Fly Line Basics
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On the package of every fly line is a code. This code describes the line in terms of line profile, line weight, and floatability. These are thee 3 most basic elements of a line and tell you much, but not all, of what you need to choose a line.
Line Profile is indicated by the shape of a line when viewed from the side along its entire length.
The top line in this illustration shows a line without a taper or a Level (L) line. These are seldom seen used except when used as running line behind a shooting head. It will not work well for delivering a fly. Due to poor disipation of energy, the line will "hinge" as it turns over and will dump the line instead of allowing the leader and fly to turn over. See: Sinking Lines & Leaders for a discussion of the causes of hinging. Hinging can occur with any fly line if the line is not terminated properly with a good leader.
The second line down is what is called a Double Taper (DT) line. It is tapered evenly at both ends, as opposed to the weight forward line below it. Double tapered lines are the heaviest along their entire length but will still fall within the AFTMA specifications for the first 30 feet of the line. Notice that this line has no proper "front end" to it as do the two lines below it. Double tapered lines are often a beginner's first line. They are better for mending than a line with a shorter head and they can be turned around on the reel if needed. They can also make longer roll casts than the weight forward lines
The third line is a Weight Forward (WF) line. This taper is the most popular of all the tapers. When shooting line, this will cast farther than the double taper because it does not have to pull as much weight behind it due to the thin running line. This same feature also allows the reel to store more backing than the double taper. It will not roll cast as far as a double taper. It is the line profile most manufacturers use when designing specialty lines.
The last line in the illustration shows a Single Taper (ST) also called a Shooting Head (SH). The level line directly behind it indicates an attached running line that increases the shooting abilities of the line due to its thin diameter. These single taper lines are usually only about 30 feet in length with up to 100 feet of running line while the other tapers range from 80 to 105 feet in length.
| Line Weight | Wt. Grains | Tolerance |
1 | 60 | +/- 6 gr. |
2 | 80 | +/- 6 gr |
3 | 100 | +/- 6 gr. |
4 | 120 | +/- 6 gr. |
5 | 140 | +/- 8 gr. |
6 | 160 | +/- 8 gr. |
7 | 185 | +/- 8 gr. |
8 | 210 | +/- 8 gr. |
9 | 240 | +/- 10 gr. |
10 | 280 | +/- 10 gr. |
11 | 330 | +/- 12 gr. |
12 | 380 | +/- 14 gr. |
13 | 450 | +/- 15 gr. |
14 | 500 | +/- 15 gr. |
15 | 565 | +/- 15 gr. |
Line Weight is an indication of how much the first 30 feet of the line weighs in grains (minus any level tip section at the end of the line - usually 6 to 12 inches). This is according to the AFFTM/AFTMA standard which attempts to simplify choosing the correct line weight for any given fly rod. Unfortunately, in recent years this has become complicated by the manufacturers trend to move to faster (stiffer) and lighter fly rods, and the tendency for a few fly line manufacturers to design some of their lines heavier than the standard to help load these faster rods.
In most, but not all, instances you can match the line to the rod by purchasing the line weight indicated on the rod blank. If the rod is rated for a 6 weight then purchase a 6 weight line. Some manufacturers will have a double line weight indication such as 6-7. This indicates that if you are using a double tapered or long belly weight forward line, the manufacturer recommends using a 6 wt line. If using a standard weight forward they recommend using a 7 weight line since it will weigh less when carrying longer amounts of line
Another factor, and sometimes the most important, in choosing a line weight has to do with your personal casting style and the action of the rod you are putting the line on. If you are used to moderate action rods and have a relaxed smooth casting stroke, you may find that the new fast action rod you bought doesn't feel loaded with the indicated line on it. In this case try casting it with a line that is one weight heavier than the line indicated on the rod. There are times when going up even 2 line weights may be called for. Since there are no standards for rating the line weight of a fly rod this doesn't mean that the rod is not truly what is indicated on the blank. It means that due to modern design trends the rod may be too stiff for your casting style.
See the Buying Gear page for more information on the best way to purchase gear.
Floatability is an indication of whether a line floats or sinks.
Floating (F) lines are made of materials that have a specific gravity less than that of water and are made to present flies at, or near the surface of the water.
Sinking (S) lines are heavier than water and sink at different rates depending on their diameter (more about that later). These lines are used to fish deeper areas of rivers, lakes and oceans.
Intermediate (I) sinking line. This line sinks, but at a very slow rate. They are usually clear and are used to fish just below the surface of the water.
Sinking Tip (ST) lines are floating lines that have a length of sinking line up to lengths of about 30 feet in length integrated into the front end of the line.