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Walter & Group...
[GH] As we delve deeper and deeper into a topic, the complexities emerge. At first this is confusing. Then we begin to unravel the casting theories in the light of the many variables which must be considered. As we do this we start to see the reasons behind different approaches and various opinions.
Finally we take the position which seems most reasonable and use what works best as we teach and cast. The remainder is background information which should help us understand one another as we discuss the intricacies of fly casting.
Gordy
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[GH] Paul Arden answers my question on how the second rod handle was attached to the student's rod. He follows by commenting on the relationship between the haul and the "stop":
Hi Gordy,
the second butt was attached with a bracket at the top and bottom of the handle. I wish I had one, he gave it to Charlie Jardine before I managed to pinch it!
I think you misunderstand me: I'm suggesting that there is no hard stop when an experienced caster double hauls, indeed I think a hard stop is counterproductive and only occurs with beginners... This is why when we teach someone the double haul we emphasize that the haul controls timing and not the other way around.
It would be interesting to compare two analyzer readings, one of non-hauled and one of hauled. Hopefully someone can do this.
Cheers, Paul
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[GH] Paul,
I see your point re the haul. Gets even more complicated as we consider the end point of the haul when false casting and the release point on the shoot and/or delivery cast.
Bruce Richards may have done this as he developed the haul analyzer. We'll ask him.
Gordy
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[GH] I had asked Grunde Lovoll for a copy of his study on the spring model. He has been following our messages. His reply is worth careful study:
Hi Gordy,
there is no "copy of your study on the spring model", I didn't do a
writeup about it (probably I should?). But I'll try to give you my
take on the "hard" vs. "soft" stop discussion in this mail. So be
warned: this will be a long, confusing and geeky :-)
I have read some of the discussion on the stop in the study group.
What actually happens during "the stop sequence"; and the interactions
between line, rod and caster during this part of the stroke is quite
complex. It is therefore a difficult task to strike the right balance
between enough (and the correctness of) information/instruction in a
teaching situation and going into the details of what is really
happening. Even if I'm a bit of a sucker for getting the details
correct I'm quite comfortable with using teaching tricks as
emphasizing "crisp stops" or "hard stops" in order to get "correct
power application" from the student.
But for more experienced casters, people who want to go for distance
and casting instructors I believe knowing and understanding more about
"the stop" is a good idea.
Before moving into the details I also have to say that I agree 100%
with Paul Arden's comments, I believe "soft stops" are more efficient
in terms of energy transfer and it puts less strain on the caster. I
use to say that I try to relax the stop, or try to let "the rod stop
itself". As an exercise I recommend the following: Cast a relative
sort line (say 30 feet or shorter) and try to put as little effort as
possible into the stop _while maintaining_ tight and good loops. If
the power application during rod loading is "correct", the effort
needed in the stop will be surprisingly small. This is also completely
in line with what Server Sadik is saying about the rod unloading by
itself (the rod will happily unload all by itself no matter what the
caster is doing). I do also believe that this is not in conflict with
the studies(s) by Al Kyte you are mentioning, I'll try to address this
shortly at the end of the mail.
The "hard" vs. "soft" stop problem is only indirectly addressed or
hinted at in "The Rod and the Cast" article. The "hint" is our
mentioning of the importance of continued rod butt rotation throughout
rod unload (interaction between swing and spring). My understanding of
the coupling between rod butt rotation and the unloading rod have also
evolved a bit since Jason and I wrote that paper back in 2006 and
2007. (Also feel free to distribute the pdf version of this paper
linked to from the SexyLoops site and found here:
During 2007 (and maybe 2008) there was several lengthy discussions
about "hard" and "soft" stops on the SexyLoops discussion board. These
discussion inspired the development of a _toy (numerical) model_ to
address and demonstrate (i.e. play with) some aspects of the problem
(the brick-spring-car model (BSC) Paul mentioned). As usual the
message board discussions are probably quite confusing for most people
and the essence of, or the take out points, can be very well hidden.
The original thread on SexyLoops is this one:
And it was followed up by this one (where the model appears):
My belief in or arguments for "soft" stops does _not_ hang on or
depend upon results from the BSC toy model. The argument for "soft"
stops is a simple work energy argument. The energy added to the line
during the casting stroke is the force from the rod tip on the line
_integrated_ over the tip path during the stroke. Continued rod butt
rotation during rod unload (i.e. between max rod load and RSP) adds to
the tip path and therefore adds to the energy in the line. This imply
that there is positive swing contribution (i.e. the torque from the
caster is acting in the direction of the cast) to the kinetic energy
of the line during rod unload, so keeping up butt rotation during rod
unload will add energy to the cast. The more rod rotation during rod
unload the more energy is added to the line. Also note that this
contribution/effect is largest close to max rod load where the force
on the line is biggest.
The results for the BSC-model does of course agree with this
argument*, and it was in fact developed to demonstrate exactly this
effect, there is also a link to Servers arguments but I guess I'll
save that for later if someone is interested...
So to sum up: Rod rotation in the direction of the cast between max
rod load and RSP1 adds energy to the cast, while rotation in the
direction of the cast between RSP1 and RSP2 (rebound hump in Analyzer
data) takes energy out of the rod and dampens vibrations in the rod as
it goes into and out of counterflex (the peak in the rebound hump is
actually as the rod goes out of max counterflex).
I'll briefly comment on the relation to Al Kyte studies on casting
styles and distance casting. I don't have the papers in front of me so
I hope my memory serves me right.
1) To my knowledge these studies did not have the time resolution to
resolve what really goes on during the stop. So my guess is that they
did not analyze the interaction between caster and rod during rod
unload**.
2) If I remembered correctly one of the main results from the distance
casting study was that the good casters utilized a larger casting arc
than the not so good casters.
* The BSC model is a simple linear model, it is much simpler than a
real fly rod and it does not include higher order mode effects which
we do have for fly rods. I still think it is a useful model for
discussion of unload of the rod, and the amplitude of these higher
modes will increase with harder stops. But I don't think the effect of
higher modes are significant compared to the first mode.
** The analyzer studies by Perkins/Richards does however point in the
direction of higher rates of deceleration for "expert casters" than
for "poor casters". I believe this is due to better power application
prior to max rod load rather than harder stopping forces exerted by
the casters.
PS. Please let me know if something is unclear or if you like me to
expand upon something.
Best regards,
Grunde
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Alejandro Vinuales enters his opinion:
Hi Gordy,
You can make good cast with a soft stop, but only if the acceleration continues until the rod is close to horizontal. It is not easy to realize this correctly and to achieve a good loop (not necessarily a narrow loop), I do not believe that it is an exercise for beginners.
Apparently, the reason is the relative displacement of the rod tip in the direction of the loop, much higher the closer to the vertical stop begins: soft stop and narrow arc seem incompatible.
In short: the movement of the rod tip forward means less speed difference between the fly leg and the rod leg at the time of the formation of the loop. The loop not progress if no tension in the line. If the rod continues to accelerate until it reaches near the horizontal, then the displacement of the tip during the stop is essentially vertical, without loss of tension. Tension increases if the movement continues after the horizontal.
A comment on the Grunde model. I think it really does not say that a soft stop is better, only that while the caster hand moves does work. But if we make a model matching the instant the rod stop completely (not when deceleration starts), then the rod that decelerate later (and therefore makes a harder stop), makes more work.
There are two ways of seeing it, but I'm afraid that does not say much about the true fly casting. Cheers
Alejandro
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