Fly Line Classification
*^@!?>WF-6-F(*&?<"

Courses Home Knots Equipment Fly Reels Fly Lines Leaders Fly Rods Insectology Flies Fish Casting Reference library Course map        Course subjects Home Line components Line classifications Defining lines Species specific fly fishing Line features Line weight History Old vs new Tapers Sinking lines Fish vs line Line & backing Color Costs Selecting a line Care & maint Glossary

The system for classifying fly lines, for some reason, has always been a bit "confusing."   It started out more mystifying than it is today, but it is still a far cry from being a self-evident system.  As line manufacturers "simplify" things by  calling various lines "trout", "bass", etc. lines, they somewhat obscure these standard classifications.  But we still need to understand the underlying criteria, so let's try to simplify this three-part classification code.

Fly lines are classified by a 3 part code representing the following:

1.   Line "Taper"   

As we point out in other chapters, fly fishing is founded upon "tapered" parts working together: a rod that tapers from thicker to thinner . . . a leader that tapers from a heavy butt to a thin tip . . . and a fly line that changes diameter along its length so as to provide the aerodynamics that enable it to unfurl in a smooth, fluid manner.

The earliest fly lines were of the same diameter throughout their length.   (At least they were supposed to be.)  The first lines were made of horsehair . . . then silkworm gut.  They were "level" lines that fly fishers found difficult to cast, at best, particularly with the fly rods of the day.  Tapering, which began in the 1870's, was a "milestone" development that contributed greatly to performance.

Taper design is a critical factor in casting performance.  Today's modern fly line manufacturers produce very high quality lines in many different tapers.   With the exacting degree of manufacturing capabilities, tapers are designed for specific casting characteristics to meet the demands of different fly fishing conditions and tasks.  Further details are covered under "Fly Line Tapers."

2.  Line "Weight"

Fly lines are manufactured according to specifications that are based upon how much the first 30 feet of the "working portion" of the line weighs in "grains".  (A grain being the unit of measure.)  The "working portion" measurement omits any tip on a taper in the fly line.

Fly lines are made in "weights" from "000 weight" to "15 weight".  They are made to match up with fly rods that are also classified by a "weight" rating that "mirrors" the line rating.   This results in a relationship where a 6 weight line is meant for use with a 6 weight rod.  (As in this course, you will frequently see the weight classification abbreviated as "wt." for both fly lines and rods.)

• "000 weight" is the smallest/lightest weight fly line (& rod)

• "15 weight" is the biggest/heaviest fly line (& rod)

An expanded discussion of this subject takes place at "Fly line weights and their uses."

3.  Line "Buoyancy"

There are 3 types of "buoyancy" in fly lines:
1.  Floating lines
2.  Sinking lines
3.  Sinking tip lines

Fly lines are made to either float . . . or, sink.  Floating lines float . . . sinking lines sink.  Fairly simple until we consider the degree to which a line is made to float or to sink, because there are many different "degrees".  And, to confuse things further, there are fly lines that float and sink at the same time.

Floating lines may be made to sit up high on top of the water. . . others are designed to sit in the surface film.  Sinking lines have various "densities" that allow them to sink at different rates or speeds.  Other lines are a marriage of both floating and sinking features: a "sinking tip" fly line has a major portion ("body") that floats, and a forward segment that sinks (again, at various rates.)  "Intermediate" lines are somewhere between a floating and sinking line.  More details are reviewed at "Line buoyancy and use."

Old vs. New . . .

Up until the 1960's, fly lines were classified using a letter code to indicate their diameter.  This diameter code, which was designed for use with silk lines, had to be "translated" to an equivalent weight, eventually leading to a match with the rod.  When nylon and dacron were introduced, this system became obsolete, because lines of the same diameter were no longer of similar weight.   (Nylon is lighter than silk, dacron heavier.)  The current system, adopted in 1961, uses a numeric code to indicate the line "weight."  For a comparison of the classification systems, go to "old vs. new".

Previous topic  For further specifics, let's look at Defining Line Classifications: