Making Waves 2.0


Back in 2019 when I wrote the Einstein Series I briefly discussed making waves in fly lines as part of what the line does. A few things were covered including line tension, tailing loops and, in general terms, mends and such. 

To recap, in tech-speak a fly line is a “string medium”. Two aspects of a medium determine how a wave will travel through it namely, the tension in the medium and its linear density. 

It’s simple really, waves travel faster through media under more tension and hence slower through media under less tension. All of that is easily experienced and clearly seen by using something like a garden hose attached to a tap, putting waves into it and varying the tension by introducing and removing slack. The link above will take you to greater detail on playing with garden hoses.

All else being equal waves travel slower through media with greater linear density and hence faster through media with less linear density. For present purposes I will concentrate on the effects of tension and leave density for another time. 

So, why revisit the significance of waves to fly casters? The short answer is that I have been persuaded, mostly by Graeme Hird, that thinking of our fly line as a medium through which we make waves is more useful than my initial treatment gave credit for.

Those with a scientific bent will understand that to be accepted theories need to clear two hurdles. First they have to provide a sound explanation of the phenomena being studied and second they need to have predictive power meaning that the theory reliably predicts outcomes in a given set of conditions. After agonising at great length about whether and when wave theory applied to fly lines has explanatory power I decided not to worry about that because it has such useful predictive power. 

For the record, it is widely accepted that any mend, aerial or not, put into a fly line being cast in the air or manipulated on the water is a wave. It is, however, much more controversial to say that loops are waves. Graeme is a firm believer that they are. I am agnostic but we both agree that, after loop formation, treating the fly line as medium with at least one wave travelling through it can be very useful. Secondly, the extent of that usefulness has been insufficiently recognised, embraced and applied. At the very least, it is a simple and practical conceptual model. For most casters, including me, that is far more important than technical correctness. 

Finally, I think Graeme, many respectable others and I agree that prior to loop formation the three laws of motion given to us by Issac Newton are really all we need to both explain what is happening and predict what will happen when we make a fly cast. Yep, waves that we create in the rod leg before loop formation are important because mostly they are unwanted as they continue travelling down the fly leg after loop formation. No-one likes a tailing loop (transverse wave) in a standard overhead cast. However, Newton has pretty much everything else covered. In my case, understanding the full implications of his second law and its simple equation (F=ma) is a conceptual model I use every time I practice. It captures efficiency of effort, perfectly. That goes in one pocket. Waves and tension go in the other one.

Manipulating Line Tension

As Graeme points out, although we can control tension in the rod leg after the loop has formed, most of us don’t consciously try to do that. However, with deliberate movements of the rod tip we can actually maintain, increase or reduce tension. This is a very important insight. Because our ability to change rod leg tension is limited, particularly withincreasing it, I prefer to call it “manipulating” rather than “controlling” tension.

Graeme has set out a list of practical ways in which he has used his understanding of wave theory to change and improve his casting. Some of them I’ve already played with extensively and some are new additions. I won’t cover all the things he has mentioned but I will cover things I have tried out in practice and will continue to experiment with. As the newer things become more deeply grooved and the results clearer, I will amend this page. For now, take this as the interim report on what I believe definitely works and also on what possibly works.

Definitely Works

Check hauls and Pullback

A check haul is when we stop the shoot suddenly using our line hand. This increases line tension and promotes turnover/ increases the (wave) speed of the loop. If you see your cast stalling a check haul might save it. If you know the shoot has gone just about far enough a check haul can stop the line and force turnover closer to your desired spot.

Pullback is when we literally pull back on the rod leg using various techniques including Graeme’s favourite of a rod lift to take some sag out of the rod leg. You can also induce crisper counter-flex by a slight reversal of the rod’s direction at the end of power application. By this time the loop has already formed and we promote its propagation through the line.

Line Mends

Graeme’s work has definitely expanded/enhanced what I can do with mends – both in the air and on the water. My mends are becoming more precise and more repeatable. By treating both our loops and our mends as waves we can understand that in a level line (which has constant linear density) the loop and the mend waves will travel at the same speed away from us and will therefore stay the same distance apart. 

Make an aerial mend after the loop has travelled 20 feet and the mend will stay (and land) about the same distance from the fly. Likewise a mend made when the loop is 30 feet away from us will land roughly 30’ from the fly. I say “roughly” to allow for changes in the linear density of the line and then leader because taper in both affect density. This approachgives us a visual cue for when to make the mend, something both new to me and very handy. 

To finish off the cast and land the mend where we want to we can reduce tension and thus kill the cast when the mend wave has gone far enough. We can do this by simply pushing forward in the direction of the cast. 

Under Powered Curve Casts 

This cast has taken on new interest since I took up Graeme’s advice on how to perform it. Instead of trying to finesse the power application I now concentrate on killing the cast when the loop has reached the desired position and thus shape. This makes the cast more accurate and more easily repeatable.

For me it has never been a fishing cast as there are usually other and more reliable ways of getting the fly to land where and as I want it to. That could change, however, as I play with it more and get to know it better.

Possibly Works

Graeme has found a lot of benefit from using an upward and sideward movement of the rod tip at the end of a stroke to produce more tension in the rod leg than would normally occur. In standard overhead casting this has allowed him to:

  • Improve his casting efficiency (less effort for the same distance cast) 
  • Increase the length of line carried

In sidearm casting he finds that loop shape can be tightened, loop speed increased and a zippy presentation can be made into small gaps in between snags and overhanging shrubbery.

As regular readers know I am a devotee of casting efficiency and finesse so I’m more than willing to make efficiency gains wherever I can – meaning before or after loop formation. (Remember, Newton before, tension and waves after, the loop is formed.)

So far I have not been able produce the same benefits as clearly as Graeme. I have seen some possible gains but they are not definitive enough to make me a follower. More practice time will tell and I will report back on these things when I am convinced that I have grooved the movements sufficiently to know if I can or can’t get more from them. 

For now I will say two things. First, I have been playing with rod lift for quite some time in dynamic roll casts and remain undecided whether the lift adds enough (distance or efficiency) to make it a standard operating procedure. Second, to date I have found that making the lift does not have a beneficial effect on my casting accuracy and might be something of an unwanted distraction/detraction. That too could change as the movements become more automatic.

Efficiency of the Cast – Further Thoughts

Since I wrote what you’ve just read above I’ve had a couple more practice sessions and some further thoughts. 

When we make a fly cast, overhead, side arm or roll, our bodies work most efficiently in ways dictated by mechanics and biomechanics. We use biomechanical efficiency to produce mechanical efficiency.

It is useful to consider casting efficiency as having two parts, before and after loop formation. However, we need to remember that these two parts make a functionally indivisible whole. Both parts need to be optimised in order to achieve overall efficiency. That, in turn, will minimise effort and therefore maximise control which helps us to put the fly where we want and how we otherwise want it to be presented. 

Having played around with rod lifts to increase line tension after loop formation I have concluded that there is something in this. I still think, however, that efficiency before loop formation is the main game. Increase that and there is less work to be done and fewer gains to be had from increasing line tension post loop formation. That is probably because pre-loop efficiency has already established line tension and will help preserve it after loop formation.

Let me put it more simply. If you make a poor cast then increasing line tension with a lift might help but it won’t turn acrap cast into a good one. If you’ve made an excellent cast then increasing line tension might add a little something but not so much as to significantly alter the quality of the outcome. Of course I can’t quantify what I’m talking about but at a guess I’d say that a lift or just keeping the rod high might add 5% or even 10% at times. Definitely worth playing around with but for me it won’t turn night into day.

One last thought. When we cast, the biomechanics involve a sequence or kinetic chain of movements. These are not performed robotically but with flow. Our sensory motor control manages both the body bits being moved and the flow of the movement. This means that whole sequence is effectively mapped out in advance and the next bit is primed to move before its turn actually comes. So, when we include a lift at the end of the cast, even if there is a slight pause, the mapping and priming incorporates it as part of the overall sequence. That also means that the preceding bits in the sequence will be adjusted and controlled to allow for and facilitate the subsequent movements. I suspect this means that when a lift is coming we tend to anticipate that movement by finishing the cast a little higher. That mitigates against over rotation which in turn adds to efficiency. 

In net terms that would mean that the efficiency gain from increasing tension with a rod lift actually increases the efficiency of our movements before loop formation. As a I said, efficiency is functionally indivisible. We can conveniently think about the two parts as before and after loop formation but in practice each part is affected by the other part – mechanically and biomechanically. 

Here’s some examples from my exploration to date. 

1. By making a rod lift during a back cast I can see how it tightens the loop and enhances propagation. That increases my confidence in shooting line into that back cast. If I keep watching my back casts, in a series of false casts, then the next time around I can produce a back cast, without rod lift, that behaves much the same. In other words I’ve just increased the overall efficiency of the back cast with and without a rod lift.

2. Making side arm casts to a decent distance (60’-70’) I can see that increasing tension with a lift improves the cast but I again I can get much the same result by focussing on an efficient cast without a lift at the end.

3. With dynamic roll casting I often cast to targets at a similar range. At sixty feet a lift makes the cast look a bit more sexy but adds little to accuracy or to reaching the distance. At sixty five or even seventy feet the lift does seem to make it a little easier to reach the distance. At maximum distance of about seventy five feet I’m more likely to get there with a lift than without one.

In short the lift does add to efficiency but for most practical purposes its contribution to my casting is somewhat at the margins. When I’m at the limit of my pre-loop efficiency it becomes more significant but maybe the message there is to improve my overall technique rather than just add something to compensate for its shortcomings.

4. My forward casting has long benefitted from a thrust finish, especially with longer casts and on the delivery. Playing around with Lancio Angolato has emphasised what can be done with a thrust which I’ve mentioned elsewhere. For me it has added efficiency. Alternating between a lift finish, a thrust finish and a thrust followed by a lift was one of the ways I experimented with Graeme’s ideas. As with the previous examples I haven’t found that the lift gave me enough clear improvement to become a standard procedure but it is definitely in there as an optional addition.

I’m not done with tension increases post loop formation and I’m certainly keen to get more from intentionally manipulating line tension for both casts and mends. My suggestion is that you try it and see whether and how it works for you. 

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