Evaluating the Haul

[Merlin]

Gordy

I copied a comment from you in the thread about measuring haul:

Regardless of the technique I would think measurements would show that incorporating a line hand haul path that opposed the direction of the stripper guide path would produce higher haul speeds since the stripper guide speed is so much higher than the hand speed.

That seems logic but the devil is in the detail. Here is the simulation of a BC that I am using: forearm length and distance from hand to stripping guide are set at 0.5 m. In the end, the distance between the stripping guide and line hand is 1.5 m and the hauling distance at that point is 1 m.

BC simulation.JPG (28.47 KiB) Viewed 943 times

The blue curve is the path of the stripping guide and the red curve is the path of the line hand. The colored arrows correspond to the starting point and the black dotted line is the distance between the stripping guide and the line hand at maximum hauling speed (5.79 m/s). Timings have been chosen to maximize that speed and there is a 0.07 s delay at start (the line hand starts later).

The black arrows represent the location corresponding to their maximum speed (7m/s for the stripping guide and 6.28 m/s for the line hand). 6.4 m/s is the stripping guide speed as the haul speed is maximum and 5.79 m/s is the speed of line hand at the same timing.

Now the simulation of the FC: in this case it is amazing to see that maximum hauling speed (6 m/s) does not vary with the change in delay between stripping guide motion and line hand motion. The delay between hand and rod motion has been set at 0.15 s.

FC simulation.JPG (29.01 KiB) Viewed 943 times

Given the trajectory of line hand, which is three times longer than for the BC in this simulation, maximum line hand speed is huge (18.84 m/s) to achieve the same timing (0.5 s) than for the BC. At the point of maximum haul speed the stripping guide speed is 3.49 m/s and the line hand speed is 9.42 m/s. The fact that the absolute top speed for line hand is 18.84 m/s (not 12.6 m/s as I posted before, apologies) appears to be unrealistic so this type of simulation is not suitable. One can imagine a direct pull from the line hand along the rod axis and to achieve a maximum haul speed of 6 m/s, and one just needs to haul along 1 meter within 0.33 s (then the average hauling speed is 1/0.333 = 3 m/s and the peak speed of a sine signal is the double, 6 m/s). To keep a reasonable delay between rod motion and line hand motion, one could use half the timing of the line hand (0.333/2 = 0.167 s). The difference in time between MAV and peak haul velocity would then be 0.167 + 0.333/2 – 0.3 = 0.033 s. Using the same pull for a BC would make disappear the passive part of that haul.

Merlin

[gordonjudd]

Merlin,
I am glad that you are digging into this but I think you will find your circular path shapes and velocity values may need some refinement to get a more accurate view of how the haul speed is affected by the relative movement of the stripper guide and the haul hand.

I can send you some actual paths and measured velocities if will help you to get some better estimates of what is going on.

Here are a couple of examples for the Henry Mattel's and Lasse's back cast that use different haul hand directions (Henry more horizontal and Lasse more vertical) at the max haul speed point. Henry's max haul speed was around 14 m/s while Lasse's was around 11.4 m/s.

Henry's max stripper guide speed was around 12 m/s and Lasse's was around 10 m/s. Henry's hand speed was around 6-8 m/s while Lasse's was
around 5 m/s.

The above haul speed for Lasse was derived from the derivative of the distance between the line marker and rod tip thus it shows a negative value.

Using the derivative of the distance between his haul hand and stripper guide gave a max haul speed of around 10.6 m/s.

Gordy

[Walter]

Gordy,

If you want to discuss hauling from the stripper guide rather than the rod hand I think this video might be more useful than the gf video.

Hauling/casting is an asymmetric activity built around a symmetric body. I find GF’s video not very useful because it doesn’t show how to get around the biomechanics of asymmetry vs symmetry. It’s more of an oddity in my opinion. That particular cast might be useful for short, quick casts on a drift boat with a cross wind while trying not to bean the rower but I don’t see much point in discussing it.

Johansson’s cast has more value imo in that he shows how to take advantage of hauling from the stripper guide on the backcast while also getting an effective forward cast.

https://m.facebook.com/groups/15493437 ... 29674452/?

[Merlin]

Let’s come back to Henry’s BC and give some insight.

Henry.JPG (29.58 KiB) Viewed 889 times

Speed patterns

Henry speeds.JPG (24.67 KiB) Viewed 889 times

It is interesting to note that the line hand begins by following the stripper guide with no haul speed generated during this « passive » period of time. Haul speed begins to rise as the line hand is stopping to move backwards which induces some passive haul. Point A illustrates the moment when line hand is starting to produce a haul by pulling the line forward. Maximum haul speed occurs just after MAV (peak of the blue curve).
This is also illustrated below:

Henry BC.JPG (36.33 KiB) Viewed 889 times

The black dotted line represents the line at maximum haul speed position. The line hand speed is not yet maximum (8.5 m/s), and the speed of the stripper guide has already passed its maximum (12.6 m/s). Approximately only two thirds of the stripper guide speed contributes to the haul at this time, due to the angle of the guide speed with the line. Hand speed contributes to 100 % to maximum haul speed (the line hand trajectory is aligned with the line).

Incidentally, the screen above was captured at maximum haul speed, or nearly.

Merlin

[Walter]

I’m not sure why Gordy keeps bringing up the GF technique in this thread either.

Walter,
Because his technique captures some of the stripper guide's speed contribution to the overall haul speed while an in-line haul direction where the haul hand is moving in line with the rod alignment on a forward cast does not.

When you calculate the haul speed as being the derivative of the distance between the stripper guide and the haul hand rather than coming up with an efficiency factor based only on distance ratios the advantage of his technique in producing higher haul speeds jumps out for me.

Gordy

Gordy,

Based on discussions with other members we came up with two reasons for hauling. One was to shorten the amount of line in the air (distance related) and the other was to increase line speed (speed) related. While it is impossible to have either a speed or distance change without the other the relationship stops there. I've already provided the example that I can make a long slow haul and have significant distance change with minimal speed change or I can make a fast short haul that increases line speed significantly while making a relatively small change in line carry.

I've already provided justification for using the motion between the line hand and the stripper guide as an acceptable way to measure haul distance and haul speed so I'm not sure why you continue to point out the exact same thing but I'll repeat it one more time so that, hopefully, we don't have to keep rehashing the same thing.

Haul distance is the change of the amount of line in the air due to the haul. We can measure it by measuring the amount of line in the air, measuring the movement of the line relative to any of the guides, or by the change of distance between the line hand and the stripper guide.

Haul speed is the change in line speed due to the haul. We can measure it by measuring the change in speed between a point on the line and the rod tip, by the speed of the line relative to any of the guides, or by the speed between the line hand and the stripper guide.

Haul efficiency and haul effectiveness I define in post 1 of this thread but I'll repeat it (again):

When we evaluate something from a physics or engineering standpoint, we look at the effectiveness and efficiency of what we are doing.

If we want to measure the effectiveness of our haul we measure the actual distance or speed we achieve as a result of our haul. Distance and speed effectiveness are not the same. Having a long haul does not mean we have a fast haul. If our haul is .5 meters long and takes 0.5 seconds, the hauling speed is 1 m/s. If we have a 1 meter haul that takes 1 second, then our hauling speed is also 1 m/s. We have twice the hauling distance but exactly the same hauling speed.

I expect most people are more interested in hauling speed but for now I will look at evaluating the haul from the point of view of distance as well as speed.

The efficiency of our haul is a measure of the output (hauling distance or speed) relative to our input. When we look at the haul our input is the relative movement of our hands during the casting stroke/haul. If our hands move 1 meter relative to each other and that causes our hauling distance to be 1 meter, then our hauling distance with respect to distance is 100%. If our 1 meter of hand movement only results in 0.5 meters of hauling distance, then the efficiency of our haul with respect to distance is 50%. Similarly, if a relative hand movement of 1 m/s results in a hauling speed of 1 m/s then our hauling efficiency with respect to hauling speed is 100%.

The reason for defining the effectiveness and efficiency of the haul is provide a means of comparing different hauling styles or movements with respect to how well they meet their intended purpose understanding that there may not only be different purposes for hauling (distance vs speed) but also different situations where hauling is used (fishing, competition, etc.).

You are welcome to propose different measures of "goodness" or better ways of evaluating them but I'm really not understanding your post about using measured speed as a measure of that goodness or your apparent insistence that GF has somehow found the Holy Grail of hauling.

I think we are trying to achieve the same goals when it comes to discussing the haul and hauling technique, but we seem to be repeating the same discussion.

[Torsten]

Merlin

Looks like the "indirect" haul seems to be an very significant contributor to Henry's back cast. A phenomenon that was so far underestimated (?)

Greetings,
Torsten

[Merlin]

Thanks to Gordy’s database about Henry’s back cast, it is possible to compute some ratios to evaluate « efficiency » and “effectiveness ».

“effectiveness”: hauling distance is about 1.8 m within some 0.2 s and hauling speed is around 14 m/s
“efficiency”: I took the middle of the cork as the reference for the rod hand. Then efficiency for distance is about 180 % since the distance in between hand achieves 1 meter. Efficiency for speed is about 140 % since hands distance speed reaches 10 m/s.

Now it does not tell you the effect on the cast: how much speed for the line, how much counter flex for the rod (loop size)? A important point is the difference in time with MAV. Here is an example for a competition cast:

If the haul is pretty late, then haul velocity (12 m/s) adds to non haul line speed (64.3 m/s) to reach about 78 m/s at RSP1 level.
If the haul timing is “not so late”; then one can take advantage from the increase in stored energy into the rod. In that case there is some loss in direct haul speed effect (12 m/s). Such an increase is not that large (7%), and corresponds to a larger counterflex leading to a larger loop likely. Where is the best compromise, if any?

Merlin

[John Waters]

Hi Daniel,

Love reading your modelling information. Interesting to compare the haul pattern of ICSF 38 gram casters to the 27 gram and MED casters’ hauls. The differences equate to your conclusions.


John

[Merlin]

Hi John

Thanks a lot for your kind comment. I'm glad to see that modeling can give good information (sometimes).

Merlin

[Merlin]

Hi Torsten

Looks like the "indirect" haul seems to be a very significant contributor to Henry's back cast. A phenomenon that was so far underestimated (?)

It could be. The indirect haul can be named “passive” if the line hand does not move at all. I made a comparison with a fixed position of the line hand (coordinates x=0.5; y=-0.2 in the third graphic of post #44). In that case the haul distance is comparable to the original one, and maximum haul speed is slightly larger (8 m/s).

I guess that the pattern is reversed for a forward cast: in that case the direct haul should contribute more than the indirect one.
Assuming that the stripper guide trajectory is not affected by a slight change in line hand timing, I tested a variation of +/- 30 ms and here is the result:

BC haul variation.JPG (40.71 KiB) Viewed 92 times

The variation in haul speed is about 2 m/s for the time increment. If the haul is made sooner (red curve), then maximum haul speed becomes larger (16 m/s instead of 14 m/s) and closer to MAV (peak of the black curve). The 2 m/s step is significant. Interesting again.

Merlin