Translation / rotation (More)

(I'm going to seek Bruce Richards' comments on this string of messages ... so no comments from me.)

I agree with Troy but probably for different reasons.

This is an animation of Jay Clark tossing a shooting head in the 2006 ACA National Tournament hosted by the Long Beach Casting Club this past August.

My definition for this discussion:

Translational phase = that forward motion of the cast applied through most of the stroke prior to the application of rotation. (Translational movement in a cast is accompanied by some rotation introduced by the shoulder and elbow joints through much of the forward stroke. Bruce can confirm this if needed.)

Rotation = that movement of the cast which is applied late in the stroke by using the wrist. (Rotation is usually accompanied some translation introduced by the body, shoulder and elbow joints, near the end of the stroke.)

In the animation:

The green line represents a straight line scribed from where the forward cast begins to where it ends at the commpletion of rotation. The measurements were taken at the wrist joint. Each frame has a small red dot at the place I feel is the wrist joint.

The magenta line perpendicular to the green represents that frame where the rod is bent farthest into the butt. It also represents the point where rotation is initially applied.

The last part of the animation replaces all of the red dots so you can see the path the wrist has traveled during the entire stroke.

Rotation is indicated by an angle change between the wrist and the rod butt.

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As you can see the rod is fully loaded by the time the rotation begins. So the translational phase does a heck of a lot more than remove slack. Rotation seems to be delaying RSP, but if you notice the rod is unloading through the entire rotational phase.

If you want to see another one, here is Renee Gillibert casting: www.castflys.com/renee.gif

Guy Manning

FFF Master Certified Casting Instructor

Moderator FFFCCI Yahoo Group

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From Jeff Wagner:-

I dont want to put any words in Bruce's mouth. So the statement below

is from my

perspective of what Bruce is describing only.

From a purely observational standpoint. Watch Steve Rajeff cast a 5wt rod a

long distance. His translational movement is very little. His stroke is

almost all power phase and rotation. I belive this from the very

minimal slack

that is present in his stroke. Steve has the ability to produce loops

with such

consistentcy, tightness, and parallel form that slack is almost non-

existent. I agree that slack is a major reason for the need of

translational movement. If, hypothetically, a caster made a cast with

no slack it would be possible to

have a much shorter casting stroke, all power phase (all rotation?) (decreased

translational phase).

In fact I would say that movement in the direction of stroke that is taking up

slack or trying to get the line moving before any meaningful

acceleration phase

would be deleterious to the cast. Simply because a tight loop with good

velocity and little slack will put a huge preload on the rod. This allows the

caster to use a shorter stroke. If one must get the line moving in the

direction of the cast, slack must be taken out, then a load put on the rod,

then start the stroke.

it just seems more efficient to take a few steps out. Make your well formed

loops work for you. In my own casting I've been working hard to getting better

loops. The more I do the shorter my stroke becomes, the less translational

movement needed and the tighter my loops.

Jeff Wagner

Master Certified Fly Casting Instructor, Federation of Fly Fishers

Fly Fishing Buyer, Jax Outdoor Gear

Fly Fishing Guide, Jax Outdoor Gear

Redington Pro Staff

970-481-5887

jeff@xxxxxxxxxxxxxxxx

www.dhflyfishing.com

Troy Miller's message, below:-

Subject: Value of Translation phase / Ron on the Belgian cast

Gary & Group...........

From Troy Miller:-

I believe I disagree with Bruce significantly on the major benefit of translation, as I mentioned before Gordy. I plan to prove this by taking a flyline and laying it on some sort of surface to support it. Then I will slightly pre-tension it, to assure that there’s absolutely NO slack in it. Then I’ll see if I can cast it as far using rotation only, as I can with my translation/rotation stroke. I already know the answer, but I intend to logically prove the point. Then someone will tell me that I’m making an invalid test, since there will be friction of the flyline along the support surface, so I’ll have to Teflon coat it, yadda yadda…

The point is, that I believe that having substantial velocity before getting into major rotation is more important than slack removal. Velocity is directly proportional to momentum, and having some of it before rotating (I think) allows more efficient continuation of rod loading (thus more accurate and consistent SLP). If we don’t have any velocity before starting rotation, neither do we have momentum (in rod or line). Further we don’t have rod loading. I don’t know if there will be a valid scientific method that could prove this one way or the other…

Regards -- TAM

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Troy: I knew that. You had so indicated to us in the past. I also had reservations about taking up the slack being the only important aspect of the translational phase. That's why I worded my message the way I did. My own take is that both the velocity and the taking up of slack (if present) are significant. In the theoretical case of a cast with absolutely no slack, the value of velocity before rotation would likely be the major value. It may be so in the event of slack since the velocity and momentum help take up this slack.

I'd also like to point out that we are talking about a specific cast.... the straight line overhead cast of sufficient distance to make the graph measurements significant. At this point, I frankly don't know how all this would apply to Spey casts, other elliptical casts, and the roll cast except for its forward stroke.

Additional studies will be needed to determine all that.

We must remember that the Casting Analyzer only measured angular acceleration, not translational movement.

Gordy