At a recent class on fly line technology, I was asked about over-lining and under-lining fly rods. I thought I’d share some of my thoughts on the subject that may help you with your casting. The subject begins in the mid-60’s when very flexilble slow-action cane and fiberglass rods required a very careful touch to avoid abrupt power application and resulting tailing loops. Anglers were quick to under-line these rods to create the illusion that the rod was faster or stiffer than it actually was. In the 80’s, the advent of high modulus graphite created a considerably less flexible, faster action rod. As a result, anglers began to overline these rods in an effort to make them load more easily. Today, there are hundreds of rods of virtually every conceivable action available to fly anglers. Yet anglers continue to over and under-line their rods.
Consider this: If a 5 weight rod (designed to cast 140 grains) casts better with a 6 weight line (160 grains), isn’t it actually a 6 weight rod? Let’s face it, casting actions are a highly subjective topic. However, my advice to fly casters looking to purchase a new rod is to select a rod that casts the corresponding line weight to their satisfaction. If it feels too stiff or too flexible, choose another rod. The simplest way to accomplish this is to line up two or three different 5 weight rods and cast each for a few minutes making short casts, long casts, and hauling each. Usually the favored rod will emerge without much difficulty.
The subject gets a little muddy when we consider different length line tapers. For example, if you want a short taper that is front loaded (perhaps 25 feet) designed to turn over more wind resistant patterns such as bass bugs, you may find that when carrying (aerialize) 50 feet of line, the weight (head of the line) is too far from the tip of the rod (into the nearly weightless running line) and may make it necessary to use one line weight heavier to load the rod better at that distance. On the other hand, double taper lines or long headed tapers (longer than 38 feet) will tend to load the rod with more weight than the 30 foot standard weight and if carrying 50 feet of line one may find the weight too much for the rod design and the rod action will slow, the loop will enlarge, and the line speed will decrease. This will reduce casting distance. Most people buying these types of long-head lines expect to make very long casts and intend to carry 50 feet or more. Thus, they often buy one line weight lighter so that the weight that is aerialized is better suited to the rod and its design.
Interestingly, a new line weight rating system was proposed many years ago that would have allowed for longer head lengths. This would be different from the single standard 30 foot rating length. For example, a 2 weight might have been rated for the 80 grains over 28 feet while an 8 weight’s 210 grains would have been rated over 46 feet. They would have the same grain weights as the 30 foot modern standard for each line weight, but each would be weighed over longer or shorter length tapers to suit the line’s common use. However, these changes were not adopted. Rather, merchandizing of unique tapers have dominated the industry, but without standardization. Big Nasty, Bankshot, Igniter, Outbound Long, Sonar, Power Taper, Quickshooter… the names and tapers are numerous and somewhat mysterious. So, if you’re considering a longer or shorter, heavier or lighter head, consider the implications and if possible, try the line and see if it suits the kind of casting and fishing you intend to do.
In conclusion, there are few hard and fast rules. Fly casters have a wide range of opinions about these issues. Rods vary greatly, lines are available in a huge variety of designs, and fishing applications are endless. The only truly hard and fast rules are the dynamics that govern the end result. To form a tight loop, one must move the rod tip in a straight path and avoid abrupt application of power. Find the rod and line that enable you to accomplish that, and you’ll be happy.
Dave Leonhard is a master casting instructor for Fly Fishers International, casting director for the Michigan TU Fly Fishing School, a life member of TU, owner of Streamside Orvis in Traverse City, Michigan, and owner of the Orvis Michigan Fly Fishing School in The Grand Traverse Resort and Spa.