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I’ve been thinking about the curves Vs line length et al.

Finally occurred to be that this was to be a fishing rod. So, the line from the tip to the fly will vary from perhaps 5' > 40' depending on just where/how the rod is fished. For that reason the arc or real length of the rod will vary and similarly the action will vary if the rod taper is not linear. In linear taper, the rod length may vary quite a lot, but various humps/bumps/hinges on some tapers will not come into play quite so dramatically.

Further, I has thought that there was a AFTMA standard for rod design and it used 30' of line. Why are we looking @ 40 or better?  (Don Anderson)

it used 30' of line. Why are we looking @ 40 or better?

Excellent point, Don, I'm embarrassed to say it never occurred to me before, but what are we counting in that 40 ft? Do we assume that the first 30 ft has 220 grains so the next 10 has 1/3 of that? Not if it's a wt fwd! And how are the lines made by the manufacturers? Even if they're DT, if the line wt is determined by that first 30 ft, do they maintain some fixed WEIGHT in the next feet, or do they underweight it so it gets dragged along better (a la shooting heads)? That hypothetical 220 mentioned above would be hard to distribute linearly over the first 30' if the microbubbles needed to float the line are what govern the thickness of it. Where it's thinner in the tip, it ought to have less weight or sink like a stone. And if it DOES have the same wt in the thin tip, why's the belly so thick - aesthetics?

I'm not questioning looking at the 40' if that's what you plan on using for most casts; I'm questioning what we should be basing that extra footage's length on! Am I the only guy here who's never thought of this before????  (Art Port)

And to put another sticker into the pot (how's that for mangling metaphors...) consider that most of the casting we do is within 30' or so.  Don't forget to include the usual 9' to 12' of leader that we have stuck on the end in that 30' or so.  For all intents and purposes, at least for those of us here on the East coast, we're only casting little more than 20' of fly line.  (Mark Wendt)

And, even assuming that the first 30' of our lines all weigh the same, dare anyone suggest that we can expect similar casting performance from one line manufacturer to the next? And casting performance is what rod design is all about.

Try six or eight lines by different manufacturers, and let all of them be 5 WF floaters. If you're a good caster, you're likely to see a world of difference in how your rod handles these lines.

The industry-standard to regulate the  weight of the first 30' accomplishes something, but probably does not satisfy us with all the "load factor" information that computer programs assume.   You DO have 220 grains. represented in the first 30' of those lines, but how that weight may be distributed along those 30' seems to become quite a different matter - and it's especially noticeable when the rod in question is actually being cast.

THAT'S what we really need to know, but that's not what our programs can tell us. Design programs can only do so much, and probably no software is going to be able to give us the rod we REALLY like. Trial and error is the only way to get that, in the end.  (Bill Harms)

Interesting you should bring that up.   Two years ago at the CRG, Jim Wilcox, myself, and if I remember correctly, Willis Reed brought three rods, all the same taper (which was Jim's Wolverine Creek), with three different lines.  Mine was hollow built, so I'm not sure how much that would enter into the equation, but all three lines cast differently on the three rods.  I think Jim had a WF 9, I had a Wulff TT 9, and I think Willis had a DT 9 on his rod.  It was fun to play around with the different lines, and how different they felt on each rod.  (Mark Wendt)

Bill is bang on here. The original criteria was 40' of what type of line WF or DT - heck of a difference when doing things to the taper. And the  problem of landing a fly as light as a feather suggests a long belly on the tip section of the line.  (Don Anderson)

I hesitate to discuss Mr. Milward’s work before I get his book, but I do notice that the conversation (like the current political debate in this country) seems to shift topics when we are not in agreement. It appears that the conversation turns to flex and not stress when discussing Milward’s conclusions. Like Max's work on dynamics, they are probably more than valid and maybe better ways of evaluating a rod.

They are all interrelated and not mutually exclusive.

Does anyone have a program based on Milward’s work?   (Jerry Foster)

Your insight is valid.  I agree with you on "They are all interrelated and not mutually exclusive."

I date want to put a word that Mr. Milward's opinion in his book is very much misleading about Mr. Garrison's stress curve. In his book, he failed to convince me on the following two point, though I admire him on his work done such as, studying the bamboo organization and making MOE experimentation.

Point 1:  Bamboo node or node adjacent is weak in his conclusion. I agree half of this.  He made his experimentation by thin sliced tips of bamboo.  It is obvious that the thin sliced node is weaker than other part because bamboo fibers are not continuous at node.  Node is weak if it is used at the very thin part of tip section.  But node is stronger than inter nodal part if it is used in thick form.

Point 2:  By looking at one shot of rod deflection, he concluded that Mr. Garrison's stress curve is outdated.  He took a high speed picture of a rod which is deflecting with much load.  Its shape is like a crescent. He reverse calculated the stress value of each part of the rod and made his stress curve.  His stress curve itself is valid and very sensational since a new idea of MOE is included in the math.  But he says that it is different from Mr. Garrison's stress curve.  It is obvious that he is comparing completely different situations or different things.

Mr. Garrison's stress curve did not intend to show a shot in a motion of a rod.  His formula is STATIC.  His formula will not imply any deflection from his stress curve.  IT IS a designed formula, not intends to show us a natural movement.  This thing is described in Master's guide.

I eventually made a simulator by taking  the idea of Mr. Garrison and Mr. Milward, Mr. Don Phillips, Mr. Bokstrom, etc., which is trying to include all the necessary idea of physics into my program.  Mass, gravity, acceleration, force of inertia, moment, stress, MOE, deflection, motion idea, etc.. When I define a casting style of a rod, every other matters are defined as related. So I could have a deflection shape of a rod, a stress curve, and other measures from the calculation.   Everything is interrelated.

I successfully realized exactly similar stress curve to Mr. Milward shot, when a rod receives a considerable load of fly line or in a hooking scene of a fish. I could draw a stress curve which is very similar (not same) to Mr. Garrison's one. These two different stress curves are derived from the same  rod. Interesting!!  What is the difference?  Calculation math are different since assumptions are different to each other.

Mr. Garrison's math is  stress = Moment / Z. Let's say as the math G.

Mr. Millward's math is  bend = PL2/EI or PL3/2EI.  Let's say as the math M.

One interesting thing between two above,  both can derive the same dimension from each of the figure.

Math G can derive dimension like, Stress -> math G -> dimension G.

Math M can derive dimension like, Bend -> math M -> dimension M.

G must be equal to M.

My formula also can derive the same dimension.  I could confirm this on my simulator which has two conversion functions, one is from deflection form, one is from stress curve (dynamic one).

Math Max can  derive  dimension  like,  dynamic deflection -> math Max -> dimension Max

G=M=Max.

So we do not need to think that Mr. Garrison's stress curve is outdated. It is still valid in designing a rod by stress curve if user understand the limitation and assumption which Mr. Garrison paved.

There was an effort including myself to draw a deflected rod curve from Mr. Garrison's moment and stress value.  It was of no use because the  assumption implemented in math G is not natural.  I mean that the 4 x weight inertia is not natural in ordinary casting. Math G's moment is not considering a deflected adjustment of a rod. The resulted deflection curve is not quite practical.  This is because the math G is an artificial design of formula.  Then do not use math G's result to draw a deflection.  Use G's stress curve as static model.

I also implemented Mr. Bokstrom method of designing method in the simulator to draw a straight taper, though I am a novice on this yet.

I wanted to introduce my simulator this time very much.  Some list members did me their favor to test it under US PC environment.  I was poor in programming or in packaging.  The test was in vain mostly, it cannot stand up in US environment though it is working in our environment.  I thank here to all those guys who helped me.

As Jerry mentioned, we do not need to be politically separated. The rod design tool would be developed further thus gathering and consolidating good ideas.

Thank you and sorry for a long post.  (Max Satoh)

What a delightful group of insights.

Does anyone know what causes nodes.

They appear to be some kind of genetic plan, they are not like tree rings, yearly. Pictures of 1 year old cane may have 7 nodes.

I do NOT agree that the fibers stop at the nodes. I wish we could dispel this myth, even though it is not important. (or maybe it is)

As Darryl Hayashida pointed out, the power fibers splay inward and outward at the nodes. indeed the inner most fibers (pith side) are predestined to feed the node and therefore some of the fibers dive into the nodal dam. However when closely examined they reappear at the top of the node, migrate toward the enamel and continue up the culm. It may be that the argument hinges around mini fibers in the sheath that we call a power fiber and they may be shorter but this would present a life form which we are not familiar. If bamboo is fed from the roots logic should dictate that an artery could not start anywhere but the roots.

I have taken thousand of cross cuts of hundreds of nodes and at both sides of the cut, it is one fiber in, one fiber out, never have I seen a new fiber appear out of nowhere, nor have I seen one disappear.

There is one other manifestation at the nodes.  The fibers may change position. appear to disappear if viewed from the side, or the top. If one applies a plane (we all have one i hope) set to .001, or finer, you cane plane the cane and actually trace the path of the irreverent fiber and see that it twists or loops around other fibers but does not terminate to be reborn elsewhere.

I attribute this behavior to to the slow down of vertical growth while the node is forming. This could sort of bunch the fibers and when relieved to get going again some of them just sort of go crazy with joy.

Some of the chipped nodes are caused by this action if it near the enamel. The other chipping factor is the lignin that fills the void where the fibers diverge at the node. This is nasty stuff.

This also explains why thin strips break at the nodes and they do. when the taper or cross section looses these inner fibers indeed this spot is weaker. This may also validate displaced Tony's method of pressing the nodes in. Unless they are displaced inward enough that the majority of the fibers that would have survived planing are now part of the missing bamboo.

I was of the impression for years that the fibers ended and restarted at the nodes, but curiosity eventually solved this mystery.

This not the law and I am no botanist, but all you need is a plane, a bandsaw and a magnifying glass to validate this for yourself.

I have printed your treatise Max for further assimilation, thank you for  sharing those insights.  (Jerry Foster)

As Darryl Hayashida pointed out, the nodes are a place where the fibers undergo much branching (anastamosis). However just like blood vessels where arteries join veins through capillary beds, the vascular bundles that pass through the nodes are continuous. There is an excellent 3 dimensional reconstruction in the Book "The Anatomy of Bamboo Culms" by Dr Walter Liese which shows this. I just bought a copy of the book (used - through Amazon). You can preview the book through Google books if you sign up for a free account. However, there is no copying the text or illustrations from the web page. They are very secure.

The book is published by Brill Press and information about it's contents is available here.  (Doug Easton)

Then we also need to dispel the myth that the fibers run the entire length of the culm...  (Mark Wendt)

Especially when we plane or mill them.  (Todd Talsma)

Let me play devils advocate on this thread. we would then be forced to dispel the myth that the culm should always be split and never sawed. Most of you have probably read Bob Maulucci's article on this subject on the rodmakers site. And he's not the only one who says that it's OK to ban saw the strips to width. One thing that has always amazed me is the saying "if you saw instead of splitting you are cutting too many power fibers." Well then ,I'm convinced that when the final taper is planed you also are cutting across fibers. The fibers run from one end to the other(the myth currently trying to be eliminated),you are planing at an angle, from thick to thin, physically IMPOSSIBLE to do this without cutting fibers if they run continuous the length of the strip! Now if the fibers are short and not long and continuous then it really  doesn't matter if the strips are sawed and not split. Ron Kusse shows on his web site just how much power accessories are needed if one is going to have a production shop. He even runs his strips through a thickness planer! His rods are not falling apart. Anyone ever watch Russ Gooding’s video Roughing and Tapering Under Power? His rods aren't flying apart. Bob Milward "proved that bamboo is damaged by heat." Paul Young ran his culms through a ring of fire. Doesn't stop his rods from selling for $3,500.00 and up. Bottom line - anybody who builds rods believes what they want to believe (even if it's proven to be a myth) and they are going to continue to build rods the same way they always have. As long as the rod is straight, casts well with the line wt it was built for, holds up for 50 years and looks beautiful while doing this ,what more could anyone ask of a fishing rod. Another question I would like to see answers on. Most everybody who builds rods is looking for a taper they can call proprietary. How much tweaking must be done before it becomes the builders taper and not a modified taper of the originator. None of this is meant to ruffle feathers, it's just food for thought while all this deep thinking is going on. I've been fishing bamboo well in excess of 30 yrs. Been restoring them for nearly 30 years and am in the build process for rod #2 (that is if you consider a PMQ is actually building a rod , if not then I'm only building #1). I have seen only 2 things in the last 5-10 years that I think is  innovative in the bamboo rod field. #1 - Mike Brooks' Permacane process. #2 Wayne Maca’s ultra sound strength testing of bamboo to see what type of rod it should be built into and his radical hollow build with which I believe he will come up with that 9' bamboo for a 5 wt that weighs only a little more than a graphite rod. (Will Price)

Yes, if anyone thinks they can plane up a section without cutting through fibers then they either have some truly remarkable bamboo or truly terrible eyesight.  Anyway, as I keep saying, it's a laminate and you don't willingly incorporate the crappy bits. If it worried everyone that much they would all go nodeless, I suppose.  Nodeless appeals to me, if I ever retire I'll set to and make some. I've got the kit, but not the time. 

You can run your hand through a Bunsen flame without even feeling the heat, it all depends on how fast you do it!  As for messrs Wayne M and Brooks, how I wish I lived in America.  Nothing happens in the UK, yet, no real market for cane rods, it's because we fish mainly in lakes and not rivers and everyone thinks they are not a real man unless they can cast 50 yards. All things change, but I'm probably too old to be part of the engine causing it.

I still remember some research done after the war which seemed to prove that bamboo was significantly less prone to fracture if the outside was left intact, I did try and make a section like that many years ago, it was a truly horrible job with a very ugly result. The thing is, I suppose that fracturing is not really one of our main problems, what we seek to do is minimize the amount of material used so as to minimize the weight for a given stiffness. This, like it or not, means hollow building.

I feel a sense of deja vu creeping up on me!  (Robin Haywood)

My original intent with this thread was to study and understand stress curves in more detail. The thought after looking at hundreds of tapers was "It appears that any bamboo with any dimensions, as long as they stay within some guidelines will cast a line"

So the quest was to hope that through this list of experts we might ascertain (by analyzing stresses) if a better rod lies within the bamboo itself.

As you and Robin asserted; in order to make a taper, of course we cut across the fibers. I have never heard anyone state otherwise.

The riddle is; if the fibers for the most part are continuous then we should minimize this severing. so the fibers that are present on the outside center of the spline should be kept intact if possible.

Sawing strips is a process used to save time. if the fibers jump sideways at the node and we make straight cuts, eventually  we will sever these central fibers when we taper. weakens the natural strength of the bamboo.

If the fibers are not continuous then none of this matters.

This whole tangent is interesting but...

What does it take to make the short fibers believers change their conviction?

Is scientific evidence enough?

Or is this a belief system that is beyond alteration.   (Jerry Foster)

I wasn't questioning or faulting your original intent and I certainly hope you didn't take it that way. The subject came up about dispelling some myths and what I see as one of the biggest going way back is the splitting not sawing (Remember Heddon used it right on the tags sewn on their rod bag - "hand split, not sawn") as though sawing was inferior to hand splitting and there are modern day makers who still cling to those beliefs AND their biggest argument is because they believe that sawing cuts through too many power fibers where as splitting follows the grain. That may be, but in my opinion (as well as a lot of other people, several who are quite well known for their rods both here and abroad) that is all negated when the final taper is planed you have now cut across many of the fibers you thought you were protecting. When a builder saws strips, sands the nodes flat on a belt sander,  rough tapers with a power beveler, uses a Dickerson or any other type of tapering beveler to get within a few thousandths of final dimensions and hand planes only those few thousandths, and that builders rods are revered by the masses as very good rods, aesthetically appealing and hold up as long as any rod that has ever been built, well then I'm of the  opinion  that that dispels certain myths. Wouldn't you agree with that? It was quite obvious that you and several other list members were thoroughly enjoying your discussions AND THAT IS HOW IT SHOULD BE!  That's why the list exists. I could actually feel the excitement that you, Max Chris and several others were getting out of this thread just by reading your posts and it was obvious to me that there was a great deal of thought going into them. I read them all and would be the first to admit that some of them were over my head as there are many engineering principles that I don't grasp, BUT if I don't want to read them or if there are ones that are over my head I know what the delete key is for. I have read just about every post that has made it's way to this site and that includes going to the rodmakers site and reading the ones that go clear back to the beginning. That being said, the only thing I would like to add before closing this already too long post on my part is. Humor and off topic posts have been a part of this web site going clear back to it's origins and my feelings as I've said before is that  there should be room for both! Do I have to spell that out? (Will Price)

Winston and Powell both saw their strips.  (Chris Obuchowski)

I took no offense at all to your post. I rather enjoyed it.

I started the myth thing trying to suggest that the fibers are long, not short. It was then switched to short not long and I became confused.

Getting old...

The point I was trying to make was that if the fibers are long, then we should attempt to preserve the integrity of as many of those fibers as we can.

These are those  at the center of the spline.

Maybe this way.

If we have a .035 tip and we have treated the cane as well as we can there should be a bundle of .035 (triangular in shape) fibers running unbroken from the tip to the butt. others will be foreshortened because of the taper. alas the best we can do - these outside fibers will be as long as they can but balanced.

If we saw in straight lines there is no way to straighten the fibers that jog at the nodes. and eventually due to  the runout we will sever all the fibers.

This is meant as part of how to build the best rod i can, not build the rod as fast as I can.

Does that help explain this position?  (Jerry Foster)

I agree. The bottom line is building the best  rod possible. I think that the reason most rods hold up as well as they do (not forget that bamboo is a pretty resilient material) is that whatever weaknesses might be in one strip, the fact that there are 5 other strips (or 4 or 3) it's probable that by combining them together into one unit the strength is realized by the negatives in each strip canceling each other out. Probably not an original thought but that's pretty much the only conclusion I can come up with for 6 splinters forged into one unit that can be so delightful to use and appealing to look at.  (Will Price)

Pardon me, I thought we were talking about the logic of sawing not glue.  (Jerry Foster)

I know there are several ideas and methods for rod design that are out there and some of us have pursued some more  than others. I sometimes find myself sitting at the workbench and wondering how proven or disproven ALL the methods may be. That reality check of sorts. The considerations I have wondered about are these. Mr. Garrison devised a method and used just one "character", which appears as others  have done. I know this may be asking for a beating. But of those using a different method. How predictable and accurate do you feel these systems are AND how flexible are they once they wonder from the creators ideas are changed? So. Share this - to what extent have folks used a system and how successful have the results been? AND Is the avenue of design been in one direction - one character of rod? And give the details. Just changing line weights? Or a from scratch design? See - I am wondering with such great rods already available how many are really looking for change.  (Wayne Cattanach)

I think the question is well asked.

I love to fiddle around with rod design, and I have enough Applied Mathematics that I can easily enough work through the calculations - but at this point I am not producing tapers that even begin to approximate to the performance of my favorite Paynes and Gillums.

So my rod work divides itself into two very distinct areas - the self satisfying area of design and the tweaking of established taper designs to produce rods that I can confidently sell to buyers with some sort of bespoke confidence.

It is perhaps disheartening that I cannot say that I have YET managed to design  and produce a rod that is as good as "tweaked" designs, and there is, as you well know, no small amount of work involved in making "experimental" prototypes.

So while I am very eager to see more discussion of basic rod design, and would be more than happy to share what I know about it, I will have to continue to produce derivative designs that I know work.

Just  one  more point - if I ever manage to design a rod that works beautifully, would it not be true to say that it will almost certainly be identical with some classic taper after all?  And that I will not, after all, be doing anything other than piddling in well paddled puddles!  (Peter McKean)

The things that you can change mathematically and entirely reliably, in the sense of preserving the original action, are:

a) Length

b) Line weight handling (IE: the weight that needs to be applied to the tip to produce a constant deflection. This means you end up with a rod of the same action, but shorter or longer and/or of greater or lesser line rating. This certainly does not mean that if you decide to make, say a Dickerson 8013 with precisely the same action but ten feet  long you will necessarily like it very much! To do this you hold a couple of parameters  constant, one is the deflection, what I have called the quarter circle bend elsewhere, although you could use any curve up to a quarter circle it is much harder to be sure that you are keeping it constant. The other is diameter in the sense that each station maintains the same proportion to all the others.

Naturally, if you lengthen a rod then each station enjoys an increase in diameter and equally obviously the distance between each station increases, you then have to recompute it all back to 5" stations to match the form. We used to just draw a good old fashioned graph and take the station dimensions off that. What you cannot do mathematically is alter the fundamental taper shape, you just have to do this by hunch and test the result. Which neatly brings me to your last point and the reason that rodmakers like fiddling with tapers - its because everyone has a different idea on how they like THEIR rod to be. I suppose you could say that this would undermine the perfect theoretical taper, but the differences are unlikely to be great enough to effect the performance of a rod in any serious way, and, anyway, few rods are ever used much anywhere near the limits of their capability. It is better to have a rod you like, albeit a bit compromised, than a theoretically perfect one that you don't!

Anyway, all this personal eccentricity is what keeps a lot of you chaps in business, so I'm all for it. (Robin Haywood)

Several people may expect that there is a way to design a rod from rod deflection.  I confess here... I show you how it is like.  (The stress, deflections used here are dynamic one,  not Garrison's).

Sure, there is a way to CALCULATE the dimension from a deflection curve. It might be a little easier for the beginners in a sense to draw a deflection curve, than to draw a stress curve in such a meaning that without the knowledge of stress curve, deflection curve can be  drawn.   But, as I  mentioned before, it is hard to draw a deflection curve actually on a paper or on PC screen, from scratch.  #confess 1

Try it by  yourself.  If you can do it well, this may become a good design tool of a taper by deflection from scratch.

So the major purpose  of the tool, becomes to copy the existing taper's deflection, and the modification of it.  #confess 2

How the deflection is modified? There is also an interesting story. In my method, an entire deflection of a rod consists of angles of each 1" section of the rod. Accumulation of each 1" angles toward tip top, will show the entire rod deflection. For example, assume two sections rod; if the bottom section is bent in 1 degree and next section in 2 degrees, as a result, the entire rod will bend 3 degrees at the top from the perpendicular angle that is the angle of the grip.

Let's come back to a longer rod example. When considering a rod which deflects 30 degrees at the tip top, we can draw numerous deflection curves. Butt is rather straight and only tip section will bent and total sum of 1" angles are 30 degrees. Entire rod section will bend respectively equally and the total sum becomes 30 degrees.   Sometimes our eye balls cannot catch the differences among those   tiny  (IE:   0.001 degree) angle differences. And the deflection curve is graphed on a small screen. (though the numbers are backed up).  So I put an option to stretch or bend a deflection by % increase or decrease applied to enter 1" sections.

Then how to verify the deflection curve if it is exactly what I want?

I look into the stress curve which matches to  the deflection curve. My knowledge I gathered around from  the beginning, will help how the stress should be distributed and verify the deflection. #confess 3

To implement a "hinge" at some point, put a larger degree of angle at the point, (then reduce the angle number from other part).

It shows the high stress value on the matching stress curve.  Then adjust the deflection or stress value.

My tool is diadic, one head is from deflection curve to dimension, the other head is from stress curve to dimension.  I must go right head and left to complete the work.   #confess 4

The good point is that I can select bamboo specie to use  for the rod. This may not hit you so much but in my environment I have many occasions to utilize different specie of bamboo, such as MOSO, Madake, Yadake, Hachiku, and  other unknown  bamboo. This tool can pick up the attributes (weight and MOE) of bamboos, and calculate to the effect.  So if I want to copy the deflection of a rod which is originally built by Tonkin cane, I just convert it to my rod by specifying "I am using another bamboo".   The converted taper is available. This is most useful for me now.

Conversion of area shape, Solid/Hollow (including how much hollow) is just a function from or to which a conversion calculation is made. As I mainly make hex rod, it is of no use now.   #confess 5  (Max Satoh)

P.S.

I thank to the following predecessors;

Everett Garrison  for everything

Wayne Cattanach for Hexrod and rodmaking

Frank Stetzer for web Hexrod

Bob Milward for MOE experiment

Don Phillips for casting style

and other friends  who educated me on the list.

I missed to add

Jerry Foster for taper archive, the list on Rodmakers web site (Max Satoh)

If we are talking about my rods, then what you say is true. LOL

But I think the point I was making was that if one straightens the nodes laterally as well as has a node treatment regimen which minimizes the loss of fibers then it is possible to have a bundle of fibers which do travel the entire rod..   (Jerry Foster)

I thought I remembered reading something not too long ago that the fibers don't travel the entire length of the culm, and that in fact, they were much shorter than we previously thought.  Anybody else remember that?  Or was I maybe a little too far into one of my single malts that evening?   ;-)  (Mark Wendt)

No, you were fine (at least that night) hee hee, I think that was attributed to Milward. And it's one of the suppositions that Max was questioning, politely.

Max sent me a great explanation of nodes, i asked him to post it for all.   (Jerry Foster)

Yes I believe it was Claude Freaner that found a paper that they totally rendered a bamboo sample down to it's individual fibers and none of them were more than a couple millimeters long.

On that same note I saw a National Geographic episode on the TV and they profiled a guy in Japan that made bamboo paper. He starts by boiling bamboo down to mush. From the looks of the stuff he was boiling down, there were no long fibers at all.  (Darryl Hayashida)

On the other hand, and just  to have a variety of "stories," I recall seeing Eileen Demarest at a rod gathering a couple years ago, holding a small bundle of individual, bamboo fibers. Each was about two feet in length, but we did not know if that's as long as the fibers got, or if they had been cut for some reason.

Neither did she know how they were extracted from the culm, nor what species of bamboo it was, but there they were - so, at least SOME bamboo produces long fibers.  (Bill Harms)

I'm just reporting what I saw. I know wood has structure, the wood grain, knotholes, vascular bundles, and when it gets pulped for paper making there is nothing except short  loose cellulose fibers. Obviously it's the way those short fibers are arranged when it is wood or bamboo that makes  the structures we see.  (Darryl Hayashida)

Paper maker from bamboo fibers requires to chop the long fibers into short tips in order to make PAPER.  Boiling is to soften the fibers and smashing it is to cut longer fibers into short.

This may not be any implication that the fibers of bamboo is NOT continuous.  (Max Satoh)

Yes - Bamboo fibers have gotten to be quite the thing for spinning into yarn, making paper and reinforcing plastics to make composites. They are obtained either by chemical maceration of the culm or by steaming at high pressure followed by explosive decompression. These procedures generate a fairly uniform length fiber depending on the species of bamboo, the age of the plant and the part of the culm. These fibers are about 1-5 mm long and represent the breakdown of the vascular bundles into their natural components. The fabric made from this yarn is supposed to be really great; remarkably supple and weaves into cloth that is  excellent material for summer weight clothes.  (Doug Easton)

You know, I  think we have to be a bit more specific here in our use of terms.  What do we mean when we say "a fiber"?  It seems that individual fiber units are short, probably about 2.5 mm, but that these are amalgamated into composite units twenty or thirty times as long.

So we are probably arguing pure semantics here.

It seems to me that if we begin with a piece of cane .200" at the base, and we plane it or saw it down to, say, .032", and assuming that we do the obvious thing and follow pretty accurately the long axis of the strip, then it probably doesn't matter whether we do it with a bandsaw, with a plane, or for that matter with a bloody axe - we are still going to lose about the same number of composite and of simple "fibers"

I, for one, am a fanatical believer in hand splitting and hand planing.  The only way to go!!!

Of course,  the fact that I do not have a bandsaw, nor a beveler, and would not be competent in their use if I did, may perhaps have some bearing on my belief.   (Peter McKean)

Do you have a source for your 2.5 mm  figure.  (Jerry Foster)

A textbook on Botany from my University days said that the bamboos had some of the longest cells in the  plant  kingdom,  up to 2.5 mm.  Cells, however, are not the same as fibers, I think;  workable structural fibers would have to be composites of cells and lignin formed into structural units.  (Peter McKean)

You are correct, that statement was made. As I recall, someone boiled and otherwise tortured a piece until it came apart, and concluded that there were no fibers longer than an inch or so. This is from memory, of course. I didn't believe it then and I haven't changed my mind yet.  (Larry Blan)

Fiber is the way of food and water for bamboo. If it is not continued... (Max Satoh)

Simply put, the ends of the cells are not flat, but at an oblique angle and joining up with the one next up or down, the end, oblique, walls are porous to allow the flow of nutrients, but at the node there is a more compact and complex joint to allow these nutrients to flow sideways to and from the leaf.

Grasses are called monocotyledonous, they are thus simple plants, characterized by unbranched "veins" in their leaves, the more evolutionary recent dicots. Have the characteristic branching effect seen in their morphological shape and the branching in their leaf veins, they tend to have much shorter cells in their structural growth.

This is one of the reasons that their wood tends to be less stiff than bamboo, but the structure is so mechanically different that I wish I'd not said that!  (Robin Haywood)

That was a most interesting discussion about bamboo and its structure. If anyone has not had a chance to read the two articles published by F.A. McClure, Associate Professor of Botany Lingnan University regarding studies on Chinese bamboo, they are well worth studying. Both articles are studies of Arundinaria. Part 1 is "diagnosis" and part 2 is "notes on culture and preparation for market." They were published in The Lingnan Science Journal. I got my copies from Harold Demarest at an early workshop at Corbett Lake.  (Ray Gould)

I am not saying that the fibers stops at the node. I agree to your statement about the fiber dives in nodal dam and comes back to the next internodal area.  What I ment was that THIN SLICED bamboo tip does not always have the shape where continuous fibers are mostly sliced out.

Let me add just a little to your knowledge of bamboo. We have a habit of eating bamboo shoot of some kind, such as Moso, Madake, Hachiku, etc..  From childhood, we took out its leaf (sheath?) one by one to eat the core part. Just recently, I watched some cooking program on TV, an old cooking lady asked to a caster, do you know how many sheaths a bamboo has? Then TV reporter rushed to the mountain and made a confirmation actions to count sheaths one by one. Almost bamboo (of some kind) and its shoot have 52 sheaths exactly. Bamboo has the same organization inside from when it is a shoot. Every thing is compressed in the shoot form. The number of nodes are equal to the number of sheath as sheath is the cover of internodal area, which comes out from node edge.

There is the part where power fibers are reduced.  The fibers start up from the bottom, go upward and some fibers say good by to the cane pole and go  into a branch.  At cane part just above a branch some dimple exists, which is we call leaf node, it is because fibers are reduced.

Hit me too.  (Max Satoh)

The only reason that we are using 40' is that was my original requirement for the dummies rod. The programs use the weight of the first 30' in grains as a initial value and then work from there.  (Jerry Foster)

A very interesting subject came up on an off list conversation. If  the AFTMA standards for line weights only determines the weight of  the first 30' of line (DT), what is the weight per foot of the middle 30'? I guess we have to assume that the first 30' of line includes the taper so if the middle 30 is constant, does it have the same  weight. I would assume it weighs more. So when we add 20' to a formula are we really getting the correct results?

The reason I bring this up that is using stress's in rod design it appears that we are changing multiple variables when we change line  weights and distance at the same time. It also seems that if we use more than the first 30' of line to do a rod by rod comparison we are  into  unknown area for a given maker of line (SA, Cortland, Rio, etc.)

And, yes, I think it does matter to those of us who would like to believe we are tuning our rods.

Any thoughts?  (Jerry Foster)

I've wondered about this myself.  I worked out the numbers for the volume of a standard DT5 Cortland 444 line and here is what I came up with assuming 30' of line, ignoring the level tip (as per AFTMA standards), and a constant rate of change of the front taper:

Body - 240"; starting diameter .047"; ending diameter .047"

Front taper - 120"; starting diameter .035"; ending diameter .047"

Formula for the volume of a cylinder (body) - Pi * r2 * h

Body Volume: 3.1415... * (.047/2)2 * 240 = .4164 cu. in.

Formula for the volume of a right circular cone (front taper) - Pi * (R12 + (R1*R2) + R22) * H / 3

Front Taper Volume: 3.1415... * ((*.035/2)2 + (.035/2 + .047/2) + (.047/2)2) * 240 / 3 = .1596 cu. in.

Total Volume : .4164 * .1596 = .5759 cu. in.

Comparing this volume to a non-tapered front 10' of line (.2082 cu. in) with 20' of running line (.4164 cu. in.) that has a total volume of .6246 cu in. gives a difference of about 8% between the front 30' of a tapered and a non-tapered line.

A DT2 has a volume difference of about 4% while a DT6 is about 9.5%.  So, the larger the line size the bigger the discrepancy.

The error difference for the weight of a 5wt line (140 grains) is ± 6 grains or approximately ± 4%.

Hope I didn't mess any of that up.  (Chris Carlin)

Sorry, didn't quite get to finish my thought.  Had to sneak in some real work...

If we figure the volume of the first 30' of fly line as .5759 cu. in., then calculate the actual line volume for the next 20', we get .9924 cu. in. for the total volume of 50' of line

Using the Hexrod, et. al. method of taking the weight, or alternately in our example volume, of the first 30' of line, figuring the average weight of each foot (or whatever) of line and extending that to 50' of line cast, we get .9600 cu. in.

Thus, the percentage difference between the volume of 50' of 'actual' line and the volume of 50' of 'averaged' line is 3.3%.  Given the allowable error in AFTMA for a DT5 is 4%, the issue is pretty much moot.

WF lines are definitely more problematic.  (Chris Carlin)

This is an interesting, important and probably unsolvable problem.

The line weights in my online Hexrod, which are borrowed from Wayne C's original program, are averages for 90’ DT lines.  That is, the weight of the entire line is divided by the length to get a weight per foot, and that is what Hexrod uses.

So the line weights are not just based on the first 30 feet, like the AFTMA standard, but they completely ignore the line taper. Since they are based on DT's, they are probably too high for WF lines.

I don't know how other stress curve programs handle it.

Ideally we would know the weight of each 1-foot segment of every line made. 15 years ago there were probably 5 distinct tapers in use; today there seem to be dozens, at least if you believe the ads. :-(

If someone has a practical way to improve on this I'd welcome hearing it.   Without cutting up a couple hundred lines into little pieces and weighing each chunk. Maybe there is formula that could be used?  (Frank Stetzer, Hexrod, Taper Archive, Rodmakers Archive)

This is what I do.

If you are going to use a WF line on the rod - 4wt and under, 35 feet line cast, never over. On those lines once the line is past the belly you get into the thin running line, and it doesn't add much weight even if you cast out to 50 - 60 feet. 5wt to 8wt - 40 feet of line cast, never over that, most lines in that range have a longer belly than the lighter line weights. Most people shoot the line once they get past the belly anyway so the rod isn't actually getting loaded with long lengths of running line. I've never made a rod heavier than 8wt.

With a DT line I use the entire length of the average cast (if I know it) and weight as if it were a level line because the weight difference of the tapered section is slight.

Most of the time the rods I build are built for a DT line because the people I know like to use DT lines on bamboo rods. The WF lines they use on graphite rods when they need to cast for distance.  (Darryl Hayashida)

I just did some basic calculations on your page and it appears the adding  5' of line to a 5 wt  rod  causes  an  increase  of from .002 to .011 on a  rod. This is almost equal to if not more than our heuristic value of . 006 for a line wt. change. I'm certainly not picking on Frank, as all  of the Hexrod programs do a similar thing. So, for those of you who  don't think a few thousands matter, ....

Frank's page is also convenient for anyone to do their own experiments.

5 feet of #5 line is @ 23.33 grains. The difference between a #5 and a #6 at  30' is 20 grains.

Changing the above rod from a #5 to a #6 at 30' gives almost the  identical results to adding 5' of line to cast.

Interesting, indeed as several of you stated, this may even be an  under-calculation. This shows why most rods have an overlapping line  weight quality. It should also show that tuning the rods to anything  beyond 30' is important but problematic. What it shows me immediately  is that you can only get an accurate comparison of rods if the line  to cast value is set to 30'. This does away with the line  manufacturers variances. Rio has that neat DT trout line that has a thinner running section in the middle. A mini double WF.

There is also the question of the dynamics of the line in motion,  inertia (well never mine)

Just some questions on "the path to a better rod"  (Jerry Foster)

I was curious, your results from adding 5ft to the line cast didn't seem reasonable to me either.

I started with the Heddon 125, an 8ft 5wt, and went from 30 to 35 ft, holding stresses constant of course.  These are the dimensions I got at 10, 20, 30, 40, 50, 60, 70 & 80 inches:

30’:  .107, .136, .162, .187, .220, .255, .273, .297

35’:  .110, .140, .167, .192, .225, .260, .277, .300

So the increases are never more than 0.005.

I don't have an idea why your dimensions jumped .011.  Maybe you were on the edge of a ferrule size and it jumped?  That would add a bunch of weight that would require a big jump in the dimension to support with the same stress???

Then I went to 40’ and the dimensions were more like the ones you saw.

But your real point is well-taken.  There is a lot of variability in the weight distribution within a line and between different tapers, and we are not taking that into account, and maybe we should do better.  (Frank Stetzer, Hexrod, Taper Archive, Rodmakers Archive)

It would seem that the only way to determine the right taper for the line you are going to use would be to get a grain scale and weigh the length of line of your average cast, and plug in the weight.  (Darryl Hayashida)

I think we are close enough, I think you said that, the way we do it,  and I agree. But what you suggest would be more accurate.

I am going to weigh the first 30' and 1 ft of level line now when I discard my abused lines. It would be interesting if we all did that  to see if it makes any difference in calculations.

I am still finding it difficult to believe that 5' of line = 1 line  weight. It may be true, but I am finding it hard to digest that to  cast 60' of 5 wt line I should get out an 8 wt rod. Maybe the range  of the sweet spot is wider than Mr. G lead us to believe. I think you  also said that the cane is very forgiving. I'm sure it has to do with  the transfer of stress down the rod, but how to present that eludes me.  (Jerry Foster)

I'll throw my beginner questions/opinions/coments in here.  I just finished rod #9 and test cast it in the road in from of my house this evening.  It's Wayne's 8' 6 wt. 2 piece (nicknamed "the Force" I think).  I didn't have a 6 weight line and there are no good fly shops in my town so I bought a cheap ($10.59) Scientific Anglers WF-6 at KMart and gave it a try.  I liked the rod (as well as you can casting in the road).  I was able to work out about 70 feet of line without much trouble.  Much more than I'll need in Michigan since a 70' back cast would end up in a tree.

Reading the posts today I was really wondering/worrying about the WF line, but for $10 who really cares.  What I really wish I could do is have about 5 reels with different lines on them and see if I can feel the difference.  This weekend I plan on trying the rod out on some fish and will probably purchase a DT-6 to try.

By the way, not to brag or anything but this is the nicest product I've put out so far.  A little untraditional - royal blue wraps double tipped in bright red and black.  My best wrapping job to date though.  I finished the rod with Tru-Oil.  I tried tinting the Tru-Oil with some brown and red artists oil pigment.  It turned out really subtle, but looking at it it doesn't seem quite blonde or quite flamed.  I like the look.  The one thing I'm not happy with yet is my singing.  I think I need to get a different pen.  (Aaron Gaffney)

<<I am still finding it difficult to believe that 5' of line = 1 line weight.>>

Easy enough to verify. Does the weight of 5' of line add up to the weight difference between the first 30' of the next line weight.

On the AFTMA line chart I'm looking at a 5wt is 140 grains for the first 30 feet, and a 6wt is 160 gr. The 5wt is 4.67 gr. per foot (140 divided by 30).

(4.67 x 5ft) is 23.33 gr.

(140 + 23.33) = 163.33 gr.

Which puts it within the tolerance for a 6wt line.

So yes, 5 feet more line puts it in the next higher line as far as total weight is concerned.  (Darryl Hayashida)

If what you say is correct then why did Mr. Garrison use 50 feet of line in his design and why did Mr. Carmichael think it important enough to mention that he changed his line  length to 49 feet so that his tip factor came out at 2.5, Chapter 14, page 243, which made for easier calculations?  Mr. Garrison's rods seem to work well at any distance from 20 to 65 feet.

What you may be saying is that a rod designed for fishing up 35 feet of line maybe designed using 30 feet of line weight for that rod, but if you try to use the rod at 50 feet, forget it, the rod will just wimp out.  There are plenty of us who use bamboo for bass and I'm afraid that 30 feet just will not do it, so as a general standard, using 50 feet of the line size you want the rod to be will give you a more versatile rod which can be used under a varity of conditions and will perform well.

By adding 5 feet of line (weight) may put it in the next higher line size but at 30 feet only. How many people do you see casting a rod at 15 to 25 feet when they are checking out a rod? Not many I would think, although you maybe right that they should because chances are, that's how they will be using them.

In summary, if you check out the Stress Curve of a rod using 30 feet of line you will find, in general, that the rod is very under loaded and will show a stress curve that is very low in value, nothing close to 200,000 and the stress curve will be hard to interpret. So, I say, in general, use 50 feet as a standard.  (Bob Norwood)

I find 50 feet to be too much, but like I have said in the past, stress curves mean different things to different people. Perhaps I fish smaller creeks most of the time than Garrison did so using 50 feet makes a rod that is way too stiff for my tastes. Funny though, I find Garrison tapers too slow. As far as what is in the Carmichael/Garrison book, I find it to be a good start for stress curves and rod building, but only a start. For example when people start discussing a taper the first thing I do is put the taper in my Hexrod spreadsheet so that I see the stress curve under conditions that I am used to - trying to make everything else equal.  (Darryl Hayashida)

For example when people start discussing a taper the first thing I do is put the taper in my Hexrod spreadsheet so that I see the stress curve under conditions that I am used to - trying to make everything else equal.

This is really the most important thing IMO.  Graphs from all the programs out there look different from each other, and stresses aren't exact either, so learning one well and understanding how the charts and variables affect the action of the resulting rod, it is easy to get a good comparative view of rod actions.  If you jump back and forth, you'll quickly find that a slight adjustment to a taper and resulting 'bump' in a graph in one program will result in a larger or smaller bump in another and easily skew what you are trying to accomplish - just ask me how I know.  (Chris Carlin)

I also wonder though, was Garrison using AFTMA designated plastic line weights, or silk lines where diameter is the rating  criteria.....  (Darryl Hayashida)

This also makes it plain to me that to build rods for the "correct" line weight, cast length has to be set at 30 feet.  Otherwise if cast length is 5 feet more or less, you are building a rod for the line weight above or below the intended line weight.

People who use 40 feet as the cast length are actually building a rod two line weights over what they are to build.

What if your average cast is actually 40 feet long? Get a grain scale and weigh the length of line of your average  cast and plug in the weight. Build your rod using that weight. Does it matter what your rod line weight is "supposed" to be as long as it performs correctly for you in the conditions that you fish in?  (Darryl Hayashida)

I didn't mean to imply that I think 30' is the only valid distance to  design to, but more to get a valid comparison between two rods.  Because of the unknowns of line design we are discussing. In fact I  think if your average cast is 40' it becomes more important to take  that into account in your initial design.

I think this is becoming more of a discussion of how wide a rage is  the sweet spot.

And yes Frank, after looking more closely at a bunch of different  tapers, it is clear that the amount of change is very relevant to the  rods action. Type of rod.

Also Mr. Bokstrom and others including Larry in his implementation of  Rod DNA have provided another way of perceiving the rate of change as  a vilid design (analysis) technique. (Jerry Foster)

I'll ask you the same question I asked Darryl. Why did Mr. Garrison, who started all this, use 50 feet of line in his calculations?  (Bob Norwood)

I won't hazard a guess as to why Garrison chose 50', but I will offer this up for digestion. Using Wayne's The Force as an example, at 50' the peak stress is just passing 200,000. I have witnessed this rod being cast with backing outside the tip guide, and it had not run out of steam. For what it's worth, my thoughts on this have always been that while the "Hexrod" peak stress may have actually occurred at some point, as the rod continues to load, the tip does not continue to bend. The tip is at it's maximum deflection, and the peak load is being carried further down in  the action.   (Larry Blan)

The Force will easily cast past the backing in the hands of one who knows how. The first time I handed my copy of this taper to Mike Roberts he had all the line plus about 15 feet of Dacron on  the lawn with two false casts. That was with a Hardy DT6 line.  (Tony Young)

And how many fish did he catch with that prodigious display of  masculinity.

If one were casting that far for real, how delicate was the presentation?  (Jerry Foster)

Absolutely none at all. It was in a football paddock. Mike would likely shy from being called masculine though he's about 7 stone dripping wet but he can shoot a line. :-)

I know what you're saying but there are times distance is good and presentation don't matter. I'm thinking nymphing for which the Force and the Para 15 is excellent and lake fishing where you're casting well ahead of a cruising fish. It's not all size 24 cripples on a spring creek stuff. It's not the ideal rod for the situation but some of the fast water places I've been fishing lately you could throw a brick into the water (the nymphs are so weighted they almost are bricks) and the fish wouldn't know as long as it's down stream and you don't line it.  (Tony Young)

I can only propose a guess.

50 ft. is probably an optimum casting distance for measuring a rods  backbone, for fishing I'm not sure. It also guaranties that within  all casting distances for normal fishing the rod will not be over- stressed. A rod must also catch and land fish so a certain amount  strength must be built into the rod for the type of fish being  stalked. There certainly isn't one way to design and make rods.

The way people pick up and wave a rod around or immediately try to  impress by testing its length is probably the most irrelevant test of  all the things we know about rods.

For my part, I was suggesting that rods be compared at 30' not  particularly built to that parameter.

Perhaps also; the range of stress for valuable rod action is much  broader that Mr. G tries to constrain it too. What we are talking  about is broadening the narrow limits set by G. in defining his own  roads. Once a different range is decided upon (each to his/her own)  the rod can still be optimized within that range.

I think we must always try to separate Mr. G.'s rods from his  contribution to rod design. I hear to much thought that the math will  only result in G style rods. Nothing is farther from the truth.  (Jerry Foster)

I normally keep the cast length in Hexrod to 30' because that is what the AFTMA standard is. It was actually a revelation to me that the guys asking for 40' average cast were really asking for two line weights over. I knew a longer average cast could be translated into a higher line rating at some point, but I didn't realize it was as small as 5 feet. There are a few 7 wt Sir Ds being used out there. A few guys wanted a 5wt and said they wanted it built for a 40’ average cast....  (Darryl Hayashida)

That's interesting. Are you saying that you made 5wt Sir D's by using the same stress figures at 40’ as the 4 wt version at 30’? This is not meant as a criticism but doesn't Cattanach list the rod as a 4/5? The 4 wt version handles 30’ and 40’  casts equal well. It seems like a very small change can be made to make the rod a solid 5wt.  (Jim Lowe)

I find it handles a 5wt very well myself, but these guys - well it started out with one guy, but the others tried out the rod, liked it and had me make them one too - wanted a "true" 5 wt, one that he could use a 6 wt if he wanted to, and he said his average cast was 40’ plus. So I tweaked the taper to be a 5wt with a 40’ cast with the same stress curve as the original Cattanach 7042.  (Darryl Hayashida)

Well, this should be simple, we have a standard, after all!

I almost think we would have to talk in terms of specific lines, because they all vary in terms of tip,  front taper, body, rear taper, and running line, to use Cortlands terminology.

Consider a shooting head spliced directly to backing. Any of the Hexy line weights will be well off the mark.

Then we have the GPX (I think that is the correct one) that is 1/2 line heavier than the listed rating, to allow the latest and greatest graphite rods to cast. Ok, lets not consider that.

In the case of a typical WF line, the running line makes up more than 1/2 the line length. Any formula that takes more  than a 45 foot cast into account is going to be off. In some cases, the running line is almost 60' long.

If we were to apply something like what Chris did to specific lines, and perhaps graph them (nice job Chris), a picture might emerge.

Does it make a difference? Not to everyone. Is it practical in some applications? I think so.  (Larry Blan)

Is everyone now using AFTMA weights as a standard? I thought I was the only one, at least that's the way it was last year.

Now, the standard is for the first 30 feet of line minus the small straight piece at each end. If you disregard that approximately one foot piece on each end and weight the next 30 feet on each end you end up with only 28 feet in the middle. So my solution is to multiply the 30 feet weighted by 3, it comes out close enough and if there is an error it's always in the same direction. A big problem solved easily.

The biggest problem by far, is the lack of any production control by the manufactures. As far as I can see you have no assurance that the line you buy is really what it says it is. I think, we as rod builders and line users, should set up a committee to help the manufactures set up a system that is both logical and functional and that the limits for each line size are tightened and controlled to a much higher degree of accuracy than the mess we have at present.

I nominate you as chair person  and second the motion. Good luck.  (Bob Norwood)

The only way you can be absolutely sure is to get a grain scale and weigh the length of line of your average cast, and plug that in to your stress curve calculations.

What I have found is that it doesn't make a whole lot of difference. The impact factor, and probably the resilience of bamboo itself tends to smooth things over so that if you use the average value of the weight of the line and average length of your cast in your design you won't be off by very much at all if any.  (Darryl Hayashida)

This discussion reminds me of a friend long ago  that was very excited showing me a graphite rod he said would cast a 5, 6, 7 or 8 wt line.  And sure enough it would.  However, I felt it lacked the delicacy to protect the tippets you might use with a 5 wt and lacked the backbone  to handle the fishing you might do with an 8 wt.  Can we really fine tune a  rod when the load varies so much with the length of line cast?  I make  short casts and long casts.  How do we get around this?  (Ed Berg)

Can we really fine tune a rod when the load varies so much with the length of line cast?  I make short casts and long casts.  How do we get around this?

The rod has to be able to handle the long casts (and large fish) because that is what will potentially put in a permanent set or break the rod. For short casts a finer tip helps, but the person using the rod has to be aware that the rod has a fine (weaker)  tip and not stress it too much when fighting a fish. That is done by holding the rod at around 45 degrees towards the fish when fighting a larger fish, not straight up over his head or letting the tip go back behind his head.  (Darryl Hayashida)

I understand the issues of cast length and fish  size.   Cast off the tip, fight a fish with the butt of the rod, etc.   Both of these parameters lead me to prefer a progressive taper where an  increased load produces a bend farther down the rod (if you'll excuse my  oversimplification).  This results in my understanding that almost any rod  design will handle a range of loads.  My 4 wt will also handle a 5 wt, a  twenty ft cast as well as a 50 ft, all within that 'reasonable range'.  How  much farther can we 'tune' a rod?  I don't expect the weight difference  between a short or long front line taper to alter a rod design.  That said,  I really appreciate the work of those that make our design processes more  accurate.  (Ed Berg)

After spending yesterday looking at fly line weights, here are a few observations.

30' of 444 DT5 line and 30' of 444 WF5 line both weight in at 140 grains (as per AFTMA standards).

Now, add 20' more line to that.  50' of DT5 line weighs in at ~231 grains, while 50' of WF5 weighs in at ~200 grains which is almost exactly the same as 50' of DT4 line (~ 202 grains)!

This seems to imply that if you design a rod, using 50' as your Line Cast variable, and use a DT4 line as your Line Weight, it should cast about the same (ignoring the line taper differences) at 50' with either a DT4 or WF5.  Of course, at short distances with a WF5 the rod will be overloaded which, if taken into the design consideration with the proper foresight, might not be a bad thing and could turn the design into a more versatile rod.

Some of this is self-evident from simply casting different lines at varying distances, but seeing it on paper, especially in relation to how it could change a stress curve vs. length of line cast, is quite interesting.

Of course, this complicates things for designing stress curves as the Line Weight variable is not as simple as a constant weight per foot of line, and would need to be calculated depending on the line taper in relation to the Line Cast variable.  It ought to be a good challenge to program it into a spreadsheet, but it would be neat to see the stress curve change with a WF line as the line cast changes from 20' to 50', especially in comparison to a comparable DT line over the same range.

Another thing to consider for those of us who use split shot or other weight on a regular basis, is the effect that that has on the weight of the line cast.  2 #4 (or B) lead-free split shot add 6 grains to the total weight.  2 size BB lead-free shot add 11 grains.

Then of course there is the lighter weight leader and tippet, which makes a Line Cast variable of 30' into 40'+ of actual line cast...  (Chris Carlin)

My two cents on the line weight dilemma:  since the line weight is KNOWN for the first 30 feet you could determine the incremental addition for line beyond 30 feet by weighing the complete line, subtracting the known weight of the first 30 feet, then divide the remaining weight by 60 to get grains/foot for additional length.  This would be a nondestructive technique to get the data.  One would just need an inventory of many line weights to arrive at a broad range of information.  I don't have but a few different line weights myself.

This technique would give you an accurate weight for the additional line without worrying over the differences in the ways line manufacturers produce the line, i.e. tapers, material density, line diameters.

I will try this method on a couple of lines this weekend and report the results.  As some suggest, it may prove to be insignificant compared to and averaging technique.   (Al Baldauski)

Personally I don't see the problem in weighing the length of line of your average cast. Measure it out, coil it up, put it on the scale. Put the rest on the table. The line on the scale and the little bit going down to the table is being weighed. The line that is on the table is not.  (Darryl Hayashida)

I don't see anything wrong with your technique and it is specific to a your line and design considerations. My suggestion was a way to come up with the weight of the running line so that it could be added incrementally as you extend beyond 30 feet. This would allow the design programs to more accurately model the chosen length of line cast. Again, the difference may not matter since, on the lighter weight lines, AFTMA allows a tolerance of ± 10%. And on the mid-weight lines ± 5% (Al Baldauski)

My suggestion was a way to come up with the weight of the running line so that it could be added incrementally as you extend beyond 30 feet.  This would allow the design programs to more accurately model the chosen length of line cast.

That would be great if any of the Hexrod type programs did that, but all the ones I've seen treat the line as having a constant weight per length. So, I weigh the line and plug in the line wt and length that equals that measured weight. No other way to do it the way the Hexrod type programs are now.  (Darryl Hayashida)

If there were a table or formula that gave weights per length for "typical" WF and DT lines, it would be pretty easy to incorporate this into Hexrod.  Its just a matter of getting the data.  If somebody has a lot of lines and time on their hands be my guest.  (Frank Stetzer, Hexrod, Taper Archive, Rodmakers Archive)

That was my idea.  In the absence of tables from manufacturers, then IF we could make the measurements I suggested collectively we could produce a formula for the increased weight per foot of line out beyond 30 feet which could then be incorporated into a design program.

Over lunch time I measured three lines  DT4F, WF5F, & WF7F and calculated the following:

DT4F  running line - 3.87 grains per foot  (Cortland)
WF5F running line - 3.30 grains per foot (Scientific Anglers)
WF7F running line  - 5.15 grains per foot (Cortland)

If we used the AFTMA weights for the first 30 feet and got an AVERAGE weight/foot for the whole line, we'd get these figures:

DT4F average - 4 grains per foot
WF5F average - 4.67 grains per foot
WF7F average - 6.17 grains per foot

So now we can calculate the difference between the average weight @ 50 feet compared to the actual weight @ 50 feet.

Using Average Using Actual grains difference % difference DT4F 200 grains 197 grains 3 1.5 WF5F 233 grains 206 grains 27 11.6 WF7F 308 grains 288 grains 20 6.5