May 19th, 2008

The Premiere OnLine Magazine for the Fly Fishing Enthusiast.
This is where our readers tell their stories . . .

A Cast from the Past

By Robert Bolton, MI

I was sitting in the family room the other day thinking about fishing when I had a sudden revelation. I realized I had a fly rod up on the fireplace that I had never cast. It was an old West Bend bamboo rod I had gotten from my father-in-law many years ago. I thought it would look nice up on the fireplace as an ornament. Now I have to admit, this was before I really got into fly fishing and I wouldn't have known how to cast it at the time. It just sat up there while I learned to fly fish and bought all kinds of other fly rods and reels and stuff. So here a quarter of a century later, I get the urge.

Now I am the first to admit, I am not the best caster in the world. But I am afflicted with another malady. I am an engineer. So, as with any other pastime I have picked up along the way, I am driven to understand the engineering mechanics behind the tools of each particular trade. That being the case, I have spent time reading and studying and even writing about how this stuff works. Doesn't help my casting any. It just satisfies that mathematical disease I am afflicted with. And being so afflicted, I have gone through the same engineering analysis with all of my other rods and compared those numbers with how I think they feel. But I had never even gotten this rod down off the fireplace. Oh what a fool am I! And here is why.

As true fishermen, most of us have evolved into the modern culture of graphite composite rods and super slick PVC fly lines with computer perfected tapers. We worship at the alter of Scientific Anglers, and Sage, and Orvis et al. Please don't be offended if I didn't name your favorite but you get my point. Now there are those who cling to glass and bamboo and chortle at our madness. And thank God they are still there to provide a mirror to our seemingly insane march towards technology. We plod on, none-the-less. But eureka. Here I sit with a perfect opportunity to get up off my duff and do a real life comparison of the old and the new. So I got up and I took that rod down from the fireplace. I also grabbed my Sage FLi 8 weight, which felt about the same stiffness (I'll explain stiffness later) and I headed to the workshop to play. My, what fun!

So where do we start. If you have read any of my writing on rods, which can be found on my website www.HATofMichigan.org under the "Mechanics of Fly Casting" articles (plug, plug), you will see that I don't buy into words like fast and tip-flex and stiff and the like. They are subjective. Yea, verily, even the line rating that most manufactures put on the rod, is subjective and open to interpretation. It is arrived at by an expert at the manufacturer casting the rod, as he thinks you will cast it, with a number of different line weights. Now I admit they are a little more scientific than that, but the truth remains, there is a tremendous amount of variation within any given factory rating. So much so that they even overlap when actually measured. "Measured how?" you ask. Let me tell you.

In my opinion, there are two numerical quantities of any rod that overwhelm all other measurable quantities. The first is its static stiffness. This can be measured by clamping the rod handle horizontally, hanging weights on the end, and measuring its deflection. In simple engineering terms, it is its beam stiffness. There are a number of subtleties in how you go about getting this number but the most comprehensive database for rods was developed under Dr. Bill Hanneman's "Common Cents" method. The resultant number is called ERN and can be found along with a database in http://www.commoncents. info/. There is more in that procedure than just ERN and you may or may not agree with all the details. But, at the end of the day, this procedure has resulted in the largest and most comprehensive tabulation of fly rod static stiffness to date. Another data base can be found on http://www.sexyloops.com/eric/database/rodtablesorted.php. Look for the ERN number in these data bases for your rod if you like. This value is the single most descriptive of how a rod will "feel" as you load it against the back cast before you start your forward cast. It is a measure of the capability of a rod to deliver energy to the line. That being said, you must remember that this number is a static number. It is what you will "feel" at the handle when you deflect a rod in a static or quasi-static situation. It cares nothing about the material or the mass distribution or the taper or anything else that may effect the static qualities of the rod.

But a cast isn't static. So we need more. There have been other attempts to gain knowledge as to how the mass distribution and taper and section modulus et al effect the cast but, in my mind, the best so far is an approach just developed by Magnus Argus, an editor and Chief Reviewer of "Fly Fishing & Fly Tying" magazine out of UK (www.flyfishing-and-flytying.co.uk). His procedure is a simple and non destructive method and yields a number called MOI. MOI means moment of inertia. It is an engineering term which in layman's words represents the resistance of the rod to being rotated about the butt and it is indicative of the force you must exert in the handle (feel) to rotate the rod. So all those quantities we pay dearly for - high modulus graphite, taper, low weight - show up here. The lower the number, the lighter the rod will feel in your hand and the "faster" it will feel as you rotate it. The data base being used to categorize rods is not nearly as complete as the ERN data base but is growing (http://www.sexyloops.com/eric/moi.php).

So there you have it. Two numbers, ERN and MOI. In my opinion, all rods will be rated this way somewhere out in the future. And here are the two rods I chose to compare.

First of all notice the ERN for the two rods is very similar. Now I don't buy into the common notion that there is a significant effect by the actual shape of the deflection path or shape of different rods. My opinion is that it is the actual load that you "feel" and not the subtleties of the actual shape of the deflection path. Now I know that many manufacturers show fancy drawings showing some rods perfectly straight two thirds of the way up and only the tip deflects and they call these "fast." And they show others that bend all the way down to the grip and call them by some other term, not as negative as, but meaning "slow." Now really good and experienced casters say they can feel this. But I cannot. In my opinion, the difference most people associate, in a static sense, is the load. I think rods, rated the same weight by the manufacturer but labeled "fast" and "slow," actually have different ERN's. But to get out of this argument quick, suffice it to say these two rods deflected along an identical path. So from a static viewpoint, these two rods were nearly identical.

Now notice that the MOI is markedly higher for the West Bend bamboo rod. This means that a great deal of energy transferred from the hand into the cast is going into just moving the rod. This will hold true both in the acceleration of the rod in the forward cast and, perhaps more importantly, in the stop. From a theoretical standpoint, this should mean that the longer the casting arc used (for higher line velocities needed for longer casts) the more difficult the stop is going to be. When you reach the velocity where a crisp stop is no longer possible, the loops should start to open and it will not be possible to carry more line. Add to this the fact that the handle on the West Bend rod is smaller and the problem will be exacerbated.

So with all these preconceived notions, I head out to the yard.

Casting Results (for me)
The Sage rod I chose just happens to be the one I cast a lot when practicing for longer distances. I am not a good distance caster but on a really good (lucky) cast I can get out the entire fly line. Most of the time I can cast effectively out to about 85 feet. I can carry comfortably about 55 feet of line and shoot the rest. On the short side, I feel the rod looses the sensitivity I like, with its rated line, at about 25 feet and below. Most of my stiffer graphite rods that I routinely use on smaller rivers, I usually over line by a size or two so I can cast shorter distances by feel rather than just by timing alone.

So for me, the Sage rod is a nice, well behaved, and comfortable rod at distances from 25 to 85 feet. Nicest range was around 60 feet. You could cast all day at that fatigue level.

Now the West Bend was a club. I immediately started having trouble with fatigue on any casts over 40 feet. Besides being much heavier and more fatiguing, I started having trouble with line carry at 50 feet. The line would not shoot at all so maximum casts were around 60 feet. On the short side, the rod cast well at around 20 feet. As far as double hauling and shooting goes, the problem with the West Bend was the guides. The stripping guide was only 3.7 mm. It was actually smaller than the tip top which was 4.2 mm. And there were only 7 guides. This compares to a 10.6 mm stripping guide on the Sage and there were 2. There were a total of 10 guides on the Sage plus a 4.2 mm tip top.

In summary, the Sage was much easier to cast at distance, would double haul and shoot line far better, and was not particularly fatiguing for all day 60 foot casts. The West Bend was a chore to cast at any range past 40 feet and would not shoot line or double haul worth a damn. We have come a long way in 50 years. I am glad. ~Bob Bolton


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