Why does the 170/stopless work

[Merlin]

Hi Paul

Here is the description of a 170 cast with the 2D model and inputs coming from the digitalization of one of your hauled 170 cast. The rod is a 908.

The cast takes place between 0 s and 1.13 s (end of data for the model). Rod angle starts at 70 degrees back from vertical. The rotation is late and starts at 0.6 s. At 1.13s the angle of the cast is 159 degrees and the rod is horizontal (butt is 89 degrees from vertical).

There is a haul starting at 0.750 s (butt 56 degrees back from vertical), peaking at 0.91 s (butt 43 degrees from vertical) and ending at 1.07 s (butt 76 degrees from vertical).

Now the main events:
• Peak rotation speed is at 0.836 ms with vertical butt (less than 1 degrees from vertical)
• Maximum normal deflection occurs at 0.848 s (butt 10 degrees from vertical).
• Unloading point is given by minimum chord angle for 0.864 s and butt at 24 degrees from vertical.
• Minimum chord length takes place at 0.893 s (butt 38 degrees from vertical)
• Zero tip vertical speed occurs at 0.929 s (butt at 47 degrees from vertical) and is assumed to be the loop shaping starting point.
• Maximum tip speed is 60.3 m/s at 0.936 s with butt at 48 degrees from vertical.
• Rod straight position takes place at 0.962 s with butt at 54 degrees from vertical
• Maximum counterflex occurs at 1.058 s with butt angle at 74 degrees from vertical

If you consider time scale, it is pretty difficult to capture tiny differences in between events. The rod starts unloading before all main speed events.

Merlin

[John Waters]

That’s great info Daniel, would love to compare a technique that was based on say a 11 to 1 arc as per the clock face or a 10:30 to say 1:30 arc, then a backward drift. Eg Steve Rajeff Casting the trout distance.

Thanks again,

John

[Paul Arden]

Thanks Daniel. I’m amazed that peak rotation is so close to the vertical. It would be interesting to have a drawing of these points show all the peaks. When is peak haul acceleration? I remember this being considered on the early side.

Cheers, Paul

[Merlin]

Hi John

I shall try something to mimick Steve style. A problem will be to set the power intensity (see James' explanations).

Paul

Timing for peak haul acceleration is 0.830 s, 5 degrees before vertical for butt angle. Pretty nice synch. What type of graphic would you like? Timing versus butt angle?

Merlin

[Paul Arden]

I was thinking of a diagram of rod positions throughout the stroke, each labelled. Could also be superimposed stills. Was this forward cast or backcast?

Thanks, Paul

[John Waters]

Thanks Daniel, appreciated.

John

[Merlin]

Putting stills on a graphic is a long exercise, although I did it in the past, and I think that a one degree difference will be invisible

As far as I remember it was a forward cast with slide loading.

I face a difficulty with Steve's style. Is there a slowmo somewhere so that I can guess a way to translate that in numbers? A problem lies in the "preload" of the rod (remember Server's explanations about that?). If I cannot include one I get a drop in the tip path because of the short arc and timing. I would like to see if there is some rise in the rod at the beginning to compensate for that.

I had a first try and the rod unloads before loop shaping, which occurs as the butt is already stopped. I have the same order of magnitude for speed but this is tunable. The question is how fast can Steve rotate? 1000 deg/s? For Paul's it is 860 deg/s in the modeled cast.

Merlin

[Paul Arden]

Ok not stills then just a diagram. I’m pretty fast with stills editing. But I’m away from my laptop this weekend. Maybe a drawing is clearer. I’ll try to knock something up when I’m back

Cheers, Paul

[Merlin]

I just checked a 2007 video from Steve, and here are my observations:
* before the final shoot, casts are rather symmetrical with plus or minus 45 degrees from vertical.
* for the final cast, the (very very stiff) rod is rotated back to minus 60 degrees and the delivery stops at 60 degrees.

If I compare with Paul's cast, the "effective" angle is pretty similar, something like 120 degrees. Paul is not stopping the rod so the final angle is about 160 degrees. The starting point is also lower (minus 70 degrees).

There might be less difference than expected, the preparation casts are different (restricted angle for Steve), the delivery cast differs when considering the starting and ending points but the effective angle on which power is applied is comparable.

I could not estimate Steve's rotation speed from the video. It just seems to be huge. I read in Joan's Wulff book that he sometimes used a #17 rod for distance (which event??). On the video I watched, he seems to cast a broomstick.

Merlin

[John Waters]

Thanks Daniel, I presume Steve would be casting the ICSF event 2 which now uses a 38 gram line, however it may have been a clip from an earlier clip that allowed a line up to 40 gram line. Interesting that results of rhe two techniques are similar. I still struggle to understand the benefit of the extensive backcast rod movement of the 170 technique.

Thanks again,

John