Thoughts regarding pullback, check hauling, CoE

[Graeme H]

Great video Dirk. Thanks for sharing it.

Cheers,
Graeme

[Paul Arden]

Hi Gordy,

If the loop fails to turn over, which can certainly be a problem with a shooting head more so than with a full flyline, then much distance is lost, since distance is measured to the fly and not the end of the line. I would think that having the loop fully unroll paramount in this situation. That’s why they have different shooting line thicknesses for different wind conditions.

Cheers, Paul

[Walter]

Here is a plot of the cast. The fly velocities begin to diverge soon (about 0.05s) after the haul starts.

Dirk,

I want to add myself to the list of people thanking you for posting that video. It’s a very good demonstration.

A couple of questions/comments:

- what is the resolution of your timer (frames per second)
- is the plot of line hand vs stripper guide distance or speed?
- looking at the plot of distance from line hand to stripper guide it appears that there is a tiny bit of reverse haul up to the 0.325 sec time frame, then a check haul up to the 0.425 sec time frame and then again a reverse haul after that. Am I interpreting that correctly?

Thanks

Walter

[Dirk le Roux]

Here is a plot of the cast. The fly velocities begin to diverge soon (about 0.05s) after the haul starts.

Dirk,
Great idea and interesting video. Was this taken with a phone at 240 fps?

I was surprised to see that a haul speed of 3-4 m/s could produce a fly speed difference as large as 15 m/s.

Could you show a plot of the two loop front velocities for that cast? Do you see the velocity of the hauled loop decreasing during the haul and then going ahead of the unhauled loop a bit after the haul ends?

What do the "propagation" and "travel" velocities in your graph correspond to?

Thanks for doing this. Marking points in a high speed video is a pain in the ass for me.

Gordy

Hi Gordy

Sorry for the delayed reply. I've been busy.

The frame rate was 240fps and you only need to tell Tracker that. I remember a few years ago when I privately shared this info I made some experiments dropping marbles or the like to make sure the calibration was fine. It was.

The check haul was made by keeping the hauled line pinched by the rod hand and the line hand operating like a pulley. So there was a mechanical advantage.

Yes, you can see the hauled loop front travel momentarily slowing during the haul. I didn't track it through and both the travel and propagation curves (which are of the hauled loop) on that plot are calculated.

You're welcome.

All the best,
Dirk

[Dirk le Roux]

Here is a plot of the cast. The fly velocities begin to diverge soon (about 0.05s) after the haul starts.

Dirk,

I want to add myself to the list of people thanking you for posting that video. It’s a very good demonstration.

A couple of questions/comments:

- what is the resolution of your timer (frames per second)
- is the plot of line hand vs stripper guide distance or speed?
- looking at the plot of distance from line hand to stripper guide it appears that there is a tiny bit of reverse haul up to the 0.325 sec time frame, then a check haul up to the 0.425 sec time frame and then again a reverse haul after that. Am I interpreting that correctly?

Thanks

Walter

Hi Walter

Same on the delayed reply.

The frame rate was 240fps.

The line hand plot was speed relative to the stripper guide, if memory serves.

There may have been a reverse haul initially but the return from 0.425s onward is just a slowing down again.

All the best,
Dirk

[gordonjudd]

I didn't track it through and both the travel and propagation curves (which are of the hauled loop) on that plot are calculated.

Dirk,

Does that mean the travel speed curve (loop velocity over the ground) was equal to 1/2(v1+v2) where v1 was equal to the velocity of the fly leg and v2 was the rod leg velocity (speed of haul) while the propagation speed (tangential velocity of line going around the loop) was equal to 1/2(v1-v2)?

Gordy

[Dirk le Roux]

That's right, Gordy.

Dirk

[Merlin]

Hi Dirk

Do you remember the line and the length you used?
The level of rise in speed puzzles me.

Merlin

[Dirk le Roux]

Hi Dirk

Do you remember the line and the length you used?
The level of rise in speed puzzles me.

Merlin

Hi Daniel

They were WF4F - the cheap Northern Sport Aquanova ones I like quite a bit. About 10m if I recall. It doesn't puzzle me really, considering for instance how easily one can get a whip crack on a slightly too early and enthusiastic stroke.

All the best,
Dirk