PLEASE NOTE: In order to post on the Board you need to have registered. To register please email paul@sexyloops.com including your real name and username. Registration takes less than 24hrs, unless Paul is fishing deep in the jungle!

Shooted cast

Moderator: Torsten

User avatar
Paul Arden
Site Admin
Posts: 13920
Joined: Thu Jan 03, 2013 11:20 am
Answers: 1
Location: Belum Rainforest
Contact:

Re: Shooted cast

#41

Post by Paul Arden » Sat Sep 05, 2020 7:44 am

I think this might be somewhat similar to Paul's touch haul on the snakehead pickup?
Absolutely. I’m quite sure that I release closer to MCL than RSP with the backcast. Forward cast I don’t know exactly what I do. I only discovered I was doing an extreme form of “slide loading” on the forward cast (because I was slipping/shooting line at the beginning of the stroke) and I noticed this on video. However I may well be releasing pre RSP on the forward cast too.

I really must video this because I think it’s breaking a few “rules” particularly with regards the release. Releasing just prior to RSP is one thing. Releasing around MCL is quite another. I have a couple of orange Infinity lines in the post to me. I’ll zebra mark one up when they arrived.

(The list of videos I have to make is amazing! When wife is here I’ll spend a day casting with the camera! :D)

Cheers, Paul
It's an exploration; bring a flyrod.

Flycasting Definitions

User avatar
Merlin
Posts: 1475
Joined: Wed Jan 09, 2013 8:12 pm
Location: France

Re: Shooted cast

#42

Post by Merlin » Sat Sep 05, 2020 3:52 pm

Here is an abstract of a simulation based on an analysis of one of Paul’s competition casts.

The first graphic illustrates the various important timings. Line and rod tip peak velocities occur a few ms before RSP but for sake of simplicity I use RSP as the reference for this point in time. A haul is illustrated in red with a perfect sine function. Peak haul velocity shows up in between MCL and RSP (the vertical red line in the middle). The haul lasts up to MCF in this example.
Histories 1.JPG
Histories 1.JPG (36.48 KiB) Viewed 407 times
The next graphic illustrates acceleration profiles for rod tip and haul (again in red). I illustrated the peak haul acceleration (left hand red line) and the peak haul deceleration (right hand red line). One can see that a very strong tip deceleration (likely exaggerated by the model assumptions for launch) occurs at RSP and lasts until MCF (then there is a rebound).
Histories 2.JPG
Histories 2.JPG (22.26 KiB) Viewed 407 times
Consequently, when the tip decelerates from RSP to MCF it applies a pretty strong deceleration on the line (blue curve), and in this case there is the same type of phenomenon due to the haul (negative values).

One can see then that from RSP to MCF the line in the loop is decelerated by both tip and haul and since it is directly related to the difference in tension in between the ends of the loop (angular momentum equation), there are chances for the tension of the rod leg to go very low, eventually beyond zero (compression). To prevent such phenomenon it is important to have sufficient tension at the top of the loop, which means that there is a change in momentum at loop level to induce an acceleration of the fly leg.

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

User avatar
Paul Arden
Site Admin
Posts: 13920
Joined: Thu Jan 03, 2013 11:20 am
Answers: 1
Location: Belum Rainforest
Contact:

Re: Shooted cast

#43

Post by Paul Arden » Sat Sep 05, 2020 4:46 pm

I remember being surprised about this at the time and always thought I accelerated the haul through to an abrupt stop. Does peak haul speed coincide with the tip deviating below the SLP?

Lots of interesting stuff in there. I know that I was casting well on that day. We had just spent three days throwing distance In KL and I was very happy with my loops.

I know it’s not what I teach because I say that the final part of the haul is the fastest. Although that’s quite difficult to accomplish in the forward cast/haul.

I find that very interesting. Thanks Merlin. I’ve thought about it often over the past few years. I would be very interested to analyse another to see if was a one off or a true representation of my casting. I know that it was a hell of a lot of work that was put into this.

Cheers, Paul
It's an exploration; bring a flyrod.

Flycasting Definitions

User avatar
Merlin
Posts: 1475
Joined: Wed Jan 09, 2013 8:12 pm
Location: France

Re: Shooted cast

#44

Post by Merlin » Sat Sep 05, 2020 6:17 pm

Hi Paul

Peak haul speed takes place some 20 ms before the tip deviates from its "SLP". Pretty close indeed since the exact position is not so easy to define, the path pictured by the model being slightly domed :)

I can change haul timing, etc. in the model. I use a rotation/translation input inspired by a record of one of your competition casts analyzed by Gordy. If you need some scenarios, I can test them. For this example I tuned the haul timing to be in a typical situation (end at MCF). The haul is also inspired from one of yours, but in real world I guess that things can variate from time to time and do not match a "perfect" haul function idealized by a mathematical formula.

If you want some specific testing, you are welcomed.

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

Michal Duzynski
Posts: 1227
Joined: Thu Jan 17, 2013 5:14 pm
Location: Brisbane-Australia
Contact:

Re: Shooted cast

#45

Post by Michal Duzynski » Sat Sep 05, 2020 11:09 pm

Hi Merlin
Thank you for the feedback on my realese. I dont have a propper footage, it was just slo mo option on my mobile.
...and yes the the line hand opened as soon as I hit the end of the haul.
That is good for me, now things gets complicated😁
cheers
mike

User avatar
Merlin
Posts: 1475
Joined: Wed Jan 09, 2013 8:12 pm
Location: France

Re: Shooted cast

#46

Post by Merlin » Sun Sep 06, 2020 8:44 am

Another run(simulation of Matthias's cast) closer to Lasse's cast . The haul ends up at RSP, the timing when Lasse releases the line. The red line represents maximum haul speed:
Histories 3.JPG
Histories 3.JPG (33.52 KiB) Viewed 366 times
Histories 4.JPG
Histories 4.JPG (27.56 KiB) Viewed 366 times
The main deceleration comes from the rod again. It must be a question of timing for release: early and you avoid the main effect of the tip deceleration, a little bit late and you get a delay in rod leg response.

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

User avatar
Paul Arden
Site Admin
Posts: 13920
Joined: Thu Jan 03, 2013 11:20 am
Answers: 1
Location: Belum Rainforest
Contact:

Re: Shooted cast

#47

Post by Paul Arden » Sun Sep 06, 2020 8:52 am

Hi Merlin, are the scales the same ie m/s? If so I appear to have a line speed of 150mph. That seems incredibly high?

Cheers, Paul
It's an exploration; bring a flyrod.

Flycasting Definitions

User avatar
Paul Arden
Site Admin
Posts: 13920
Joined: Thu Jan 03, 2013 11:20 am
Answers: 1
Location: Belum Rainforest
Contact:

Re: Shooted cast

#48

Post by Paul Arden » Sun Sep 06, 2020 8:54 am

On the other hand Matthias’ cast appears to be ~50mph which seems rather low!
It's an exploration; bring a flyrod.

Flycasting Definitions

Mangrove Cuckoo
Posts: 361
Joined: Tue Jan 29, 2013 7:51 am

Re: Shooted cast

#49

Post by Mangrove Cuckoo » Sun Sep 06, 2020 1:16 pm

Merlin,

Thanks for those diagrams... it's not uncommon for me to need a drawing to understand something and using big crayons is also commonly necessary.
"Technique is the proof of your seriousness"

Wallace Stevens

User avatar
Merlin
Posts: 1475
Joined: Wed Jan 09, 2013 8:12 pm
Location: France

Re: Shooted cast

#50

Post by Merlin » Sun Sep 06, 2020 3:11 pm

Paul

It's 160mph for this example, the problem is that we do not have any measurement of the line speed for your cast(s), just the translation/rotation input record. Both peak haul speed (11.8 m/s) and peak rotation speed (920 deg/s) may be overestimated. Nobody believes you can reach 160 mph, even yourself :p

Matthias exact record was 53 mph, in this example the haul is slightly faster and the launch speed is 54.2 mph.

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

Post Reply

Return to “Flycasting Physics”