This was incredibly confusing to me at first, then upon investigation I found it to be pretty straight-forward.
Picture of a typical fly line box.
WF-5-S is the common format for fly line description on the packaging. Each of the three parts of the code tell the angler something different.
WF:
This first component indicates the taper style. There are only two that as
a beginner we need to think about; WF (weight forward) and
DT (double taper). WF fly line is designed
with extra weight - you guessed it - at the head of the line. This helps when
casting against the wind and/or to get some extra distance. If you purchase
this type of line, make *sure* that the proper end is attached to the backing
(reel side) so that the weight is actually at the forward end.
DT: Double taper is line that has a narrower diameter at
the head and the tail (15 ft), so that you get <---narrow 15ft------thicker
60ft------narrow 15ft---> clear as mud?
L and ST: Level and Shooting Taper are less
common and more often used by experienced fly fishers. I have been encouraged
to ignore these for the first few years, so I am.
5: The second component of the code indicates the weight. This number should be matched to your rod/reel weight number as a beginner. Many, many fly fishing articles discuss the benefits of using a weight (or two) smaller than your rig, but that is another advanced technique, and for now just make it match. For the sake of knowledge; the number is the weight in grains of the first 30ft of fly line.
S:
The last component is an indication of whether the line is Sinking or Floating
line. S or F. Floating line is the most versatile as split-shot weights can
always be added to help get a streamer or nymph down the water column. Sinking
line sinks... there really isn't any middle ground. I have two reels, one
with each type of line.
S/F and I: Sinking/Floating is line that
floats, except at the tip. Also called Sinking Tip line. A sort-of floating,
sort-of sinking line is Intermediate or I.
So, when you see DT-7-F; that's Double Tapered, 7 weight, Floating line. Just to repeat what I have been told, use WF or DT, match the line weight to the rod/reel and start with floating line if you only have one rig.
Color
The
general rule of thumb is; if it sinks, match the water color or darker. If
it floats, pick a color that you can easily see, because the fish will see
it no matter the color.
*Taper chart showing
standard taper sizes - exact measurements will vary.
