On Tom Rowland Podcast Episode 53 (How 2 Tuesday #16), I show you how to tie a bonefish leader from scratch using Lefty Kreh's rule of halves. Instead of buying a pre-tied or knotless tapered leader, I build one from fluorocarbon using a simple tapering formula, blood knots between each section, and a double surgeon's loop at the butt end. It is the same system I use for bonefish, redfish, trout, and general saltwater fly fishing, and it means you can always rebuild a leader on the water when yours gets beat up.
Listen now: Spotify · Apple Podcasts · or press play in the player above.
I build my bonefish leaders from scratch using fluorocarbon and a tapered formula rather than buying a pre-tied leader. The setup works for bonefish, redfish, trout, and general saltwater fly fishing. I prefer fluorocarbon because it sinks and disappears better, and I match the butt section to my fly line. I walk through the exact materials in the episode.
A nine-foot leader is about average and a good general starting point for bonefish. In the episode I also build a thirteen-and-a-half-foot leader using the same formula for situations that call for more length. The length you choose comes down to conditions and how spooky the fish are that day.
I call Lefty Kreh's formula the rule of halves. You start with a butt section, then each following section is half the length of the one before it as you taper down in diameter, and the final tippet section doubles back to a longer length. For a nine-foot leader I start with four feet, then two feet, then one foot, then double to two feet of tippet.
I use two knots for this leader. A blood knot connects each tapered section to the next as the diameter steps down. A double surgeon's loop goes on the heavy butt end so I can make a loop-to-loop connection to the welded loop on my fly line. I explain how to tie both in the episode.
I prefer fluorocarbon for my bonefish leaders, though monofilament will work. The detail that matters most is not the material, it is matching the diameter and flexibility of your butt section to your fly line. Pound test is secondary to diameter, so I look for line that is similar in stiffness and thickness to the tip of my fly line.
I look for fluorocarbon or mono that is similar in diameter and flexibility to my fly line rather than picking a pound test first. For a nine-weight line that is often around fifty- or sixty-pound test depending on the manufacturer, and for a six-weight it might be closer to forty. The goal is a butt section that turns the leader over smoothly.
Here is the rule of halves I use every time I build a saltwater leader from scratch. I walk through it in full in the episode, so press play in the player above and tie along.
I cover both a nine-foot and a thirteen-and-a-half-foot example with the exact pound tests in the episode. Press play in the player above.
The mistake I see most often is grabbing a spool of heavy fluorocarbon and assuming the pound test is what makes a butt section work. It is not. What actually turns a leader over is matching the diameter and flexibility of that butt section to the tip of your fly line. A nine-weight line wants a thicker, stiffer butt than a six-weight does. I explain how I pick that match by feel and by diameter in the episode, and why I let pound test come second. Press play in the player above.
There are only two knots in this system, and neither one is complicated once you have done it a few times. The blood knot joins each tapered section to the next as the line steps down in diameter, and the double surgeon's loop sits on the heavy butt end for a clean loop-to-loop connection to your fly line. If you have never tied a blood knot, hearing me walk through the rhythm of it is easier than reading a diagram. I also point to a companion video in the show notes. Press play in the player above.
This is really the whole reason I recorded the episode. Knowing the formula before your leader gets chewed up is the difference between rebuilding in five minutes and losing an hour of fishing. I have watched it play out on my boat more times than I can count, where the bonefish are right there and somebody has no spare leader and no idea how to build one. The rule of halves lets you make a leader from whatever spools you have in your bag. Listen to the full walkthrough in the player above.
This is one of those skills that separates someone who fly fishes from someone who is ready to fly fish. When you can build a leader from scratch, you are never dependent on a tackle shop or a pre-packaged leader to have a good day on the water.
Lefty Kreh's formula works because it is simple, and it carries across bonefish, redfish, trout, and any species where you need a leader that turns over well. I kept this one short on purpose. Ten minutes, and you have a system you can use for the rest of your life. Practice those knots, and I hope you catch bonefish. Press play in the player above.
Lefty Kreh · the rule of halves · fluorocarbon leader material · monofilament · blood knot · double surgeon's loop knot · welded loop fly line · bonefish leaders · redfish leaders · saltwater fly fishing · How 2 Tuesday
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 professional fishing guide based in the Florida Keys, host of the Tom Rowland Podcast and the Saltwater Experience TV show. On the podcast's How 2 Tuesday series I break down one practical fishing skill at a time, from knots and leaders to casting, gear, and tactics, in short focused episodes you can put to use the next time you are on the water.
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