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
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)
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)
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? (See Cortland table)
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)
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. For examples, see here.
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. Again, stay with Cortland.
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.
Some of these differences can be due to style (WF Vs DT), different manufacturers, and/or manufacturing tolerances. It seems that it is more important to consider actual values when designing with WF lines since there is a greater proportion of the weight in the "head" than in the DT lines. It also seems there is enough potential variation in running line from each manufacturer that we would have to have THEIR tables or else an independent project to tabulate the data for 3 or 4 manufacturers, 12 different line weights and the myriad "head" styles would be almost endless. (Al Baldauski)
When we get all that figured out, How about a parameter that affects the
stress curve even more than line wt. What impact safety factor do you use? (Darryl Hayashida)
I just sent Frank a few tables containing the calculated weight per foot of Cortland 444 DT and WF lines, as per the taper dimensions on their web site. If anyone else wants a copy of the table, it can be downloaded here.
There are two sheets in the spreadsheet. One for DT and one for WF. Both are weights for that number of feet of line, so 30' on each chart is the weight of the first 30' of line, 35' is the weight of the first 35' of line, etc.
Weights at each foot interval are calculated using the given taper dimensions from Cortland's web site for Cortland 444 Floating Double Taper line and Cortland 444 Floating Rocket Taper (WF) line.
I used a standard 240 grains / cu. in. which is the density that Cortland appears to use. The slight discrepancy in the weight of the first 30' of line (compared to Cortland's web site) is due to this standardized number which, empirically, varies from ~237 to ~242 depending on the line. Rather than fudging these figures to get round numbers I decided on a standard density. (Chris Carlin)
I was able to get the WF and DT line weights programmed into the stress curve spreadsheet that I use so that it uses the actual weight of the line cast from the 444 line weights listed in the spreadsheet whose link I posted earlier. The results can be seen in these stress curve charts.
The Z axis on these charts is a line cast variable that ranges in 3' increments from 3' to 60'. Imagine 30 standard stress curve charts shown on top of one another, where the line cast variable increases in 3' increments.
The first chart uses an averaged weight per foot of DT line (using the first 30' as the baseline).
The second chart uses actual DT line weights per foot, and shows an increase in the stresses due to the extra weight of the non-tapered line after the first 30'.
The third chart uses actual WF line weights per foot. As can easily be seen, once the line cast reaches beyond the line taper and goes into the running line, the stresses change considerably as the running line is so much lighter in comparison to the tapered part.
PS - If anyone downloaded the Cortland444_weights.xls spreadsheet immediately after I posted the email, make sure the lower right value on the WF chart (90' WF10) is 579.7. If it is smaller than that the sheet was a previous, incorrect version. The correct spreadsheet is now in place and, again, can be downloaded here. (Chris Carlin)
Jerry pointed out that a double taper line has to be handled differently from what I suggested which was for a WF line. The calculation for a DT line would be: Total weight minus the 2 X the weight of the first 30 feet then divide by 30 feet to get grains/foot of running line. (Al Baldauski)
You nor Jerry still have not taken the first foot of line on each end into account, this is not included in the weight measurement of the first 30 feet. This now leaves only 28 feet in the middle. (Bob Norwood)
Is this a bonus ft.? I think it is included in the AFTMA standard, or it is irrelevant, much like a leader, tippet (and the fly itself can be a factor, weighted woolys or wind resistant dries). Yes it could be or is a factor, but very hard to quantify.
The fact that the length of the tapers are not standard is enough to skew the exact wt of each section slightly, but you have to have something standard to resolve to. First 30 ft. seems to be all we can hang our hat on. (Jerry Foster)
We've fairly well beat the line wt question to death so I've got a less technical question.
Two tapers one a 4 wt and one a 5 wt. If I put line on them, chuck them in a clamp side by side and put exactly the same amount of stress on the end of the lines (the rods are pointed at an identical 45 degrees and are the same length.) should the bend in the rods be identical?
It seems to me they should be. If one bends in the center more than the other, the rods won't cast the same. (Terry Kirkpatrick)
Here's my $.02 for what its worth. If when you say "Two Tapers", you mean that the tapers are both meant to have the same action and the only difference in the stations measurements is do to the change in line weight then I'd agree that theoretically the bend in the rods should be very similar.
However if the "Two Tapers" represent rods with significantly different action, (slow or fast) or different intended flex points (full, mid or tip) then I wouldn't expect them to have the same bend. (Wayne Daley)
No, the rods should not bend the same. If they did, it would indicate you have identical tapers. A rod's ability to handle a larger (heavier) line is a function of having proportionately larger cross-sections (mass). This means greater resistance to the forces of bending, so a 5-weight rod will deflect less, under the SAME weight, than a 4-weight rod.
The difference between a 4 and a 5 weight rod isn't necessarily that the former "bends in the center more." Rods that are meant to feel the same (though different in line-weight) have their tapers distributed is similar proportions throughout their lengths. A more appropriate question might be: "If we hung a weight equal to the first 35' of a 4-weight line from the end of the 4-weight rod, and hung the weight of a similar amount of 5-weight line from the 5-weight rod, would the bends in the rods be the same?" Now, I think, if we have similar designs, the answer should be "yes." (Bill Harms)
I would have to agree with Bill, I misunderstood the question when I replied and thought that the weights being attached were the weight respective to the relevant line weight and not the same weight. (Wayne Daley)
I agree with your last paragraph regarding testing to rods with weights equal to some amount of line except that the weight should be many times the equivalent line weight extended. The reason is this:
When you cast a rod, you are accelerating the rod and line at some rate. The force on the rod is equal to the rod mass plus the line mass all multiplied by the acceleration. This is where Garrison's "mysterious impact factor" comes into play. When I looked at his calculations, it was clear to me that he used a factor of four times the acceleration of gravity (4g's) to arrive at his stress values. As many have argued, it's all relative. Everyone accelerates a rod differently and the same rod differently for various situations. But, for the sake of comparability, Garrison used a factor of four for all calculations. So, for a static bend test, a weight must give the equivalent deflection of the rod when cast. For example, I found, on a Para 15, the weight required for a typical deflection was about "10 times" the equivalent of 30 feet of line (about 3.8 ounces).
Using a weight equivalent of just 30 feet of line will give such a small deflection that the differences may not be noticeable. (Al Baldauski)
Let me be a little more clear. (As usual I didn't say exactly what I meant. Sorry.)
I just taped the guides on a 7 1/2 ft 2p 5 wt today and put a line on it. It casts okay but it's a little stiff. I've run into this problem before and have never been able to diagnose why a copy of an existing rod comes out with a very different action. I decided to try a simple test.
I wedged two rods of equal length, side by side, into a sawhorse. I secured a line on each and ran the line through the guides. I measured the lines so they were as exactly even as I could make them, then I tied them together. Next I put a weight on the loop in the end of the two lines. The weight put a bow in the rods until it touched the ground. The rod tips were side by side both at the beginning of the test and with the tension on them.
The 4 wt, which was my prototype, seemed to have a more uniform and gentler curve out to the tiptop. The new rod, the five weight, seemed to bend more at the tip. The differences were very slight, Maybe 1/2 inch at the maximum different in deflection, but they were there.
I remeasured the tapers on both rods, and found that there are some unusual differences. In theory the 5wt should be .006" wider at each station than the 4wt. It isn't. Some are less than .006" and a few are larger than my target. One is almost twice the increase I've got to go back to my original numbers because when I removed the glue binding, things were very close (002" or less) to my target.
Another variable that I'll have to explore is the fact that the prototype is a two tip rod. Maybe the second tip is different than the first?
Anyhow, that's where I am. (Terry Kirkpatrick)
I'm doing a bad job of explaining what I was trying to accomplish. I wanted to see "where" the rods were bending, not how much they were bending. It's my belief that if a rod has the correct line wt on it and bends at the same place as another rod with the correct line wt on it (if both rods are casting the same amount of line. Lot of variables here.) the rods should "feel" the same to a caster.
Am I way off the mark here? (Terry Kirkpatrick)
I understood your question the first time you asked it, but the answer seemed obvious. They should bend the same amount in the same places if they have the same action for different line weights. However, a "parabolic" action will not bend the same as a "fast" action rod. The parabolic will bend more in the butt and less in the mid part of the rod.
But if you want to convert a taper from one line weight to another, or from hex to penta or quad, this could be a valid means of comparing the result. There are a number of methods to convert rod actions: Bokstrom's controlled modification, Garrison's stress curves, equal area, etc. It would seem that ultimately, the objective is to duplicate the action of a rod while changing some characteristic. This could be an objective empirical means of evaluating how successful the conversion is. (Robert Kope)
When designing a taper and plotting a curve, the amount of line expected to fish is what should be inputted into the calculations and then, when comparing to another taper, you would input the same amount of line fished as that to the rod which you are comparing to, correct? (Ren Monllor)
When comparing tapers via stress curves or any other method it makes sense to keep as many variables as possible the same. In the latest issues of Power Fibers Chris Bogart makes a very good case for always using 30' as the standard of comparison. (Harry Boyd)
I agree so long as the comparison is made between two tapers of the same line weight. I'm still learning the art of taper design...but as it stands today, I compare 2 wts @ 20’, 3 wts @ 30’, 4wts @ 40’, 5 wts @ 50’, etc... Nothing scientific about multiples of 10. It just seems to be in the ball park. As I understand it, a taper extrapolated from a 4 wt to a 5 wt should cast either a longer line or a heavier fly. I realize there are exceptions...like catching carp on a 6 weight rod (short line, small fly and big fish). The additional line helps validate the comparison between dislike line weights.
I may change my mind next week, but I've been using this method for about a year. I've validated the incremental line length assumption on paper using published line weights for popular tapers. The correlation is statistically significant...whatever that means. (David Bolin)
That method works, but has some limitations. I agree 100% that when comparing tapers you need to have some sort of standard. The ideas you put forward should work well in just comparing tapers as long as you keep comparing apples and apples. And you're not the only one to think that way. One well known author (and friend of mine) wrote the following to the list exactly eight years ago today -- 1/14/1998
The individual maker can determine the casting distances for a particular rod but personally I usually use the following:
line #2 - #3 45'
line #4 50'
line #5 55'
line #6 65'
I've never make a #7 rod but I know that for the FFF instructor a 70' roll cast is required
(Of course, the last line isn't correct. The required roll cast for the FFF Casting instructor is NOT 70 feet. :-) )
But I wonder, David, how the line lengths you suggest translate into Hexrod? For example, suppose you have a 7' 4 weight and you'd like to extend that same exact action to an 8' 5 weight.... Do you determine a stress curve for the 7' #4 at 40 feet, then ask the program to design a similar curve for an 8' #5 at 50 feet? If so, does that create a similar feeling rod? I'm really not sure, so I'm asking. (Harry Boyd)
If I may be the first to not answer your question
This is not intended to start a discussion of neuron function, I'm not sure myself of what we are feeling when we cast a rod. Is it the weight (taper) of the rod? under accelerated deflection? + the weight of the line under acceleration? + gravity? I don't think we feel the stress of the rod..I think that's an internal to the rod picture? They certainly relate to the dimensions, but not a closely as I used to think. Static vs. dynamic changes.
I think the case for going up and down line wts. can be depicted by stresses.
When you change rod length you bring other characteristics into play. Timing.. probably another element of feel. I think you can produce a similar feeling rod when you lengthen it if you slow the butt down a little. But a pure stress curve doesn't relate this very well. This is not new with me, many have stated this before.
Now for deflection.. (don't get mad at me Max) The rod deflection may be a better instrument for changing length. not only the inch to inch deflection pattern but the total deflection angle of the rod and the tip angle. Of course, just like stress, the change must be re- distributed in the new rod length properly.
In your example you went from 7' to 8' and from #4/40 to #5/50. In essence that is a 3 line wt. change + the '. The key to that change using stresses (this is only my opinion, well all of this is JMO) is to know the Hi/Low stress values that you, or your customer prefer. Assuming the action type is set in stone. hee hee.
Stress will certainly get you closer than just adding .012 to the entire rod. But you already knew all this dribble. (Jerry Foster)
What about vision? The coordination of eye and hand is essential because we input distance of the cast, wind, angle, weight of the fly(s), loop size, and desired line speed, thus constantly changing rod loading from cast to cast.
Our evaluation of rod performance is a result of judging it under a large set of variables using some extremely subjective senses. Almost mystical, isn't it? Like playing cool jazz. (Steve Weiss)
Be careful, you'll blow my cover..hee hee
I keep telling people to close their eyes when they first cast cane, so they can feel it work. I think it helps mask the micro-timers in our brains that most graphite guys use exclusively because their rods have no soul. Of course, I don't think we should fish with our eyes closed. (Jerry Foster)
While my casting skills are moderate, at best, it is my experience that the greater curve of the arc traced by the rod tip during the casting stroke, the larger (wider) the line loop. conversely, the flatter the arc of the tip, the narrower the loop. the path which the line travels must follow the path of the rod tip. the relative stiffness of the wrist would seem to be the culprit (as it were). (Roland Cote)
What I'm looking at is what is in the rod that makes the best casters have to tune their style. Most experts can throw an elegant line with any rod. Some they still like more.
What I am looking for is same expert, same casting stroke (no adaptations), different rods will inherently throw different loop sizes.
At the top of the backstroke the line is at a given height. As the rod is accelerated forward the rod, flexes, deflects. The result is the rod is foreshortened during its travel. So now the tip is at a different height than when it started. Just before the stop in the stroke the rod is at max acceleration. No loop yet.
I am in the camp, mostly, that the wrist snap is the loop forming portion of the cast, but.....I think that is because that final rotary burst of power defines the rods max deflection.
This also defines the rods stop position tip height (Z) . But where is the rod tip at this time. How does get to where my hand says to be (Z).... everyone knows. it unsprings.
Did the max stress in the tip location (garrison) define the loop. Did the total flex of the rod define the loop. Did the max stress value.
I ask this part because, my thoughts are
By the time of the the wrist snap we have been dragging the line into a certain plane. + Gravity assist. Xfering energy, all kinds of stuff.
So now we snap-stop. The top height of the plane is set. normal cast. The tip is at its most deflected point.
The rod unfurls to pt. Z.
The loop is indeed the tips trajectory.
Para 15 Vs. Pinky
Why wouldn't it always be that little 5" downward move I have described by my stroke? (Jerry Foster)
You seem to be a little confused there are many top casters out there that use no wrist action at all in the casting stoke, Mel and Steve to name two. The loop is formed only by the deviation of the rod tip from the original straight line path, convex open loop concave path tailing loop. Granted if you use a soft rod to form a straight line path the casting stroke must change, this is why I tried to explain. Moving the hand straight forward and back will not form a straight line path of the rod tip, the rod is bending under load on the back cast and the forward cast. If you simply did this your casting stroke would be convex and your loops would be open The casting stoke to form tight loops with different rods actions must be adjusted accordingly. A softer rod requires a longer casting stroke than a stiff tip action rod to force a tight loop.
If you wrist snap the at the end of the cast the amount you turn the wrist will in effect alter the size of the casting loop providing the snap takes place before the stop. Also, the stopping of the rod is very important in forming a tight loop. It's a very forcible stop, squeeze the rod handle hard at the completion of the cast.
It's not possible to cast for distance without altering the casting stroke. The soft rod with the same casting stroke same line carry would of course throw a wider loop. (Gary Nicholson)
I've spent my forty years of rodmaking trying to solve that question with not much success, and with even less success in trying to work across the different geometries. But don't we have fun in trying? (Bill Fink)
Could you tell me exactly how you compare, say, 2 wts @ 20 feet. What are you comparing them to? (Bob Norwood)
I enjoyed the presentation at SRG and visiting afterwards. I intended to buy the CD but didn't get it done. To answer your question, I've dissected about 150 classic and contemporary tapers on paper. I'm using a deflection model built by Jim Utzerath in Excel. It's not particularly user friendly, but very powerful once you get the hang of it. I've linked a list of tapers into the model so I can run all the calculations, store the results in a list and compare the tapers.
I struggled with the 30 foot assumption for months. I know it's in the ball park for most trout class rods (4 to 6 wt), but I kept producing exceptions in the data for rods on the small (2 & 3 wts) and large (7 to 9 wt) ends of the list. A taper that was posted to Hexrod or where ever that was said to be a 2 wt produced an extreme deflection curve with 30’ of line in the model...like they were all noodles. A taper posted as a 9 wt would produce an equally distorted deflection curve...looked like broom sticks at 30 feet. If Jim's model is consistent in the calculation of every bent angle, the distribution of tension and bent stress calculations (and I believe it is), and the maker that posted the taper is correct that the rod will cast a 2 wt line comfortably, then that only left me with the line length, fly weight and size of fish to be landed.
I threw the size of the fish out, I rarely (if ever) catch anything to big for a 4 or 5 wt anyway. Fly weight isn't an input in the model. So line length was the only thing left to work with. It didn't seem to make any sense to evaluate a 2 wt rod with way more line than an average cast would demand or a 9wt with way less line than would actually be used. With that in mind, I blindly changed all the line length inputs to be 10 times the line weight and ran all 150 tapers back through the deflection model. That fixed the extreme deflection curves on the majority of the tapers.
So...if I want the action of my favorite 2 wt while casting an average of 20’ to carry over to my 5 wt rod casting an average of 50’, then it wouldn't make any sense to average them both at 30’ in Hexrod...or would it? I can get lost in this in a hurry, but when I go back a population of 150 tapers and their posted line weights, the line length can't be averaged from 2 to 9 wt and produce meaningful deflection curves...or stress curves for that matter.
You're more than welcome to have Jim's model and the database of tapers I've built. All Jim asked of me is that his work would be appropriately credited as it was passed along. But nothing about it is user friendly...especially after I've cobbled it up with macros to link up my list of tapers. (David Bolin)
Thanks for the fast response as to what you are doing and why you are doing it.
First let me say that I am posting a reply to Harry Boyd about a question I asked him on RodDNA and the 30 foot Golden spot. It may shed some light on the current Hex Rod programs and their problems.
Second, there is no harm in looking at rod tapers at any line length, although I would be suspect of the program you are using if you have no idea of fly line weights in the program. The reason Mr. Garrison and I stress the line length of 50 feet is that's how he set the maximum stress value of around 200,000 and rods designed with stress values over this value may not perform well. The 6'6" 4 wt I showed at SRG6 is this type, but remember I said that it was designed for 5' to 40' the stress reaches 200,000 at 37 ft. But then I had one caster, can't remember his mane, take the rod and proceeded to put out 70 feet of line with no problem. I guess that shows what I know.
Send me the names of some of the tapers you are looking at shorter lengths and we can discuss them. (Bob Norwood)
This thread really got me to thinking about how I evaluate a taper. Don't know if thinking is good or bad, but here goes.
I've been evaluating a taper with stress curves using the "normal" distanced fished, which for me is about 30 feet. I haven't designed tapers, only use it to select a taper that should work well under my conditions. So far, I'm 2 for 2 with a Thomas 703 and Dickerson 7012.
But, after reading this thread I learned some new things. I wasn't aware that the Garrison calculations were optimized for 50 feet of line. I plotted 2 rods of the same length; a Dickerson 7612 4 wt and a PHY Perfectionist 5 wt. I've posted the graphs here.
Surprisingly (to me), comparing the plots for 30, 50 and 70 feet, the shape and slope of the curve changes fairly significantly. On the Perfectionist, the slope changes from an upward slope at 30 ft. to a downward slope at 50 ft. That, in particular, could completely change the feel of the rod solely based on casting distance.
One interesting observation is the position of the base of the initial curve stayed the same regardless of casting distance.
Maybe I should take my engineer's hat off and quit thinking! (Rob Holland)
The problem is in actual usage. Line manufacturers do not guarantee line weights for any length other than 30 feet. 50 feet of line will be way different from different makers, and will be different even from the same maker depending on the line type. Most of us design rods to use DT lines and extrapolating line weight out to 50 feet will be the closest for that type of line, but what if your user puts a WF line on it? Most WF lines are well into the thin running line at 50 feet, and a lot lighter than your design weight. Even DT line weights vary at 50 feet from the same maker. Take a look at the Cortland web site to get an idea of how a line can vary at anything other than 30 feet.
On the other hand if you aren't actually thinking you are using 50, 60, or 70 feet of line, it's just an input parameter that you are accounting rod characteristics with, and you know how that relates to casting 30 feet of line, then that will probably work for you. (Darryl Hayashida)
Before you change anything, your initial thoughts are correct.
I don't know why Bob said it the way he did, but the choice of 50' by Mr. Garrison was probably (I'm guessing here) because he didn't have a PC. Slide rules are a bitch for all that iterative calculation. Even if he did choose 50' for another reason, it doesn't matter, the math is valid at any distance. And, as you have seen, can point out weaknesses in a rod. Changing the line length is a great way to evaluate the sweet spot of a rod.
In our discussions the last few days you will have noticed that feel is also an issue. I think the values that EG used (140-220) at 50' were his sense of where the rod would work best. Again that was using his sense of feel, not yours or mine. I think he made great rods, but you must also like his particular shape of taper.
I think if you play with it some more, you will find that many of the rods you like will fall in the same max/min stress ranges and then it is up to the shape of the curve to convince you that is a good, or better rod. Or you may find you like all kinds of different curves and shapes, that just means you can adjust your casting style more easily.
And yes the length of line is a tunable parameter. I don't really want a 2 wt rod made to cast 20'30' tuned to 50'. (Jerry Foster)
Thanks for your well worded response. I didn't draw any conclusion in my post because I couldn't figure out how to say what I was thinking. Your words did just that. For me, it's the SHAPE of the curve that is important. I know from experience that I don't like a rod with a soft butt. The stress curves will tell me that at a glance.
The Dickerson 7012 that I built tops out at just over 180k at 30 ft., with a fairly sharp peak. That rod is just a tad soft in the tip for my liking. Now that I know that, I can avoid it with other tapers just by plotting the graph. The Thomas 703 tops out around 130k at 30’ with a well rounded peak. I like this rod a lot with a 4 wt line (a touch stiff with a 3 wt.). Just as you said, identifying shapes of the curve.
If I had to go back to a slide rule or even a pocket calculator, I'd give up analyzing tapers! (Rob Holland)
I've got a question that might stimulate discussion.
If you are designing a rod from scratch, so you don't have it in hand yet, how do you design for a certain line weight? My method seems to be to look at the stress curve for the line I want & a reasonable cast, and get the peak stress about 180k-200k. That peak might occur at 15 inches on a fast rod or way down in the butt for a parabolic, or all along the length for a Garrison, but its the peak stress I look at.
But I've never thought about it too much. What are some other ways?
FWIW, my best trout of this Hex season (not really a monster) came as I tiptoed thru some deep water with my fly dragging 10 feet behind be in the dark. A good read on central Wisconsin trout fishing is Le Shack. No financial interest. (Frank Stetzer, Hexrod, Taper Archive, Rodmakers Archive)
Personally first select mid ferrule point dimensions as determined by personally established ferule to line weight ratios - IE 7' 6" #12 ferrule - 4 wt, #13 ferrule 5 wt, etc - with the butt diameter adjusted next having the desired action mainly in mind - ie how deep will the rod flex. From there go back up thru the ferrule station to the tip - again PERSONALLY -generally like to make the tip top as thin as I can while still maintaining its strength and purpose - it cant bounce around - thus basically find it to be the last #'s determined -- For me anyway that’s basically how I go at it. I also try to build similar line weights for a while too as find that I have a better feel for variations or modifications to a taper and the subsequent strips that way. JM2cents. Curious how others go at it. (Rob Smith)
I'm with you.
I had a chance to cast Jerry Foster's "little" experiment. I was more than duly impressed. It put in my mind what exactly what I like in a rod. I wish Jerry could put his work on this, on the road and let it travel the rod makers get-together's for at least one season. I don't personally care what the ferrule size ends up being. Just how the rod casts to my inepitudes (is that a word?). Because of what Jerry did, I know what max stress' I like, where I like those stress' to break on the rod and what type of rod I want those stress' placed on.
It was mind opening! Do you see the colored swirls in the background? Belch... (Mike Shay)
I tried to get it on the road, but there weren't any takers.. As you can see it takes a little managing, and you've got to explain the paper that goes with it..and there's the logistics of sending 9 rods around with reels etc.
Secondly, I believe anyone who hasn't cast the rods thinks I have some kind of agenda. I don't. Other than the fact you have to be able to cast well enough to decide for yourself what you like and don't like. As I said Corbett Lake was a hoot..even Glen admitted that it was enlightening. They'll be at the Met again. (Jerry Foster)
Anyone who puts a year of work into this little experiment has my hat tipped toward them!
I do understand though, folks thinking you might have some ulterior motive...no, I really don't! I do understand though, you not just sending this around the country.
There is NO agenda here. I take that back. There IS an agenda. It's to see why you like what ever rod you like...and why!
I wish you and that wonderful display were going to CO this year! More than you know!
It takes more than a little managing. It takes the guy who knew what he was making and why he made it. Sorry, you'll have to travel with it. What you made and put together will take more than a casting pond to explain. Any gathering that this doesn't show up at is at a loss...sorry, unabashed promotion! And I didn't even make these!
Jerry's not offering rods for sale here, he's just showing what the difference in the stress' placed here or there, on such and such type of rod means in your hand.
I can't even begin to tell you what I learned in a half hour casting these! (Mike Shay)
I'll second what Mike said; I've had the chance to cast the set twice, and it remains very educational.
Jerry's only agenda is to get rodmakers & fly casters thinking for themselves, rather than simply swallowing the pablum handed down as "conventional wisdom." (Mike St. Clair)
This may be a little off topic, but is interesting nevertheless.
Phillip Sicher of Switzerland brought 13 rods to the European Bamboo Rod makers gathering last May. They all had the same taper (adjusted for geometry), but all were different in one way or another. There were 4 or so hex versions, 1,2 &3 pieces, hollowed, fluted etc. One solid penta. One solid and one fluted quad, a hepta, an octa etc.
The two most interesting rods were triangle shaped rods. One was solid, made of 16 strips (I believe) and the other was a 6 strip triangle rod that was hollow. The 6 strip hollowed rod seemed to be the favorite. (Larry Tusoni)
I've been fishing my tri-rods for years. They do cast and fish well and are interesting and easy to make if you just get real.
By the way, I have a couple of not expensive tri-rods available. If anyone is interested contact me off line.
And we now have bears in south Jersey. And wild turkeys are plentiful here. But, sadly, no trout. (Bill Fink)
Anyone that hasn't cast Jerry's rods really is missing out.
Especially if you're a beginning rod maker or designer. (Jim Lowe)
I haven't had the opportunity to cast Jerry's rods, but I would like to. I am a new builder, with 6 done and two in progress. I am interested in tapers, obviously, and just can't build everything to see how it works. (Well, I can try...) So where and when might I have an opportunity to try Jerry's rods? (Dan Zimmerlin)
If I understand your question, you are asking how is a rod designed to be most effective for a specific line size and length. Is this the question you are asking ? (Bob Norwood)
I think that is the question. We already have 3 different answers: by maximum stress (me); by ferrule size (Rob Smith); and starting at the tip (Ken Paterson). I'm just interested in how people work it out.
I'm always wary when I see "most effective" used in conjunction with rod design. (Frank Stetzer, Hexrod, Taper Archive, Rodmakers Archive)
First: lets look at tip values. This approach has a lot going for it, the tip values are given, however only one value for each line size is needed. the thing that is lacking is a given station increase, this would give us a starting point for both the tip and the increase and one for each line size would give a starting point for any rod size.
Second: I don't think that ferrule size is a proper starting simply because there is such a vary of sizes dependent on what type of a rod you are shooting for.
Third: Stress. I don't think that this is a good measure of line size either. for example a garrison 212 could be a 8 wt at 38’ or a 7 wt at 43’ or a 6wt at 50’ or a 5 wt at 57’ or a 4 wt at 67’.
I feel that a standard starting point for line length is needed so that we can all have a common starting point, this would apply even for the use of a given tip size.
I have heard it mentioned that you should design the rod for the distance it will be used, however I have never seen it done and don't know if it works or not.
So, right now my vote would be for a standard tip and constant station increase as a starting point. (Bob Norwood)
p.s. If you could specify you taper values to one more decimal point it would solve the problems specifying them at the one inch points.
Thanks for all the responses and requests for the tapers...If you can run excel I'd be glad to send them to you. So post a private email and I'll get them to you..(it would be easier if I could post them here..Larry) These rods were all designed using Max's deflection program and then brought back to Garrison stress because that's what most are used to seeing.
So here's the deal.
I built a series of 9 rods (1 of which I must make again.) The idea was:
1. To test Garrison's assumptions for Max/Min stress in a non Garrison taper.
2. To see if I could isolate various parts of the rod for personal evaluation.
3. To let people evaluate these rods on their own and draw there own conclusions about various aspects of the stress curves. Hopefully this would give everyone a relationship between what you see in a stress curve and what you actually feel when casting. The byproduct I was hoping to achieve was to give both makers and fishers a feel for what they see when the look at the multitude of stress curves out there and what the may or may not like before they make or acquire a rod.
The rods are all 8' 5 wt's stressed at 50' with matching reels and lines. I try to lay them out on the ground so people can progress from one to the next rapidly. Some of the differences between them are so subtle that you must cast them in quick succession to retain the feel of the feel.
There are 3 groups of three rods. Most of them are based on a linear taper to avoid any trickery. All were cut on a CNC mill so they pretty well represent the stress curve that was implied. This all hinges around finding the sweet spot on the rod and then trying to feel the differences between them. Then relating it back to a stress curve.
The first set of 3 rods are linear rods with a natural rollover point stressed at 180, 200, and 220 max. tip stress. These rods might feel the same at different distances to people or they may just like the feel of a particular rod.
The second set of 3 was to see if people had a particular like for the tip turnover, or transition point. These rods were all stressed at 200 and had transition points of 8, 12 ,and 16 inches.
The third set is for mid feel or shape. they are tippy, soft, and stiff.
It's really interesting what people like and don't like, and most are inclined to give me some feedback, which I appreciate, but since it is all personal, my usual response is "great", or if i know them well, "so what". I get great satisfaction from the fact that they can feel the differences, and do have preferences.
If after seeing the stress curves you have anything else to suggest if terms of things to test, I will take it under advisement.
I may have to ad a para and a double para ( for Mr. Harms). Maybe a Garrsonesque..Since I design all my own tapers from scratch, mileage may vary. (Jerry Foster)
PS: I recognize that the rod is a whole and you can't really isolate various parts but this was my best attempt.
I'm trying to come up with a set of parameter with which I can determine line weight from a computer generated deflection curve. If we assume the rod is a spring to store energy, then the amount it is deflected is some measure of that energy and its ability to give it up to the line. The more energy available, the heavier the line it can handle. By heavier line I mean the product of the line wt # and the length of line outside the tip. Since the rod bends during casting it becomes shorter so too much deflection reduces its efficiency at throwing line. Too little deflection and there isn't enough energy stored in the spring to throw a particular line wt/line out combo. And all that stored energy is proportional to the acceleration the caster imparts to the system. So far, with an assumed 4 g's of acceleration (BTW, I have done some measurements which suggest that is more than "normal") I have found that a rod will deflect 52% if is "loaded properly". 52% deflection means: the Y coordinate of the tip on a deflection graph divided by the X coordinate then multiplied by 100. This assumes the rod starts out vertical when unloaded. (Al Baldauski)
Yes, it seems that a better answer to the question of line weight must depend somehow on the whole rod, not just a measurement at a single point like I am doing. Your deflection curve solution may be on the right track. (Frank Stetzer, Hexrod, Taper Archive, Rodmakers Archive)
I like to start with the tip size and work from there. This is my guide that I use:
Line weights to tip size
Line Weight Dry Tip or Min Mid Range Wet Tip or Max
1 42 44 46
2 48 50 52
3 54 56 58
4 60 62 64
5 66 68 70
6 72 74 76
7 78 80 82
8 84 86 88
9 90 92 94
10 96 98 100
11 102 104 106
12 108 110 112
After that it's rise over the length for the rods action and playing around with the stresses. (Ken Paterson)
This is the way I do it.
- Start with a tip diameter equal to the line you intend to cast.
- Next determine the rise of the rod. Fast slow ect.
- Draw a straight taper from the tip diameter to the rise point and right on to the full length of the rod.
- Next design where you want the rod to be stiffer and also weaker remove and add material were you would like it along the straight taper line (you need experience here) or some other tapers to work from.
- Last, input your diameter on the stress graph this has been covered well.
If it looks OK, that's fine. I don't think ferrule size is a good method because it depends on the speed of the rod you really have in mind. The ferrule of the rod will change with the speed of the rod design. (Gary Nicholson)
Well this is going to sound like a stupid question, and the answer is one that I should know after 35 years of flyfishing, but here goes.
What is the actual meaning of say a 4/5 or a 5/6 line weight designation for a given rod versus a rod labeled for a single weight only?
I always thought that a rod labeled with two line weights meant that it could fish both lines under different conditions. Such as a 5 weight double taper or a 6 weight, weight forward line.
I was in the new Cabela's last night and caught part of a conversation between two guys, one of which said it doesn't make any difference, but of course it does.
Anyway, it just got me to rethinking this, and a Google search doesn't bring up a true explanation either, at least not that I could find. (Tom Vagell)
I've always believed it was an "either/or" thing. But that may just show my ignorance. I'd be interested to read the real meaning, myself... (Mike St. Clair)
Designated line weights inscribed on rod shafts are "Advisory only," IMHO. You may agree exactly with the number written there. Or your own opinion may be that the factory person was drunk when they wrote that number on the rod. Whichever, I think it's always in the eye (and hand) of the beholder. The weight-slash-weight could be regarded either as more honest or as the factory hedging its bets. Take your pick. (Steve Yasgur)
Always thought it meant DT4/WF5 or DT5/WF6
Leastways that's what this former Pennsylvanian was taught. (Paul Julius)
I consider a given line weight as just somebody's opinion. I may or may not agree. I then will cast the rod with lines above, at, and below that weight. The combination of the rod and my particular casting style tells me what it really wants for a line. (Mike McGuire)
In my experience, any good rod will handle more than one line weight. Usually, when I think of a rod being, say a 4/5 wt. it means to me it will handle a DT4 at longer distances and a WF5 at fishing distances (about 35 to 45 feet). Like someone said, its usually just guidelines anyway because if I like my rod to flex more I will probably go for a slightly heavier line weight than is written on the rod. Likewise if I'm doing a lot of dry fly work at over 40 feet, I might underline by half a line wt. or more to keep the rod from overloading with the extra line out. (Bill Walters)
I certainly don't know, and don't have the experience to speak from personal use. I only buy DTs because I'm cheap and can't cast far anyway, nor do I need to where I fish. I thought a 4 was a 4 and a 5 was a 5 regardless as far as line weight and DT/WF, but the DTs tapered quicker having less constant casting weight for a trade off of using the other end of the DT when the 1st end had wear. If you have to eventually cut off 6' of a DT you have less line weight per foot, where as if you cut off 6' of a WF the line weight is still the same per foot (or close) till it tapers a lot. Then the WF has less taper if any and a more constant weight and diameter for more distance when casting. I then thought the rod designation was sometimes what lines might best be used on that particular rod depending on the caster, fly type/weight, leader and fishing conditions etc.
My local fishing friend has always said most (not all) rods can go up or down a line weight size. Probably more plastic thinking than bamboo for his experience.
Here is a link to something Lefty K wrote about line weight and rods. (Jerry Woods)
I said less weight if 6' cut from a DT, and it should have been more weight since the taper increases towards the middle. Lack of experience even on what I use. (Jerry Woods)
Somewhere along the line, I learned that on cane rods a double line weight designation referred first to a DT line, second to a WF line. On graphite/carbon/fiberglass rods I don't think the same usage applies and usually more than one suggested weight on those things points to a budget rod, at least in my experience. Again, any of these are subjective and should be looked upon merely as starting points for further experimentation...which brings me to this question: Would the 'sweet spot test' as suggested by Jerry Foster and explained further by Marco G in earlier posts be a good way of finding the best line weight for any caster/rod combination? eg.; a rod says 5/6 wt; you find the sweet spot for 4,5,6 & 7 weight lines; the one that casts further with equal effort (sans hauling) would be the best. (Bob Brockett)
Line wt goes by the wt in grams of the first 30' of line be it a WF or a DT. A 4 wt will be 8 Grams, a DT or a WF. 30' of DT will weigh more than 30' of WF In that case a rod with a double line wt would take a WF 5 or a DT 4. Thats is the way I learned it. Cutting back a line as you mention will change the weight of the first 30' therefore changing the line wt. This might be only a half line wt. depending how much is removed. (Tony Spezio)
IMO, the way this addresses the dual line weight designations (assuming they aren't listed in an erroneous manner) is that a normal 5wt rod might cast a DT (or WF) 5wt line very good up to the 40' mark at which point using a DT4 or WF5 would be worth trying, or even an WF4 if you 'need' to cast 80' all day long and don't want to overload your rod too badly. This rod could be marked 4/5. Or, the other scenario is a rod that is a 'heavy' 4wt and/or a 'light' 5wt - one of those rods that is designed to be fished heavy in close then a line weight lighter at distance. (Chris Carlin)
You are right about the weight of WF and DT lines, the only other thing that I have found is that each line has an AFTMA standard value plus a tolerance which actually allows say a 5 wt that is on the upper end of its limit to be almost the same wt as a 6 wt that's at its lower end sort of like half size lines. (Bob Norwood)
Every year the line manufacturer's tapers get more complex & its harder to know what you are dealing with. I'm sure its just marketing; anything not "new" is of course "obsolete". And of course you need a different line for fishing under stratus vs. stratocumulus clouds. I see why old people get cranky.
This year's Rio "Trout LT" lines in WF seems to be really more of a triangle taper, as near as I can tell from their web site, which is fine with me cuz I like triangle tapers and I need one. I liked the Airflo delta taper but they don't seem to make it anymore. (Frank Stetzer, Hexrod, Taper Archive, Rodmakers Archive)
Thanks for the additional info, I am a bit more knowledgeable now about WF and DT lines. (Tony Spezio)
One consideration is that a rod may handle a 4 wt with 30+ feet of line out but may need the extra weight of a 5 wt line when less than 30 feet is in use. Most bamboo rods will often toss over a range of 3 line wts. Tapers also come into play since a rod with a really light tip action may be able to flick a 3 wt line but also may have the backbone to work a 4 or 5 wt line as well. And as others may have said a 4 wt that feels "right" to one caster may need a 3 or 5 wt to feel "right" to another caster. (Larry Puckett)