Fly Line

Fly line is a specialized fishing line that supplies the weight or mass necessary to cast an artificial fly with a fly rod. The first fly lines were constructed of woven horsehair that eventually evolved into woven silk fiber lines. As plastics technologies improved, synthetic materials gradually replaced natural materials in the construction of fly lines. Today’s fly lines are generally constructed of an outside synthetic layer that determines the line’s slickness, buoyancy, shape and weight over an inside core material which determines the line’s strength and flexibility. The typical fly line is 90 feet long although longer fly lines are manufactured. Fly lines have several characteristics which can be used to describe any given fly line. Some of these characteristics are based on industry standards and norms while others vary considerably between manufacturers.

Taper – Taper describes the change in cross-sectional diameter of a fly line from one end to another. Taper is a significant determinant in the casting performance of an individual fly line particularly the ability to present different types of artificial flies from the very delicate to the heavy and wind resistant in differing on-water conditions. Fly lines in general are said to be:

Weight forward taper – the cross-sectional diameter changes from smaller to larger to small within the front 30 feet (9.1 m) of the fly line. Weight forward taper lines have only one end to which the leader is attached.

Double taper – the cross-sectional diameter changes from smaller to larger to smaller symmetrically along the entire length of the fly line. Double taper fly lines may be reversed by the angler with the leader being attached to either end of the line.

Level – the cross-sectional diameter is identical along the entire length of the fly line.

Shooting heads –Shooting heads and tips are level or tapered sections of fly line designed for exceptionally long distance casting.

Weight – Fly line weight is an industry standard measure of the actual weight in grains of the first 30 feet of fly line. Fly rods are designed to cast fly lines of a specific weight. Fly line weights vary from 1 weight to 15 weight using standards established by the American Fishing Tackle Manufacturers Association. A 5 weight fly line is designed to match up with a 5 weight fly rod. These relationships are not absolute and anglers may prefer to over-line or under-line any given rod depending on their casting style and rod action. Some sinking and sink-tip fly lines do not carry a numbered weight, but instead are identified by the actual weight in grains of the first 30 feet (9.1 m) of line, such as a 250-grain (16 g) sinking line.
AFTMA standard fly line weights
(grains per first 30 feet (9.1 m) of line) Designation Weight (grains) Acceptable range (grains)
1wt 60 54-66
2wt 80 74-86
3wt 100 94-106
4wt 120 114-126
5wt 140 134-146
6wt 160 152-168
7wt 185 177-193
8wt 210 202-218
9wt 240 230-250
10wt 280 270-290
11wt 330 318-342
12wt 380 368-392
13wt 450
14wt 500
15wt 550

Buoyancy – Typical fly lines have a buoyancy characteristic that describes how the line behaves on the water after being cast.
Floating – Floating fly line is designed to float on the surface of the water along its entire length. Floating fly line is essential for presentation of artificial flies that must remain on the surface such as dry flies, poppers, bugs, etc. Floating fly line is also necessary to fish nymphs effectively with strike indicators.

Sink-Tip – Sink Tip fly line is designed so that some length of the tip section of the fly line sinks while the remainder of the fly line floats. Sink Tips are generally characterized by a sink rate in inches per seconds and are used when it is necessary to get artificial flies deeper in the water column.
Sinking – Sinking fly line is designed to sink along the entire length of fly line and is typically used in fly fishing deep waters or where the artificial fly must reach the bottom of the water column rapidly.
Fly line manufacturers design and formulate their fly lines with other characteristics as well. Some fly lines are specifically formulated for warm water and cold water conditions, fresh and salt water conditions as well as designs that target a specific type or fish or fishing.

Backing
Fly line is typically attached to a length of braided or gelspun line wound on the fly reel known as backing. The length and breaking strength of the backing required depends on the overall line capacity of the reel and the type of fish being sought. Backing may be as short as a few yards up to 100s of yards if the reel has the capacity. Backing can serve two purposes. One is to create a larger diameter spooling surface that allows the fly line to fill the entire fly reel. The other is to provide additional line for fighting heavy or hard fighting fish. A fast running or hard fighting fish may take line from the reel and get into the backing.