Rod unloading during acceleration

[Merlin]

Yes Paul, correct analysis in line with model indications.

Merlin

[Paul Arden]

Thanks Daniel

[Bernd Ziesche]

Hi Nils,
I agree, that it all is possible in fly casting, too.
But...

Shoulder Problems Often Start Early for Pitchers
Overuse is typically to blame. Repetitive strain on the rotator cuff and surrounding stabilizers and tendons is known to cause cumulative damage with serious consequences

🫣
Cheers
B

[gordonjudd]

This morning I gave a look at files corresponding to a fishing cast with a progressive rotation speed increase (Matthias’ cast), and a mild haul. The (marginally) best line speed is achieved for a peak haul velocity occurring just before MAV (36 ms).

Merlin,
Is this the video that optimum haul timing determination was based on?


You can see that Mathias actually hit his maximum haul speed of 5.4 m/s about half way between MAV and RSP1 in that cast. Does you model indicate that he would have produced more line speed if he shifted his haul timing 110 ms earlier in the cast?

Gordy

[Merlin]

Gordy

Here is an example:
40 ms before MAV : 26.57 m/s
MAV: 26.42 m/s
Halfway between MAV and RSP : 25.27 m/s
RSP: 23.45 m/s

If there was no drawback (tailing loop), the benefit in line speed would be about 5% in this example. It is always safer to stay between MAV and RSP because of the risk of tailing. Rule of the thumb: closer to MAV if the cast is gentle and for moderate distance, and closer to RSP for a distance cast with fast haul. If one can keep its peak haul speed halfway between MAV and RSP, that's always fine.

Merlin

[Bernd Ziesche]

Hi Gordy, hi Merlin,
Haul speed refers to line hand speed independant of it's direction relative to the first guide, right?
What does this tell about the moment of max speed of the line thru the guides and the best moment to release the line?
Thanks
B

[Merlin]

Hi Bernd

I consider the speed of hauled line in the first guide as being the same all along the rod, for all guides. Line speed is maximal after the tip has left the trajectory in the direction of the cast, unless you delay the haul beyond RSP (which is not very efficient). The maximum line speed in the direction of the cast (could it be the best time for release?) occurs before maximum line speed. This is a question of milliseconds (less than 10).
I never experienced early release; I use to let the line go as I feel the rod leg pulling on my hand.

Merlin

[Bernd Ziesche]

I consider the speed of hauled line in the first guide as being the same all along the rod, for all guides.

Agree. Moving the first guide away of the line hand and the other way round creates that speed thru all guides.

I never experienced early release; I use to let the line go as I feel the rod leg pulling on my hand.

I like to teach, that the line should always pull on the line hand during rod rotation. Because, if it doesn't the student most likely has focused on the line hand (learning to haul) and forgotten to properly rotate the rod. Properly rotated the rod = no slack between line hand and first guide, because the tip accelerates the line and thus the line wants to slip thru the guides.
That almost leaves the question of what level of line pulling on your line hand you are referring to in particular.
Almost because, if the rod-leg exists it must be quite post RSP1, I assume. I would not want to wait until the fly leg has overtaken to pull the rod-leg out. That is because my hand probably needs more time to open as I think or as it feels. Exactly about the "sensation" of the so called early release.

[gordonjudd]

Haul speed refers to line hand speed independent of it's direction relative to the first guide, right?

Bernd,
No my haul speed is calculated by taking the derivative of the distance between the haul hand and the first stripper guide. That speed should also be equal to the speed of the line going through the guides.

In Ulrik's study the haul speed was approximated by:

Outcome variables used for analyses were maximum translational and rotational speed of the rod butt (vrod and θrod, respectively) and maximum speed of the movement of the line hand relative to the rod butt (vline).

The timing of the peak speed difference is close to the peak haul speed on the forward cast but not on the backcast since the haul speed on the back cast is dominated by the stripper guide speed that results from the rotation of the rod.

That almost leaves the question of what level of line pulling on your line hand you are referring to in particular.

Can you tell from your videos when elite distance casters release the line? In the few cases I have measured it appears that the release of the line happens around MCF not before RSP1.

Gordy

[Bernd Ziesche]

Thanks Gordy! I didn't really think you added such details. The colored line of the line hand path put me on the wrong track. You probably have told me about this before, so I appologize! Didn't remember this from having read Ulrik's study either. 🫣

From my videos, no chance. I agree with Lasse, who said we can't see that detail in vids without extra equipment in use.
But I was asking a fair number of experts about what they thought. My resumee was: "Think early" shall help.

I can tell, that on an non hauled static roll cast it makes an incredible difference for me (to release early, whatever early in detail is).
I believe that pulling the line down the rod creates quite momentum in the wrong direction to be overcome when hauling.
I always wanted to mark a line black,white,black,white and then compare the moment of the line running out for a hauled and a unhauled cast.
My thought is, that for the hauled cast we may see a tiny bit extra time for the fly-leg to overtake.
But hey this might very well be some crazy thoughts not matching reality at all. 🫣
Question is can an early release have the same impact on a hauled cast or does it need more fly-leg first?