Describing Fly Rod Actions

By Rick Rappe

Let's make the point right up front: The usual designations of slow, medium or fast actions used to describe fly rods are incomplete, not to mention often inaccurate in describing how a rod will perform. Slow, medium or fast actioned compared to what? Well, compared to the other models in that maker's line - sometimes, but seldom identical to the same designations given rods from another source.

It isn't hard to imagine the frustration of the rod designer. After creating a well thought out and tested rod action that matched the graphite content of the rod with sophisticated compound tapers, he must now describe his design in one word so it will fit into one or the other of these categories.

I wanted to begin this essay with some comment about how the fly rod industry would be better served by having a standard and more thorough set of criteria by which to describe the action of each particular fly rod marketed. Before I even had the sentence formed, I realized it will never happen for at least three reasons.

    1. The decisions as to where a particular specimen "fit" would be too subjective as different casters have styles that change how a rod performs depending on who is using it.

    2. The categories would get too complex for anyone other than a dedicated student to figure out.

    3. Manufacturers would resist because buyers would likely realize how many similar if not identical performing models there are that are differentiated only by marketing.

I applaud rod houses such as Orvis who use proprietary flex ratings to describe their rods, or the one large mail order sporting goods chain that shows a flex graph along side their various models. My real problem with the latter though is that whoever creates the catalog copy seems to rely on the maker's description of slow, medium, fast, and the rods when actually tested often don't match the graph.

Let's see if we can explain to the next level of detail what the variables in rod actions are by defining some terms:

First, lets agree to ignore for a moment that there are different levels of graphite content and accept that all raw graphite material in rods is the same. This will make the explanations more simple.

Slow, Medium, Fast Actions

A slow rod is defined as one in which the rod flexes more evenly along most of its length (see Progressive Taper below). A medium rod has a greater percentage of its flex in the upper 1/2 of the rod while the lower 1/2 is more stiff. A fast action has more flex in the upper 1/4 to 1/3 of the rod and begins to stiffen sooner along it's length. Pretty vague isn't it?

Progressive Taper

A rod design that starts with a small diameter at the tip and has a smooth and even increase in the thickness of a rod all the way back through the grip. It is easy to imagine that a rod with a smooth progression of the increase in diameter will get gradually stiffer as the diameter increases.

Early rod makers in the solid wood days before the use of split bamboo, did indeed begin with a smooth progressive taper and created rods with machines not unlike a pencil sharpener. But they were immediately up against the problem that in order to stiffen a wooden rod's rate of flex much, the rate of taper increase would have to be more rapid and the butt of the rod would get to large to be useable. Thus virtually all early rods were very whippy (slow) or were pool cue thick. In either case, rods were not cast as we do it today.

Compound Taper

A progressive taper in which the rate of increase in diameter is varied along the length of the rod to alter the flex characteristics.

An early factor the rod design "thinker" came up against was that unless the rod was in one piece, the introduction of the ferrule interrupted the smooth flex progression. It didn't take the thinker long to realize that by speeding up or slowing down the rate of increase along the length of a rod, the "action" of a rod could be altered. But it wasn't until a material with great power fiber tructure was discovered (split bamboo), that at last the rod maker could invent more complex progressive tapers and the modern casting fly rod was born. Inexpensive bamboo rods were built by the perhaps millions based on simple progressive/compound tapers. But a few masters and small production shops took this new material and experimented with taper variables until marvelous casting tools were created with patience and much hand work. Rods some would call works of great craftsmanship if not art were built.

What if we decided to get radical and design the taper so that the middle of the rod had less flex, and we put a bend or flex point down near the grip? The result would be an action not unlike a catapult.

Parabolic was the term adopted to describe this type of action. The first Parabolic rods were said to be capable of casting great lengths of line. But they were also said to be poor at casting short and with delicacy. So it took rod builders only a sort time to begin to use compound tapers in combination with the parabolic action to add short casting ability and the term semi-parabolic came into use. Never mind that mathematically a parabola is a term to describe a smooth curve, and is inaccurate when applied to a compound taper. Nor is there any such thing as a semi-parabola. But the name stuck.

Today, the rod designer has two other variables to work with that the earlier generations using Bamboo did not. He can vary the percentage of graphite fibers within a rod to alter the stiffness and recovery rate (how fast the rod returns to its original position when flexed) in combination with compound progressive tapers to achieve casting characteristics never before possible. And because of graphite's great strength to weight ratio, the designer can build rods longer and lighter than ever before.

Because using a material such as graphite that is so light for the power it can provide, many graphite rod makers reverted back from complex compound tapers to those closer to the original progressive design which simplifies manufacture. And in that context, a rod can be made in any flex from slow to fast. But from that base, very many (and typically the more expensive models) are tweaked with various compound taper adjustments, and graphite thickness (power) variables to alter the actions just as the bamboo masters did in times past.

For example, I have two 8 1/2 foot 4wt. rods from the same manufacturer. One is of their excellent mid-price line that the company calls a "moderate" action. With my casting style, it throws tight loops with great accuracy and power at all distances. The second rod is from the company's top line and is rated as a fast action. While the graphite content is somewhat higher, when cast side by side, the fast rated rod throws the same line the same distances, but by paying close attention the caster can see that the maker used compound tapers to give the rod subtle performance improvements. The loop is more open, making the rod more suitable for casting nymphs, yet the quicker recovery of more graphite content gives both rods the same power. Rod two has a compound taper step near the tip that adds a bit of flex there that might theoretically protect a light tippet better as well as swim a streamer with a bit more motion. And there is a second more Parabolic-like taper step in the lower third of the rod that makes casting short a bit more forgiving.

While both rods cast well and are excellent rods, the expensive model, which costs 60% more, has performance improvements that are the result. And in fact, the "moderate" action rod is actually faster than the rod labeled fast.

Two points. I cast and test a lot of rods as a part of my business selling fly rod building kits. Still, I had to cast these rods side by side to detect the subtle differences. So I believe the average caster would be just as pleased with the mid-priced rod and would not be able to notice or effectively use the improvements found by paying 60% more.

Point two is that the medium rod cast faster than the fast model and that it is clear that such simple descriptions as medium and fast tell the buyer next to nothing about these models.

Is there a solution? Well yes, several actually. The first is to stop worrying about it. Either rod is great and will make a first rate fishing rod. The second is to understand the limitations of simple rod action descriptions plus one's own casting limitations and test cast a variety of rods before making a buying decision. I seldom recommend the third, but see it happen a lot.

If the choice is between an expensive rod you like and a less expensive one you like; buy the more expensive one under the fisher's optimism that if your casting ever does improve, you have a tool you won't outgrow. ~ Rick Rappe

Publishers note:

If you have any tips or techniques, send them along! Help out your fellow rodmakers! ~ Publisher, FAOL

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