The strongest way to attach a saltwater leader to a fly line is a loop-to-loop connection built off a whipped loop, which in my test held to 33.7 pounds and broke outside the knot, beating a nail knot with a figure-eight lock that broke inside itself at 30.4 pounds. In this How 2 Tuesday I bring Knot Wars to saltwater fly fishing and put these two fly-line-to-leader connections on the scale.
Listen now: press play in the player above and follow along.
In this test the whipped loop with a loop-to-loop connection was stronger. Using the same fly line and 50-pound leader, the nail knot with a figure-eight lock broke inside the knot at 30.4 pounds, while the whipped loop held to 33.7 pounds and broke out in the line rather than at the knot. Because the whipped loop did not fail at the connection, it is actually stronger than 33.7, which made the loop-to-loop the clear winner for the day.
It is a nail knot reinforced so it cannot strip the coating off your fly line. I tie a nine-turn nail knot clamping the leader onto the fly line, then add a figure-eight knot on the other side, snugged right against it. The nail knot grips the coating and the figure-eight knot locks everything together, so the connection has to do far more than just slip off the PVC coating to fail.
Because a fly line is usually a core with a slick PVC or plastic coating over it, and a nail knot that only clamps down on that coating can strip it off under heavy load. You set up on a tarpon, fight it for a second, and the leader, the fly, and a stripped section of coating all come back to you. Adding a lock, like the figure-eight, guards against that by giving the connection something more than coating to hold onto.
For testing and for fishing I like a surgeon's loop because its tag end runs parallel to the line, so it feeds smoothly through the guides. A perfection loop is strong and I like it for strength, but it has a 90-degree tag end that hangs up in the guides. Some anglers coat the loop with epoxy to form a smooth bubble that runs even better, though you will not always have that option rigging on the boat.
Often it does not change your day, as long as the connection is stronger than your tippet. If your fly-line-to-leader connection holds 33.7 pounds and you fish 20-pound tippet, it will always break in the tippet, which is exactly where you want it to break so you do not lose your whole leader. Once both options clear your tippet by a wide margin, you choose based on how well the connection runs through the guides, how fast you can tie it, and which you trust.
Because where it breaks tells you the real strength. The nail knot with a lock broke inside the knot at 30.4 pounds, so that number is its true ceiling. The whipped loop broke out in the line at 33.7 pounds, meaning the knot itself never failed and is stronger than the reading. Watching the failure point keeps you from underrating a connection that is actually holding more than the scale shows.
Knot Wars is back, and this time I am taking it into saltwater fly fishing. One of the most important connections in this whole game is how you attach your leader to your fly line, and a lot of anglers coming over from the trout world have never tied a connection strong enough to handle the pressure we put on tarpon, sailfish, marlin, or sharks. Get it wrong and you set up, feel the fish for a second, and lose the fly, the leader, and a stripped strip of your fly line coating.
The first connection is a nail knot with a lock: a nine-turn nail knot clamping the coating, plus a figure-eight knot snugged against it so the thing cannot simply strip off. The second is a whipped loop, where the line is formed into a loop with a nail knot and then joined to the leader with a loop-to-loop. Both are streamlined enough to run through the guides, and plenty of people will argue the loop-to-loop is the better connection. I wanted to actually test it.
I ran both with the same fly line and 50-pound Daiwa J-Fluoro. The nail knot with a lock broke right inside the knot at 30.4 pounds. The whipped loop held to 33.7 and broke out in the line, not at the connection, so it is actually stronger than that number. The loop-to-loop is the winner for the day: smooth through the guides and very strong. If you fish 20-pound tippet, it will always break in the tippet, which is exactly where you want it. The full test is in the episode above.
Watch or listen above to get the full breakdown in my own words.
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.
I'm Tom Rowland, a lifelong fishing guide, tournament angler, and the host of the Tom Rowland Podcast. I spent decades guiding in the Florida Keys and competing at the highest levels of saltwater fishing, and I've fished everywhere from the Seychelles to Louisiana. How 2 Tuesday is my weekly tutorial series where I pass along the skills, gear choices, and small refinements that have made the biggest difference in my own fishing.
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