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Knot Strength Query


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33 replies to this topic

#16 Patriot

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Posted 04 January 2020 - 12:05 AM

Hi Patriot, SilverCreek's explanation is pretty much what happens and almost all knots fail where the main line enters the knot. It will look like the line parted in the middle because there will be no curl or trace of knot left.

I had some time so I did the search for you. I probably didn't find all the instances of knot testing but these should give you an idea of how they did it and the resulting strength ratings.

https://www.fix.com/...t-encyclopedia/
https://www.saltstro.../fishing-knots/
https://www.knotsfor...strength-chart/
https://www.fieldand...-fishing-knots/
https://www.bassreso...ines-knots.html
https://www.saltstro...ot-vs-uni-knot/
https://mattsbucket....ot-testing.html
https://www.fieldand...-fishing-knots/
https://www.fieldand...-line-strength/
http://www.leeroysra...trong_knots.htm
https://www.bdoutdoo...h-chart.596379/
https://www.fieldand...nofilament-line

and how to tie some of them can be seen here https://www.animatedknots.com/
or here https://www.netknots.com/

 

I use nail knot for leader to line  and Double Fisherman’s Bend to join sections of leader or tippet to leader, easier for me to tie and I can step down a greater difference in diameter, I've never had these knots fail, any failures are always the tippet, it being smaller.  I did use blood knots for years and tied as Silver describes they work very well. I usually use a Duncan knot or a Double Davy knot at the fly.

 

I'm speechless!!!   I perused the first link and the information is precisely what I was hoping to find on knot strength.  I will read and bookmark each link that you so kindly provided.  You have provided a ton of very useful information that all of us can benefit from.  I have never heard of the Duncan or Double Davy knots.  I have much to learn.

 

Thank you very much for taking your time to find and post this invaluable knot information.  With your permission I may add your entire post to my website.

 

Thanks again!



#17 Dave G.

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Posted 04 January 2020 - 07:00 AM

Patriot, I never tried the Palomar knot on tiny flies but I can tell you it holds very well on what I have used it on. Many times stronger than, or maybe less abrasive to itself, than standard clinch or trilene knots. It works well. So I also do loops. And by the way, I mentioned I use the double surgeon knot for leader to tippet but it dawned on me that I switched to loop to loop there and back at the fly line in the last couple of years..

 

On another note about the size 24 midges. I could tie them I just don't. Yes I too would need to us a magnifier but the real issue is around here there are two prolific ponds that have midges that small and they don't have good access.. And several others where they run more in the 18-20 size, even 16 in one and easier to wade with great fishing and a boat launch area if I want to use the boat. So there is more to it than just the flies being small. And in Maine where I really prefer to fish anyway, I don't use midges at all.

 

I'll end here, you're really getting a bunch of great information in this thread !!


John 7:38 ESV  is about "Rivers of Living Water"


#18 tjm

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Posted 04 January 2020 - 11:35 AM

 

I have never heard of the Duncan or Double Davy knots.

You may know them by different names, many useful knots  have several names, either by locality or because they are used in differing circumstances. Also I find that some knots had one name 50-100 years ago and got a new name when someone writing an article in a magazine or such used a name that he preferred and it caught on. An example is the "perfection loop" that I learned 60 years  ago as the "central draught (draft) loop", it was named "central draft' because the draw or pull came in the center of the knot, I have no idea who or when named it "perfection" but all internet people refer to it as such. Another is the "surgeon's knot"  to join lines, the one commonly seen by that name now is what used to be a "double overhand knot" and what I learned as a "surgeon knot" was somewhat different. I can't imagine a need to join two lines during a surgery, so I'm unclear on that connection. What is a 'buntline hitch' to a sailor is also known to wearers of neckties as a 'four in hand knot'. 



#19 tjm

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Posted 05 January 2020 - 10:31 AM

This was posted on another forum yesterday and if you follow the links in the article, you can learn a bit about the latest knot  testing by MIT etc.

https://www.popularm...601/math-knots/



#20 Capt Bob LeMay

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Posted 05 January 2020 - 12:04 PM

Knots, as a general proposition are almost always weaker than the line, itself... The holy grail for anglers looking to set records or just to catch the biggest fish on the lightest tackle... are knots (or ways of combining knots ... ) that are as close to "100%" line strength as possible... Much of freshwater fly fishing never bothers itself at all with these kinds of concerns.

 

Some years back I belonged to a long established fishing club down here in paradise, south Florida, that actually had a tensile strength meter available to all of us.  We used it both to check our knots  but also to check the breaking strength of our lines - since a world record application has to include a line sample that the IGFA would use to verify that the submission met the line size requirement...  It was an eye opener to use since once you connected the line (or knot ) sample, then gradually increased the pressure shown on the dial you could actually watch any knot begin to change shape as it came under increasing pressure...   I was one of the minority of club members that did a lot of fly fishing (as well as all the other tackle categories we all competed in...) and was quite handy since fly leaders for the salt had multiple knots at times - and were quite often made up of more than one kind of line...as they tapered from the butt section down to the class tippet and then the much larger, heavier bite tippet (some called that the shock tippet...).

 

At any rate my bible for knots was the book written by Lefty Kreh and Mark Sosin, PRACTICAL FISHING KNOTS.  I'm sure you'll be able to find a used or new copy on Amazon (and if used it will be very low cost...).

 

For folks without some other way of testing lines, knots, and hooks (don't forget the terminal end...) the simplest way is to hang that hook with leader attached on something like a nail fixed in place - then slowly pull on the leader end to see just how much it takes to break the knot or the line - or does that tiny dry fly hook open up - before the line or knot breaks?

 

Hope this helps.  I once undertook to make (hand tie) one hundred fly leaders for big tarpon for a shop...  The leaders were 15lb hard Mason leader material connected to 110lb Maxima mono... By the time I was done my strong hand looked a bit bigger than the other hand...and I could do all the knots required (two Bimini twists per leader - then an Albright knot to connect the heavy, heavy bite tippet to the tippet,  15lb mono)... In my sleep....


Tight lines Bob LeMay (954) 435-5666

#21 DFoster

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Posted 06 January 2020 - 11:03 AM

Patriot here is a link to the Davy and Double Davy knot.  These knots are about as simple as they come.  I tend to change flies often so I like that it's simple and fast.

 


"I am not against golf, since I suspect it keeps armies of the unworthy from discovering trout."
- Paul O'Neil

 

 


#22 SilverCreek

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Posted 06 January 2020 - 11:07 AM

 I once undertook to make (hand tie) one hundred fly leaders for big tarpon for a shop...  The leaders were 15lb hard Mason leader material connected to 110lb Maxima mono... By the time I was done my strong hand looked a bit bigger than the other hand...and I could do all the knots required (two Bimini twists per leader - then an Albright knot to connect the heavy, heavy bite tippet to the tippet,  15lb mono)... In my sleep....

 

Bob,

 

I understand that there are reasons for using a hard mono but for the purposes of knots, do you think that tying a harder mono to a much softer mono of about the same diameter will result in a weaker knot because the harder mono can "cut" into the softer? Logically, it sounds like that would happen but I've never seen it proven or written about. I'm curious about your personal experience since salt water is where knots really get stressed.

 

I understand that in the knot you described the hard mono is MUCH weaker than the soft so it is unlikely to happen, but what if the breaking strengths and thicknesses of both were closer?


Regards,

Silver

"Discovery consists of seeing what everybody has seen and thinking what nobody has thought"..........Szent-Gyorgy

http://tinyurl.com/lgkbu7v

#23 SilverCreek

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Posted 06 January 2020 - 11:22 AM



Patriot here is a link to the Davy and Double Davy knot.  These knots are about as simple as they come.  I tend to change flies often so I like that it's simple and fast.

 

 

The Double Davy is stronger than that Davy BUT it is a weaker tippet to fly knot compared to the Orvis Tippet to fly knot.

 

"This Double Davy Knot proved to be a very good knot given that it has an impressive breaking strength while being super quick to tie. But it was not able to match the strength of the Orvis Knot in terms of strength."

 

Orvis vs Davy:

 

https://www.saltstro...cles/davy-knot/

 

Orvis vs Double Davy:

 

https://www.saltstro...ble-davie-knot/

 

In the knot test portion of the Yellowstone Angler Tippet Shootout, the Davy Knot tested as the weakest over all of all the tippet to fly knot for almost all the strengths and thicknesses of both fluorocarbon and nylon mono tippet materials.

 

48314991397_04a632014b_z.jpg

 

Here is the Yellowstone Anglers comment on the Davy Knot:

 

https://www.yellowst...ippet-shootout/

 

"The Davy knot was developed for one purpose – speed. In fly fishing competitions, lost time means lost fish, and often lost competition.  Once you practice this knot it can literally be tied in a few seconds.  Once your muscle memory is trained, you can even tie the knot without looking at it, allowing you to watch for rise forms.  It also uses up very little material.  Like the Orvis knot, when you pull this tight there is less friction.

 

The only problem we found with the Davy knot was its knot strength.  Reportedly, it is supposed to test nearly 100% break strength.  Our data revealed it breaking strengths to be reduced by as much as 40-50 percent.  For example, Rio Fluoroflex 2X has a straight pull break strength of 11.19 pounds. After averaging 6 Davy Knot breaks (or slips), breaking strength was reduced to 5.32, which is roughly 52 percent weaker. 

 

Bottom line:  This knot is super fast and wastes very little material, however it tested weaker than a wind knot.  Unless you are in a competition where time is of the essence, (or fishing to 8 inch trout) it only makes sense to pick a stronger fly knot.”


Regards,

Silver

"Discovery consists of seeing what everybody has seen and thinking what nobody has thought"..........Szent-Gyorgy

http://tinyurl.com/lgkbu7v

#24 chugbug27

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Posted 06 January 2020 - 12:05 PM

For tiny flies (22 & under), Davy or Orvis?
cb27

"Fly tying is replete with unproven theories and contradictions and therein lies much of it's charm and fascination." George F. Grant, The Master Fly Weaver

#25 DFoster

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Posted 07 January 2020 - 08:40 AM

I haven't had an issue with the Davy knot failing over the past 5 years I've used it.  I usually fish 6x tippet so I have to be delicate while fighting one in anyway.  I've never heard of the Orvis knot but it looks easy enough from the video.  

I landed this large bow in fast water on a Davy knot-

Attached Files


"I am not against golf, since I suspect it keeps armies of the unworthy from discovering trout."
- Paul O'Neil

 

 


#26 Capt Bob LeMay

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Posted 08 January 2020 - 01:49 AM

For silver creek... I frequently tie dissimilar leader materials together.  fluoro to mono, fluoro to hard mono,  each of them to braid (usually braid doubled with a bimini twist )etc.  You have to vary the number of turns on each side of the equation so that each side comes tight at the jam with a uni to uni or a slim beauty knot since that's where the knot strength comes from and it doesn't seem to matter whether you're using hard or soft mono....

 

Here's a pic or two of one of my heavier leaders with 20lb hard Mason tippet joined to 80lb fluoro bite tippet.  Note that at each end of the tippet there's a bimini twist to double the tippet before the next knot to keep as much of the tippet's strength as possible... 

 

3UiTmwv.jpg

this shows the end of the tippet that's formed into a double surgeon's loop after the bimini twist... can't find the next pic that shows the other end of that same leader with a second bimini - then the doubled tippet tied to 80lb fluoro with a hufnagle knot.

 

ZpVMh65.jpg

I pre-tie all of my more complicated leader setups (two leaders joined by a common, 30" bite tippet, then looped to the next pair in a continuous chain so all you do is pull off the top pair, cut the bite tippet in half and you have a completed leader ready to tie a fly onto before looping it to a generous butt section with a matching loop on the bitter end.  Note the different bite tippets shown for various purposes....


Tight lines Bob LeMay (954) 435-5666

#27 SilverCreek

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Posted 08 January 2020 - 10:59 AM

Thanks Capt Bob!


Regards,

Silver

"Discovery consists of seeing what everybody has seen and thinking what nobody has thought"..........Szent-Gyorgy

http://tinyurl.com/lgkbu7v

#28 ihang10

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Posted 09 January 2020 - 10:06 AM

I use a Davy knot for most tippet-fly connections. My 20lb line doesnt like a Davy so I use an improved clinch on heavy lines.

Doesnt need to be any more complicated than that for me.

#29 Poopdeck

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Posted 09 January 2020 - 08:34 PM

When it comes to knots, ease of tying is my only concern. I use a regular old clinch knot for all flys that don't fish better with a loop knot. Line weight records are of no concern to me, Losing the fish of a lifetime is not something I worry or even think about and I couldn't tell you which knots are stronger then the next. I have found most if not all of the few and rare knot failures I've experienced were due to improperly tying the knot and not the strength of the knot. We've all (at least I have) tied a knot and kind of thought something was amiss but chucked it out anyway because we wanted to get back to fishing as soon as possible only to lose the first fish hooked on it.

#30 Dave G.

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Posted 10 January 2020 - 06:53 AM

When it comes to knots, ease of tying is my only concern. I use a regular old clinch knot for all flys that don't fish better with a loop knot. Line weight records are of no concern to me, Losing the fish of a lifetime is not something I worry or even think about and I couldn't tell you which knots are stronger then the next. I have found most if not all of the few and rare knot failures I've experienced were due to improperly tying the knot and not the strength of the knot. We've all (at least I have) tied a knot and kind of thought something was amiss but chucked it out anyway because we wanted to get back to fishing as soon as possible only to lose the first fish hooked on it.

Yes indeed, and to me the improved clinch has forced me to take that one last step and make sure it pulls down and tightens up right. However, clinch knots fail in salt water with the heavy wire sized hook, in my experience. So there like most everyone in my area fishing for striped bass, I use the palomar knot.


John 7:38 ESV  is about "Rivers of Living Water"