HI,

I read a post here discussing the misuse by the media of associating IM designation with rod sensitivity/lightness, etc. It was a great and informative post. But if I can't go by IM designation to determine sensitivity, what are some good factors/materials to consider and actual tests I can do, before purchase, to compare the sensitivity of one rod over another? Before I spend between $$$ on a custom built rod or a factory built rod, I would like some sort of determination of the rod's sensitivity.

Then I would look at the stiffness to weight ratio, or the CCF rating if that's available. Obviously, you'd have to be comparing blanks of the same general action and power.

Generally, the lighter any blank is for any given amount of power, the more sensitive it will be. There are other factors to consider certainly, but most of these won't be available in the manufacturers' catalogs.

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

Hey Bill,
I am the one who started that string about modulus and IM ratings. Glad you found it informative and helpful. My opinion is that the type of line, and the way in which you handle your line has a tremendous amount to do with sensetivity. Think back to when briaded lines came out...everyone remarked as to how much more sensetive they were because of the lack of stretch. So i think there is more to sensetivity that just the rod. HOWEVER, before I open a can of worms by bring line into the sensetivity equation, TOM, would you mind relaying that story about your swimming pool experiment?

Andy Dear
Lamar MAnf.

Some years ago a several of us took turns donning a blindfold and trying to discern the movement of a plastic worm in a swimming pool. One guy would get in the pool and smack the worm as it passed by. Nobody ever felt the worm being hit, slapped, smacked, etc., no matter how hard it was hit or what rod or line was used. But, if you stopped that worm, even for an instant, you would easily feel it. Our conclusion, though perhaps not scientific, was that you can't feel anything unless your line is completely taut - something has to stop your lure in order for you to feel it.

Sensitivity is something that is hard to measure although I tend to view in within the scope of a rod's overall effciency. A rod that weighs less for the same stiffness, or one that has a higher resonant frequency, is generally more efficient and should be more sensitive.

But again, what you can actually "feel" your lure doing in the water, or what is happening to it, has a lot to do with the tautness of the line. Remember playing with tin cans as a kid - making a telephone by putting a string between them, pulling them taut and then talking into one and having a buddy listen in the other? Move towards each other and put some slack in the string and what happens to your communication? Easy - you get nothing.

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

The original post posed the question of buying a custom rod vs a commercial rod. If you take the best blank in the world and botch the construction with poor and sloppy techniques the sensitivity question really is a moot point. Take your dremel tool to your local dealer and split one of the reel seats off of one of the IM 22XPs so you can take a look see as to how it was built. In my opinion the blank is certainly important but the real sensitivity is in the hands of the builder of the custom rod.

Gon

Bill,

I think you nailed it!!!!

Mike

Bill

What do you think is the best material for arbors on a seat ??

I use blank exposed seats for most of my inshore and bass casting rods. A shoulder turned on the front end of the cork grip to fills the big hole in the back end of the seat . Maintain a good stock of seats to get a snug fit with the blank dry. Use a piece of Flex Coat arbor material and Rod Bond adhesive under the front hood. For those "sensitive" types of customers I am using split grips and no foregrip to reduce weight and allow for more direct hand contact area to the blank.

Gon Fishn

I use the graphite arbors; they're lighter yet than the Flexcoat.

Walleye bite predominantly not by slashing a bait, but by 'flushing the toilet' - they suck water through their gill rakers drawing the bait into their mouths. This CAN be felt as it tightens the line. The mood of the fish dictates how much water they flush and how easily the bite can be felt; like a light tap or a THUNK! They're moody critters and sensitive rods are a must to be able to feel those light flushes!

Putter
Williston, ND

I still think sensetivity has as much to do with "line choice, line handling and line management" AND individual ability than does the rod material..... perhaps more.
A couple of years ago I was teaching my brother-in-law to worm fish. He was using an AllStar Titanium BAT727...very light...high modulus blank. He couldn't feel a darn thing with it, because he didn't know what he was feeling for. I however could see the strike happen when the line reacted a certain way, like a small jump in the line or a slight shift in the tightness of the line. We developed this systen where he would work the lure and when I saw the line "tick" or "move" a certain way I would say, "set the hook now" Fish on everytime! So, it wouldn't have mattered to him how sensetive his rod, he hadn't developed the ability to read the line, much less to interpet what he was feeling.
Certainly a good light rod with a fast taper will help telegraph the signal better, as will a good quality braided line, but if you haven't developed the ability to know what your feeling for, the most sensetive rod in the world won't do you any good. Tha come form fishing...a lot.
I will say this, those Lamiglas blanks with the Titanium butt section do have an interesting "amplification" effect. It's not that they are more sensetive, but somehow that hollow titanium section amplifies the signal that the rod receives from the line in a more discernable way.
Ralph O' Quinn and I argued about this for 30 minutes until he put it to the test. I think he was ready to punch me in the face......however he agreed with me after trying one.


Andy Dear
Lamar MAnf.

Andy,
The titanium piece in the Lamiglas blanks MAY transmit vibrations better than graphite and therefore give the user more feel but the titanium does not amplify. There must be a non-linear device in the system somewhere for there to be amplification and there is no non-linear device in the Lamiglas blanks.
By the way, I was given a bunch of scrap pieces of the titanium several years ago and have done a good deal of experimenting with it. In fact, I gave some to Ralph.

Emory,
Here you go again trying to confuse the issue with "technical terms". I am sure that your engineering textbook definition of "amplify" is true. However to me it FELT like it amplified the signal. My use of amplify may not be "technically correct", but to me how it feels is more important, not what the textbook definition of amplify says.... that's how it felt, like it amplified the signal, and I am sticking with that whether you like it or not. (haha).
Let me ask you this...when one of those good lookin' cheerleaders at a football game yells through a megaphone, how would you define what is happening to the vocal signal.? Insert whatever technical term makes you feel good....that's what I felt was happening with the titanium butt section

ANdy

Emory,
I thought you might be interested to know that in Lamiglas' 2002 catolog they use the word "amplify" twice when describing what the Titanium butt section does to the signal. They also use it on their websit in the description of the Ti2000.
Also in the Angler's Workshop catolog, they use it as well in their description.

Somebody wasted a lot of time, and an even greater amount of money printing catologs and websites with such blantant mis-information...

Andy

P.S. Don't get mad....I made this post just to jab you in the side a little...

Andy,
I am well aware that Lamiglas used the term amplify in some of their advertising. It is not the first time that an incorrect or misleading term has been used in advertising. However, in this case I am quite sure that Lamiglas did not do it to intentionally mislead. They were just incorrect, just as you are. But I would not be too upset about it if I were you. It is not the first time that you have been in error and it will not be the last. (ha,ha)

As far as your cheer leader example is concerned, when a megaphone is used all it does is focus or direct the sound coming from the cheer leader, it does not amplify it. In fact if you were to stand off to one side of the cheer leader you could hear her better without the megaphone than with it because the majority of the sound of her voice is being directed out through the megaphone in the direction that the megaphone is pointed.

I agree with what Tom said in that I'd generally look for the lightest weight for the equivalent power rod.

I would also consider the distinction between the sensitivity of a rod vs. the idea of strike detection, both of which will contain multiple material and design components. For example in strike detection, are you holding the rod at the optimum angle and how tightly are you gripping it? The line type, perhaps even a heavy, sloppy old reel vs. and new lightweight reel with a tight infinite anti reverse will all play a role in how the signal is detected. Where and how you grip the blank will also be a key variable. Rods with exposed seats or no foregrip provide direct contact points for detecting the vibration.

The sensitivity of the blank is also going to be function of the material and beside the finished weight, the fiber density of the composite will also be important. The finish (or not) on the blank and how heavy the coatings are can also be a factor.

The Lamni Ti rod makes for a very interesting discussion. It boils down to how you want to define amplification. Consider that the square of the vibration amplitude goes with the inverse of the mass. Then you could construct and argument that says, as the vibration passes along the blank from a heavier section to one which is lighter, (energy conserved and damping aside), you could experience an increase in amplitude in the lighter section....an "amplification" of sorts. Of course the system is good bit more complicated than that since you have a transition zone at the joint and there will likely be a frequency shift. It would be fairly easy to measure the difference in amplitude at a couple of different contact points to prove it, but I've never wanted to spend the bucks on the Ti blank just for that purpose.

mark

Mark,
If you can make the measurements I have a bunch of scrap titanium that I got from Lamiglas several years ago and would be happy to send you several pieces and pieces of scrap graphite blank to go along with it. You will not be able to measure any true amplification but the results of the measurements would still be very interesting and informative.

Mark,
Just out of curiosity I just measured the weight of a piece of titanium and a piece of graphite. Both pieces were about the same diameter and were about two feet long. The weight of the titanium was 57 grams. The weight of the graphite was 45 grams and this was a piece of standard modulus (33 million) graphite. However, the wall thickness of the graphite was over twice that of the titanium. So the density and mass of the titanium is higher than that of graphite T



Edited 2 time(s). Last edit at 09/14/2005 05:22PM by Emory Harry.

Emory,

Thanks for checking on those weights. The only way the scenario I speculated on would work is if the Ti was significantly lighter than the Carbon Fiber composite.....got you thinking though didn't I? lol If you take it as a solid state physics problem, the square of the elastic wave (phonon) amplitude would go with the 1/density so that goes against the Ti as well.

One other thing to consider would be the frequency shift and how different frequencies would be felt by the hand?

mark

Mark,
Yep, you made me think about it.
I am not sure about this, but I don't think that there can be a frequency shift if the vibration in the graphite is a sine wave. I can see how there could be a frequency shift only if the waveform in the graphite were more complex containing other frequency components or other frequencies are somehow introduced and the transition or joint somehow acts as a mixer. Be careful now, I have not forgotten my Fourier analysis.
I have no idea how the sensitivity of your hand varies as a function of frequency. There must be a bandwidth to feeling just as there is to sight and hearing but you could really snow me on this one.



Edited 1 time(s). Last edit at 09/14/2005 05:37PM by Emory Harry.

I say we go back to talking about the cheerleader.....


Andy Dear
Lamar Manf.