Q: How does hauling work?

[jarmo]

Merlin,

that is an excellent answer, thank you very much. So we would need a casting machine - even better than Lasse, if we can imagine such a thing exists - to truly replicate the same experiment with and without a haul. But video analysis and modelling combined support the idea that the primary result of a late haul is direct increase in line speed. On the other hand, for an earlier haul, it is... more complicated?

Graeme: Looking forward to your video.

Is there a web page / article somewhere about these results?

[Merlin]

Here is an illustration for a fishing cast and a gentle haul (tiny tail risk), the ordinate is in m/s.

gentle haul illustration.JPG (31.44 KiB) Viewed 2468 times

If one could capture a video, he might find that the difference in between line maximum velocity and tip maximum velocity would range from 7% (of 5 m/s, the peak haul velocity in this example) for an early haul, and 87% of PHV for a late haul. That depends on the timing of the haul.

For an early haul, the (change in momentum over time) extra force created on the tip generates a tip speed during unloading which is nearly equivalent to the haul speed if you compare it to the non hauled cast. The effect is indirect but you get nearly all haul speed back from the rod in that case.

The spectrum of results is then from a nearly complete indirect effect (extra rod speed generation, thanks to the haul) for an early haul; to a nearly complete direct effect for a late haul.

Merlin

[jarmo]

The spectrum of results is then from a nearly complete indirect effect (extra rod speed generation, thanks to the haul) for an early haul; to a nearly complete direct effect for a late haul.

Most interesting. Let me see if this is simple enough for me.

• Is the immediate effect of hauling an increased bend in the rod, or a direct increase in line speed?
• Yes.
• Is it possible to be a bit less cryptic?
• If you have a noodle - or an "unbent" rod - and you haul, the immediate effect will be an increase in the bend. This will be converted to line speed when the rod "unloads."
• On the other hand, if you have a pool cue - or a "bent" rod - and you haul, the stiffness of the cue will resist bending, and line speed will increase immediately.

But wait. I was just handed a hammer, and suddenly I see another nail.

• Is the rod primarily a spring or a lever?
• Yes.
• Please do not do that.
• Oh, sorry. If you have a noodle - or an "unbent" rod - and you rotate it, the immediate effect will be an increase in the bend. This will be converted to line speed when the rod "unloads."
• On the other hand, if you have a pool cue - or a "bent" rod - and you rotate it, the stiffness of the cue will resist bending, and it will work like a lever.

[Merlin]

Jarmo

I’m afraid this is bringing confusion since you try to combine the haul mechanism to others in a simple way. You haul with a bent rod, being soft or stiff, this is secondary - but for tailing which depends of the relative importance of rotation input and haul speed - for understanding. By the way a rod never acts as a pure lever unless it is a damn broomstick, but bends and unbends continuously.

The haul mechanism is dual with a “spring side” and a “speed side”. Those mechanisms are always playing together with more or less importance. If you haul early and in synch with the ongoing bending of the rod due to the cast itself, you increase that bend and get speed back as the rod unbends. It is as if the haul effect had been nicely injected into the spring mechanism which gives it back to the line.

If you haul late the rod is unbending as you induce an extra force which reduces its speed of unbending (recovery). This is why the loop is going to be smaller, you use the haul to delay the unbending of the rod, and consequently the amplitude of its counterflex. You lose tip speed (visible on the graph, red line), but the haul speed is then directly transferred into line speed.

In between you get a mix of both, some speed from the rod (coming from the haul), some speed directly from the haul itself. On the paper the best line speed is obtained from rod bending which may be the reason why some people relate haul efficiency to rod bend. The price to pay is a risk of tailing and a larger counterflex. Minimizing those risks with a late haul has a price in terms of line speed. However, it is the safest compromise and at the end of the day it might be rewarded as the line unrolls.

The actual issue is to time the haul properly with a window of a few dozen of milliseconds. I think that we miss the target we have in mind quite often.

Merlin

[jarmo]

I’m afraid this is bringing confusion since you try to combine the haul mechanism to others in a simple way.

I am actively trying to simplify this to the point where it makes some sense and can be communicated relatively shortly. It would help if the simplified version would be approximately correct too.

You haul with a bent rod, being soft or stiff, this is secondary - but for tailing which depends of the relative importance of rotation input and haul speed - for understanding.

Ok.

By the way a rod never acts as a pure lever unless it is a damn broomstick, but bends and unbends continuously.

I know - again, simplifying.

The haul mechanism is dual with a “spring side” and a “speed side”. Those mechanisms are always playing together with more or less importance. If you haul early and in synch with the ongoing bending of the rod due to the cast itself, you increase that bend and get speed back as the rod unbends. It is as if the haul effect had been nicely injected into the spring mechanism which gives it back to the line.

If you haul late the rod is unbending as you induce an extra force which reduces its speed of unbending (recovery). This is why the loop is going to be smaller, you use the haul to delay the unbending of the rod, and consequently the amplitude of its counterflex. You lose tip speed (visible on the graph, red line), but the haul speed is then directly transferred into line speed.

In between you get a mix of both, some speed from the rod (coming from the haul), some speed directly from the haul itself. On the paper the best line speed is obtained from rod bending which may be the reason why some people relate haul efficiency to rod bend. The price to pay is a risk of tailing and a larger counterflex. Minimizing those risks with a late haul has a price in terms of line speed. However, it is the safest compromise and at the end of the day it might be rewarded as the line unrolls.

Excellent explanation, again. Let me try to reformulate. (If there is one virtue I have, it is patience.)

• Is the main role of hauling an increased bend in the rod, or a direct increase in line speed?
• Yes, but there is actually a third role: decreasing the rate of unbending.
• Care to elaborate?
• Sure. If you haul "early," while the rod is still being accelerated, the haul will increase the bend in the rod, in addition to directly increasing line speed. The relative proportions of these two effects vary.
• On the other hand, if you haul "late," while the rod is already decelerating, the haul will not increase the bend in the rod, but instead decrease the rate of unbending. This will, in fact, decrease the amount of line speed obtained from rod bend alone. At the same time, though, the haul still increases line speed directly. Decreasing the rate of unbending also decreases counterflex, which can help in getting those ultra sexy loops.

Any better? If I got this (approximately) correct, this certainly helped me!

[George C]

Hi Merlin

Your model uses a fixed haul speed to show the effects on line speed of different haul timing.........but mightn't hauling later allow one to haul faster and thereby achieve a higher end line speed than a haul peaking closer to MCL.

Here is my thinking. For a given casting arc the rod needs to bend a certain amount to maintain a SLP towards target. Not enough and the cast arcs, too much and it tails.
Effectively then, for any given arc, the necessity to strive for a SLP puts a limit on how much force one can use to reach MCL ,whether through rotation alone or through rotation and haul (let's ignore translation). For a given arc then, only by stiffening the rod (or changing hand path?) can one apply more force prior to MCL without causing a tail. This relationship means then that for a given trajectory, hand path and arc there is limit to the amount of elastic energy you can store in any particular rod while still maintaining a SLP and hence a limit to the line speed contribution the rod will deliver as it unloads.

Once past MCL, however, additional force can be added by hauling harder/faster without adversely affecting SLP. So even though you slow rod unbending and tip speed some, can you compensate or even gain additional line speed because you can now haul harder and faster without ruining the cast?

Is this (rather than counterflex/loop concerns), perhaps, why big distance casters haul so late ? They have a fixed arc (at their maximum ROM and desired trajectory), they have a fixed rod stiffness (the one they picked to cast), and they want to impart as much energy (via force) into their cast as possible while still directing it in a straight line. They impart that force through their rod hand and line hand. By spreading out when they apply that force they can apply more of it without ruining the cast?

Thanks for considering my ramblings.

[Lasse Karlsson]

Merlin, how long an arm does your model caster have?

Cheers
Lasse

[Merlin]

Hi Lasse

For the example I am using for Jarmo, the input is Matthias' one (hand path, rotation speed) for his Paradigm cast.

Merlin

[Merlin]

Hi George

All you say makes sense to me. IMHO you describe the desired long distance cast conditions pretty well. SLP is a limitation because of the risk of tailing, but I have heard different opinions about the best compromise: some prefer to get the best of delaying the haul; some prefer to take their chance for maximum line speed without tail: a “not so late” kind of haul. I’m not sure anyone can tell which option is the best, if they can be sure of the haul timing they use (and not they think they use). MCL timing appears to be a convenient reference for hauling although no one can really know exactly when it happens.

Merlin

[Merlin]

Jarmo

Let’s try to go progressively to something like the way you introduce the topic. There are always subtleties in rod behaviour, this is why I illustrate several parameters below:
• Minimum Chord Length as a function of haul timing. There is always an increase in rod bend.

Haul MCL.JPG (29.73 KiB) Viewed 2381 times

• There can be a decrease in speed of recovery getting larger as the haul is delayed.

Haul unloading duration.JPG (26.96 KiB) Viewed 2381 times

• The amount of energy left into the rod after the line has been launched is reduced as the haul is delayed:

Haul left energy.JPG (31.2 KiB) Viewed 2381 times

You never have an “all black” or “all white” situation but a range of various greys, from dark to light.
If I use your presentation I would say:
• Is the main role of hauling an increased bend in the rod, or a direct increase in line speed?
• It does both, and their relative importance depends on haul timing
• Care to elaborate?
• Sure. The haul will increase the bend in the rod, especially if it is an early one. In addition it directly increases line speed, especially if it is a late one. The relative proportions of these two effects vary with haul timing.
• Hauling late reduces the energy left into the rod as the line is launched; part of that energy is used to shape the loop, the other part goes into rod counterflex.

Merlin