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How To Knots

Best Fly Fishing Knots

by Ross Purnell, Editor   |  May 17th, 2016 0
Best Fly Fishing Knots

Joining your backing, fly line, leader, tippet, and fly into one strong system is your key to landing trophy trout like this one. This large black/chartreuse streamer was connected to the tippet using a no-slip loop knot to allow for maximum movement. Photo | Grace Smith

The best knots to create a seamless system from your reel to the fly

There is a school of thought that proclaims knots are a major obstacle to participation in fly fishing. Eliminate the knots—they say—and more people would enjoy this wonderful sport.

“Hogwash,” I say. Knots are as integral and important to fly fishing as they are to Boy Scouts, rock climbing, and sailing. Can you imagine anyone saying “I’m not getting into yachting because there are too many knots!”

The reality is that knot tying is a skill with some degree of inherent satisfaction, just like casting or tying flies. While tying a Bimini twist, or a Duncan loop, isn’t as exciting as landing a large tarpon, or fooling a brown trout sipping from the surface, it’s all part of the wonderful, complex world of fly fishing. If you wanted it to be simple, and easy, you wouldn’t be reading this right now. What makes fly fishing so fascinating is the many interlocking facets, and the depths to which you can plunge into every single discipline.

Skin the Cat

Your backing, fly line, leader, tippet, and fly are all one continuous system, but unless you buy a preassembled package, each independent part must be connected by a knot.

Fly line companies have gone a long way toward making connecting the pieces much easier by selling lines with loops, but even so you’ll still need to know some knots. And by “know” some knots I don’t mean you’ll have to memorize 20 different knots.

The knots you use to add a tippet, or tie on a fly, you’ll have to know by rote, but many other knots can be tied using a reference. It doesn’t make you less of a fly fisher if you need to look up a lesser-used knot like an arbor knot from time to time—just as a refresher. And it’s always fun to try new knots. Over time, you’ll find some knots are easier than others, or you’ll find new ways to tie old knots—for examples of this, see the speed blood knot or the sheet bend illustrations in this article.

As the old adage goes, “there are many ways to skin a cat,” and there are also many ways to connect all the pieces of your fly line system—here are my preferred methods, and the reasons behind them.


Let’s start with your backing because if you are at home right now, starting with an empty reel, that’s the item you need to deal with first. The backing literally “backs you up” if you hook a large fish that takes out more than about 100 feet of line. In trout fishing, this is a rare event, but it can happen if you are in a big, fast river, and/or you are using small flies or very light tippet.

In any event, you require backing to fill up the extra space in your reel, as your reel is designed to hold a fly line plus a certain amount of backing.

Even if you don’t plan on catching anything larger than panfish, you must fill the reel arbor with the appropriate amount of backing. Otherwise your fly line will be coiled too tightly around the narrow spindle, and will be difficult to straighten and use effectively.

Many reels have a mark on the inside of the spool frame to indicate how far to fill your reel with backing. If not, fill it to about a third or half full. (Usually 100 to 150 yards of 20- or 30-pound-test Dacron for most trout reels, and more than 250 yards of backing on large saltwater reels used for tarpon, billfish, or other large fish.)

It’s a good idea to buy your backing and fly line at a specialty fly shop, not only because the employees there can advise you on the best line for your local conditions, but because they have a line winder that spools exactly the right amount of line onto your reel effectively and quickly. They’ll charge you for the backing of course, but they won’t charge you for the service.

Winding backing onto a reel is time-consuming (150 yards at one inch per crank), and the backing must be wound tightly and evenly, back and forth across the width of the reel arbor. If you wind loose coils of backing near the base of the arbor, then wind tighter layers on top (such as when you land a large fish, or merely when you complete the job of winding the backing onto the reel) then the tight coils bury themselves under the loose coils, creating a snarl that jams your reel. Wind your backing onto the reel properly to avoid problems later.

If you can’t have a fly shop put backing on your reel, you can do it yourself but you should exercise great care in doing it right. First, it’s easiest to wind the backing if the reel is attached to the rod butt, so attach your empty reel to the rod in the position you intend to crank. If you cast with your right hand, you’ll probably want to crank counterclockwise with your left hand, so lock your reel onto the reel seat with the reel handle facing to the left.

Take the end of the fly line backing from the ­product spool, thread it through the rod’s stripping guide, through the reel line guard, around the spool arbor, and back out through the line guard. This is when you use an arbor knot to attach the backing to the reel spindle.

To ensure that you wind the backing under tension, have someone run a pencil through the backing spool and hold the ends of the pencil so the spool turns freely. As you wind it onto the reel, the backing should pass between the pages of a phone book or under your stocking foot to create tension. I recommend running the backing through a folded towel. Then you can step on the towel to create the tension you need to wind the backing tightly.

As you crank the reel to wind the backing, move the backing back and forth across the width of the spool so it winds evenly and does not pile up on one side of the spool or the other.

Fly line

Most top-end fly lines today come with a welded loop at the front and back. I’ve heard some old-timers say they cut the loops of their lines, but this begs the question, “Why did they pay the extra money for a fly line with loops in the first place?”

You pay a premium for a line with loops, and the loops are strong enough to land any trout that swims. I’ve landed tuna and tarpon on welded loops and have never had the front loop break on a fish.

To attach the fly line to your backing, tie a surgeon’s loop or double
surgeon’s loop in the end of the
Dacron backing. Make sure the loop is large enough to pass the line spool through it.

To connect the two loops, pass the large backing loop through the small loop in the fly line end and then pass the whole fly line spool through the backing loop to create a loop-to-loop connection. Make sure your loop-to-loop connection is seated correctly. The loops should lock together like a reef knot (square knot); otherwise the connection is bulky and won’t easily pass through the rod guides.

If you have an older or value-priced fly line, you may not have a welded loop at the end and you’ll need to tie a nail knot to connect the fly line to the backing. The nail knot is strong enough to hold most freshwater fish, but you may want to coat the knot with Dave’s Flexament or Softex to make the junction extra smooth.

You cannot use the loop-to-loop method with thin, gel-spun polyethylene backing as under pressure it will cut through the welded loop of the fly line. If you are just getting started in fly fishing, use Dacron backing. It’s cheaper, and easier to work with.


Once your line-to-backing connection is complete, the next step is attaching the tip of your fly line to the leader—typically 7 to 12 feet of tapered monofilament, which eventually joins your tippet and fly.

As I mentioned previously, most fly lines have a loop on the tip, and knotless tapered leaders also have a loop, making it easy to connect the two. Pass the loop in the leader butt through the fly line tip loop, then pass the leader tip through the leader loop. It’s also important here to seat the loops correctly so they form a compact square knot.

If your line has no loops, there are many options to connect the leader. The most common method is a nail knot, but an easier alternative I’ve been fond of recently is the sheet bend, also known as the weaver’s knot, LAP knot, or flag knot. I learned this knot as a Cub Scout when I was 10 years old. To earn my knot-tying badge, I not only had to demonstrate the knot, I had to explain its uses, which included “tying two ropes of different diameter, or different stiffness together.” Sounds also like a perfect connection for a fly line and a leader butt.

The advantage of the sheet bend is that the knot won’t strip the coating off the fly line as a nail knot does with some coatings, and more importantly it’s simpler to tie.

(As a side note, this knot also has been called the Castwell knot by author James Castwell, who reported that it was the original method of attaching a silk fly line to a gut leader prior to the invention of nylon monofilament.)


The tippet is the final piece of monofilament between the leader and your fly. Unlike the leader, which is tapered, the tippet has a uniform diameter, and should be the same diameter or slightly thinner than the terminal end of your leader.

Monofilament means literally a “single filament,” and it can be made from nylon or fluorocarbon material.

Of course, each brand has slightly different manufacturing processes and additives, which leads to slightly different qualities from brand to brand. Nylon monofilament is generally more limp, which means it is easier to seat properly, and supple materials allow your fly to move more ­freely in the water and achieve a better dead-drift.

Fluorocarbon is stiffer, and more resistant to abrasion. It is also more expensive. Its main selling point is that its light refraction index is close to that of water, which means light
passes through it at much the same angle, making it less visible than nylon monofilament. This “invisible line” is seen as an advantage by many anglers, especially in situations where the water is clear and the fish have sharp eyesight.

The tippet serves two purposes: Every time you change your fly, you lose a bit of monofilament. If you tie your fly directly to the leader, you will have to frequently replace it because as you switch flies, the leader becomes shorter. By attaching a 2-foot tippet section, you are constantly decreasing only the length of the addition, not the leader itself.

Second, a level-diameter tippet section—especially a fine, thin 4X, 5X, or 6X tippet—is extremely limp and doesn’t turn over and land straight like your leader. It therefore adds slack into your system, allowing you to make drag-free presentations to picky trout. [For a more detailed explanation of leaders, tippets, and how to modify them to suit your fishing conditions, see “Intelligent Design” on page 38. The Editor.]

The standard knots for connecting two pieces of monofilament are the blood knot and the surgeon’s knot. There’s no need to learn both since they serve the same purpose and both are strong.

Some people find the surgeon’s knot a little easier to tie. The blood knot is more streamlined and therefore less likely to pick up stream weeds and other debris.

I use a variation of the blood knot called the speed blood knot. My friend Greg McDermid showed me this knot two decades ago—he learned it while he was a guide on Great Bear Lake in the Canadian Arctic.

The speed blood knot isn’t just faster, it’s easier to tie—particularly with cold hands in freezing temperatures—because you don’t have to separately deal with two independent tag ends. You tie the tag ends together, making them easier to control and handle (see illustration).

The knot you end up with isn’t a true blood knot because the tag ends wind up facing the same direction, instead of in opposing directions as in the original blood knot.

I’ve shown this knot to many people over the years, and have been told it’s also easier for people with vision impairments or arthritic hands.


Your final knot—and the most important knot in many people’s estimation because it occurs at often the weakest part of the system—is the tippet-to-fly connection.

The most popular knot to attach your fly is the improved clinch knot. Although it is an easy knot to tie, and many fish have been caught with it, I’m not going to recommend it or explain its uses because it’s weaker than most other knots, and you probably already know how to tie it.

What I am going to try and do is talk you out of using the improved clinch knot. One of the strongest and most dependable knots is the Pitzen knot—aka the Eugene knot or 16/20 knot. When I first learned this knot, it was called simply the “fisherman’s knot.”

You can find out for yourself how much stronger this knot is by simply tying two hooks together with a single strand of nylon monofilament.

Use a Pitzen knot on one hook, and an improved clinch knot on the other. Then, dig one hook into a board and pull the other hook with pliers. It doesn’t matter which one you pull, the improved clinch knot will always break first. Why use the weaker knot, just because it may be “strong enough?”

Breaking strength isn’t the only consideration when you are tying a knot. If you are using 6X tippet, you want the knot to be as strong as possible because you have no margin for error, but if you are using 15-pound-test fluorocarbon, a weaker knot is still pretty strong.

Another important consideration when using heavy tippets is the way the fly moves in the water, and when you use a cinch-type knot with heavy tippet, the fly acts unnaturally stiff in the water.

The solution is the no-slip loop knot, which Lefty Kreh wrote about in Fly Fisherman more than a decade ago, when I was a rookie editor. Soon after, I noticed permit guides were using it, then nearly all saltwater guides, and now it’s popular anytime you have a heavy tippet, but you want maximum movement out of your fly.

It works because the fly isn’t rigidly connected to the tippet, it’s free to slide up and down the monofilament. Use this knot for trout streamers, for smallmouth bass fishing, for attaching large musky flies—I’ve even started using it to attach large steelhead flies.

Knot Tips

Lubricate the knot with saliva or fly floatant before you pull it snug. George Anderson—owner of George Anderson’s Yellowstone Angler in Livingston, Montana—uses lip balm before he ties two monofilament sections together. He forms the knot, then uses his lips to lubricate the monofilament before he pulls it tight.

If you pull a knot tight and there are curls, abrasions, or other deformities in the monofilament caused by the heat and friction of closing the knot, you should cut it off and try again.

Deformities show you that the monofilament has been significantly weakened, and although the knot itself may not break, the line will break where you have damaged it.

Pull the knot snug and make sure it is seated and tightened correctly. Most knots require you to hold the tag end so it doesn’t slide out when you tighten the knot.

Clip the tag end of the monofilament only after the knot is completely tightened and seated correctly. Clip it short and neat, but do not clip it so close to the knot that the tag can slip through completely, or so close that you risk nipping the knot itself. It’s okay to leave a short tag no longer than the diameter of the hook eye, and your knot is probably stronger as a result.

Tie a new knot after you catch a large or toothy fish, snag trees on the backcast, or drag your line on the bottom. Inspect your entire leader regularly for nicks and abrasions. If you don’t, you may regret it when you lose the fish of a lifetime. You should always be thinking that the next fish could be “the one” and prepare accordingly.

Ross Purnell is the editor of Fly Fisherman magazine.

 Best Fly Fishing Knots

Illustrations | Andy Steer

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