Walter & Group:
More on casting stroke and casting arc with relation to loop size and shape from Laurence Baggett, with my comments to follow:-
Gordy:
Thanks: This makes sense to me. My
“novice” solution is that if you move a lever from the same point forward and
back the tip has to move in an arc regardless of how flexible the lever is. The
only way to keep the tip somewhat straight is to adjust the level of the hand as
it moves through the arc. None of the books that I have read really deal with
the timing of the hand movement during the power stroke (when the lever is
moving through the arc). Is that is
because it is possible to throw a good loop with a level hand movement and let
the rod tip go through the arc (i.e. up and down)???? Don’t both “work” but just
require different timing issues? An example might be in a casting “style (?)”
where the rod is almost parallel to the ground in a long back cast. Or is the
rod tip path being straight only important during the power portion of the
stroke? I would think with all the mathematical brainpower out there (which I am
certainly not part of) there would be a simple answer to either a beginner or an
experienced caster. Have a good time in Colorado and teach them how to get a
long cast quickly into the wind- with or without a level hand!
Regards
Laurence
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Laurence....
The tip does NOT have to move in an arc unless the angle of the butt section from the beginning of the cast to its end changes. When it does, you have rod arc. If I have only stroke and no arc, then I have only the path of the hand exclusive of its rotation at the wrist. This would be what would happen if I kept my rod straight up vertical in all planes and moved my hand toward the target. Casting this way with no rotatory movement leaves us with no torque at all and would result in a very short, inefficient cast, indeed.
Now, I can cast with no motion of the hand in the direction of the target.....in fact no motion at all except that rotatory motion which gives us rod arc without stroke (stroke being defined as the path taken by the hand during the cast). This would, also, be very inefficient (a convex path of the rod tip would result).......but would allow us to make a longer cast than the example above. Thus, we could say that the casting stroke, while important, is not as important as the rod arc. BOTH, however, are needed for most casts.
The timing of each overlaps during the cast. For most casts, I see that both are employed during the entire cast, but many casters use more wrist rotation resulting in greater torque during the, "power snap" or, "speed-up-and-stop" near its end. Some casters use almost all rotation and almost no stroke if any at all at that interval. This has been debated a lot, lately, when discussing distance casting. So even when both are used during the same time interval the relative use of one over the other becomes the issue.
I think your question of the rod tip travel being straight at times other than during the power snap is a good one. During the power snap, it MUST deviate to some degree from a straight line path lest we have a collision between the fly line and the tip. Dipping the tip down from the path of the oncoming line and, "unloading" the rod a tiny bit below this path yields a small, tight loop. Dipping farther below the oncoming line yields a controlled larger loop. The rod leg of the loop is low, while the fly leg is more or less straight.
Now, that can be seen as placing a bit of convexity to the path of the tip at that interval.
If we have gross convexity throughout the entire stroke, we have the poorly controlled, inefficient wide or open loop often seen with beginning casters. I have witnessed examiners on an MCI exam not accepting this way of making wide loops on command unless the act is qualified by describing it as, "the way a beginner often does it." At that point, I'd be ready to demonstrate at least one of the other ways of doing it as well.
Applying increased convexity to that tip path at the beginning of the stroke and then having an almost straight line path of the rod tip with a minimal dip in the path of that tip at the end of the stroke, yields a different wide loop. This one has a fairly straight rod leg and a high fly leg. It's sometimes used when casting with the wind.
In each instance, I see it as convexity of the rod tip path being produced mainly by wrist rotation. It's WHEN you apply it that determines the final loop result.
The utterly simplistic statement that, "a straight line path of the rod tip yields a small loop, while a convex path of the rod tip yields a wide loop" is not wrong.....but doesn't give the whole picture. If given that answer on a Masters exam, I'd accept it as a good short answer. Then I'd ask for more detail.
Reducing all this to mathematical analysis, I think, would be a daunting task for even the experts in the field !
Gordy