
  ---------------------------------------------------------|  < -- bight tip
 |_________________________________________________________ _ _ _ main line

 ^ fold of bight back from mainline.

>>> If I am correct, we have dispensed with placing
>>> the line around something solid, making 20 -30 outward twists

Well, did I say any of that?  (no).

One might have a *thin* at the "fold...back" point,
which will be where the bight tip ultimately tucks out
though to become the eye.

So, one needs adequate length to
twist main line & bight rightwards (per above sketch),
and then come back with bight overwrapping these
twists (which should be easier than what I just watched
  for the Alberto, where one brings back a fiddly little single line!)
until reaching the fold-back point now reduced to small aperture
to tuck out the overwrapping bight to become the eye.

Generally, a "TWIST" will be a helix w/much greater angle
than the ensuing "OVERWRAPS" --though these in being
done with a bight (so, twin lines) won't be so numerous
as the single-line wraps in the Bimini.  AND one is hoping
for some good "imparting twist" action of the eye legs
going into the counterwraps so one might not need so
many, to effect & hold the mainline's being twisted/curved
in the knot's core.
YMMV ??

As for setting, in rope at least I find myself just working
--as presented orientation above-- right-to-left tightening
the overwraps, working around the structure getting the
material set well and excess moves leftwards into eye.
Then perhaps some tensioning of eye vs. knot as a first
step is good?


Damn typical of fishing-knots presentation,
but one simply canNOT see what the final knot
is supposed to be --you have to gander at an
ambiguous squiggle, just hoping that your tying
has got you to the right state (and, frankly, many
*expert* advisors/teachers might not know what
that state is --or what possible variety of set states
exist-- themselves!).


(-;




PhilBendy

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Re: Operating limitations of knots
« Reply #10 on: May 30, 2020, 01:40:36 PM »
Hi Dan,

Your comment about fishing knot presentations is so right! I think to execute a good instructional video, you need some serious skills - which, unfortunately, I do not have ... though I have released some. For instruction and usefulness, I prefer the 'freeze frame' technique whereby you use a regular camera, thick cord, and use annotated photos of each stage of the knot-tying process. My impression, however, is that the video medium is the preferred study source ...

Once I got the Bimini out of my mind, your knot looks not so different from something I would advocate myself.

Many thanks for your patience, Dan, and apologies for being rather slow on the uptake.

Phil

Dan_Lehman

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Re: Operating limitations of knots
« Reply #11 on: May 30, 2020, 08:32:01 PM »
THESE '|' (bars) are material making a turn!  [artist's rendering]

My flattened "Z" structure:

   v----: tail
    ________________________________________
  ---------------------------------------------------------|  < -- bight tip
 |_________________________________________________________ _ _ _ main line

 ^ fold of bight back from mainline.

/.../

As for setting, in rope at least I find myself just working
--as presented orientation above-- right-to-left tightening
the overwraps,
working around the structure getting the
material set well and excess moves leftwards into eye.
Then perhaps some tensioning of eye vs. knot as a first
step is good?
The above "working" the overwraps tighter I suppose one
could see done in some sort of "nail knot"-aided way ::
with a short hollow cylinder at the SPart-Uturn /eye end,
turn that while working overwraps tighter,
and then tuck out the eye bight through the cylinder.


--dl*
====