Knot testing

This summer, I read the excellent book, Art Scheck's Fly-Fish Better: Practical Advice on Tackle, Methods, and Flies,

and in it he performed some in-depth knot testing. A couple of knots that he said tested strong were the non-slip mono loop as well as the Orvis knot and 16-20 knot. He said the clinch knot and improved clinch knot both faired poorly by comparison. Here is a summary article of his findings (thanks for posting the link to this article, McTage). I decided to verify some of Scheck's tests as well as test a few of my favorite knots. Here are my results from strongest to weakest:

1. Non-slip mono loop
2. Davy knot with an extra turn
3. Davy knot
4. Orvis knot
5. Palomar knot
6. Clinch knot

My methodology:

I tested both 8 lb Trilene XL monofilament and Seaguar Grand Max FX 4x Fluorocarbon Tippet, which is rated at 7.0 lbs. Happily, my results were consistent for both lines. That is, I didn't see any difference in the knots' strength relative to each other, between mono and fluoro. The above list holds for both kinds of line. Scheck asserts that fluorocarbon has much poorer knot strength than mono. I didn't test the strength of equally rated mono vs. fluoro, though I've been very happy with Seaguar so far. I'll tie some knots using each and try to test them head to head someday.

Here's how I performed the tests. Make sure to wear safety glasses!

• I tied knot A to the eye of a #8 hook and knot B to the eye of a second #8 hook.
• I then embedded hook A into a piece of secured wood.
• I then pulled on hook B in a straight line with a pair of pliers.
• I did 10 tests for each knot-to-knot comparison for both mono and fluoro.  I alternated which knot was on the hook being pulled by my pliers. Which knot was on which end made no difference to the results.
• The winner was obviously the knot which held.

By performing lots of head to head tests I saw which knots were stronger relative to the other knots.
I didn't test all knots directly against each other. For example, once it was clear the non-slip loop was stronger than the Davy I only tested the Davy against the Orvis knot.

As you can guess this took a few months of spare garage time to do all this. You get a lot better at tying these knots and tightening them correctly. I found that the non-slip mono loop became much stronger once I got more practice at tying it. At first, the Davy knot often beat the non-slip loop, but once I got better at tying it then the non-slip loop won every time.

What it means:
Well, the Davy knot is about 372% easier to tie than any other knot, and it's clearly stronger than any non-loop knot I tested. That is really cool. I still like to use the non-slip loop most of the time if I have time to tie it because I like using loop knots to allow flies to move more freely. However, in a hurry, darkness, or where a very small knot is useful, the Davy rocks. It's very strong and everyone who uses the clinch knot for fly fishing should immediately start using the Davy knot.

Photo from: http://www.pechetruite.com/Noeuds/Davy-knot.htm

A note on the Davy knot. To tighten it, wet it, pull it mostly tight from both ends, but perform the final tightening by pulling the standing end. Don't finish the tightening by pulling the tag end. Pulling the standing end seats it properly. This is especially important when tying the Davy knot with an extra turn. I'll post pics of the "extra turn" Davy knot. You'll know you got the "extra-turn" version right when it tightens at the end with a little "click" like the 16-20 knot.

Someday I'll do some tests in stronger line, but I believe the results will be consistent in lines up to 15 lb. test. Also, I didn't test the 16-20 knot effectively since it was such a pain to tie that I couldn't see myself using it on a river. I'll report back once I do some trials with that. It lost to the Davy and non-slip loop knot in my few trials but I think I was tying it poorly.

One final note on knot tying. Make sure you wet the knot. Seaguar, the world's largest fluorocarbon manufacturer, even states this on their web site. So, if they say it, I would believe them. I wet all my knots and it makes a difference. I think you can get the knot tighter so it doesn't slip once you actually have a fish on. A partially tightened knot is going to be a weaker knot since it may not tighten how you want it to when it is challenged.

Still on my todo list is to test the Davy knot with extra turns, test the 16-20 knot, and to test tippet-to-leader knots.

10-24-11 Update

- I've tested the Davy knot using 2 extra turns instead of one and it breaks easily. The knot is hard to tighten with the extra line in it. One extra turn is the magic ingredient. More than that is junk. The original Davy with no extra turns is still an excellent knot, and only slightly weaker than the extra turn version.

- I'd also like to test the 16-20 knot when I get time. However, Art Scheck has shown that it breaks more often than the Orvis knot in head to head tests. Since the Davy beats the Orvis every time that's enough evidence for me that the Davy would beat the 16-20.