The Uni Knot may be the most versatile fishing knot there is. Let’s make believe the orange line is monofilament, fluorocarbon or braid and the carabiner is the eye of a hook. Insert the mono down through the hook eye and bring it underneath and parallel to the running line. Then, bring the tag end over top of the two lines, near the hook eye to form a loop that looks like this. Remembering this configuration is probably the most difficult part of learning to tie a Uni knot. But, with just a little bit of practice, it will become second nature.
Now, get hold of the loop with your left hand and the tag end with your right, and start wrapping the tag end around the two lines. I like to do a minimum of five turns, I think seven might be ideal. But, honestly I’ve had as few as 2 wraps actually hold quite well.
With the wraps complete, pull on the tag end to draw the knot closed. You can also close it down by pulling on one of the legs of the loop. This will help to keep the tag end fairly short. It’s a good idea to lubricate the knot before drawing it down really tight. Once you have the knot tightened almost all the way, pull on the running line to begin closing the loop. In the end, the knot should rest tight up against the hook eye. You can then snip the tag end off fairly close. And that’s the most common application for the Uni Knot.
Unlike many other knots, the Uni Knot can also be tied without anything attached. The tag comes back under and parallel, it’s taken over top to form a loop and then it’s wrapped around the two lines five times. You can then lubricate the knot and draw it tight to form a nice neat loop. This comes in really handy especially when attaching a dropper off of a hook bend.
Yet another use for a Uni Knot is to attach two lines together, similar to doing a blood knot or a double surgeon’s. Just run the two ends of the lines past each other and parallel, then loop the tag end on the right over as you did before and start making your five wraps. When these are completed, lubricate and draw that knot tight. Then, flip the whole mess around and repeat the procedure with the tag end of the other line segment. Although it looks a little more complicated, I find a double Uni Knot like this far easier to tie than a blood knot. Once you have both Uni’s looking good, pull in opposite directions on the line segments to bring the two knots together. I’ve also found the double Uni works better than other knots when attaching lines of different compositions or diameters.
Here’s what a basic Uni Knot looks like with a more realistic hook eye and monofilament. Run the mono down through the eye and bring it back underneath and parallel to the running line, then back around to form a loop with the tag going over top of both lines. Start wrapping with the tag around these lines. Again, 5-7 turns are usually plenty. Lubricate the knot and draw it down tight to form a loop. Then pull on the running line to close that loop down at the hook eye. It’s a good idea to leave just a little bit of a tag to accommodate any knot slippage. When tied correctly, a Uni Knot up close should look something like this.
Like before with the heavier line, you can do a Uni Knot without attaching it to a hook. Use the same exact procedure, making sure to lubricate the knot well before drawing it down tight. The result is an infinitely adjustable loop that can be attached to just about anything.
As I said earlier, I find tying a double Uni Knot to be easier than a blood knot. I also find it somewhat more reliable than a double surgeon’s, particularly with differing line diameters.
Snipping off the tag ends close can be a little tricky because they run parallel to the line and knots, as opposed to at 90 degrees like on a blood knot. But usually it’s not a big obstacle to overcome. I’m sure you can do better than I did here.
The Uni Knot has been my knot of choice for most angling applications, for almost 50 years.