I've been hearing how ridiculously sensitive NFC's C602 blanks have been for anglers who have built and fished them . Reading many comments on how they are superior to even the X Rays when it comes to sensitivity .

Here's a thread on NFC's C602 material below:


[www.rodbuilding.org]

Michael,

The damping should be what's causing the rod to "come to rest"


For those who want to go down the rabbit hole of understanding dynamics, Siemens has a good introduction to vibration.

[community.sw.siemens.com]

There's also a good video in the article.

There's a lot of topics regarding dynamics and how it relates to fishing rods. But it's time to pack up the gear so I can go fishing tomorrow.



Edited 1 time(s). Last edit at 10/31/2023 03:15AM by Ray Morrison.

Ray, I know damping is what is causing the vibration of the blank to stop. What I don't know is what causes some blanks to damp out faster than others. I believe it, like sensitivity, is likely a combination of factors, blank geometry, mass near the tip, material characteristics, etc.

The equation that best matches what we are talking about, IMO, is the equation for the natural frequency of a tapered cantilever mounted beam.

That is a pretty complex equation, but it is similar to the one for a uniform beam f = [K / m0] 1/2. The numerator includes structural stiffness and the denominator includes the mass. Sort of sounds like stiffness to weight ratio.

Length-Only test should be pretty easy to do. Take a 7'6" blank and measure it, either by TNF or NFC's vibration test or both, then chop it to 7' from the butt and do the tests again. Same exact blank means that all other variables would be accounted for. Of course whoever is doing the test would need to have a reason to 'waste' the blank this way, but maybe someone would be planning to cut down a blank anyway.

Equations and math are nice and all, but real world is better. Is a 9' 3wt fly rod more sensitive than a 7' MH/F hi-mod bass rod? Maybe, technically? But it's moot because in the real world you'd never be able to fish the same baits or techniques with both rods...You aren't using a 1/2oz spinnerbait with a 9' 3wt and you aren't trying to fish #14 dry fly with a 7' MH/F. You can tell me the fly rod is more sensitive, but if my concern is feeling the blades turning on my spinnerbait it has zero value to me even if you irrefutably prove it to be true.

But, it's very plausible that you would fish a 1/2oz spinnerbait on either a 7' MH/F or a 7'6" MH/F.....Or a 7' MH/F hi-mod or a 7' MH/F mid-mod or glass blank...So those comparisons are MUCH more valuable because it can help me pick the best blank for my spinnerbait rod. To me, if people were going to test for this type of thing it makes more sense to compare similar rods because it's more applicable when someone is actually fishing, which is sort of the whole point of all this :)

Regardless - this is interesting reading so thanks to all for posting their info.



Edited 1 time(s). Last edit at 10/31/2023 09:37AM by Logan Summers.

To repeat, the selection of rods was only a tool in the discussion of the predictive ability of the lever arm argument. . There was no intent to imply the importance of sensitivity to any technique or type of rod.

I find it interesting that there are so many who profess to have no interest, that this all is irrelevant and has no value, but in less than two weeks this string of posts has been viewed over 1800 times.

Ernie Blum Wrote:
-------------------------------------------------------
Another undeniable
> issue because lever arm physics are what they are,
> is that what is really happening at the end of the
> lines of those rods when fishing them with
> identical lures is that it will take more effort
> to retrieve the same lure with the longer rod than
> the shorter rod. The lure will be able to exert
> more force (resistance) on your end of the longer
> rod. And if work is defined as force times
> distance, at the end of the day, the guy with the
> longer rod surely had to work a lot harder after
> casting that lure several hundred times than did
> the guy with the shorter rod. That's issue 2.
>
> Yet...I see discussions on the use of various rod
> components in order to shave off a few grams of
> weight for various reasons. Maybe they just need
> to build shorter rods.

I agree, one of the reasons that I switched to shorter rods was a fatigue casused by working with a 'long lever arm'. Specifically, when working jigs in 'tip up' techniques. I thing tha sea / offshore anglers will agree that shorter rods for jigging cause significantly less pain.

Best regards,
Pavel

Re: TNF Revisited
Posted by: Logan Summers (---.washdc.fios.verizon.net)
Date: October 31, 2023 09:25AM

Length-Only test should be pretty easy to do. Take a 7'6" blank and measure it, either by TNF or NFC's vibration test or both, then chop it to 7' from the butt and do the tests again. Same exact blank means that all other variables would be accounted for. Of course whoever is doing the test would need to have a reason to 'waste' the blank this way, but maybe someone would be planning to cut down a blank anyway.

Equations and math are nice and all, but real world is better.


Equations and math are based on proven theorems, and are 100% applicable to real life. Subjective thinking is based on one's own perceptions, experience and inherent bias. Both can apply on how or why you like something, but the math or physics reveals the truth, whether one agrees with it or not.

If you cut 6" off the butt of an 7.5 foot rod to make a 7 foot rod you will chance its frequency. Its frequency will increase and it will become more stiff. A 7.5 foot blank is designed to perform at that length, when shortened its performance dynamics and capabilities will change along with its frequency.

This golf shaft video does a decent job of explaining what happens when you cut a shaft.:

[www.youtube.com]

There is an interesting trend in golf around "single length" irons. In a single length iron set all the irons have the same exact shaft and shaft length and all the heads have the same exact head weight. The theory is that this will enable one to swing all irons in the same manner and on the same plane, making the game easier due to all irons "feeling" and flexing the same and the golfer needing only one repeatable swing. The only difference in the irons is the loft angle of the iron head. In a normal set of golf irons, as you move from low irons to higher numbered irons, shaft length decreases by 1/2" per club, and head weight increases by about 7 grams per head. Bryson DeChambeau is the only pro golfer who uses single length irons, and he is known as a club geek and nicknamed "The Scientist."

david taylor Wrote:
-------------------------------------------------------

> If you cut 6" off the butt of an 7.5 foot rod to
> make a 7 foot rod you will chance its frequency.
> Its frequency will increase and it will become
> more stiff. A 7.5 foot blank is designed to
> perform at that length, when shortened its
> performance dynamics and capabilities will change
> along with its frequency.


--
All I was saying is that there's several posts talking about sensitivity in long vs short rods....But then people want to start comparing rods with wildly different specs, materials, and intended uses. If the question is long vs short, you can eliminate all the other variables by using the same blank. It's not perfect, but we're not in a lab and don't need to be perfect....It's as close as you can realistically hope to get.

The 2nd part is that if you prove to me that the 9' 3wt is more sensitive than the 7' MH/F, I'll agree with you....But I also won't care because I need to throw a spinnerbait and not a fly. "More sensitive" is something that really doesn't matter unless the question is also framed around the same or similar situations/usages.

Logan:

I understand what you are saying, and am not arguing, only trying to underscore a few points.

I agree that sensitivity is only one factor for me, as it is for most, when choosing a rod. In my case, that is a fly rod. The greatest benefit to me in a fly rod's sensitivity is in nymph fishing, and the sense or "feel" of the nymph, weight and strike being transmitted through the line and rod. Of course if you nymph with a bobber that changes some of that need.

But as indicated at the top of this thread, unless defined, which Michael did for his TNF purposes, sensitivity means different things to different people.

And as you correctly indicate, sensitivity may not be a key factor to some or a key factor in some forms of fishing. I am not sure I would be too concerned about a rod's sensitivity when fishing for Blue Marlin, where I would be more concerned about the rod's fish fighting power.

You are correct and, to some degree, quite pragmatic in saying "we're not in a lab and don't need to be perfect." My point is that a rod's raw and performance measurements, or at least what is revealed to the public, gives us far less data and fact-specific data than many other consumer products.

A top fly rod now costs over $1,000, and basically for that price you are told its length and line rating. Most, but not all, will also indicate the rod's overall weight. And most in their marketing materials will indicate the rod's action, but that is not stated on the rod, and there exist no standards as to rod action.

Common Cents and TNF attempt to provide rod makers with some objective tools to accurately measure the physics of a rod, from which one can deduce certain performance characteristics or parameters. I think the ability to get far more specific and measurable facts about rod blanks is easily out there in our digital world, and that the sport lags others in terms of developing, utilizing and promoting those tools and measurements.

In golf, with easily determined metrics of one's swing and related club performance, in a matter of an hour you can determine -- by science and the irrefutable laws of physics -- the best set of iron heads, driver head and shafts for you, and by such easy custom fitting have a set of clubs made that will perform optimally for you. And when being fit you can see the real-time data and watch it all on a giant screen TV. There is not reason that cannot be done with fishing rods.

I have tried on or purchased many pairs of pants that claim to have a waist of 34 inches and an inseam of 32 inches. You would think those would be pretty easy measurements to get correct. Yet only about 25% of pants I try on in that size fit me correctly.

No, perfection is not required, but if you can get closer too it by more precise measurement, my point is that you are better off. The more performance characteristics of a product I can know, the better informed buying choice I can make, and the better the product will meet my personal performance needs. Missing a casting target by 1% may be the difference between the fish of a lifetime and a non-take.

It is fun for me to be a rod or golf club geek. So a thread like this is fun, not exhausting for me. But I never forget that it is much more fun and rewarding to just be fishing, even if it is with less than optimal equipment.

Hey, maybe REM had it right: "What's the frequency, Kenneth?"

[www.youtube.com]