Leaders / Fundamentals

Gordy--Bill Nash and I often discussed knots. He told me that he did not recommend wetting fluorocarbon with saliva because many peoples' salvia contains a bit of oil that he found sometimes caused a fluor knot to slip under pressure. I later found the same thing.

I believe there are many "myths" in fly fishing that should die. One such myth is a dry fly fisherman can determine what "X" leader tippet to use by dividing the hook size by three or four. A Catskill sparsely dressed Quill Gordon is not going to turn over the same way a heavily dressed Royal Wulff or Hunpy. My experience is that you have to adjust the dry fly tippet to the fly's design or construction and comparable hook size has little to with the selection of a tippet. This is one of those old myths I think should die.

Hope I don't sound like some old grouch.

Lefty

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Lefty....

Thanks for the feedback on lubricating knots tied in fluorocarbon. I didn't know that, but I figured Bill had a good reason for including that advice.

I'm afraid I can't grant you any curmudgeon or grouch points ! You are right. Those two flies are so different in bulk and air resistance despite the same hook size that those "rules" really don't apply.

Many of these "rules" fail to apply now that we have so many different brands of leader material with widely varying properties including tensile strength, suppleness, diameter, etc.

This includes the "rule of elevens" for converting the X designation to tippet diameter in thousandths of an inch and the "rule of nines" for determining the lb. test tensile strength of tippets from the X designation.

I remember, a long time ago, when you came up with a simple formula for determining the approximate grain weight of the first 30' of a fly line my multiplying the designation number of the fly line by a factor ..... don't, now, recall that number. (May have been 30 ... as that would get one roughly in range for line designations 3 - 5 .) You were careful to qualify it as a very rough estimate.

When we use the word RULE we make it seem that it is written in stone on the mount !

Rather than using the term, "rules", perhaps they should be listed as "rough guidelines".

Best,

Gordy

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From Aitor Colederon :

Hi Gordy,

I think that Bill Kiester?s approach to this issue is a good one. The question about loop turn over isn?t energy transfer but energy conservation: a better mass/diameter ratio allows for less energy dissipation due to air drag. Also we must take into account the momentum conservation principle, that is, momentum is conserved in absence of dissipative forces; since P = M x V (momentum = mass x velocity) when mass decreases velocity increases. When the loop is turning over the moving mass is decreasing so the velocity of the fly leg increases.

In the real world air drag acts as a dissipative force, and the higher the velocity the higher the air drag. Considering the difference between a short/thick front taper and a long/thin one the latter has a more pronounced decrease in mass; that means an equivalent increase in velocity; that higher velocity means a higher loss of energy due to air drag.

So, for a given mass a sinking line turns over more forcefully than a floating line. It is the same case with heavier vs. lighter line weights: the heavier ones are better for positive curve casts or casting into the wind. Again the same applies to lines with a shorter/heavier front taper.

Casting in the moon puts air drag out of the equation, so due to the momentum conservation principle all lines of the same mass would turn over with the same energy, whatever their density or mass profiles.

A lead ball and a ping-pong one of the same diameter released from a position 30 m over the ground would fall to the ground with different speeds, but that is not due to the lead ball being more efficient in overcoming air drag but due to the phenomenon known as terminal velocity:

http://www.grc.nasa.gov/WWW/K-12/airplane/termv.html

Hi Gordy,

I've forgotten to add one advantage of the better mass/surface ratio of a heavier line regarding casting instruction:

As the heavier line has less losses due to air drag you can cast it with less speed than a lighter line to get to the same distance. It is an advantage when teaching or during a casting test, where the examiners want to see slow loops.

Cheers,

Aitor

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Aitor.... However, as I read it, terminal velocity was determined by the experiment done in air. It still seems to me that if the lead ball and the ping pong ball were of exactly the same shape and size (profile) that they would land at the same instant if dropped in a situation with no atmosphere. G.

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From Bill Kiester :

Gordy,

In Shaun Ash's original comments he made two points which are diametrically opposed:

1 transfer casting energy along its length to turn over and present the fly

2 dissipate energy to help with a soft but deliberate presentation

In reading all the comments about transfer of energy I always think about it in a positive way. Transferring the energy from the fly line to the leader so the fly will turn over. But, Shaun's second point may be closer to the mark. We all know it is practically impossible to keep a fly line from 'kicking' when we cast without a leader because the fly line almost always comes to the straightened position with excess energy. Without the leader and fly the presentation would be a very splashy thing. So maybe leaders are more important for controlling energy dissipation than energy transfer. I guess it is a perspective kind of thing.

Bill Keister

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Bill... Perspective ? I think so. Reminds me of the little poem :

Twixt the optimist and pessimist

The difference is droll :

The optimist sees the doughnut

But the pessimist sees the hole.

Optimist and Pessimist by McLandburgh Wilson. 1915

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FUNDAMENTALS

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From Mark Milkovich :

Gordy,

Sometimes you ask ?off the top of the head? questions; sometime you don?t (at least as they apply to me). This one digs deeper. Here?s my take on the topic

Short answer: For the most part, the structural fundamentals which apply to leaders are the same as those which apply to fly lines. In leader construction we employ those structural fundamentals to perform one of two functions:

1. to enhance the function of the chosen fly line (e.g. a short powerful leader at the end of a bass taper to punch a big fly into the wind), or

2. to compliment or modify the function of the fly line (e.g. a long George Harvey style leader to sap the energy of a powerful line taper and land the fly with soft ?S? curves).

Long Answer:

Structural Considerations ? The three most commonly discussed structural features of leader material are: Diameter, Length and Stiffness. Of the three, Diameter is probably the most important because for leaders, the diameter is the variable which dictates Mass. When we create a leader we are creating a certain ?Mass Profile? which we refer to as the ?Taper?. It works in exactly the same way as the Mass Profile of the fly line and both are subject to the same notion that Energy is the product of Mass times Velocity. Although we are typically creating a leader taper (mass profile) which will increase the speed of the cast fly at the end of a conventional fly line. We could also use leader material to create a ?fly line? itself. Swisher and Richards in the 1970?s suggested the use of flat mono as a ?level fly line? for nymph fishing. Joseph Kissane gives formulas for 3 & 4 Weight Forward leader material fly lines in Drag Free Drift (Stackpole, 2001). The mass profile dictates most though not all of its casting performance characteristics of that fly line. Beyond diameter/taper issues, there are others which apply to both Fly lines and leaders:

· length - particularly of long level sections,

· stiffness ? think of using cold water lines in tropical waters and vice versa,

· density - e.g. fluorocarbon vs. nylon,

· coatings - floatants and sinkants apply to leaders just as they do to fly lines.

Primarily because of construction differences between conventional fly lines and leader materials (a coating over a core material vs. a simple version of the core material) the considerations are not perfectly identical but very similar none the less.

Functional considerations ? Because they are inexpensive (compared to fly line), easy to modify and the final link to fly presentation, leader materials are the ideal place to either enhance or modify the presentational characteristics of the fly line itself. The functional enhancements or modifications are again dictated by the Diameter, Length and Stiffness of the material as it is knotted into a taper.

· Diameter at the thicker end of the taper controls the ability to transfer energy from the fly line to the balance of the leader and on the thinner end it controls the speed and wind resistance of the fly to control final presentation. Following the delivery, for sunken flies, it also determines the tendency for the fly to plane up toward the surface under tension.

· Length determines the amount of time potentially available to modify the speed of the fly as the leader loop unrolls.

· Stiffness plays a major role in determining the extent to which the leader hinges, smoothly unrolls or collapses.

· The knots themselves provide a convenient way to present he tippet ?in-line? or at an acute angle to the fly line.

Thanks Gordy,

Mark Milkovich

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Mark .... Any credit is due not to me but to Al Buhr. I got the idea from a comment he made. G.

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