Most discussions of a rod's performance today mention "sensitivity." Is these any reliable way to measure "sensitivity," or is this simply the new term for what used to be called "feel?"

There is probably some machine somewhere that can measure stimuli input and output - but feel is a good word
Herb

Phil,
There have been lots of discussions on this subject, and it seems that at the end of the day, besides getting folks upset - it seems to be a pretty individual opinion.

You can use scientific measurements to measure the amount of vibration coupled down the blank to the butt of the rod, but at the end of the day, it seems that this subject is a personal combination of many different variables - some of which can be easily measured and some of which are simple - "feelings" by the individual person using the blank or rod.

Bottom line - there are blanks out there that folks really love to use and catch a lot of fish. Sometimes these particular blanks are called "sensitive" and in other case, are simply called a wonderful blank to catch fish.

I personally think that it is probably better to just leave the term sensitivity out of the equation when you talk about blanks. You can take 100 different blanks and get 1000 different opinions on sensitivity. Rather, ask question of - is this blank good for this style fishing, or that style fishing. Is it the right length, and does it have adequate or excess power to catch the fish being pursued?

Better to ask questions like "is this the right blank to catch this species of fish, using this fishing technique.


Good luck

Do A search for Emory Harry

Rolly Beenen
Rovic Custom Rods

Sensitivity is an ability. A god fisherman knows what he is feeling.

Sensitivity is hard to quantify unless you can put a set of relative numbers on it.

Generally, the lighter a rod is for any given stiffness the more sensitive it will be. Or, for two rods with the same weight the stiffer one will be more sensitive. The higher the stiffness to weight ratio is, the more sensitive a rod should be. However, there are additional factors involved such as how the weight is distributed, how the rod is constructed, etc. So again, without a relative number to go by, most of what you read or hear about a rod is largely based on opinion or marketing.

..............

Light weight and stiffness appear to be the determiners of "sensitivity." Weight is easily measured. "Young's Index of Flexibility" quantifies stiffness. The use of new materials such as carbon nanotubes and graphene should eventually produce rod blanks literally as light as a feather which won't bend at all except under extreme stress - the ultimate in "sensitivity" if not utility.

Phil,
the basic wisdom is quite well summarized in Tom's post.
alas, there are complexities involved on the subject. leaving aside the ideal and useless case of a weightless perfectly rigid bar, the rod's ability to transmit vibration to the fisherman's hand depends also of the frequency of the vibration, so a given rod may be transmit well ("sensitive") some kind of imput and less well another kind.
people using a lot of soft plastic have often reported strange a deafness for a specific kind of shad tail vibration in an otherwise perfectly sensitive rod...
even worse: such phenomena are probably dependent on rod construction, so blank ID won't be enough to predict accurately a rod's performance.

so, I guess it boils down to the disappointing and familiar notion: there's no substitute for hands on feeling.

_______________________________________________
If I'm not going to catch anything, then I'd rather not catch anything on flies.

Prostaff Rodhouse
[www.rodhouse.fr]

Laurent: I agree with you. Tom did provide a definitive statement about the term "sensitivity." I may not live long enough, but carbon nanotubes and/or graphene technology will eventually make its way down to rod blanks, and the result might well be be a blank which is virtually weightless and close to being perfectly rigid - especially when compared to today's blanks. These extremely low weight/high rigidity blanks in the future could provide oodles of sensitivity, but at what price? What will anglers give up to gain sensitivity, and how much are they willing to give up - both now and in the future?

One of the issues about sensitivity, is that different folks fishing different methods want rods with different sensitivity definitions.

In several of the posts printed above, they mention a very stiff rod to give the maximum feel or vibration passage from the tip to the butt of the rod.

However, there are many many fishing methods where a rod that is very stiff as discussed, simply is not the right rod for the task.

So, then we can talk about a "visual sensitivity" . I define this to be the amount of tip deflection for a given load on the line.

Be safe

You're right, Roger. Sensitivity is just a physical property, with no moral value. When using high vibration lures, such as spinners, you don't want the rod to be too sensitive.
but then marketing does its thing, and who wants an insensitive rod ? or a slow one ? or to have low modulus ? I think that a considerable population of fishermen use wrong tools just because of this.
(too fast fly rods being overlined is my paradigmatic case)

_______________________________________________
If I'm not going to catch anything, then I'd rather not catch anything on flies.

Prostaff Rodhouse
[www.rodhouse.fr]

Laurent: "Too fast" for a fly rod is a relative quality. For an accomplished fly caster double hauling for distance on a windy day I don't believe a too fast rod exists. Blank and rod makers sandbag in the same way as do line advertisers: e.g. "The strongest ten-pound test line you can buy." [because it tests 22.5 pounds breaking strength] Same with 9 weight fly rods marked as 7 weights. Anglers like to say they fish with light tackle but in practice like to use heavier tackle.

Phil Ewanicki Wrote:
-------------------------------------------------------
> Laurent: "Too fast" for a fly rod is a relative
> quality.


I cannot agree more.
The rest of my sentence was meant to explain the phrase: imho, a rod is too fast for a fisher(wo)man when (s)he feels the need to overline it to fish properly. In such a case, I think (s)he would be better off with another blank design, best suited to his/her casting style.

_______________________________________________
If I'm not going to catch anything, then I'd rather not catch anything on flies.

Prostaff Rodhouse
[www.rodhouse.fr]

I'm sure Emory is out there watching. This thread got me thinking a bit more about sensitivity and what it takes to feel something in the rod. Emory, feel free to bring me back to reality if I can't see the forrest for the trees again.

For the longest time, I had been convinced that what we were feeling was a vibration, but I'm finally convinced that that isn't the case. Emory convinced me that what I was feeling at least to first order is impulse, or a change in momentum. Momentum and Impulse are vector quantities, meaning that the direction matters as well as the size. What sets the direction of things that we feel is the direction of the line attached to the lure. As has been noted before by Tom's pool test is that you can move the lure perpendicular to the line just about all you want, and you are not going to feel a thing. You only tend to feel the sudden stops as ticks in the line.

Now lets take this a little further. When fishing, say a curled tail grub, a lure where the angler doesn't feel much other than the tension on the line, an experienced fisherman may be able to detect the subtle changes in tension on the line that comes when a fish smoothly takes a lure from behind and swims toward the angler. This take results in a change in momentum (impulse) of the lure. The result is a change in the tension on the line. Now suppose the fish takes the lure from behind smoothly and slowly stops. The angler may notice an increase in the tension on the line giving the angler a signal to set the hook. Now imagine the fish quickly pulling the lure in and the lure stopping briefly when it tumbles over a rock on the bottom of the lake/river, or a lure that is stopped suddenly when a fish @#$%& it in quickly. This is felt as a tick in the rod (albeit a different feeling tick in each case). What is different here is that the lure changes velocity in a different manner. In the case with the fish taking the lure in a subtle manner, the change in velocity of the lure occurred more slowly over time than the lure that was stopped suddenly.

This leads me to believe that while the impulse of lure is important, the jerk (change in acceleration divided by change in time) may be more important. In oder for the angle to feel the tick in the rod, the jerk needs to have a component parallel to the direction of the line. Clearly line tension also plays a role. Nothing can be felt on a slack line, hence the difficulty in feeling a fish take a lure from behind because it decreases the tension in the line. The mass of the lure is important as well, I believe we could say that the magnitude of the tick is directly proportional to minus the mass of the lure times the scalar product of the jerk of the lure with the tension of the line. |tick| prop to -m(d^3/dt^3)x(t).T(t). This gives a larger tick when the tension and jerk are in opposite directions. It requires that the tick be zero when the jerk is perpendicular to the line, and allows the tick to go away when the tension decreases as the lure is taken from behind or in a smooth manner.

Joe

Joe, that's a lot of good ideas, thanks.
I think vibration is not opposed to impulse, it's just a particular case but you're right, we shall concentrate on the general frame
(even if I still think some of the more important aspect must be understood from the perspective of wave theory: (i) impulse propagates along the line and the rod as a wave; (ii) resonance and harmonics probably play an important role.)

_______________________________________________
If I'm not going to catch anything, then I'd rather not catch anything on flies.

Prostaff Rodhouse
[www.rodhouse.fr]

Sensitivity --- over rated

cast your lure out

Hold the reel and HOLD the line This way you have a direct connection to the lure or bait

Can not be any more sensitive then a dirrect line too where the fish bight ???

Bill - willierods.com



Edited 1 time(s). Last edit at 10/10/2013 06:30PM by bill boettcher.

a rod *might* be more sensitive, Bill: the lever of the rod might act as an amplifier.
wouldn't bet on it, though.

_______________________________________________
If I'm not going to catch anything, then I'd rather not catch anything on flies.

Prostaff Rodhouse
[www.rodhouse.fr]

As stated above if the fish swims toward you you may not even know he is on

Bill - willierods.com

Bill: You can't push a rope.

So true

Bill - willierods.com