The action of a rod is the result of it’s taper. Taper is the diameter of the rod along its length or; the shape & distribution of rod material. For anyone other than a rod maker it isn’t necessary to get down to that level of detail to understand how a rod will perform, or how it compares to other rods. So when thinking of a particular rod’s action, let’s not get its taper thrown into the mix. For a basic understanding of rod action, it will only add confusion.
I have found that the easiest way to understand rod action is to think of it as “feel”. Rod feel is, in my opinion, a better description. So, the “action” of a rod is how the rod “feels” to you when the rod is flexed, cast, & when landing a fish or mending line.
That being said, rod action is mostly divided into three categories:
1.) Fast Action: The rod has a stiff feel when flexed. When casting a line, etc the rod straightens quickly.
2.) Medium Action: These rods are more flexible & pliable than fast action rods. They straighten a little more slowly & have a smoother feel. Medium rods will bend more than a fast action rod under the same line weight.
3.) Slow Action: These rods are very limber & have a much softer feel than the other actions. A slow action rod flexes much more than fast or medium action rods. This flexing, or bending, is felt much farther down the length of the rod, usually to the butt section & maybe even into the grip.
No matter which action you prefer, a good, well designed fly rod will flex progressively from tip to butt under different loads.
Also consider the number of ferrules in your rod. Obviously, multiple piece rods have more ferrules than one or two piece rods. Any ferrule will, to some degree, interrupt the action of a rod. Ferrules are (by their nature) stiffer than the rod shaft. For this reason - & not considering the practical needs of transporting & storing your rod – a two piece or one piece rod is best for feeling the action of a rod. In other words, the less ferrules your rod has, the less the action of your rod will be interrupted.
What’s the best general use fly rod? This is a common question. In my opinion, for most anglers a medium action rod is best. A medium action rod is the most adaptable to the angler’s individual timing & reflexes. Medium action rods are much more forgiving than fast action rods & they also protect delicate tippets from snapping. By making slight changes to your casting you can “speed up” a medium action rod a little, but it can be very difficult for most anglers to slow down a fast action rod. Still, the choice of rod action is a personal one & it is very important, too. Before you purchase your next fly rod, you may want to give some considerable thought to the action of the rod you choose.