Knot Strength, part 1

In another post, we were discussing the Uni-knot.   I got out my Mustad 50# spring scale and a new spool of P-line copolymer CXX 15# line.  Tied 5foot section to the hook of the scale with a 6-turn Uniknot, wrapped the free end around a piece of broom handle, and pulled till it broke.  Did this 5 times: 
 
1  broke in middle of line
2  broke at knot
3 broke at knot, at 24 1/2 pounds
4 broke at knot, 23 #
5 broke in middle, 25 1/2#  and I had to quit for dinner

   I plan to do at least 20 ties to get a good sample, and will do this for the Uni-knot, the Palomar, the Trilene knot and the improved clinch.  Whichever knot, if any, gives 100% breaks in the main section of line, rather than the knot, will be the "go-to" knot from now on.

None of the Uni-knots pulled out, BTW---they all held until they broke. Good news for those who prefer the Uniknot (except for the fact that 3 of 5 broke at or in the knot, but 5 tries is a small sample).

Nice experiment KT. That's the line I use as a leader so looking forward to more results.

Z

Pretty significant strength for a nominally 15# line!  If I can find my micrometer, I'll mike it and see what the diameter is., mono is usually about 1# per 1000th.

Science!!  IIII like it!
Nothing better than doing it yourself with you own equipment for real life validation.
Can't wait to hear the results of the Palomar with mono.

Go KT!


as another reference I saw this on the idiot box one morning

http://www.fishingclub.com/ExtraContent/ExtraContentDetail.aspx?id=132344

I'm looking forward to seeing how your results compare.

What's the diameter of the hook on the scale?  Is it bigger than the hooks/swivels you normally use?  If so, it could affect the knot ... don't ask me how, just my intuition kicking in.  Perhaps tie to a swivel and hook the swivel with the scale hook.

-Allen

A god thought---I'm trying it with 10# Big Game now, I too thought of the hook diameter and am now tying to a welded ring and attaching that to the scale hook.
All 5 Uniknots failed so am on to the Palomar.
  I'm also taking pix...

make that "Good thought"!!

   Here's the setup---Mustad 50# spring scale:



and the first uni-knot, tied to a ring that is slipped onto the scale hook:



And here's a properly tied, spit-lubed uni-knot with new 10# Big Game, about to be pulled tight before testing



And the Palomar, before testing:



  First, 5 uni-knots.  These were tied to the scale hook, not to the ring, so must repeat:

1. Broke at knot, 10#
2. Broke at knot, 8#
3. Broke at knot, 9#
4. Broke at knot, 8.5#
5. Broke at knot, 8.5#

   Then changed to the ring over scale hook, and on to the Palomar. 

1. Broke at knot 9#
2. Broke at knot 8#
3. Broke on mainline 9.5#
4. broke at knot 7.5# (loose tie?)
5. Broke on mainline 9#
6. Broke at knot 10.5#
7. Broke on mainline 8.5#
8. Broke at knot 9#
9. Broke at knot 9.5#
10. Broke on mainline 8#


   This is difficult to explain, the Palomar is supposed to be a near 100% knot.  I tie it as shown in Berkely's little card of knots.  When it fails, there is only one of the 2 wraps around the ring remaining.  Here's a shot of a failed Palomar:



That straight piece is the original loose (tail end), the curved broken part is the main line failing at the wrap around the ring, I think.  Wore safety glasses and a glove, as the ring went flying the first time, and
the mono snaps back pretty sharply and stings!

   This is food for thought!  I have always tied my mainline to my swivel with a Palomar.  For now, I'm going to use an improved clinch knot.  After lunch, I'll pick this up again, I want to  do 10 improved clinch knots, and 10 "Berkely improved" knots---the one where you go twice thru the hook eye, 5 wraps, and put the tag end thru both loops around the hook eye before tightening down.

   Maybe I need Palomar lessons???

Now do the same test with Knot Glue....

I would be interested to know, if it improves strength like my personal experiences seems to show.

YotF

Do you mean this stuff???

 Loon UV Knot Sense

UV Knot Sense is an amazing product that is great for coating bulky knots to form smooth, clear connections. It cures in seconds when exposed to sunlight. For nighttime or indoor use, use the Loon UV Mini Lamp to cure. UV Knot Sense is also very handy for fly tying, allowing you to create hard, epoxy-style heads and bodies in seconds.

could it be that when the knot breaks, it's because the break area is where all the friction and stress occur when tying it??

Here's a neat trick.  For lines under 30# you can generally get almost any knot to push up towards 100% by doubling the line before tying the knot (tying on a bight if you will).  The one gotcha here is that you need to make sure the lines lay next to each other and don't get all crisscrossed.

-Allen

That's the idea with the Palomar--you're tying a simple overhand knot with doubled line, and tossing a loop around it for (I guess) holding power.  Disappointing results with my tests, though.  Now doing the "Trilene" knot---twice around whatever you're tying it to, then a clinch knot through both loops:

Here's the data for 10 trilene knots:

1. knot broke at 11.5#
2. line broke at 11#
3. knot broke at 9
4. line at knot broke at 10.5 (tie??)
5. line broke at 8.5#
6. knot broke at 8#
7. line broke at 11#
8. line broke at 11#
9. knot broke at 8#
10. line broke at 11#

Clearly, in my hands, the Trilene knot is not only strongest in terms of preserving line strength, but also most reliable in  terms of not breaking at the knot.  The downside?  It's a pain in the ass to tie right, at least with this light (10#) line. I noticed in a couple of the knots that broke at 8# , the line coming out was a little kinky as if the tightening down was faulty, or not lubed enough.  (No kinky lube jokes, please).

   The Uni-knot is the easiest to tie, I can do it a night with gloves on.  Next easiest is the Palomar, but I'm leery of it now.  Next to test---the regular clinch knot with 6 times around.  How about an "improved" Uni-knot?  Maybe loop thru the hookeye (ring) twice like the Trilene knot, then a regular uniknot.  If it's at least as good as the Trilene knot, I'm calling it the Tramp Harbor Special.

Regular clinch, 6 wraps

1. knot broke, 6#
2. knot broke, 8.5#
3. knot broke, 7.5#
4. line broke, 9.5#
5. knot broke, 7.5#

Now to try the Tramp Harbor special.

Forget the THS---no better than the regular uniknot

1. knot broke 11#
2. line broke 9#
3. knot broke 9.5#
4. knot broke 9.5#
5. knot broke 8#

  Conclusion----for now, I'm using the Trilene knot, it's the only knot that consistently broke at higher than rated line strength.  The palomar is the second choice, for when I'm in a hurry.  The Uniknot??  I'm knot sure yet.Anybody have any other knots to suggest for tying on hooks and lures???
   Bear in mind, these were done with light line..15# Pline breaks at around 25#. I am using 20# Maxima  for my mainline on the trolling rod and same for mooching with the Pline leaders. 
   It would be fun to repeat these tests using 20# line, but it's hard on my spring scale, not to mention a little dangerous.