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  • SLP - tracking / Physics



    Walter & Group...

    From Peter Morse:

    Gordy, In Jason's images and most of this discussion it seems to me 
    that we are looking at SLP horizontally - from the side. Surely its 
    just as critical when viewed through the Z-Axis from either the front 
    or the rear - or is this just "tracking"?

    Peter Morse
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    Peter:  That does need clarification.

    Technically, SLP means STRAIGHT LINE PATH OF THE ROD TIP IN ALL PLANES.

    If we have true SLP, then is is as though the rod tip passes through an imaginary straight pipe with very small internal diameter.

    The term "TRACKING" refers to the side to side deviation from this path.  With perfect tracking, there is no deviation.  Of course, this can only be seen from in front or behind or above the caster.

    If we have poor tracking, yet SLP in only the vertical plane, then we could have a bystander wondering why the caster had what appeared to him to be a nice tight loop.... but it wouldn't go through a suspended hoop at the casting games.

    A deviation from SLP in any plane can be desirable or undesireable depending upon the outcome desired.  If we have absolutely no deviation from SLP, we'd have a collision between the fly line and the rod tip.  Fortunately, in the real world of fly casting even the best casters have a tiny bit of deviation in the path of their rod tips.

    We often purposely deviate from a straight line path of the rod tip ..... for example, when we cast a weighted nymph where it is often best to use a wide loop.  This is done by casting with the rod tip traveling in a convex path.  If we have too much convexity, then we might have an "open loop" or "no loop" which would result in no effective ability to propel the line.

    By placing convexity in a chosen point in the rod tip path, we can accomplish diffrent things.  Examples:

    # Convexity placed all through the cast.

              a. A very small amount prevents collision.  It is used by most elite casters.

              b. A lot of convexity yields a very wide loop (the way a beginning caster might do it.).

              c. Convexity at the conclusion of tip travel, can yield a well controlled wide loop (such as that used for a weighted fly).  The fly leg of the loop is fairly straight while the rod leg dips down.

              d. Convexity applied at the beginning of tip travel, with SLP until the very end (with just enough dip - down of the tip to avoid collision) yields a loop the fly leg of which is way up in the air while the fly leg is more straight.  This can be used to kite the fly line loop with a back wind.

                                                                                  Instructional practicum :

    When teaching fly casting, we'll occasionally have a student who appears to have good tight loops which don't travel well enough to gain the desired and expected distance.  The temptation is to suggest that more force be used.  This is rarely the solution.  If the instructor steps behind or in front of the caster, he sometimes finds that the problem lies in mal tracking yielding a loop which appears nice and tight from the side, but is actually wide in the horizontal plane.

    Gordy

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                                                                                      PHYSICS

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    As moderator, I see my task as an attempt to gain a reasonable commonality of opinion between opposing authors of the physical parameters of fly casting.  To do that I need to ignore emotional statements and implications and try to understand both sides as best I can.  To this end, I've had private messages and conversation behind the scenes.

    I see no place for combat as we try to learn from one another. 

    I've had an explosion of negative messages on the physics series and need to deal with them carefully.

    In order to avoid offending any of you who are simply not concerned with the details of fly casting physics, I'll place the long dissertations as attachments so you can choose to review them or not.  I've had so many, that I doubt I can include them all.  For that I beg your understanding.

    Gordy

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    Brief comment in this direction by Bruce Richards:

    Comments re: Servers below...    I think I see what is happening now,
    Server has been focusing on the rod tip all along while the rest of us have
    been thinking of acceleration and deceleration as angular motion of the rod
    butt....
    Bruce

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    We're beginning to come together !      G.

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    From David Diaz:

    I am aware that the point I emphasize has been made previously.   The point is at least as  important as understanding  the physics correctly. 
     
    Troy Miller's four-paragraph comment is a letter-perfect example of the proper place of casting theory in teaching actual students who have paid for useable results.  The theoretical informs the teacher. The theory is what the teacher understands  that enables him to provide practical guidance to the students in front of him.   But to succeed with his students, the competent  teacher uses plain speech, animated and visually connotative,  commonplace  examples and analogues, and avoids couching the understanding to them in terms of a free body diagram because ". . .that would be too heavy for 98% of students."   To succeed with his students, the teacher uses a theoretically inept analogy that is " I know, not 100% scientifically accurate, but plenty close enough to make the point.  A la Lefty-style. "   Result of the deviation? The students will understand the problem and the solution.   And that is the teacher's  job. 
     
    I am going to print twenty copies of Troy's comment, have them laminated, read it before I teach any casting class, and give a copy to any one whom I recommend for MCI certification.  
     
    Best, 
     
    David Diaz
     
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                                                                            Valsesiana
     
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    From Raf Mascaro :
     
    Hi Gordy,

    some infos about Valsesiana.

    The first written document about Valsesiana technique has been found around the XVI century. The origin is from Valsesia, that is a valley (Val or Valle is the italian translation of Valley) in the North West of Italy (one and half hour driving from Milan).
    It's one of the most scenic and beautiful valley of the Alps. Sesia is the River running in the valley and borns from Monterosa (the second highest peak in the Alps). Sesia River hosts a good population of rainbow, brown trout but is famous for marble trouts and bluefin grayling (a specie almost extinct)...and they can create headaches to the best  anglers in the World (political explanation, in reality for me they are very b.....d !)
    I doubt anyway that at the period (...and I guess even nowadays) Valsesia inahibitants had any knowledge about Dame Juliana Berners and her book.
    Al explained very well the technique and the tackle used . One curious detail: horse hair line is made only with male horse tail, the reason is that pee can weaken the fibers.
    I confirm what said by Guy: in Japan there is very similar technique (Keiryu) but length of rods is getting shorter than 20'.
    Traditionally Valsesia anglers use hand-tied flies, mainly spiders and set of 3 flies. Now they use modern hooks but in the past these were bent nails . A piece of leader is integrated into the fly.
    Constant tension cast is required, particularly with 3 flies on the leader otherwise the risk is to land in big troubles , particularly if windy.

    About Two handed vs Single handed, I don't want to repeat about common points but in the last couple of years I'm using more and more single handed Spey Casts and I'm really enjoying. Why ? Because I started fishing stretch of the rivers, normally avoided by fly anglers because of the limited back space, I started using fishing techniques like greased line, waking flies, riffle hitch , set of 3 flies (where allowed) not worrying about wind , or wading limitations , at the begin and/or end of trout season  (limit is water maximum at the ankle and wading for no more than 7ft from the bank), and etc...

    "Troy:  I guess the epitome of the "soft stroke" is the one we use to yield what many term the "negative curve cast" or the "decelerating curve cast".  Obviously, the caster has to have some acceleration in the beginning of the stroke, then "softens" it by bringing it to zero followed by a period of negative acceleration.  An "underpowered" curve layout occurs, but no true loop formation at or near RSP.

    This is usually a cast which gains little distance and isn't easy to control, especially if its windy.... but it has its uses on the stream in windless weather when a short curve with gentle and not necessarily accurate presentation is desired. "

    Gordy, this is a way of casting I use a lot for dry fly fishing in some streams, particularly when I want to present the fly in the "V" created behind a boulder or if I want the fly dragging along a bank but with a slower pace than the current. As you said it isn't easy to control, yes if all the job is done only by the rod-hand, less difficult if you create the loop and control the shooting (slowing down or anticpating) with the left hand. In this way you can be precise and get an accurate presentation. Coordination of both rod and left hand can make a wide range of underpowered curve casts

    Best Regards
    Raf
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    Raf.... Never thought of that!   Thanks.  I'll try it.

    Gordy

     


     

     

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