We have come a long way since the days when a manually applied coating of Mucilin or something similar was needed to float your "Braided Silk" fly line. Today we have lines that are made with proprietary coatings, impregnated with some form of self-lubricating treatment and/or contain small "pockets" that trap air to aid in floatation. As such, today's floating fly lines are far superior to those available just a few short years ago.
Add to this radical changes in taper design, changes in materials (both inside and out), and a broad range of colors, stiffness, etc., and today's fly fisherman has more options than ever before! However, how many anglers actually know what makes one line different from the next and in fact, which one is best for them? In addition to the conditions one can expect to encounter, the tackle (rods and to a degree reels) we choose should influence what lines we buy.
Starting with the basics, today's fly lines are made up of two parts, a core and a coating. The vast majority of today's floating fly lines use PVC (Polyvinylchloride) for the coating. However, British fly line manufacturer Airflo has introduced floating lines with Polyurethane coatings that while not real popular here in the US, have been well received in the UK. Even within PVC coated lines there are radical differences in regard to suppleness and smoothness.
While the smoothness of a given line can be influenced by the coating as well as by treatments such as Scientific Anglers AST (Advanced Shooting Technology) or RIO QuickShooter, the suppleness of a line can be equally influenced by the construction of the core. Most of today's floating fly lines either a braided core (typically Dacron or nylon) or a monofilament core (typically nylon or some proprietary copolymer).
While it's tough to nail down which coatings and treatments are best for any given situation, there are some basic concepts that the angler should be aware of. Although most lines may feel (and perform) similar to the average angler, treatments and how they impact performance and longevity vary considerably. As a rule, those that are "impregnated" (Scientific Anglers AST, etc.) are far better and last much longer than those that are "applied".
As for cores, there are some real differences that can impact the angler. Typically, braided cores are the most supple and therefore good for delicate presentations. Conversely, they can become quite limp in very hot conditions such as those found when fishing out of a boat in the ocean (especially those made of Dacron). As for monofilament cores, they are usually stiffer and as such offer some level of advantage for distance but tend to coil in cold water.
Level fly lines have no taper per say; they are an even width through their entire length. As a result, they do not cast well and will not present a fly well. As such, level lines are best suited for trolling. As this is their only real purpose, we will not address level lines beyond saying that they are a cheap alternative to DT or WF lines for those looking for a fly line to troll with (and who plan on doing nothing else with them).
As for DT lines, while once the choice of most fly fishermen, they have fallen out of favor over the past few years. However, I personally believe that they still have a place in modern angling and as such still use them. While the old school of thought was that DT lines were a good choice for economic reasons (you could turn them around when you wore out one end), that was more theory than reality. The simple fact is that by the time most anglers got around to switching them, they were too far-gone.
The basic premise of a DT line (forget the economics!) is that you have thicker and heavier line (the belly) rolling over thinner and lighter line (the front taper). While somewhat detrimental to distance casting due to increased friction, this has a positive impact on presentation as the fly is delivered with a gentle roll versus a drop. This is not to say that accomplished anglers cannot get a similar effect from the correct WF line, just that it is tougher.
Another benefit of DT fly line is that the belly (which is in this case the running line) floats higher than that of a WF due to its larger diameter. However, this only comes into play when you have enough line out that a WF would be past the head and into the running line. This is primarily an issue when line-control and mending is critical. DT lines also offer superior roll casting due to their long belly (thin diameter running line does not roll well).
WF lines have grown in popularity over the years to a point where they are now the de facto standard. This is due to the fact that WF lines will cast further due to their design and in the eyes of many of today's anglers, further is better! While this may be true in certain circumstances such as pond fishing, this is rarely the case when river fishing (your fish are very close). The concept is that the thin running line causes less friction than the belly of DT lines (the belly is the running line in this case).
The basic premise of a WF line is that you have thicker and heavier line (the head) pulling thinner and lighter line (the running line) through the guides. While somewhat detrimental to presentation due to increased weight and bulk up front, this has a positive impact on distance as the line is delivered with far more forward thrust than a DT line. This is not to say that accomplished anglers can not get "acceptable" distance from the correct DT line, just that it is tougher.
Another benefit of WF line is that it takes up less room on your reel. This allows for more backing or in some cases, smaller reels. The difference between the bulk of a WF vs. DT line can be almost 50% which can radically increase the amount of backing one can put on a given reel. When shopping for a reel, it is important to note that most reel capacities are listed in regard to WF lines. As a rule, a DT line will take up a little more space than the next size up WF line.
So, which type of dry line is best? The industry says that WF lines are best and the sales numbers support this. I will also concede that today's WF lines are far more friendly than those available in the past due to changes made to the taper design. Even as a lifelong die-hard DT fan, I find myself using more and more WF lines these days. For me, DT lines have become niche products used for very specific situations where stealth and presentation are a must.
Now that I have cleared that up, let me confuse you by telling you that all WF lines are not created equal and you must do your homework to ensure that you select the right one for your specific needs. For example, front taper lengths vary from under 5' to over 12'. This can have a huge impact in regard to presentation, turning over large flies, or casting into a stiff wind. Additionally, the length of the belly can impact distance as well as floatation.
Note: All items above are based on a WF5
It is also important to note that many WF lines no longer follow the old front/belly/rear/running construction that was once the rule. Many of today's WF lines employ a multi-stage front taper and/or belly (RIO WindCutter, RIO Grand, etc.), or a concave front taper and/or convex rear taper such as that used in Scientific Anglers Trout line. Add to this the "Specialty Tapers" such as Wulff Triangle Taper, which has no belly (just a front taper, rear taper and running line), and the game really changes.
Another important note is in regard to how line weights are determined. While there are long standing industry standards (AFTMA) used to rate fly lines (see chart below), some manufacturers step outside those guidelines. For example, Scientific Anglers GPX fly line is in their own words "made heavier to more fully load high-modulus graphite rods". As such, while a typical 5-weight line weighs 140 grams, a GPX weighs 150 grains (and the same holds true for several other makes and models).
The actual weight of a fly line is important to fly fishermen for a couple of reasons. First is that while an over weighted fly line will help "tame" a fast-action rod by making it load easier, it can make a medium-action rod feel slow. Conversely, putting a line that is accurately weighted on a fast rod such as a Sage TCR may make if real difficult to load. Additionally, some anglers "overload" their rods. If this is done with a heavy line, it could result in a higher level of overloading than anticipated.
Note: As defined by the AFTMA standard, the physical weight of a line refers to the first 30' only. As such, the length of the "head" of a given line can influence its performance at long distances (one of the reasons most "performance" lines employ long bellies). This is also true in regard to DT lines which although they create more friction than WF lines due to their diameter, they are heavier than WF lines when casting beyond the head.
One of the last things I would like to mention in regard to floating fly lines is color. Unlike wet lines that rarely come in more than one color, many floating lines are offered in two colors. As a rule, I prefer stealthier colors such as olive, gray, etc. However, there are some advantages to highly visible colors such as orange or bright green (they are easier for the angler to track). Another new idea is glow-in-the-dark lines such as RIO LumaLux which can help in low light conditions such as Hexegenia hatches.
With all the options available to you, let me offer a few guidelines that may help you select the right line for your specific situations:
Bob Mallard has been a flyfisherman
and fly tyer for over 25 years and is the owner of Kennebec River Outfitters
on Route 201 in Madison, ME. He can be reached at (207) 474-2500 or