Blood Knot vs Surgeon's Join Knot
The Blood Knot is slim and elegant when both lines are similar diameter. The Surgeon's is dramatically easier to tie and works on any diameter.
Side-by-Side Comparison
| Blood Knot | Surgeon's Join Knot | |
|---|---|---|
| Overall Strength | 90% | 95% |
| On Monofilament | 90% | 95% |
| On Fluorocarbon | 88% | 93% |
| On Braid | — | 88% |
| Tying Time | 60 sec | 30 sec |
| Difficulty | Intermediate | Beginner |
| Best For | Joining mono or fluoro lines of equal diameter | Quick line-to-line — easiest joining knot |
| Video Tutorial |
Use the Blood Knot when:
- You're joining two lines of equal or very similar diameter
- You want the slimmest line-to-line profile (best through fly rod guides)
- You're fly fishing where a clean leader connection matters
Use the Surgeon's Join Knot when:
- You're joining lines of different diameters (e.g., 30-lb mono to 12-lb tippet)
- You're new to line-to-line knots — the Surgeon's takes 30 seconds to learn
- You need to tie on the water in poor conditions
- You're joining mono to fluoro or any mixed-material connection
The Verdict
The Surgeon's Knot is the better choice for most anglers most of the time — it's faster, easier, and works on lines of any diameter. Save the Blood Knot for fly fishing leader connections where a clean profile matters.
Blood Knot Tutorial
Surgeon's Join Knot Tutorial
Frequently Asked Questions
They're roughly equal in strength (~90-95%) when tied correctly. The Surgeon's actually edges out the Blood Knot when joining lines of different diameters.
It's literally just a double overhand knot — you tie an overhand knot with both lines together, pass the lines through the loop twice, and pull tight. The Blood Knot requires interleaved wraps that take practice to master.