Taking Up the Slack – guest shot

January 2016



By special guest Greg Holt


A good cast is the foundation or a properly swung fly.  (Greg Holt Photo)


Points to be considered:

1) What exactly is slack in our model?  Let’s agree to define slack here as an “absence of uniform tension” in the line, either complete or partial. When there is a complete loss of tension, slack is visible to the caster (more about that below), but when there is only a partial loss of tension it can be invisible to the naked eye, since it is merely a lack of or loss of uniform stretch in the line. It may be felt in the hands if the caster is “tuned in” to how it feels, but that often comes only with experience and awareness. Absence of uniform tension is much like a tow chain laying on a hard surface containing links that individually are not tight against their neighbors—when you begin to move the chain from one end, the opposite end will not move instantly. Obviously, this is not a good thing for our purposes. You absolutely, positively have to tension the line before you attempt to move it!

2) Why is Slack the enemy? Because it robs an otherwise good cast of energy, costing us distance, accuracy and stamina—in a word, slack is inefficient. Slack can degrade or even ruin the nice well-formed loops we all want to achieve. It can cause the caster to make additional mistakes in trying to neutralize it. I know, someone reading this will say “but there are times when slack is good, right?” Yes, in certain specialized cases slack is desirable, such as presenting a nymph in a dead drift. But what we’re talking about here is typically a sustained anchor cast intended to swing a fly under tension, so let’s stay with that.

3) How does slack exhibit itself?  There are many manifestations of slack and each has its own cause, but let’s first try to identify what the effects of slack can look like. Something as obvious as a drooping in the line that’s supposed to be evenly tensioned and straight? Sure. How about a loop that collapses, or shock waves that form in the bottom or top of the outgoing loop, or even the D loop? Yes, those can be signs of the effects of slack (non-uniform tensioning) as well! The evidence of slack can also be seen as uneven or bunched line lying on the water in different stages of a sustained anchor cast, such as after the lift over in a double spey or other re-position (perry poke excluded, where this is an intentional step before loading a relatively short shooting head).

There are also more sinister forms of slack that involve the partial loss of tension mentioned previously, because they are the “silent killers” of efficiency—they don’t show themselves readily to you as distortions or abnormalities in the loop forms. They may reveal themselves in a line that seems unresponsive to rod movement during certain parts of a cast, or a “spongy” feel that comes and goes during an individual cast. Insidious though they may be, don’t worry, we won’t let them get away without being exposed! (Getting rid of them for good is difficult, much like dealing with gophers—you just have to keep after them).

4) Is there a relationship between slack and line construction?  I don’t have the scientific credentials to prove it, but yes I believe there is such a relationship. Imagine a line with no stretch at all, and one with a great deal of stretch. When subjected to the force of being pulled quickly by a rod tip, they will each exhibit different elasticities as they try to “catch up” with the moving rod tip (unless it moves in perfect harmony with the line speed or slightly faster). In this example, the line with the most stretch will likely seem more “forgiving” and less likely to exhibit visible slack once tensioned, because it can more easily absorb and spread through its length the shock of sudden movements of the rod tip, and give them back over a longer interval of time. Note that this doesn’t mean a stretchy line is always a better choice—many modern short shooting heads have low stretch cores for supposedly better “performance” and “feel” when fishing. A short, non-stretchy head may be just the ticket for you, but your timing may have to be better (or your rod more flexible) to avoid showing the effects of slack in your casting. All I’m suggesting here is that a line with some stretch may be easier to work with, especially if you prefer quick rod movements in your casting. Feel free to disagree.

5) Is there a relationship between slack and rod flex profile? If you agreed with the previous point, I may be able to convince you that rod flex profile has a relationship with slack too! A rod with a regressive flex profile and stout tip section for example, will apply force to the line more gradually than a rod with a stiff overall profile. Additionally, the more deeply you load any rod, the longer it takes to recover, thus the less likely it is to exert sudden forces on the line that may cause uneven line tensioning (I promise to describe below how that can occur!). Imagine if you were a light fly line trying to follow along behind a very stiff rod moved in quick start and stop motions, alternating between having your neck and body stretched and relaxed—if the rod were not moved expertly, you might be showing some evidence of “slack” too!

6) How can casting errors (including using too much force) cause slack? Numerous authors and instructors have filled volumes and become hoarse explaining this phenomena, and I won’t attempt to upstage them here. Let me just list a few of the most common casting errors that create slack, then in the next section deal with avoiding these errors and correcting them when they do occur. Here we go: Moving the rod tip too abruptly from a stop rather than smoothly accelerating, which causes it to suddenly become tight against the line, over-bending the rod tip and allowing it to recoil rather than remaining bent, thus creating slack in the line behind it. Pausing (even so briefly that you can’t see it) during any phase of a cast that requires maintaining constant tension on the line. Completing a re-position move such as a snap C or lift-over in a double spey with a sudden stop of the rod tip that leaves line on the water in anything other than a relatively straight and smooth pattern (now you’ll have to pull all that slack out before you can hope to move the line!). Momentarily overloading the rod tip by jerking or “hammering” the forward stroke, which promotes shock waves (uneven tension within the line). The common pattern of movement in all the above examples is a lack of smoothness and constant effort, and as a result, a lack of uniform tension—in other words, slack.

7) How can I detect, avoid, and correct slack in the cast? OK, here’s where the rubber meets the road. When performing a sustained anchor cast strive for smoothness of motion while avoiding sudden changes in force application. Make certain that when the rod tip moves, so does the line—instantly. Don’t jerk the line about like it is something wild in need of taming. Lead it with purposeful, thoughtful movements that result in maintaining even line tension. Observe the results of each action on the following line—how it travels, how it lands on the water, the various shapes it describes. Look for smoothness and consistency, the marks of efficiency—power will come on its own in due time. Feel for the consistent tension level of the line and rod in your hands, arms, and body—it is your best feedback mechanism, along with eyesight. If the feeling of tension changes when you would rather it be constant, work to discover where you’re going wrong. If you observe results you know are wrong, deconstruct the cast, find and correct the individual mistake before proceeding. This is the best way to avoid making additional mistakes that only complicate and degrade the entire process. This is not easy work, it is why we practice—so that we can learn and improve. Enjoy the journey.


About Greg Holt

Screenshot 2016-01-27 at 9.18.29 AM
“Greg Holt is a 66 year old Washingtonian who began fly fishing at age 12 and never stopped despite hooking himself, nearby objects and people, and occasionally fish of various species. Like many of his generation he began learning the two-handed game about a dozen years ago, eventually attaining a skill level that allowed him to practice his craft in public without undue fear of embarrassment or harm to himself or his fishing companions. While both his writing and casting skills are works in progress, few individuals are more enthusiastic about the process of improvement.”

7 thoughts on “Taking Up the Slack – guest shot

  1. After reading this article I find myself using the words tension and “traction” all of the time when helping people revamp their casting strokes. Good terminology, Well done Greg.

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