The nail knot with a lock is a fly line to leader connection where you tie a nail knot and then add a figure-eight lock behind it, so the knot will not slip when you are fighting big fish. On this How 2 Tuesday I tie the nail knot with a lock for fishing big fish like tarpon, then test it. A plain nail knot can slip under heavy pressure, and the lock is meant to stop that. Here is how to tie it and what the test showed.
Listen now: press play in the player above and follow along.
A nail knot with a lock is a standard nail knot connecting your leader to the fly line, with a figure-eight knot added behind it as a lock. When you are fighting really big fish, a plain nail knot will oftentimes slip, so the lock holds it in place. The lock is the figure eight, and I use a figure eight rather than an overhand because the figure eight will not come untied.
In my test the nail knot with a lock broke at 28.58 pounds, which was slightly disappointing, and it broke within the knot itself. That is the 50-pound butt section to an 11-weight fly line. It is more than you will exert on a tarpon, and it is a slightly smoother connection through the guides, but the loop-to-loop with the welded loop is much stronger.
I use a figure eight for the lock because the figure eight will not come untied. Some people just do an overhand there, but I have had overhands come untied, so I started doing a figure eight a long time ago. You tie it tight up against the nail knot lock, seat it, then trim, and you have a secure lock that stays put.
The loop-to-loop with the manufacturer's welded loop is stronger, but when you tie a loop in the leader and connect it loop-to-loop, that knot can stick going in and out of the guides. The nail knot with a lock gives you a smoother connection that slides through the guides better. It is the dilemma: a little less strength for a cleaner pass through the rod.
There is no set pound test for the butt section of your leader, but you want it similar in diameter and stiffness to your fly line so the energy transfers smoothly. I used 50-pound J-Fluoro to an 11-weight, 50-pound fly line, which is about the same, then tapered down from there for a nice smooth transfer of energy on the cast.
This may be the better knot in certain situations, where the stronger loop-to-loop causes problems going in and out of the guide. That is for you to decide based on your setup. I keep a free knot guide at tomrowlandpodcast.com with this knot and every other one I have tested so you can pick the one that works best for you.
When you are fly fishing for tarpon or offshore fish you really have to pull on, every connection from the backing to the fly matters. A plain nail knot can slip under that kind of load, so I add the lock. I explain where it fits in the episode, so press play in the player above.
I walk through each of these in the episode. Press play in the player above.
The lock is a figure eight, not an overhand, because I have had overhands come untied on me. The figure eight stays put. That small choice is the difference between a lock that holds and one that quietly fails. I show how I seat it in the episode, so press play in the player above.
It broke at 28.58 pounds within the knot, less than the welded loop's loop-to-loop, but it runs through the guides much more smoothly. That is the real dilemma, strength versus a clean pass through the rod. I break it down in the episode, so press play in the player above.
The nail knot with a lock is not the strongest connection on the tester, but it is smooth through the guides and the figure-eight lock keeps it from slipping. In the right situation it beats the stronger option that hangs up in your guides.
That is exactly why I tie and test so many of these, so you can pick the best knot for your setup. Grab the free knot guide at tomrowlandpodcast.com. Press play in the player above.
How 2 Tuesday is my weekly series where I break down one fishing skill at a time, from knots and casting to gear, tactics, and the habits that make you a better angler. Watch and listen to every How 2 Tuesday episode from Tom Rowland.
Nail knot with a lock · nail knot · figure-eight lock · fly line · J-Fluoro · Tie Fast knot tool · tarpon · welded loop · loop-to-loop · Danco pliers · How 2 Tuesday · Saltwater Experience
I'm Tom Rowland, a professional fishing guide based in the Florida Keys, host of the Tom Rowland Podcast, and the longtime host of the Saltwater Experience television show. On the podcast's How 2 Tuesday series I break down one practical skill or lesson at a time, from fishing technique and gear to the habits that make you a better angler, in short, focused episodes you can put to use right away.
Subscribe to get the latest episodes, show notes, and exclusive content delivered straight to your inbox.