If you fish enough to wear out a fly line over the course of a season, you should absolutely tie a leader to your fly line with a nail knot. The result is a smooth connection that will not only slide through your guides with ease, but also facilitate the best transfer of energy. In other words, casts and presentations will be optimal because there is no hinge point between your line, leader, and fly.

However, if your fly lines last a few seasons or are used in a variety of situations, you’re better off with a loop-to-loop connection. These systems allow for replacing leaders, adding poly-leaders, and making quick  crisis management. If you’re prepared, fishing with “loops” means  no complex knots while on the stream.  All you have to do is thread a leader through two small loops and you’re ready to fish.

But not all loops are created equal. A bad loop will effect your cast and/or presentation. A bad loop will get hung up in your guides, leading to lost fish or damaged equipment. A good loop is a simple and great thing.

Also, I think this is important to mention: With minimal effort you can do better than tying your line and leader together with an overhand knot. I’ve seen it countless times. And I’ve heard the justification of “it’s easy and it works.” But your casting and fishing will benefit from a little extra work. Really, all you need is a few minutes and the knowledge of a simple knot.

Whether you are buying a new line or making a repair, it is worth considering how you’re going to attach your leader. Here are my thoughts on four common loop-to-loop methods:

Welded Loop

This is now the industry standard; a factory-made loop  at the terminal end of your fly line. But all aren’t created equally. Larger loops seem convenient, but aren’t good for flowing through your guides. It isn’t during casting that it is an issue, either. The problem can arise when you’ve bought a fish in and then it makes a run.

Loops that are too big, too rigid, or seem to sink quickly are worth cutting off. Otherwise, fish until it wears out.

Braided Loop

These Chinese finger trap-looking accessories were the normal quick fix a generation ago. For most trout and light-line applications they work just fine.

But they require heat to affix. It is easy to damage the braided loop itself or the line. Also, they don’t float well. For finesse presentations, they are a liability.

Nail Knot, Looped Line

This is a great way to create a welded loop on a line that doesn’t have one. Double the line over on itself and tie a long nail knot with backing. Take a long time to make sure the wraps are lined up perfectly when tightened. Then, apply some material-safe sealant. Test the strength after it dries, and you’re good to go.

To make a smooth loop under the knot, cut the tip of the line at a diagonal. This way, the terminal end tapers down flat as it is doubled over.

Nail Knot, Mono/Fluoro

This is my favorite approach (outside of a good, factory-made welded loop). Using heavy monofilament or fluorocarbon, take the time to tie a foot-long section to the end of your line with a perfect nail knot. Perfect: smooth, lined up, and pulled tight into the line without cutting it. Then, tie a small loop in the leader material a few inches away from the nail knot. This creates a good transition between the materials and diameters.

Gear Worth Having

• Knot Tool: I like the Loon Ergo Knot Tool. It fits in my hand better than anything I’ve bought or made.
• UV Resin: Knot Sense, from Loon, is an excellent way to add some smoothness and protection to these pivotal knots.

Things Worth Doing

• Check: Look for cracks where the line is doubled over, where the knots are cinched, and where the knot ends.
• Clean: Get the grit and grime off the end of your line – any texture will attract gunk.
• Learn: If you have questions, go to the fly shop. They know what they’re doing. If they’re worth anything, they’ll take the time to show you.