The blood knot is a line-to-line connection used to tie two pieces of leader together, ideal for trout, tarpon, and bonefish leaders and for joining fluorocarbon to fluorocarbon or monofilament to monofilament. It is easy to tie and a reliable way to build a leader. On this How 2 Tuesday I walk through tying it step by step, then test it on 15 pound to 20 pound fluorocarbon, breaking it three times to get an honest average of its strength.
Listen now: press play in the player above and follow along.
The blood knot is used to tie two lines together. It is a good choice for trout leaders, tarpon leaders, bonefish leaders, or any time you want to join two pieces of line. It works for fluorocarbon to fluorocarbon and monofilament to monofilament. In this episode I tie 15 pound fluorocarbon to 20 pound fluorocarbon. It is a fundamental leader-building knot, easy to learn, and one of the standard ways anglers connect two sections of line into a single tapered leader.
Cross the two lines to form an X. Wrap one line four times up and bring the tag end back through the hole in the middle. Then wrap the other line four times back and pass that tag end through the opposite direction from the first. Moisten the knot, pull it tight, and trim the tag ends. That is the whole knot. It is genuinely easy to tie once you have done it a couple of times, which is part of why it has stayed a leader-building standard for so long.
In my test on 15 pound to 20 pound fluorocarbon, the blood knot averaged 9.95 pounds, which is 66.3 percent breaking strength. I broke it three times to get that average: the first at 9.14, the second at 11.27, and the third at 9.46, so it is not the strongest connection out there, retaining roughly two thirds of the line's strength, but it is a clean, low-profile, easy-to-tie knot that performs consistently enough for building leaders where that smooth join matters more than maximum strength.
I tied identical knots in the same fluorocarbon and broke it three times. The first break came at 9.14 pounds, the second at 11.27 pounds, and the third at 9.46 pounds, for an average of 9.95 pounds. Against the line that works out to 66.3 percent breaking strength. Testing three times and averaging is important because any single knot can pull down a little differently, so three breaks give a more honest picture of what the blood knot actually delivers than one pull would.
In this test I used four wraps up with the first line and four wraps back with the second line before passing the tag ends through in opposite directions. Four turns per side is a common, reliable count for fluorocarbon in this range. The key details beyond wrap count are crossing the lines into a clean X, bringing each tag end through the center, moistening before you seat it, and pulling it tight evenly so the wraps draw down smoothly against each other.
The blood knot ties two lines together, and it is a good way to do it for trout leaders, tarpon leaders, bonefish leaders, any line you want to join. It handles fluorocarbon to fluorocarbon and monofilament to monofilament. Today I am tying 15 pound fluorocarbon to 20 pound fluorocarbon. It is a leader-building staple. I explain where it fits in the episode, so press play in the player above.
Here are the steps I walk through in this How 2 Tuesday. I cover the detail behind each one in the episode.
I unpack each of these in the episode. Press play in the player above.
It is easy. Cross the lines into an X, wrap four times up and bring the tag through the hole, wrap four times back and pass the other tag through the opposite way. Then moisten, pull tight, and trim. That is the whole thing, and once you have tied a couple it goes fast. I walk through each move in the episode, so press play in the player above.
I broke the same knot three times in the same fluorocarbon: 9.14, then 11.27, then 9.46, for an average of 9.95 pounds. That is 66.3 percent of breaking strength. Testing three times matters because any one knot can seat a little differently, so the average tells the real story. I read the numbers in the episode, so press play in the player above.
The blood knot is easy to tie and dependable for building leaders, averaging 9.95 pounds, about 66 percent breaking strength, on 15 to 20 pound fluorocarbon in this test.
It will not out-pull every connection, but for a clean, low-profile join on trout, tarpon, or bonefish leaders it earns its place. Press play in the player above to watch me tie and test it.
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.
blood knot · trout leaders · tarpon leaders · bonefish leaders · fluorocarbon · monofilament · Knot Wars · 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.
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