Knot strength

[Brandon Khoo]

I spent a number of hours today experimenting with the knot strength of various knots. What I did was tie a number of knots and then place them under a shock load. What I did was tie the braid to a fixed point and then got a good grip on the leader and exerted a shock load. if it didn't break, I continued increasing the magnitude of the shock load till something broke.

I used 80lb TF XP for the test which i then changed to 130lb FINs. Twisted leaders were made from 100lb Penn 10X and single strand was 170lb Fisherman.

Twisted leader/bimimi double - pretty much as expected. I did a number of tests and on every test, the braid broke, not the bimimi double. It really took some breaking too requiring a very hard shock load. On the test I conducted without a shock load where I loaded it gently, I found it very difficult to break the line.

FG knot - I was actually really impressed with this knot. Again, all breakages were on the braid and not at the knot. It handled the shock load very well and it also really took some effort to break the braid.

PR knot - I was also very impressed with the PR knot. I managed to break one knot where the knot itself slipped under a heavy shock load but that was my fault in how I tied the knot.

Albright knot - not a popping knot but I tested this anyway as I use it a bit for jigging. I was shocked by how easily the knot broke. I then tested where I tied a bimimi double before tying the Albright. This was like chalk and cheese. The albright tied with the bimimi double was much, much stronger but I did manage to get the knot to slip completely twice.

Uni knot - this was a connection where I tested a double uni knot with a single strand braid to mono leader. Again, I was shocked at how easily this broke but like with the Albright, the difference is chalk and cheese when you go to the effort of tying a bimimi double first.

Overall, for popping purposes, I think it simply confirmed to me that the twisted leader connection or a PR or a FG all will work fine provided you tie the knots well. The FG and PR are unforgiving knots if you do not tie them well. What I was surprised by, however, was how easily 80lb and 100 lb braid broke when placed under a heavy shock load. On the other hand, if I increased the pressure slowly, I could barely break the line at all.

[Luke Wyrsta]

[Jon Li]

Guys ,

Braided line will break easily under heavy shock , that is why nowaday we use " shock leader " more and more to give a little
" shock absorber " , in the absence of stretch the line will just part unlike nylon line which can stretch up to 30% or even more before breaking and the less filaments the line is braided from , the more prone the line to break under shock load . It's suffice to say a 4 filaments Tuffline will break easier under shock load than a 8 filaments Avani line .

Jon .   

[Luke Wyrsta]

[Jon Li]

Hi Luke ,

I find Avani GT to be a better line than Tuffline XP , YGK Ultra and other brands in all department , that is why I use them for GT popping but will still use Tuffline XP when popping for YFT which does not need high drag setting . It's my experience only but was confirmed in my latest fishing foray into sailfish popping , I had 2 breakages on the line itself and it was on YGK Ultra while the Varivas Avani GT survived albeit we use those line with approx. breaking strain of 60+ lbs. .

Sailfish popping needs a reasonably high initial drag setting due to the necessity to facilitate the piercing of the hard bill of the sailfish by means of hard jerking repeatedly ( 10~20 times ) to ensure solid hook up , any weakness in the line will be a lost fish be it a weak PE line under heavy shock , abraded leader , etc. .

All these are my own experience , for any scientific tests one must ask the manufacturers of the various PE line using testing apparatus , not during real fishing conditions , in my opinion .

Jon .   

[Brandon Khoo]

Hi Luke - I will replicate the test with Avani GT when I have the time - probably in the next fortnight to three weeks. It takes quite some time to do this due to the time taken to tie the knots!

[Brandon Khoo]

one further comment I'd add at this stage and that is the effort taken to break braid in comaprison to monofilament.

About the time I started fishing for GTs the modern way about five to six years ago, I did a test with 80lb braid (can't remember what brand) against 80lb monofilament and this was to test what impact the stretch that mono had it would have in a real situation in comparison to braid. The test I did was to tie the line to a fixed point and then stand a fixed distance away and initiate a shock load onto the line to see how hard it would be to break.

Basically, what I did was tie one end to a foot ball post and then initiate the test from the quarter line, the half way line and the opposite try line.

The braid at the quarter line broke with a firm pull and turn. On the half way line, it broke again with a little more effort and  had to take about a step backwards to get into tension to break it. From the opposite try line, I had to put in noticeably more effort to break the line and I had to take about three steps backwards in order for it to break. This indicated to me that while some people argue there is zero stretch in braid, I don't think that is the case. There is, at least from my very rough test a couple of percent of stretch in it.

Monofilament was a completely different kettle of fish. from the quarter line, I had to take a number of steps backwards and pull quite firmly to break it. It was the same at the half way line except I had to take what felt like about five to eight steps before it would break. from the opposite try line, I struggled to break the mono. I had to go past the dead ball line and pull like hell before it would break.

To me, this indicated the importance of the leader, that the elasticity in monofilament was important in absorbing the shock load induced by the strike from a big fish.

[Greg Burt]

The long Gt rods should help against shock as well as mono leader, more so on strike.
I found out the hard way on a smaller scale 10 years ago trolling for macs with baits and lures with 15-20lb Braid, the hooks would pull consistently on strike until I changed to a 3m 20-30lb leader and used 7ft 'softish' rods like the Penn Powersticks, now no worries.

[Stephen Polzin]

Brandon,

I think to get a measurable result it would be necessary to incorporate a scale in your tests.  If you're just going on feeling or perception then I think there is room for considerable error.  I read a test some time ago (I think by Neil Griffiths) using a scale to test various knots that was very comprehensive.  Just my 2 cents.

[Brandon Khoo]

Stephen, I'm not looking for a measurable result. The primary objective of my test was not the breaking strain pe se but how well the knots would hold up under a shock load. While I could have used a scale on it, this was not what I was primarily interested in. To facilitate such a test would mean I needed to ensure a consistent length of braid, a means of measuring and facilitating the level of the instantaneous shock load etc.  In addition, I have no access to the type of equipment Neil used for his test especially when, If I remember correctly, he had to borrow the equiment from UQ. Whatever mathematical error there is in what I tested is not an issue.

What I am trying to establish (again seeing I have done this on a number of occasions) is how well my knots will hold under a shock load as well as taking into account the fact that I will strike very firmly a couple of times after the fish is hooked.

I know the bimimi/twisted leader works really well for me. I've tested this numerous times in the past so I have full confidence in this atatchment. What I wanted to test was the strength of my single strand leader to single strand braid attachments and how these hold up under a shock load. The fact that my FG knot and PR knot result in the braid breaking provides me with enough confidence that the knot will hold. I used to use a FG for a little while but lost a really good fish on it when the knot slipped. This was of course my fault, not the knot itself. I think I have enough confidence in how I tie the knot now to start using it again on some applications.

[Stephen Polzin]

yeah sure, but unless you can measure the shock load for consistency, it's just guessing

[Brandon Khoo]

I'm not sure you read my last response.
the guessing aspect is irrelevant - the objective of the test was the knot, not the breaking strain of the line under load. If the braid is breaking before the knot, I think I can rely on the knot as it is tied.

[Stephen Polzin]

Oh right.  I think I see your point now.  Fair enough. 

[Russ Roberts]

Brandon:

I am drawing a blank on what is meant by the "FG" and te "PR" knots. 

I have conducted numerous tests myself (involving straight pull--not shock as you did) using 80 pounds YKG Jigman PE6 and 130 pound Jerry Brown hollow, which I use, respectively, for YFT tuna popping and chunking for tuna here on the Texas Coast.  I am of course not quite so worried about shock as you GT folks are, but I am very interested in knot strength.  With both lines, I used 80 pound fluorocarbon leaders with a 40 turn Bimini in the braided line tied with a 12 turn Albright to the fluoro.  The only test I did was to put a straight pull on the line using a Chatillon scale.  If I could reach 70 pounds (or roughly 90 percent of the nominal breaking strength of the fluoro), without breakage anywhere OR slippage in the Albright,then I was a happy camper.

The only failures I ever encountered were slippage (not breakage) in the joining knot.  And in all cases, I am confident that in tying the Albright, I had either overlapped the loops of the braid OR not pulled strongly enough on the tag ends prior to trimming.  I have never even thought of tying an Albright without doubling the line.

The only other tests I have done were straight pulls on braid of various types to test various turns in the Biminis.  Despite claims for the 12 turn or fewer knot, 40 turns works best for me.

I don't think you folks over on the other side of the world use Jerry Brown Hollow, so this may prove to be interesting but not very: I found out through an obscure reference on the internet that the manufacturer does not recommend a Bimini in their hollow lines but rather a 7-turn surgeons loop.  I have tied that in some of the YKG as well and have been impressed--however, I have not done any comparison testing versus the Bimini with a scale.  I do intend to do this in the future.  Thanks.

Russ

[Brandon Khoo]

Russ, the FG and PR knot are Japanese knots which were developed to facilitate casting. If you do a search on the internet, you will find how these are tied. It's too hard to describe it!

You'll find most GT fishermen will go with a 60-70 turn bimimi these days. I find the 12 turn bimimi a nonsense even from some very rudimentary testing. Like yourself, my big problem with the albright is slippage. I have found it unreliable in this respect as it is a knot that is very unforgiving if you do not tie it properly. I do like the albright though because of the way which the braid knots around the mono leader.

The one thing I don't like about the Jerry Brown is that it is very thick for its breaking strain. I would be ver intersted though if how it tests.