Fly Line Selection
You have your new fly rod, a five weight for example, and need a line. Go to the fly shop and say, “I need a weight forward floating line with a typical trout taper for my five weight rod.” Take what they hand you, and you will be able to fly fish successfully for years to come. You just bought the most common fly line sold, and it’s a better fly line than your grandfather could have bought at any price. But there are many options, some of which will enhance your fishing experience.
I just received a catalog listing 18 Scientific Angler and 24 Rio fly line types, not counting line sizes, plus there are other manufacturers with similar numbers of lines. Let’s narrow this down by using the decision tree in the image, knowing that we are fishing in the Rocky Mountains, and if elsewhere we won’t stumble over one of the decision blocks.
Your five weight rod can range from a very fast action graphite to a very slow bamboo, with medium or progressive action being a common choice. Rods are tending to be faster, and line manufacturers know this. You can now buy a five weight line that is a 5 ½ or even a 6. It’s called “over-lining”, and it will make the rod load more quickly. On the other hand, you may cast better with your really slow rod “under-lined” with a 4 or 4 ½. Try over or under lining your rod to see how it feels.
Freshwater is an easy decision for us, but if you are going to fish salt water in a warm climate, you will need a stiff line, not to mention a rod bigger than your five weight.
The type of line is almost as easy of decision. A floating line is a must. How else will we fish dry flies? Your second line will be a sinking line, most likely an intermediate (sinks, but not much). This will facilitate stripping streamers in lakes and bigger rivers. Should you begin to specialize, there are floating lines with sinking tips and full sinking lines with different sink rates.
Now we get to style, and this is where manufacturers encourage specialization – lines for bass, trout, salmon, etc. But, there are two basic styles: WF (weight forward) and DT (double taper). The mass of a WF is in the head or front end. This makes for good “shooting” or long casts, but diminishes line control. Mending and roll casts are harder for the inexperienced. Still, faster rods perform better with WF lines, and most casts distances are within acceptable line control range. The mass of a double taper line is spread over the body of the line. This makes for good mending and roll casts along with delicate fly deliveries, but it shortens distance.
Rule of thumb:
WF for faster rods (maybe over-lined), or when mostly nymph fishing.
DT for slower rods (maybe under-lined), or when mostly dry fly fishing.
A common “trout” taper in either case.
Remember, as you casting skills improve, your fly line of choice for a particular rod may change. What feels best in your hands matters. Finally, the best line choice will improve a mediocre rod, and the worse line choice will ruin a great rod.