Fly Fishing Lines: How to Choose

When I teach an E.I. Fly™ course, I emphasize the need to balance the combination of your fly line, rod and reel. Specifically, I feel the most important aspect of any fly rod set-up is the fly line design and its physical properties. For the beginner, it starts with a basic understanding of the weight difference between monofilament and fly fishing lines; how the weight of the fly line is designed to produce flex in the fly rod vs. the weight of the lure creating flex in a spinning rod.  You don't hear much talk about fly lines, but experts agree, to achieve a great casting stroke, it has very little to do with the rod or reel. The use of the highest quality fly line, combined with sound casting mechanics, is the key to becoming a successful fly caster. 

To get you moving in the right direction, legendary casting champion and instructor Joan Wulff defines the fly-casting stroke as: 

“The fly casting stroke is a straight-line movement of the whole rod by the rod hand, in an acceleration to a stop.  During the acceleration, the weight of the fly line flexes the rod from the tip downward.  When the acceleration is ended and the butt section of the rod is stopped, the limber rod tip flips over and the long flexible line continues on its path, passing over the tip, to form an open-ended unrolling loop. “  J. Wulff. Fly Casting techniques.

Line Design: The Core

Unlike monofilament, it’s the core of the fly line that determines the tensile strength, as well as how much it stretches and the general stiffness of the line (or lack of stiffness).  As a general rule, all cores are built to be much stronger than the heaviest tippets that are used with them.  For example, a 3 weight floating line may have a break-strength as much, if not more, than 20lbs.  Heavy fly lines such as 10Wt.  may have a break strength well over 50lbs.  Chances are, the leader and tippet will break off 99.9% of the time before your fly line will.  With respect to stretch, it’s important that a fly line core have the right amount of stretch.  Not enough stretch and the line may develop memory problems.  Too much stretch and the fly line may become mushy and difficult to control.  Lastly, the stiffness of the core will determine the action of your fly-line.  For example, lines intended for tropical fishing are designed to withstand high heat extremes.  Equally, lines developed for more temperate water are made with cores that are less stiff.  This reduces the problem of line memory that occurs when stiff line meets cold waters.

The Coating: Floating and Sinking Line

The basic function of the line coating is to provide the casting weight needed to load the fly rod.  Precise weight standards are set by the fly-fishing industry and manufacture associations.  How does a line float or sink?  The density of the line’s coating will determine whether a line will float or sink.  Specifically, floating lines (as seen in photo to the left) have micro-balloons mixed into their coatings.   The micro-balloons create buoyancy, thus allowing the line to float.  However, if too many micro-balloons are added, this will add thickness to the line and adversely affect the lines castability properties.  Manufactures also apply hydrophobic coatings on the line that are H2o resistant.  These H2o coatings actually repel the water… much like car wax beads water on a car.

Sinking Lines

As seen to the left, sinking lines have a high-density material built into their coatings, thus, allowing the lines to sink in water.  Generally speaking, manufactures use powdered tungsten because it is denser and more environmentally friendlier than lead (though lead core lines are still available).  By controlling the amount of metal powder added to the line, the manufacture can set the sink rate per line.  For example, a sink line can sink 1.0 inch per second, or +10 seconds per minute.  Lastly, since the line sinks and you cannot see it, nor do you want the fish to see it, colors are often brown or grey.

Taper Designs

Tapers: Level, Double, Forward, Long, Triangular, Shooting

The fly line’s shape or taper determines how energy is transmitted and dissipated during casting.  By varying the lengths and diameters of the various parts of the line, specific performance attributes can be accentuated.

Parts of the Taper

1.  Tip: a short 6-12 inch level section where you attach your leader.  This section is to protect the lines taper. Since many anglers cut off a small part of the fly line when they change leaders, the tip allows these changes without shortening the front taper and altering the way the line casts.

2.  Front Taper: this section of the line determines how delicately or powerfully the fly is delivered.  Typically, 4-8 feet long, the Front Taper decreases in diameter from the Belly section to the Tip.  This graduation of the line’s mass (weight) determines its ability to transfer your casting energy.

3.  Belly: because it’s the widest diameter and longest length, this section is where most of the weight of a line is located, and, consequently, where your casting energy is carried.
4.  Rear Taper:  decreasing in diameter from the thicker Belly section to the much smaller diameter running line section, the rear taper creates the transition so important to smooth casting.

5.  Head: a term used to describe the combination of parts (front taper, belly and rear taper).

6.  Running Line: typically a much smaller diameter from the belly, this section of line has been designed to make casting distance easier.

Taper Types

Level Fly Line (L):  are the easiest to understand and the least used.  A fly line that has a level taper, in essence has no taper.  A level taper fly line is of uniform weight and width for its entire length (+/- 75 ft).  In other words, it has one diameter (thickness).  Level lines float extremely well due their constant weight and width, but are much difficult to cast and control. Delicate fly presentation may be difficult because the line tends to splash on the water during a cast.  Further, level lines do not shoot as well, thus, limiting your ability to make longer cast. Take Away: Low Performance features. It transfers energy erratically and is hard to control while casting.   The best function of the level lines is in the form of fine diameter shooting lines or sinking lines to be cut up for tips for custom lines. 

Weight forward (WF): The line has extra weight and width (diameter) built into it the front potion of the line.  Taper design can vary by Manufacturer and targeted species.  But generally speaking, a WF taper is about 30 feet in length, with a short belly and short back taper followed by 60 feet of thin diameter level line. The advantages of the WF line: works over a wide range of conditions.  Casts ranging from 20-100 feet with normal size flies.  More effective line to cast in windy conditions. Take Away: easy to false cast and good for long cast. 

Special Note WF Lines:  because the extra weight and width are on one end of the fly line, it is crucial that the line be put on correctly.  Today, almost all manufacturers will assist you in this process by adding a tag(note) on the line.  A WF line cannot be reversed.  Lastly, any line whether floating or sinking which has a “head” and “running line” section which are seamlessly joined can be termed a WF fly line.  For example: Rocket Tapers, Saltwater Tapers, Steelhead Tapers, Triangle Tapers, and Teeny are well WF fly lines.

Double Taper (DT): Historically speaking the DT fly line was the most popular line at one time, and the fly line of choice for trout fisherman.  DT lines are perfectly balanced; both ends of the fly line weigh the same and each end gradually increases in width and weight the closer it gets to the middle section of the fly line at an equal rate. Thus, due to identical tapers at each end, the DT line is reversible.  If one end becomes worn, simply switch ends.  Specifically, the DT line is 90 feet long.  The first 15 feet of the line, from one end, gradually thickens .  Thereafter, the line maintains its diameter throughout the belly for 60 feet.  Upon the last 15 feet of line, the DT line gradually decreases in thickness (at an equal rate of the front taper) till it reaches the end point.  Take Away: designed to make short/medium cast at 20-50ft.  The belly of the line makes this line difficult to shoot line (you must make more false cast with line over 30ft).  Advantages: Easy to mend and roll cast due to weight of line in belly section.  Great line for dry fly delicate presentations.

Shooting Taper (ST):  Also, called Shooting Heads, were originally designed for fly-casting distance tournaments.  Like the WF line, the front portion of the ST line (or, commonly called the head) has 30 feet of heavier weighted line.  The remaining running line is uniformed in diameter and weight, but is much thinner than a traditional WF fly line.  The “Head” is joined to the shooting line by a loop-to-loop connection.  The purpose of this configuration is to reduce air resistance, and reduce friction in the rod guides.  Take Away:  Great for long cast +100f feet (world record over 200 feet). Can be highly effective in strong wind conditions (Ocean, Patagonia, etc).  Disadvantages: delicate fly presentations are almost impossible. Line control is challenging.  thin running line tends to coil and gets knotted up. To avoid these known issues, many experienced Anglers use stripping baskets.

Teeny Taper (TT): Developed by Jin Teeny, this taper does not have a front taper and has a smaller than normal running line (similar to a shooting taper/head).   The taper is designed to be very fast sinking…think deep fast water. 

Standard Line Weights

AFTMA the former American Fishing Tackle Manufacturers Associations -- now the ASA -- American Sportfishing Association states:  Fly Line Standards were developed to help fly fishing tackle manufacturers create a system that would match fly line weight to fly rod performance.  Cortland Line Company’s Leon Chandler was instrumental in initiating and completing the project.  In theory, this would standardize fly tackle manufacturing across the industry and enable fly fishers to select and balance their equipment for optimum performance. 

The system uses the weight in grains (a very small weight measure of the first 30 feet of fly line as a standard).  The table below shows fly line weight designations and their grain weight.  The system also established a tolerance level that is acceptable. (Copied from Cortland Line Company website).

Number Designation	Standard Weight	Margin For Error
1-Weight	60	54-66
2-Weight	80	74-86
3-Weight	100	94-106
4-Weight	120	114-126
5-Weight	140	134-146
6-Weight	160	152-168
7-Weight	185	177-193
8-Weight	210	202-218
9-Weight	240	230-250
10-Weight	280	270-290
11-Weight	330	318-342
12-Weight	380	368-392
13-Weight	450
14-Weight	500
15-Weight	550

Tip:  The sooner you start thinking and talking in grains, in the long run, the better your fly line knowledge will be. Why? Experts and most of the world other than the USA, speak and label products in grains.  

Advice from the Experts

How To Choose the Right Fly Line Weight.  By Lefty Kreh.

Let me begin by saying that rod manufacturers design rods for the average person to use under average conditions. So unfortunately, most fly fishermen use only one weight of line on their favorite rod.

Written on the rod blank or handle is a code number, which indicates the line that the rod manufacturer suggests is best for most customers; i.e., 6 line. To most fly anglers, this means that they should use nothing but a 6-weight line with this rod. But to get the full potential from different fishing situations, you may want to consider using several line sizes on your rod — perhaps varying as much as two line sizes from the one suggested on the rod.

Manufacturers know your rod may be used in a host of fishing situations, but they can’t judge your casting style and fishing skills. So when they place a recommended line number on your rod, it is implied that it’s for average fishing conditions. First, understand that you’re not going to damage a fly rod using fly line a little lighter or heavier than is recommended. Certainly, at times, the rod will fish better if different line sizes are used.

Match line weight to conditions:

Let me cite several examples of when you might want to use various line weights on the same rod for different fishing conditions you may encounter.

First, if you fish a swift, tumbling mountain brook, you can use a rather short leader with a dry fly. A leader of 7-1/2 feet in length would probably do the best job. But if you fish for trout with the same outfit and dry fly on a calm spring creek, beaver pond or quiet lake, that short leader could prevent you from catching many fish. While many fishermen automatically know that on calmer water they have to use longer leaders, many of them don’t really probe any deeper into "why" they need a longer leader.

It isn’t the leader’s length that’s so important. In calm water, what frightens the trout is the line falling to the surface. The longer the leader, the farther away from the fly is the splashdown of the line.

But with a longer leader, the more difficult it is to cast and there is a reduction in accuracy. Thus, a 9-foot leader is more accurate and easier to turn over than a 15-footer. Considering this, plus the fact that the splashdown of the line is what is frightening the trout, there is a simple solution. Use a fly line one size lighter than the rod manufacturer recommends. Jim Green, who has designed fly rods for years and is a superb angler, mentioned to me more than three decades ago that he almost always used a line one size lighter when fishing dry flies where the trout were spooky or the water was calm. I tried it and have routinely followed his advice. So, for example, if you are using a six-weight rod, you can drop down to a five-weight line with no problem. In fact, in very delicate fishing conditions, I often drop down two sizes in line weights. There is a reason.

Weight and speed need to vary:

Fly rods are designed to cast a particular weight of line — with a good bit of line speed. If you drop down a line size, you benefit in two ways. One, the line is going to alight on the water softer than a heavier line. Two, because it is not as heavy, it doesn’t develop as much line speed. A line traveling at high speed often comes to the water with a heavier impact than one that is moving slower. Even with a line two sizes lighter, you can still cast a dry fly or nymph far more distance than what is called for in delicate trout fishing situations. So you don’t hamper yourself at all by using a line lighter than the rod suggests. Best of all, you can now use a shorter leader, since impact on the surface has been lessened.

There is a second situation where a lighter than normal line will help you if you are a fairly good caster. The wind is blowing and you need to reach out to a distant target. Many try to solve this common problem by using a line one size heavier. The usual thinking is that a heavier line allows them to throw more weight and, they hope, get more distance. Actually, going to a heavier line means that they complicate the problem.

On a cast, the line unrolls toward the target in a loop form. The larger the loop, the more energy is thrown in a direction that is not at the target. When fishermen overload a fly rod with a line heavier than the manufacturer calls for, they cause the rod to flex more deeply, which creates larger loops on longer casts. Overloading the rod wastes casting energy by not directing it at the target.

If you switch to a lighter line, you may not have enough weight outside the rod tip to cause the rod to load or flex properly — if you hold the normal amount of line outside the rod during casting. But if you extend this lighter line about 10 feet or a little more outside the rod than you normally would for this cast under calm conditions, you can cast a greater distance into the wind. By extending the additional amount of lighter line outside the rod, you cause it to flex as if you were false casting the normal length of the recommended line size.  Since the rod is now flexing properly, it will deliver tight loops, but the lighter line is thinner. This means that there will be less air resistance encountered on the cast.

If you are forced to cast a longer distance into the wind, switch to one size lighter line and extend a little more line outside the rod tip than you normally would. This means, of course, that you need to be able to handle a longer line during false casting. But the line that is lighter than the rod calls for will let you cast farther into the breeze.

Heavier line is often necessary:

There are situations where using a line heavier than the rod calls for will also aid in casting and catching fish, such as when fishing small streams for trout. Where pools are short and casts are restricted in distance, a heavier line can be just the right answer. For example, on many brook trout streams, the pool may be only 10 or 15 feet long and you are forced to use a leader that is at least 7-1/2 feet long. That means that only a few feet of your fly line — the weight that loads or flexes the rod — is outside the rod tip. When fishing where distance is very short and only a few feet of fly line are outside the rod tip, it is important to switch to a line that is heavier. For example, if you were using a rod designed for a four-weight line and had to cast most of the time at targets less than 20 feet, placing a five- or even a six-weight line on the rod would let you load the rod, and casting would be much easier.

This same principle applies when you are bass fishing in the southern swamps. Often, you are casting in small, winding creeks, or where there is a lot of brush immediately behind you. This also holds true when fishing the backcountry of Florida for Snook, where you are close to the target and back cast area is limited. If you are using a rod designed to throw an eight-weight line and you’re fishing at 30 to 40 feet from the target area and the back cast area is less than that, a nine-weight line will permit you to cast much better because the heavier line will load up the rod and let it flex.

Heavily weighted lines, like the Wet Cell III or Uniform Sink +, can and should often be used in one to two sizes heavier than the rod calls for because, for some reason, a line one size heavier seems to improve distance casting. Try one and you’ll see what I mean.

Use shooting TAPERS for greater distance

Finally, consider shooting tapers (also called "heads"), which are generally used to obtain greater distance. When casting with normal line, if you cast well, you never hold just 30 feet of line outside the rod tip to get distance. Instead, you false cast with considerably more than 30 feet of line outside. When using a shooting head, try using one that’s a size heavier than you usually do and you’ll be pleasantly surprised at the distance you gain.

So don’t limit yourself to the standard guidelines given by rod manufacturers. Experiment with different line weights for special fishing conditions. You will be pleased with the results.

Double Taper vs. Weight Forward Fly Lines…Which Is Really Better?

ST. PAUL, Minn. - Few fly line subjects have been discussed more than which is the better taper -- double taper (DT) or weight forward (WF). The answer, according to Bruce Richards, fly line product engineer for 3M Scientific Anglers, "is neither is inherently better, but one may be better than the other for you."

Richards has designed fly line tapers for Scientific Anglers for more than 20 years. There are not many in the fly fishing industry who possess Richard's knowledge on fly lines - and he shares the following on the DT vs. WF question. John Mazurkiewicz

A lot of generalizations are made about these two tapers based on outdated or incorrect information. All fly anglers have heard that double taper lines are more delicate, give better control, roll cast better, etc. In some cases, these performance features of double taper fly lines are true, but not always.

Delicacy of delivery is determined by the mass of the front part of a fly line. This is determined by line diameter (which relates directly to mass), and taper length. A line with a small diameter tip and a long taper has much less mass up front than a line with a large tip and short taper. Don't be mislead by taper length alone -- a line with a long front taper but a large tip diameter will not deliver delicately. A DT and a WF line with the same taper and tip diameter will deliver the same.

For many years, most DT and WF lines were made with the same tip diameter and front taper length so there was no difference in how they delivered, although many claimed there was. Today, many of the DT lines are actually designed specifically for use in spring creek-type fishing and do have longer tapers and/or smaller tips.

Anytime a fly line (or any product for that matter) is designed to do one thing very well it usually has a shortcoming somewhere else. Lines that are designed to be very delicate have little mass in the front to carry larger or heavier flies, and will not handle windy conditions well. It takes a better caster to throw the kind of loops it takes to make these lines perform their best. And no, DT lines are not a more "accurate" casting line-- that is entirely in the realm of the skill of the caster.

It is very true that DT lines are easier to control and roll cast at long distances than WF lines. At shorter distances, there is no difference. The key to line control and roll casting is to make sure the large diameter line belly is in the rod tip. If the small diameter running line is in the tip, it's nearly impossible to transmit enough energy through it to the belly to make the line do what you want. What many fly anglers don't consider is that WF lines control and roll cast as well as DT lines at the distances most of us fish.

Almost all WF lines have heads that are 35-40 feet long. Add a 9-foot leader and the distance to the fly from the end of the head is 44- to 49-feet. Up to this distance when both DT and WF lines control and roll cast the same. There are not many typical trout fishing situations that require longer casts. What this all means is that DT and WF lines work pretty much the same at the distances we fish most often. Certainly if someone fishes a big river that requires a good deal of long distance roll casting and mending, a DT or a WF line with a long head should be considered. Either a Mastery Series XPS or GPX double taper or Mastery Series XXD weight forward taper would work well.

Everybody knows that WF lines are better for distance than DT lines, but is that really true? Well, yes, but the difference isn't as big as you might think. Because of their small, light running lines, WF lines shoot better. But remember, this benefit starts at 44- to 49-feet when the running line is in the rod. If your fishing situation calls for many long casts, it is certainly a little easier to do with a WF line - but don't think that DT lines won't shoot. They will, just not as far.

For most fly anglers in normal fly-fishing situations, it probably doesn't make a lot of difference what taper you use. Most of us fish at distances less than 50 feet, which is where weight forward lines start to shoot better, but with less line control. Most of us don't have the need, or the ability, to roll cast longer than 45 feet.

So, how do you decide which is the right taper for you? Double taper or weight forward? For short to medium casting range situations, there is no reason not to have a DT line rigged and ready. If you are consistently throwing longer casts, you can make them with fewer false casts with a WF line. But if the need arises, you lose the ability to do long roll casts and mends. For most, it doesn't make much difference which taper is used most of the time. Base your decision on DT versus WF on how much small fly, short distance fishing you do - when a delicate DT line like a Mastery Series XPS would offer advantages, against how much fishing you do where longer casts are needed - and the advantages of a WF line.

Scientific Anglers offers taper diagrams on all its Mastery Series fly lines - providing the length of tip, front taper, belly and rear taper, and the total head length and running line length - on its web site at: www.scientificanglers.com ~ Bruce Richards, Scientific Anglers

Share this post