Fly Blog

By Mark Waldin Custom Fly Rods – I recently had an exchange with Bruce Richards at Scientific Anglers about overlining for heavy flies and thought I’d share it with you. SA markets a fly line that is 1/2 weight heavier than a standard line. So, their line for a 4 weight rod is actually 4.5 weight. One of the things they note is that it improves casting of heavy flies like nymphs and streamers. I asked Bruce why this would be the case since putting a heavy fly with a heavy line would overweight the rod more rather than less. If anything I would have thought that underlining the rod would be in order. Here is Bruce’s answer.

The best solution to throwing a heavy fly on a line that isn’t capable of casting it properly is to use a heavier weight rod with a line that hefty enough to swing it. If you are in a situation where doing that is not possible then increasing the fly line weight and over lining the rod is the next best solution.

According to Bruce “There are a couple good reasons that using a heavier lines makes casting bigger or heavier flies easier. First, the mass of the line is responsible for carrying the mass of the fly, the heavier or more wind resistant the fly, the more power it takes to drive them and a heavier line does that better. Also, for most casters,using a heavier line on a rod will tend to make the loop a little bigger, and slower. Bigger, slower loops are better for throwing bigger flies.”

My interpretation of Bruce’s comments is that you want the fly line to carry the fly. You don’t want the fly dragging the fly line behind it. If the fly weighs too much for the line you are casting, the fly will drag the line along and your fly line loop will be too tight and the action will be compromised. So, you might think you want to cast a lighter line so that the total weight matches your fly rod but you will wind up casting what amounts to a rock tied to a string…no loops, no turnover, no subtle presentation.

Going to the heavier line will cause you to lose some effectiveness of the rod by having the line weight unmatched to the rod and you will have to adjust your casting rhythm accordingly. But you will have a better loop and better presentation. Of course, moving to a heavier weight rod with a matching line weight is the best solution.