Blood Knot vs Surgeon's Join Knot
The Blood Knot is the classic — slim, elegant, ideal when both lines are similar diameter. The Surgeon's is dramatically easier to tie and works on lines of 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.