Force.. in this case, in the macro sense, is the human caster. I have only so much strength (and waning at that). I can apply my force poorly or efficiently, but even if I were 100% efficient, there is still only so much of it. When I am blind casting, covering water, I am throwing for distance and working at maximum efficiency so that I can do it for hours. My casting stroke, Force, settles into something repetitive that satisfies my need to maximize distance and minimize fatigue. It becomes a stable, measureable FORCE.
Mass…in this case the payload is the cumulative weight of the line, leader and fly. That can easily be defined, measured, and stabilized. Note that the location of the mass in 30’ of fly line, leader, and fly is complicated whether the line is stretched out or noodled up so the exact center for calculation purposes is best described by the mathematical single point Center of Mass, which for a 30’ level line would be at the center point, 15’ from either end. In a perfect cast one has not cast the mass to 100’, only the far end point of a 100’ mass with an equal amount of mass always closer to you than than the Center of Mass.
Immediately, one would ask, what about the weight of the rod, the mass involved in Momentum of Inertia which must be moved to make the cast. Acknowledging its potential, let’s put that question aside for a moment.
Acceleration is the progressive and constant (given F and M stable) increase in velocity of the mass (line, leader, and fly) taken as a whole, or as measured at any single point (assuming straight in line with the Force). Acceleration over time results in a final velocity, in this case line speed at the end of the casting stroke. And, putting aside all the mostly stable variables, such as air friction, line speed = distance.
So….., in the most simplified sense, if I am the same casting force, and certainly 300 grains of line, leader, and fly are the same…it is ordained that my casting distance is going to be the same…..for the past 50 years and into the future (I wish).
Without getting bogged down in questions of whether my casting efficiency has increased (I don’t think it has), whether I am weaker than I was (maybe…but keep reading), whether line performance and friction has changed ( IT HAS…but that would be offsetting to a loss of strength) then one had better be prepared to consider the very real possibility that, as a casting tool, all the so-called improvements in materials, resins, graphite, modulus, taper, even…. “suspending gravity”, have not substantially changed the basic fly rod as a distance casting tool.
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