How to objectively judge a rod? - Fly Fishing Forum
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Old 09-01-2007, 01:13 PM
kmckiou kmckiou is offline
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How to objectively judge a rod?

Hi!
I'm returning to fly fishing after 40 years and have done quite a bit of reading in this forum and others. One of the questions that comes to mind is

How do you objectively judge the performance of a rod?

It seems the standard answer is to use what feels good to you. My feeling is that answer is valid, but only as a final way to screen your choices. I'm an engineer by profession so I am naturally curious about what makes a rod perform well.

As a first rod, on my return to the sport, I picked up a used 9 ft 5w 2 pc Orvis Trident TL. So, this is my point of reference. The rod is beautiful and seems to cast OK for me, but in talking with a couple experts, I get the impression that the rod got some kind of bad reputation for "not casting". I searched the internet and only found rave reviews when it was released and not too much else. So, if this rod is not "well behaved" how do I spot the problem?

So, I start to think about the mechanics of casting and objective criteria for judging a rods performance - without casting it. I say, without casting it, because, surely all rods of an excellent performance - whether full flex, mid flex or tip flex - must share some common characteristics.

Let me give you an example. When I give the rod a "wiggle" at about 2 cycles per second, I see a vibration node at my hand an another about 2 feet from the tip of the rod. To the extent that the rod resonance contributes to the cast, I would think that this means something to a rod designer.

Another example. When I abruptly stop my backcast there is some undamped vibration of the rod. Maybe this is my fault and all rods would do this with my back cast, but this vibration would most likely seem to take some power out of the forward cast.

So, what objective behavior should I be looking for in a high performance fly rod?

Cheers!

- Kevin
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  #2  
Old 09-02-2007, 12:50 PM
kmckiou kmckiou is offline
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5wt Shootout

For anyone interested in some testing results on 5 wt rods, there is an interesting article on George Anderson's "Yellowstone Angler" site. Sorry, can't post a link, but I am sure you can either guess it or search for it...

They did a side-by-side comparison of 10 rods and had some really interesting results. I think a lot of the results boiled down to subjectivity of one guy (George) - so there is some question of the outcome if the test had been done with a range of expert and not-so-expert fly fishermen. Still, there was some real, honest to goodness, objective data in the testing. It is that data that I really found interesting....by the way, if I were going to go buy a rod right now, I'd probably make it an Albright A-5.

My interpretation of the testing is that the objective in rod design should be to make the butt to the center of the rod pretty darned stiff. Then, it should get progressively softer as you go toward the tip. The way the test is structured, you need a rod that you can accurately flip a fly 25 feet (that's the flexible tip) but also should be able to power a line 70 feet (that is the power in the lower half of the rod).

If you will indulge me, I am going to think out loud a bit. This is the picture I am getting:

Of course, a lot of the power is transferred from the rod to the line relies on how the power is applied to the rod by the user. That is, the angler needs to be in tune with the harmonics of the rod. For example, if you have a relatively flexible rod, you need to slow down and lengthen your backswing and slow the start of the forward swing; otherwise you will "out run" the flex on the rod and it will not fully load. As we know, there are limits to how far you can lengthen your back and forward swings, so softer rods beyond some limits are not going to be able to apply all the power available in the average angler's arm. One nice thing about a softer action is that it will load power smoothly on the backswing. That is, the energy will transfer from the line flowing backward into the rod and "preload" the rod prior to the start of the forward swing.

At the other extreme you have fast rods. A fast rod will load more quickly and requires more force to keep it loaded. So, the rod must be accelerated quickly on the backswing. Here is where it appears there is a problem with fast rods. They are going to unload/transfer their energy very quickly so they will just sit there and quiver/resonate as the line flows to the rear. There is not enough momentum in the line to effectively load the rod. In fact, it looks like there is the possibility that the rod could make it (more) difficult to time the forward swing. To compensate, the angler must allow the rod to drift back during after the end of the backswing so as not to impede/kill the momentum of the line unfurling. Then at just the right moment, start a forward swing that accelerates hard enough to prevent the rod from unloading in mid-swing and killing the momentum of the line going forward.

So much of the effectiveness of a rod depends on the skill of the angler to match his/her swing to the ability of the rod to load/unload energy. So, this leaves me to ask if there are objective criteria for rods or, are we left to judge a rods performance by what works for our "heroes" and try to match our skills to them?

It does seem to me that there are at least 3 objective criteria of "goodness":
  • Rod mass
  • Swing Momentum
  • Ability to apply a force at the tip

The first two criteria are linked and, as everyone knows, smaller is better. The smaller the rod mass and less the swing momentum the less energy is lost in accelerating the rod.

The last criteria is tricky. Here is my take on it. You must pick a maximum distance you want to reasonably cast a line. Then, determine the energy that must be transferred to the line. Then, pick a distance to apply that energy. This is the arc distance where the power is applied to the line. From this you can calculate the force required assuming some level of average acceleration.

The problem is, you could apply this required force with any rod strong enough...right up to a "telephone pole". So, the force required only gives us a starting point. We can calculate how much force must be applied, but do not know how it should be applied. That is, how much deflection is "just right". This comes down to harmonics of the rod matching with the harmonics of the swing of the angler. And that is what the "speed" of a rod is all about. The faster the harmonics of the angler, the faster the rod needs to be. The harmonics of the rod (how fast it can transfer energy) can be estimated by looking at the deflection of the rod tip at various loadings. That is. how much does it deflect with an 8 ounce, 16 ounce, 32 ounce, 64 ounce load - up to the maximum force required for the maximum distance. This is probably the "secret sauce" of any rod designer. They all probably have a known set of deflections for the fast, medium and slow rod. This is something we could actually reverse-engineer with the cooperation of the angling community. That is, if we all took measurements on our rods, it would be pretty easy to build a database for rod characterization - against which we could then use to judge our next rod purchase. Let me know if there is any interest in this.

Getting back to the test criteria - weight and swing momentum. George actually called it "swing weight" in his test. For grins, I tested my old Orvis 905-2 Trident TL midflex (6.5). Despite the markings on the rod of 2 7/8 oz, it actually weighed 3.58 oz. Maybe the 2 7/8 oz was the blank weight... This weight would have placed my rod next to last in George's shoot out, but in overall weight you must also consider the weight of the reel...so I am not sure how much difference a half ounce makes - though George would have characterized it as a "rug beater", which seems sort of harsh.

On to the next test: swing weight. Though the overall weight of my Trident was not impressive, the "swing weight" was killer. I measured the swing weight as described in George's article and my Ohaus balance beam gave me a swing weight of 4.6 ounces! That is a full 1.4 oz below the best rod in his test - the $1145 Tom Morgan. Before I get too excited, I think I'll check in with George about his procedure for testing. I sent him an email yesterday, but have not received a reply.

I hope you don't mind my rambling, but I find it helpful to understand the characteristics of "goodness" when it comes to something that can be measured (like rod performance). Has anyone else tried to characterize their rod performance? While opinion is helpful, it is also subjective.

- Kevin

Last edited by kmckiou; 09-02-2007 at 06:11 PM.
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  #3  
Old 09-02-2007, 06:44 PM
flytyer flytyer is offline
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Kevin,

You also have to take into consideration the recovery rate of the rod after it has been deflected (bent) during casting. The faster the recovery rate, the easier the rod is to cast because the faster recovery helps put energy into the cast.

Also, whether the rod taper is linear in its stiffness progression from softest at tip to stiffest at butt. Whether the taper is more geometric in its stiffness progression. Whether there is some degree of regression (i.e. the degree of stiffness increase is no longer following a progressive curve) meaning it has some degree of less increasing stiffness as you move from tip to butt.

The thickness of the blank wall contributes to rod action with thin walled designs much more prone to flattening or becoming very ovoid under heavy casting loads. And whether the wall thickness changes at points down the blank from tip to butt to inrease stiffness or strength at specific points.

Then there are things such as how much a rod changes from stiffness at the butt to softness at the tip, the steepness of its rate of change if you will. Whether the blank is made of uni-modulus graphite or multi-modulus graphites.

And you can't leave out things such as soft tips matched with stiff butts. Stiff tips matched with moderately progressively stiff middles and stiff butts. Soft tip, stiffer middle, and soft butt. Etc.

All of these are why when I speak of rod action I speak in terms of tip stiffness (or softness); how far down the blank the rod flexes under small, medium, or large casting loads; how quickly it recovers from being bent; how stiff the middle of the rod is; how stiff the butt section is; and how progressive the blank's stiffness is from tip to butt. I do this because simply desribing a rod as fast, medium, or slow doesn't tell me much about the rod.

For instance, I like rods with stiff tips (which force the casting load a bit further down the blank and help to support longer-belly lines I prefer to use), fast recovery, that are stiff overall, with smooth, progressive action (or increasing stiffness from tip to butt), with good butt strength. George Anderson probably wouldn't like such a rod nearly as much as I do based on what he wrote in the article you mentioned because the stiffer tip means you have to put a little extra force into the rod when casting short to load the stiffer tip.

This is just one example why the rod that one person really likes, is one that another person can tolerate, but doesn't really care for and why the simplistic tip-flex, mid-flex, full-flex desciptors used by Orvis and the fast, medium, slow descriptors used by most fishermen are not that useful.

There is a system called the Common Cents System (or CCS) in use by some to supposedly quantify a rod's action and to let you compare one rod to another, but it too has limitations, especially since the fellow who came up with it has decided that if you have a stiff tipped rod (such as like what I prefer), it should be rated as a higher line weight because the stiffer tip supports more weight. Anyway, you can find the CCS at rodbuilding.org. But since it only measure the stiffness of the rod's tip, I don't find it all that useful.
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Old 09-03-2007, 01:18 AM
kmckiou kmckiou is offline
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Quote:
Originally Posted by flytyer
There is a system called the Common Cents System (or CCS) ... you can find the CCS at rodbuilding.org. But since it only measure the stiffness of the rod's tip, I don't find it all that useful.
Flytyer - Thanks! That is what I was looking for. It looks like Dr. Hanneman has come up with a reasonable approach to characterizing the action of a rod. I really like this stuff. Maybe my next rod will be one I build myself. I have quite a bit of experience working with carbon fiber and really light structures. I have ideas....

But first, off to Yellowstone and maybe catch a few brown trout.

Thanks again for the pointer to this site. It is good to see there are a number of people seriously interested in the art and science of fly fishing.

- Kevin
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Old 09-03-2007, 09:55 AM
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teflon_jones teflon_jones is offline
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I don't know who these so-called "experts" were that said the Orvis Trident TL doesn't cast well, but those rods have an excellent and well-deserved reputation for being great rods in every respect.

As for a system of judging rods, I have two simple tests that I do. The first thing I look at is how well you can pick up line. I will cast until I have a normal length cast out on the ground, then pick up that entire length of line and with a single back cast try to put it back out exactly as before. Any good rod should be able to do this without a lot of trouble. I'll keep lengthening this to see when the rod can't handle it any more.

Another test I like to do is false casting back in forth in one direction, then turning the cast 90 degrees and laying it out to my side. In tight casting quarters I do this pretty frequently. I've found that it takes a good rod to be able to adjust to this changing line load quickly and easily.
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Old 09-03-2007, 12:39 PM
kmckiou kmckiou is offline
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Quote:
Originally Posted by teflon_jones
I don't know who these so-called "experts" were that said the Orvis Trident TL doesn't cast well, but those rods have an excellent and well-deserved reputation for being great rods in every respect.
Hey teflon_jones, thanks for the feedback on the Trident TL. I don't know what their agenda might have been, but because of my experience level, it is hard not to be influenced. That is one reason I am trying to understand a bit about what is behind a "good" or not-so-good rod performance.

I really like the range of people in this forum - many experts from all over the world. It is good to know there is a place I can come for straight advice.


- Kevin
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Old 09-04-2007, 12:30 AM
kmckiou kmckiou is offline
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Re-tested my Trident TL 905-2

Well, I cleaned my Ohaus triple beam, zeroed and calibrated it. It turns out that either I or someone in the family reset the zero.

My Orvis Trident TL actually weighs 3.0 oz, which would tie it for 3rd place in George Anderson's 5wt shootout. I also reread his procedure for determining the "swing weight". I am doing it right and got a reading of 4.8 oz which is 1.2 oz better than the best in the shootout. George is a bit perplexed by this too and is going to check his notes on the tests. Perhaps the description of the procedure in the article left something out.

I also characterized my Trident TL by the Common Cents System (CCS, common-cents.info) and got the following results:

Effective Rod Number is 5.8 - which is near the upper end for a rod rated a "5"

Action Angle = 65 deg - which is right on the border between mid-fast and fast action

CC Frequency = 85 cycles per minute with a line weight of 5 - which indicates a pretty high recovery rate. It is right at the top of the scale for graphite rods.

Looking at the CCS database, the rod that comes closest to the Trident TL is the G. Loomis GLX 905-2. Performance characteristics are very close.

My conclusion is that the Trident TL 905-2 is really closer to a 906-2 and, if similar to the G. Loomis GLX, it should be quite a nice rod. In any case, it looks like it is all the rod I am going to need for a while.
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