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Walter & Group...
[GH] From Mark Surtees :
Hi Gordy
A happy new year to everyone.. J
"[GH] Ally showed that the launch may occur well before RSP where the line starts to overtake the rod tip."
Ally possibly showed that if you define “line launch” as the point at which the “effective mass” of the line has sufficient momentum to complete the cast under its own steam then this point is before RSP. Peculiarly, this means that if the line doesn’t have sufficient momentum to complete the cast you never reach the point where it can be “launched” so you could have part of the line passing the rod tip without the line ever actually being “launched” which would be a slight problem to explain clearly in the field I think.
If you define line launch to mean that point when the line has sufficient momentum for just part of it to extend forwards then this is very likely to be very early in the cast. I’m struggling to see how this concept could be practically useful.
If we define line launch as occurring at the point at which the line passes the tip these problems don’t arise.
" [AG] Line launch is “the CAST”. RSP is just a state of the rod that has somehow been elevated to importance, in the same way that rod tip speed has."
My “cast” is over when the fly hits the water, launching the line is just a part of it. RSP is just used as an analytical point of reference common to all casts, it is not in itself a “useful” part of the cast. Without some rod tip speed your line won’t move, this justifiably elevates it above RSP to a position of some importance IMO.
Mark Surtees
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[GH] Mark,
If the line has insufficient momentum to complete the cast, then it seems to me that the cast was simply never completed .. a "collapsed cast".
When Ally said "the line launch is "the cast", I note he used parentheses. That suggest that he meant something to the effect that the launch is the essence of the cast. My take.
Lefty has tried to demonstrate this idea as he launches the line and then drops the rod to the ground... the loop continues on its way and unfurls.
Some have likened that to shooting a rifle and then immediately dropping the gun. The bullet goes to its destination anyway. (Not a perfect analogy, however, since the bullet isn't tethered to anything.)
We could argue forever to no purpose as to when the cast is complete.... a matter of opinion. That is handsomely reflected in your use of the term, "My 'cast' ".
Gordy
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[GH] For a short while, my direct mail (for our Group messages) was down so I sent Mark Surtees' entre, above, to Ally. His reply (PM = prime minister) :
Hi Gordy,
Thanks for your message, obviously my teaching skills not always up to the task! Ex UK PM Harold McMillan was asked by an aggressive interviewer “Is it true PM that you always answer a difficult question with another question? His reply – “Who told you that?”
I have made some further comments in red:
For the sake of simplicity my discussion about casting and line launch is based upon a simple cast but if the theory is correct it must be possible of extension to explain all possibilities and I believe that is so in this case.
That is not the case with some of the statements that are sometimes used to explain or teach fly casting, particularly at elementary level.
The danger is that the limitations of certain “rules” or perhaps the rules themselves are sometimes not properly understood. Explained and used in context several expressions have over the years proved valuable for teaching but taken literally they don’t make complete sense.
Examples of a couple of untruths used whilst teaching fly casting (there are many more – Gordy maybe we should organise a trawl for helpful “untruths”):
The line follows the rod tip? - True but only for some of the line all of the time, all of the line some of the time but not for all of the line all of the time.
Accelerate to a stop? - Stopping what? Casts can be made without stopping and indeed most are made without stopping.
"Ally showed that the launch may occur well before RSP where the line starts to overtake the rod tip."
" A]ly possibly showed that if you define “line launch” as the point at which the “effective mass” of the line has sufficient momentum to complete the cast under its own steam then this point is before RSP.
Peculiarly, this means that if the line doesn’t have sufficient momentum to complete the cast you never reach the point where it can be “launched” so you could have part of the line passing the rod tip without the line ever actually being “launched” which would be a slight problem to explain clearly in the field I think."
How can any of the line pass the rod tip without having greater velocity than the rod tip and therefore being launched?
If you define line launch to mean that point when the line has sufficient momentum for just part of it to extend forwards then this is very likely to be very early in the cast. I’m struggling to see how this concept could be practically useful.
Where did this definition of line launch come from?
Line launch occurs when rod tip velocity component in the direction of the line momentum is less than the line velocity. It is impossible to prevent this. Note that the energy possessed by the line at that time and the final layout of the line is irrelevant.
If we define line launch as occurring at the point at which the line passes the tip these problems don’t arise.
According to this definition factors affecting line launch will include, how long the rod is, how the rod is held, how far the casting arm is extended etc. Explain the logic please!
Line launch is “the CAST”. RSP is just a state of the rod that has somehow been elevated to importance, in the same way that rod tip speed has."
My “cast” is over when the fly hits the water, launching the line is just a part of it. RSP is just used as an analytical point of reference common to all casts, it is not in itself a “useful” part of the cast. Without some rod tip speed your line won’t move, this justifiably elevates it above RSP to a position of some importance IMO.
I’m confused by this comment but I think we can agree that all casts are over when the fly hits the water. Most instructors hold the opinion that the cast is over much sooner because energisation of the fly line is complete at line launch. Like throwing a rock or firing an arrow after it is launched you can’t thereafter change the direction or increase the distance.
Perhaps another case of two fishermen and three opinions?
Best wishes,
Ally Gowans
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[GH] From David Diaz :
Thanks, for all the good work. Especially worthwhile has been the recent line-centric discussion of forward casting which contrasts with but doesn't conflict with the rod-centric understanding that is more commonplace.
Theoretical understandings are inevitably colored by perspective, and the strength of your list-server-based discussion group is that you stage the contrasts among views so that none are slighted, you tone down the very loud ones, and you make the best out of the fuzzy ones.
To complement the rod-based and line-base perspectives from Richards and Gowans respectively, we need a hand-based perspective which sees forward casting through the lens of muscle action.
Thanks, again, Gordie for the great work. DD
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[GH] With his message, above, I think David Diaz has "cracked the nut" as he describes the various ways in which we can discuss fly casting mechanics. Let me outline this and add a couple of well known names :
You are getting the point which appears in our summation this morning as David Diaz cracks the nut by describing :
1. Rod centric discussion. (Bruce Richards and many others)
2. Line centric discussion. (Ally Gowans & Mark Surtees..... our recent topic.)
and adds the concept of
3. Hand centric (Caster-Body, Hand/arm, muscle) discussion. (I think Joan Wulff and Lefty come closest.)
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