Initially developed to hold the two sides of a suture closed while the surgeon completed the stitch, the Surgeon’s Knot quickly gained popularity among anglers. Very easy to tie even with cold, wet hands, the Surgeon’s knot is ideal for joining lines of different diameters and/or materials.
Often tied with two twists, the addition of a third will dramatically increase this knot’s integrity in all line types.
Table of Contents (clickable)
How to Tie the (Triple) Surgeon’s Knot
- Overlap the ends of the two lines you wish to join.
- Make a small loop with the two lines.
- Run the tag end around the loop for three turns.
- Wet the knot and carefully cinch it down. You’ll want to pull on all four strands evenly to ensure integrity - and then test before using!
Why Rely on the Surgeon’s Knot?
- Strong - The Surgeon’s Knot is very, very strong when tied properly, especially in similar or identical lines.
- Fast - I’m not sure there’s a faster knot out there, especially in real-world conditions. Wet hands, cold hands, rocking boat, fish slime, or blood--no problem!
- Easy - Tying the Surgeon’s Knot is a little easier than tying your shoelaces! Anyone can quickly learn to tie this knot well.
What’s Not to Love About the Surgeon’s Knot?
The Surgeon’s Knot has been with us for a while, and it’s won a devoted following for its strength, ease, and speed. There are other knots that can join dissimilar diameter lines, but none that are faster or easier to tie in the real world.
But it does have some issues.
Perhaps the most important potential problem is that, according to experts like Brant Oswald, a fly guide and instructor, “If one strand cuts across the other as the knot rolls over into the figure 8 as it is tightened, the knot will be quite weak, and it is not due to any error on the part of the angler tying the knot.”
For that reason, you should always test your Surgeon’s Knot before using it.
The second issue is that while you’ll often hear it advertised as a “100% knot,” that’s only true under two conditions. First, that it doesn’t cut across itself during cinching, and second, that it’s used to join very similar line diameters.
But the Surgeon’s Knot and its many extra turns are nowhere near 100% when the lines vary in size. Indeed, careful testing by Field & Stream revealed that, when tying 10-pound Seaguar InvizX fluorocarbon to 10-pound Trilene Big Game monofilament with a Triple Surgeon’s knot, integrity was compromised at around 6 pounds or 65% of the line’s rated test strength.
When the Surgeon’s knot is applied to a fluoro-to-braid connection--say 10-pound InvizX fluorocarbon and 30-pound FireLine Braid--knot integrity (Quadruple Surgeon) failed at 80%.
That’s a darn good number given the materials involved!
Ultimately, however, there can be stronger knots for joining lines of dissimilar size: the J Knot or the Palomar to swivel to Palomar - but there are none faster or easier to tie.
Whether you choose the Surgeon’s knot or not is up to you and how important speed and ease are when you need to make a decision.
The Surgeon’s Knot in Braid and Fluorocarbon
Nylon monofilament has what engineers call a high coefficient of friction, meaning that it likes to grip and bite against itself. That makes it relatively easy for knots to hold in this material, and as you’d expect, the Surgeon’s Knot holds well in mono, especially when the lines are of similar diameter.
Fluorocarbon is much like mono in terms of its friction against itself, and it really likes to bite. But rarely, if ever, will you need to join fluoro to fluoro; it’s far more likely that you’ll be using a fluorocarbon leader on braid or mono and that these will be of vastly different diameters.
And that’s where the Surgeon’s Knot shines!
Despite the fact that braid is as slick as a seasoned politician at a fundraiser, adding loops to the Surgeon’s Knot--up to four--will improve its ability to hold. Mono and fluoro to braid connections can be very strong with a well-tied Quadruple Surgeon, and I recommend making the extra two loops with any superline.
When Do Surgeon’s Knots Fail?
The Surgeon Knot, especially with three or four turns, is very strong and reliable, but it can fail. The most likely culprits are:
- Tying your knot with frayed or damaged line - Damaged line will definitely compromise knot integrity. Always check your line for fraying, abrasion, and nicks.
- Not wetting the knot before cinching - Don’t skip this step! Spit or water helps lubricate the line, allowing it to slide into place and form a tight knot.
- Strands cutting across themselves during cinching - During cinching, if equal pressure is not applied to all four ends, the ends can cut across one another and cause knot failure. This can happen even if you do everything right, so always check your Surgeon’s Knot before you trust it!
- Radically different line diameters - The Surgeon’s Knot is designed to handle a lot of difference, but joining 30-pound braid to 80-pound fluorocarbon might be too much even for it.