Double Uni-Knot

A step-by-step guide for tying a double uni knot.

How to Tie a Double Uni

Step 1: Set two lines end to end, overlapping for several inches. 

Step 2: With the first line, make a loop, circling the working end over and around the second line.

Step 3: Wrap the working end around both lines 4 to 6 times.   

Step 4: Pull the tag through the loop, in the same direction as the line is running, tightening the knot.

Step 5: Repeat with the second line.

Step 6: Pull the standing lines in opposite directions and cinch down the two uni knots snug against each other. 

About the Double Uni

A fisherman’s knot, the double uni joins two lines of different strengths or materials. It’s two knots seated against each other and keeps much of the fishing line’s original strength. Plus, it’s easier to tie than other knots for the same purpose. 

The double uni comes from the single uni knot, first published in 1944 and still used today. Savvy knot aficionados will see it used on the reality show River Monsters. While it is most commonly used for fishing, don’t disregard the double uni’s usefulness while camping around the house, or in survival situations.  

Related Knots

Uni knot: the original fisherman’s knot used to attach hooks to the end of a line/ 

Double grinner knot: the British name for the double uni. 

Nail knot: use a nail or tube with an uni knot to tie one line around a second. 

Slim beauty knot: a complex knot for tying together two lines of different thicknesses. 

Blood knot: two lines wrap around each other similar to the double uni but without an initial loop. 

Grapevine knot: use the same steps as the double uni, but with two wraps instead of six. 

When to Use the Double Uni

Whenever you need to join two lines together, you can use the double uni, but it’s most often used when joining uneven lines.

For Survival

Anytime you need to tie two lines together of varying materials or thicknesses, the double uni knot performs reliably. It’s faster and less complicated than other knots for tying in low light or limited vision situations. It’s not the strongest knot of this type, but well-suited for light and medium loads, and adapts to join incongruous lines. 

While Camping

First used as a fisherman’s knot, it works best when tying together lines of different materials. You adjust the number of turns within the knot to reflect the kinds of lines you’re joining. Most knots underperform when joining braided lines with monofilament. With the double uni knot, just add more loops with the braided line (ie, 8), and fewer with the monofilament (ie, 5) to get both knots to hold. 

With Other Knots

The wrapping and cinching method are typical for knots joining lines together. It’s a useful technique to master, before moving on to tie more complicated and stronger knots. 

Around the House

The double uni is strong enough for most projects around the house and DIY solutions. It’s also simple to tie once you’ve practiced a few times. Anytime you have two uneven lines joining end to end, rely on the double uni. Just remember to vary the number of times you wrap the cord to adjust for the difference in size.