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The Triple or Check Haul

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gordonjudd
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Re: The Triple or Check Haul

#11

Post by gordonjudd » Sun Aug 02, 2020 2:55 pm

but is it the same in real life?
Merlin,
That is always the question, but getting some experimental data would not be easy. Maybe Dirk could the the marked line he used for his square snaps measurements to track some markers on the fly leg, loop front, and rod leg to see how they compare to your model results.

Was the timing of the late check right at the end of the cast when there the fly leg length was quite small? It does not appear to have had much effect compared to the base case.

Gordy

Dirk le Roux
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Re: The Triple or Check Haul

#12

Post by Dirk le Roux » Sun Aug 02, 2020 6:32 pm

Not great footage, though this suggests that the fly speed-up in reaction to a pull-back check is more immediate than Merlin's graphs have it.



Line out the tip is mostly a 4,5m tapered mono leader. Length calibration on Tracker is a rough estimate based on the rod length, so don't take the velocity scale as super accurate.

I may be able to shoot some casts with a level line later this week, and I trust others may contribute better footage soon.

Merlin, is there any leader between level line and fly in your model?

All the best,
Dirk

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Merlin
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Re: The Triple or Check Haul

#13

Post by Merlin » Mon Aug 03, 2020 4:57 am

Gordy
The check is very late and likely too late, I shall test intermediate cases.

Dirk
I think the length of line has a role, at this stage I use 10 meters and no leader.
I can simulate the case you are showing with 4.5 m of mono, thanks to let me know its diameter and the approximate size of the loop. I am away from home till saturday without my PC, and will likely make the runs on sunday.

Many thanks in advance for info about your test in the video.

Merlin
Fly rods are like women, they won't play if they're maltreated
Charles Ritz, A Flyfisher's Life

Dirk le Roux
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Re: The Triple or Check Haul

#14

Post by Dirk le Roux » Mon Aug 03, 2020 11:07 am

Hi Merlin

The leader is Maxima Ultragreen 1.9m of 0.50mm, 1.1m of 0.42mm, 0.7m of 0.37mm, 0.5m of 0.32mm and 0.3m of 0.22mm.

Loop size was approximately 0.6m.

Cheers,
Dirk

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Paul Arden
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Re: The Triple or Check Haul

#15

Post by Paul Arden » Mon Aug 03, 2020 2:31 pm

Hi guys,

That makes me think about loop size. Near the end of loop unroll the loop will most likely be tighter than at the beginning. It’s not really possible to make a long check-haul because mostly we will have made a haul during the stroke as well.

For me it would be something I would always do late, mostly as the leader is about to unroll, or fail to unroll. This would normally be the point when I would firmly check the shoot and if the thing is dying in midair I will give it a little pull.

Cheers, Paul
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gordonjudd
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Re: The Triple or Check Haul

#16

Post by gordonjudd » Mon Aug 03, 2020 4:13 pm

Near the end of loop unroll the loop will most likely be tighter than at the beginning
Conservation of angular momentum would argue it would be the other way around. The diameter getting smaller when the linear mass density (rho_l ) increases in a sink tip line shows that effect.

The boundary conditions for the final layout of the leader are different however, so it would be good to see a slow motion video of the final roll over of the leader (it amazes me that someone has not done that) affects the diameter of the loop as it gets to the end of the leader.
Image
Gordy

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Re: The Triple or Check Haul

#17

Post by Dirk le Roux » Tue Aug 04, 2020 4:54 am

Dirk le Roux wrote:
Mon Aug 03, 2020 11:07 am
The leader is Maxima Ultragreen 1.9m of 0.50mm, 1.1m of 0.42mm, 0.7m of 0.37mm, 0.5m of 0.32mm and 0.3m of 0.22mm.

Loop size was approximately 0.6m.
Merlin
I forgot to mention there was also around 1.5m of 4 weight fly line out the rod tip.

And the 0.6m loop width is at its widest. The loop had a pointy nose which was fairly narrow, say 0.2m.

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Merlin
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Re: The Triple or Check Haul

#18

Post by Merlin » Tue Aug 04, 2020 1:49 pm

Thanks Dirk
That sound more complicated than I expected :D
Do you have an idea of the check timing by assuming time zero to be the point when the loop is just shaped? When does the check starts and when does it end?
Merlin
Fly rods are like women, they won't play if they're maltreated
Charles Ritz, A Flyfisher's Life

Dirk le Roux
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Re: The Triple or Check Haul

#19

Post by Dirk le Roux » Tue Aug 04, 2020 8:35 pm

Merlin wrote:
Tue Aug 04, 2020 1:49 pm
That sound more complicated than I expected :D
Do you have an idea of the check timing by assuming time zero to be the point when the loop is just shaped? When does the check starts and when does it end?
One can afford such complications in the real world :cool:

With time zero at RSP, the check started at 0.400s and ended at 0.634s. My best guess for LSP is 0.950s.

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Merlin
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Re: The Triple or Check Haul

#20

Post by Merlin » Sun Aug 09, 2020 1:16 pm

I started a few tests with a shorter line (5.5m) and I can get a speed reaction 50 ms after the end of the check. This check starts 100 ms after the loop has been shaped and lasts 220 ms.
I am not yet in a position to come closer to an actual test, for that I need to enter some taper for the line/leader.
I also need the amplitude of the check for a comparison, today I use 3 feet for the "short line".

Merlin
Fly rods are like women, they won't play if they're maltreated
Charles Ritz, A Flyfisher's Life

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