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Shooted cast

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Mangrove Cuckoo
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Re: Shooted cast

#31

Post by Mangrove Cuckoo » Thu Sep 03, 2020 12:16 pm

Paul Arden wrote:
Thu Sep 03, 2020 6:10 am

I know that I teach Down-and-Up for a distance haul because there is not very much shooting going on and “downup” often creates slack.
Paul,

In other words... you pause before feeding line back up the rod? Instead of "bouncing" the haul?

What about on non comp distance casts?

Is that slack created what you sense when you say you can detect RSP in your line hand?
"Technique is the proof of your seriousness"

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Paul Arden
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Re: Shooted cast

#32

Post by Paul Arden » Thu Sep 03, 2020 12:22 pm

Hi Merlin,

there must be an immediate loss of tension at RSP because if you haul through RSP with a softer cast and less aggressive haul you can clearly feel the tension suddenly disappearing. So no line can be shot at this point as far as I can see. Tension reappears later as the loop propagates. At least that’s what the line hand is telling me.
the middle of the loop can represent the lowest level of tension
So the point of the loop is low tension? I find that quite difficult to visualise. :ninja:

Thanks :)
Paul
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Lasse Karlsson
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Re: Shooted cast

#33

Post by Lasse Karlsson » Thu Sep 03, 2020 3:08 pm

Merlin wrote:
Thu Sep 03, 2020 9:03 am
So not what I think, but what actually happens

We may be right and wrong at the same time Lasse. I checked the video with the light as the reference this time. In the first case the light is on just after RSP (10 to 15 ms maybe if I can rely on the time scale). In the second case it is just in time with RSP. The second sequence is then not “release before RSP”, but a little bit earlier than in the first case.

In both cases the haul ends up at RSP or very close to it. In both cases max haul speed is in between MCL and RSP (excellent). Only in the first video the shoot is delayed by 60 ms if the scale time is correct. So there appear to be a loss in tension during a short period of time.

Merlin
I took the original file appart and looked at stills, not trying to hit pause while trying to find the differences. And I slowed down the untersting sequences alot so even the casual viewers would have a chance to spot it. I can see I should really also have put some stills in, but seeing how I was later accused of photoshopping videos of me casting a stiff and a soft rod, I'm glad I opted for just slowing it down alot :D
I shall see if I can find the originals on the external harddrive, haven't had a computer for several years, that might prove a fun excercise.

Cheers
Lasse
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Paul Arden
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Re: Shooted cast

#34

Post by Paul Arden » Thu Sep 03, 2020 4:39 pm

Paul,

In other words... you pause before feeding line back up the rod? Instead of "bouncing" the haul?

What about on non comp distance casts?

Is that slack created what you sense when you say you can detect RSP in your line hand?
Sorry Gary, missed this. Have a look at the bottom video on this page.
https://www.sexyloops.com/flycast/compe ... ance-cast/
There is a defined pause at the end of the haul. Shorter line carry it can be pretty much Immediate but still not immediate in my opinion.

It’s not slack exactly. It’s just that you can feeL all resistance gone. Try it (I’m sure you will! :D ) if you “haul through the stop” you will feel the tension drop. There is tension and then there is not.

Cheers, Paul
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Merlin
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Re: Shooted cast

#35

Post by Merlin » Fri Sep 04, 2020 2:14 pm

Hi Paul
There must be an immediate loss of tension at RSP because if you haul through RSP with a softer cast and less aggressive haul you can clearly feel the tension suddenly disappearing. So no line can be shot at this point as far as I can see. Tension reappears later as the loop propagates. At least that’s what the line hand is telling me.
It’s possible indeed: let’s take some picture to illustrate my comments. The first image corresponds approximately to the time when the tip is going to deviate from its initial trajectory. The second one is RSP (Lasse’s haul has ended) and the third one corresponds to some time near the end of loop shaping.
Loop shaping 1.JPG
Loop shaping 1.JPG (34.03 KiB) Viewed 349 times
Between the two yellow arrows in the figure above, and in fact since MCL, the line is accelerating less and less until RSP where it reaches zero acceleration (maximum speed). After that point (below) the tip is decelerating the line until it reaches MCF.
Loop shaping 2.JPG
Loop shaping 2.JPG (23.06 KiB) Viewed 349 times
If the timing of the haul is such that maximum haul speed has taken place before RSP, the line is being decelerated by the caster’s hand. A haul is made of four steps, approximately equal: at the end of the first quarter, positive acceleration is maximal which impacts rod bending. In the middle of the haul, speed is maximal and at ¾ of the haul, the deceleration is maximal. At RSP time, you may then cumulate two decelerations acting on the line, the one of the tip plus the one of the haul, which can also be at its maximal negative value if RSP is achieved at ¾ of the haul. The corresponding total maximal peak deceleration value appears just after RSP likely and before MCF.

This point is important since considering angular momentum allows estimating the difference in tension at both ends of the loop (completely shaped or not), and this difference strongly depends on the variation of speed of the line along the loop. It also depends on skin drag and loop mass distribution which act against each other, enhancing the importance of the variation of tangential speed along the loop on the difference in tension. If the line decelerates, then rod leg tension lowers by comparison to fly leg tension, which incidentally may be somehow weak if the cast is gentle, and there may well be circumstances when rod leg tension goes to zero or even beyond, meaning that the bottom of the loop is under compression. The line is stiff enough to handle that compression but a shooting or a running line can collapse. Such compression or zeroing delays any release effect at such period of time. The fly leg must accelerate to induce tension again at the bottom of the loop. For that the loop must be shaped first since an adequate variation of (horizontal or so) momentum of the loop is needed.

Merlin
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Re: Shooted cast

#36

Post by Dirk le Roux » Fri Sep 04, 2020 3:38 pm

Hi Merlin

Have you proven all that experimentally?

If not. Please describe the ideal/worst case (for compression) cast to make and I'll see what I can film and measure.

Cheers,
Dirk

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Re: Shooted cast

#37

Post by Mangrove Cuckoo » Fri Sep 04, 2020 8:21 pm

I will read through Merlin's explanation a few more times before I give up...

But, what about hauling (and releasing) well before RSP?

I am not positive what I am doing, but it seems like I can sense when the rod butt begins to unload (SDM?)... and at that point I haul and release. The response from the rod is impressive!

I think this might be somewhat similar to Paul's touch haul on the snakehead pickup?
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Re: Shooted cast

#38

Post by Mangrove Cuckoo » Fri Sep 04, 2020 8:36 pm

"If the timing of the haul is such that maximum haul speed has taken place before RSP, the line is being decelerated by the caster’s hand."

That statement is going to take me a while to digest.. :upside:

The 4 parts of the haul I get, but can't the line be released essentially at the second phase where acceleration is maximum and deceleration has not begun?
"Technique is the proof of your seriousness"

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Merlin
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Re: Shooted cast

#39

Post by Merlin » Sat Sep 05, 2020 7:28 am

Hi Dirk

There are two real world experiences behind, starting with Paul's
There must be an immediate loss of tension at RSP because if you haul through RSP with a softer cast and less aggressive haul you can clearly feel the tension suddenly disappearing.
And the fact that in the first part of Lasse’s video, the line does not shoot immediately after he releases it, this is clearly visible in the slo mo. Those are facts that a complete loss in tension at rod leg level is possible. And what I tried to do is to find a technically possible explanation bearing in mind the analysis of angular momentum.
Cheers

Merlin
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Re: Shooted cast

#40

Post by Merlin » Sat Sep 05, 2020 7:30 am

Gary

I shall make an illustration with all references (MCL, RSP, MCF, haul timing, etc.) of what is happening on the speed/acceleration histories during a hauled cast. That will make things clearer I think (and I hope).

Merlin
Fly rods are like women, they won't play if they're maltreated
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