The double uni knot is a bit of a misnomer because there is a version of the uni knot where you double the line and tie a uni knot and it is also often called the double uni knot. But for our purposes, the double uni knot will be two individual uni knots used for attaching two fishing lines together like a braided line and a fluorocarbon leader. This is technically two uni join knots and is also known as uni to uni knot. This knot makes a solid connection with a lot of knot strength. It’s a big bulkier than your FG knot or Alberto knots. But it’s highly effective.
We’ll discuss the steps on how to tie the double uni knot.
How to tie the double uni knot
Start by overlapping the tag end of your braid and your fluorocarbon several inches. Now create a loop with your braid that you can wrap the tag end around the two lines inside of the loop.
Tie a simple uni knot by wrapping your line 4 times inside the loop you created. Pull your braid tag end tight to hold the knot in place as you create a loop with your fluorocarbon along the braided line.
Wrap your fluorocarbon around the braid and itself 4 times inside your fluoro loop.
Pull the fluorocarbon tag end and snug the knot down. Now pull each main line to slide the two knots together. Pull firmly on each tag end again and then pull firmly on each mainline to finalize the knot.
When to use a double uni knot
Different diameter lines may require experimenting with more or less wraps and getting a nice solid connection between the two uni knots. The nice thing about a uni knot is you can tie it with as many or as few wraps as you like. With larger lines, you don’t need as many wraps. Often 3 will do. With smaller lines, 4 should be the minimum.
The double uni is great when you need a strong connection and don’t mind a little bit larger knot. It works great with thicker short leaders like guys might put on heavy braid with a topwater or heavy braid with a swimbait. It works for smaller diameter and finesse applications as well.