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I am now in consideration of improvements for designing a rod by manipulating its deflection. If you have good idea about this, please advise me. I have one rod (a known classic taper or a sample taper) which now shows its deflection as a calculated result. I can have a degree of deflection which is the angle made between butt end and tip top (like a bow and its string). One method of designing a deflection is this angle, I am thinking. This is related to how deeply the rod would deflect in a certain assumptions. I can manipulate the angle when I design a rod, which is to be related to "fast", "medium" or "slow". Then if the deflection design is fixed, I can get a corresponding set of dimension, that is taper. But!!! One angle of deflection can be made in various ways. By linear (straight) taper, by bumping several points with straight sections in between, flexing at butt with less flexing at mid or tip, flexing mid with less flexing butt and mid, entire rod would evenly flexed, etc.. What method could you consider practical next in trying to implement such variations into the target deflection as an input specification? Example: Specifying a section in from-to form, then specify like straight, a little flex, mid flex, much flex. Specifying a percent to increase/decrease flex degrees over an entire part of sections evenly. Specifying a specific point to flex more or less. Have a set of patterns of deflection, parabolic, progressive, crescent and apply it totally. Specify 1" flex degree number one by one. Of-course we can do these along with looking at the corresponding stress curve by calculation. This is a repeated work. It is very much appreciated if your have any idea. Which helps me very much. (Max Satoh) In this discussion I think we all have decided that NO two casters are alike and therefore no two guys will cast the same rod to the same effect. So, we are left with trying to STANDARDIZE more variables so we can begin a "ball park" design. The Garrison method has made assumptions so that a stress analysis could be accomplished but only after a set of dimensions was decided, or conversely, a set of dimensions could be derived after a stress curve was determined. But designing a stress curve for a particular application is not an easy, intuitive project without A LOT of experience with many different rods. I think the challenge is to define the Quarter Circle (or less) deflection shapes for fast, medium, and slow tapers. This could be done by a panel of respected casters evaluating what are considered to be good examples of each class. Then, measure the tangent angle at some increment along the QC deflection curves of each of the rods tested. The change in slope along the curve would define the shape and hopefully be similar in each class. If a change-of-slope graph consistently defined a fast, medium or slow taper then it could be used to back-calculate stress and cross section. So then you could TRY to determine if a prospective customer needs or wants a fast, medium, or slow rod to suit his style. Maybe then you come close to satisfying him with a rod design. But you are still hoping to have consistent quality bamboo, heat-treating, fabrication techniques, glues, varnishes, etc, etc. from maker to maker! (Al Baldauski) I've been sitting this one out (except for reading and attempting to digest most of it) but now I have to toss in a new thought. As I understand it, Robin's "quarter circle" doesn't truly describe a quarter-circular arc, it is a curve defined by the fact the the butt is pointing skyward and the tip is horizontal (for example). Then the two tangents would intersect at right angles. If my interpretation is correct, then the faster the rod, the farther away from the butt the tangents would intersect. I don't think you'd need anything more than to measure that distance UP the (imaginarily - still vertical) line of the rod's butt. You can get those tans to be at 90 degrees and have the the top 6" bend over, or the top 3 FEET contributing. The more rod that goes into the bend, the farther down the action starts, the lower the tip with respect to the level of the butt and the slower the rod, no? This may be useless to indicate whether the rod is linear of parabolic or a club (TYPES of action) but it SHOULD tell whether it's faster or slower. You'd have to reckon the distance with respect to the rod's length (4' up a 6 footer is faster than 4' up a 9 footer), but that could be accomplished by using a %age of rod-length, couldn't it? Bill Fink, that would take the Common Cents idea beyond measuring the angle at a certain position to continuing the bend till the tip points at the floor, then seeing from the tangent intersection where the rod BEGAN to bend, relatively. (Art Port) A very valid approach I think but it may be difficult to define the point you measure down the rod to the point where bending starts as this will involve a degree of subjectivity. An alternative that may also achieve what I think you are after would be to do the quarter circle load test (in the UK the load that is needed to cause this 90 degree rotation is called the rods test curve) and measure the actual deflection of the tip at 90 away from a line passing through the butt. This dimension will be more for a through action rod and less for a tip actioned rod. You could then characterize a rod by the ratio between its right angle deflection and its length. So a rod with a ratio of one would have described a genuine quarter circle and be a real through action whereas a rod with a ratio less than one would be a faster action, smaller the ratio the faster the rod. Again this is not all the story as a rod that bends throughout its length may give the same answer as one that bent primarily at the butt but the method would certainly identify the more tip actioned tapers quite well. Any takers? (Gary Marshall) Yes, I do think it's an after-the-fact thing, Jerry. I never considered it to be anything else. You HAVE a rod, and you want to describe in an objective manner to either copy it or make it faster or slower. I think that must've been the way the seat-of-their-pants guys did it too, no? Make one, like it or dislike it, make another. But Gary, I don't think you need to measure where the rod BEGINS to bend, since the point I'm talking about would be very precise - where the two perpendicular (OK, orthogonal for you math/science guys) tangents meet. The distance from that point to the butt plate of the rod could be measured to the 32nd of the inch or even more accurately. If I'm not clear, consider fixing the rod so it's vertical and drawing a straight, vertical line from the butt upwards. Then apply force till the tip POINTS horizontally. Now draw a level line from that tip top's position back to intersect the vertical. Now the tangents of the two ends will be crossing at right angles somewhere directly above the butt. The height of that point above the butt should tell how far down into the rod the curve begins, but just relatively to that measure of other rods. I can see where one type of rod might begin to bend and then continue bending (faster and faster) to the tiptop, and another might begin to bend, sort of straighten out, then resume bending. That last example is probably what a para would if, if I understand paras. Lemme know if I make sense AND if you agree or disagree! (Art Port) With you now, what you describe would give a useful parameter for rod description and can readily be measured as you say. Being able to express the result as a percentage of rod length appeals. It was actually clear on your original post, or would have been if I had read it properly! (Gary Marshall) This QC thing is very interesting, I would think if you had a database of several thousand rods whose deflections were measured you would know something. The other variable is the weight it takes to get the deflection. The CC system seems to make more sense. But they are not trying to make some larger assumption about the rod (speed) but line size. The other fallacy I think in this QC issue is it just shows 1 static point in a rods deflection and trout rods bend more than 90 degrees. I think Robin’s findings may involve the type of rods he is measuring. (Jerry Foster) On the contrary, the CC system DOES try to assess the speed, by measuring the angle at which the tiptop is inclined to the ground when it deflects that distance (I forget what it is now, but think it was 1/3 the rod's length) CC prescribes from level. I found, when doing the grunt work for Bill Fink in the Catskills that the CC part actually had little reference to the line weights of the rods tested - I think Tom Smithwick threw up his hands and said "That's it, I'm gone" when the CC said that a Garrison 212 was a 3 wt at an earlier test at Bills home! But the angle (I think it's called the "action angle") seemed to predict pretty well what the builder considered the rod to be! I'd have to see that they bend beyond 90 in photos to be sure, but I guess you're right that when the butt is slanted forward at the end of the forward cast, just before the stop, the tiptop is pointed rearward beyond the 90 deg point (but not necessarily below horizontal). I suspect though, that while some may not want to bend all of 90 and others may grudgingly go beyond, it's as reasonable a place as any other to COMPARE lots of rods, one to another. (Art Port) I have been slow to comment on this QC thing. But I think people are paying it too much attention, while all the while it is just a construct in the mind of Robin Haywood. In practice, it could be 90 degrees or 20 degrees, or 37 degrees for that matter - you just need a constant parameter. I am inclined to think that rod design is a bit like that. One must not get obsessive about small details, not, at least, at every stage. I have enjoyed this discussion, am still enjoying it, and hope it goes on as a core thread. But I am not certain even now that I quite understand the implications of Garrison's stress curves. As an analysis tool, OK, I can see that; but I have my serious reservations about their pertinence in rod design. There seems to me to be a fair bit of "begging the question" when we try to use them for that. The reason that Ferraris are different from Maseratis and Mercedes Benz is that perfectly sound design principles, applied rigorously by competent designers, can still produce very different end products. (Peter McKean)
I seem to keep trying to tell everyone this and the subject keeps reoccurring. I would never try to stifle creativity or innovation, on the other had, spinning wheels just leads to poor gas milage. Mark.....everyone. Please go look here. Max has worked out the dynamic solution for both stress curves and for deflection. The secret weapon in his arsenal Is the unique approach of designing by deflection. Or you can use stress, but it's dynamic so it looks a little different. But the design tools are so neat to play with. It's a fairly complex program but is easy to use, once you give up some of the "in the box" concepts we are use to dealing with. I have no monetary interest in this stuff at all. I think there is still a free timed download so you get enough time to evaluate it for yourselves. This is by far the most advanced rod design software I have seen, period. Many of you, I know, have made or are selling great design tools, but most are based on pure Garrison stuff.. Max's is truly different. (Jerry Foster)
Here’s a question for anyone listening and with specific experience: How do you design a rod to fight a 10 to 20 lb fish, say a salmon or steelhead, and know it’s not going to break in the butt while fighting. My deflection program calculates that if I exert 2 pounds of force to try to haul in a big fish using an 8 foot 8 wt, I will be stressing the rod near the butt at about 1/2 it’s breaking strength. That’s cutting it mighty close if your fish suddenly finds a spurt of energy and thrashes against an already loaded rod!! Sure, you say: beef it up to a 9, 10 or 11 wt, but aren’t there a lot of 8 wts used for this job? Is the force on a rod a LOT less than the fishes weight. I know it’s a lot less while fighting compared to the force you might exert while “lifting” a fish to net. I’ve fought 4 lbs trout on a 7’6” 5 wt and won. I’ve fought a 5 lb trout on the same rod and broke it, though I believe it broke at a brittle node, and I was struggling up close to net the fish. The rod was bent nearly 180 degrees. Does anyone know of any measurements made on line tension versus fish weight while fighting and landing?? (Al Baldauski) Not sure what program your using but here is a few things to conceder. - does the program calculate stresses based on an upright rod – makes sense for casting but not reality. Most of the time I fight big fish with a rod pointed at around 45 degrees. - The program doesn’t factor in arm movement. Think Lee Wulff with a 6 foot 5 wt. - If you break an 8 wt at the butt – who cares. – Must have been one monster of a fish & in my mind well worth the effort. (Jon Babulic) The Garrison 221 shows approximately the same stresses in the butt (actual stress when bent as opposed to Garrison Static stresses) under the conditions I mentioned. So, empirically, you can say that these are in a safe range. John, my program does calculate base on a rod held perpendicular to line out to the fish which maximizes the stress calculated. Certainly holding the rod at a 45 degree angle reduces the stress a lot. I’ve had little experience with BIG fish. If you are alone, do you beach 10 pounder still holding your rod at a 45 rather than netting it? (Al Baldauski) I've caught some 24" wild trout in current on a Payne 101, 6X tippet, and with just enough to the side line pressure, allow the fish to beach themselves. (Just remember that if you have a "wind" knot in your tippet you lose 1/2 the strength of that tippet). To try and net them alone and allow a rod to almost bend 180 degrees is asking for trouble. For the health of the fish, I'm not trying to battle the fish to exhaustion and desire to end the fight as quickly as possible. It might seem weird but my personal experience says that Bamboo tires fish quicker than graphite? This might be because I can feel the fish better! I never thought a Reel's drag system was that important but after having lost some big fish I now consider it just as important as the rod. Oh by the way Ross Evolution for me or Ross has introduced a made in China Ross Worldwide Flywater reel that has the same drag as their famous Gunnison Reel and is considerably less expensive. (Doug Alexander) Anyone remember Lee Wulff? He caught Atlantics on fly rod tips with a reel taped on. He also waded swift streams by leaping from rock to rock. But maybe he was not your ordinary everyday flyfisher. (Bill Fink) A friend of mine has the Lee Wulff video collection on DVD. I believe the videos were made during the 1960's or 70's. Anyway Lee fishes with Curt Goudy, Jack Nickelson, his wife Joan and of course by himself with that 6' bamboo rod catching Atlantic Salmon which is just awesome. You got to love it when he Skeeters his fly across the water for 10 lb. brook trout. I also enjoyed watching Trout Bums Patagonia or Fish Bum Mongolia. Those guys are truly hard core fishermen especially when you pull out local Yak tail hair to tie flies because the material you brought isn't long enough for the 5 foot long Taiman Trout your fishing for. (Doug Alexander) Here's a mathematic representation of Harry's dead weight experiment. This is the counter weight required to balance a rod nine inches from the butt with two pounds hanging from the tip top for several rod lengths: 6 ft = 16 lbs Note that the force required for the same size fish is less with a shorter rod. The further the weight from the fulcrum, the more force required to balance the rod. That may be why Lee Wulff used a short rod. Or maybe not. I haven't seen the taper he was using. For the FlexRod users, input tension in ounces and the rod angle in columns AK and AL of the tapers sheet and run the calc macro. Update the Summary or Detail charts to see the impact on straight stress (Garrison methodology), bent stress, and the deflection curve. Make multiple copies of the taper in the spreadsheet with incremental changes in the rod angle to get a feel for how the taper might handle a fish of the given weight at various rod angles. If you haven't used FlexRod, the current version is available on my blog. Read the introduction before you download it. (David Bolin) I went out to the shop and actually measured the deflection for a one pound weight. I think the rod, even though it is a stout 8 wt would be over powered by 2 pound, besides I didn't have 2 pounds. I put the rod on my deflection station and here is what I got.
It certainly felt heavy when I held the rod in my hand and applied the weight, don't think I would like to hold it for long. The rod felt very heavy and if there were a fish on and it made a sudden run, I would have to just let the fish make the run. In other words, 2 pounds at the tip is too much for most folks and even those that could hold it, would soon fatigue, The rod might take it for a while but I don't think the rodder? would. (Bob Norwood) I doubt there was one damn thing that was average or normal about Lee Wulff. I fear he and all the rest of his kind have done gone the way of cowboys, gunslingers and schooner captains. We should mourn for ourselves. I think on the whole we are lesser for them no longer being among us. (Timothy Troester) I think its really irrelevant. I have had a 9 pound fish on a 3 wt. Did it break the rod? NO. The angle of the rod and the drag setting are far more important. I bet I could land a 20 salmon on a 3 wt. Just point the tip and walk back. It not the rod but the way to do it. (Gary Nicholson) It does make sense. As I’ve said, coming from limited experience in big fish I’m not aware of all the nuances of the fight. I guess another way to ask my question is: has anyone broken an 8 wt rod while fighting a big fish and what were the conditions when it broke. These answers may provide some empirical data points to place limits on design stresses. (Al Baldauski) Two pounds of force is amazingly difficult to exert with a fly rod. Try this experiment. Tie a 2 lb weight to a broomstick and try to lift it. It's more difficult than you might imagine. Few twelve weight rods can dead lift two pounds without collapsing. I realize you aren't talking about a dead lift because of the spring involved in a fly rod, but the experiment will show how much effort it takes to lift a coupla pounds in real life. I haven't caught huge numbers of 10 pound plus fish. But I successfully fought King Salmon in heavy Alaskan waters on a nine weight bamboo rod. The largest landed was 35 pounds, and yes, the rod survived. (Harry Boyd) Even though the rod bends, the net effect is the same as your broomstick example. The rod bends and the “lever” gets shorter but there’s a lot sticking out. So, yeah, a two pound load at the end of the stick/rod is going to feel like 10 to 15 at the grip and that’s more than my wrist can handle!! I’m trying to quantify the actual amount of force you would exert during an “epic struggle.” (Al Baldauski) Here is a video of a 5 wt attached to a motorcycle. Harry’s spot on – doesn’t really have a lot to do with dead lift stress (unless you plan to fish from a bridge) (Jon Babulic) It seems to me that in almost any case the tippet would break before the rod -- unless the rod has a weak spot. I watched my son-in-law land a 28" steelhead on a 4 wt. with 4x tippet, no problem. Took a while though, maybe not so good for the fish. It was pretty tired by the time he netted it. (Neil Savage) I think Harry is right that it is partly the spring in the rod, but also lifting a fish in water is much different than lifting a fish in air. The buoyancy of the water reduces the effective weight that goes to the rod. (Bill Lamberson) That's correct, you should never try to lift a large fish clear out of the water with any rod. Even north sea boat anglers don't do that. And they’re in the 30 lbs class range. You should really never bust a rod playing a fish the tippet would go first keep the rod tip down and get a decent reel. (Gary Nicholson) Interesting responses. Having just come back from a week of landing 8# to 10# Alaskan Salmon on an 8-wt graphite rod, let me make a few observations. First, as you have already surmised, you do not net them, you either beach the fish, or have a friend net it for you. You do not bend your rod double and then try to control the fish, and I would never try to lift a salmon with the rod. I don't think there is an 8-wt out there that could take the strain. The fish may only weight 8#, but with a flip of the tail, he is exerting 16#, or more, of stress. Even graphite rods snap under those conditions. Second, it is not uncommon to bring a salmon all the way in, almost to the net or beach, and have them rocket off into a second drag screaming run. Having the rod held at an angle (between 30 and 60 degrees to the horizontal) is key preventing a break off at this point. The angled, partially loaded rod will dampen the surge, and enable you to bring the fish back in. I would suggest, for salmon, you build a swelled butt 8-wt rod. This will give you backbone to handle an unexpected surge or fight, and yet still be light enough for a full day of fishing. (Paul Gruver) I guess I can't attach photo's to my emails because it doesn't seem to be making it to the list. If it has already made it twice and I am not receiving it, sorry for the wasted bandwidth. I'll put links to where they are on the net. Having just come back from a trip to Canada fishing for musky in a lake, I'll try and provide you with what little insight I have. I built a hollow 8 wt based on the Garrison 221e with a long gradual swell in the butt section. This was a taper that Bob Norwood gave to me and I slightly modified it for hollowing. Granted this was only #8 for me so I am still new to this. Musky are not salmon and they don't make long drag screaming runs but they do dive, roll, jump, and do everything they can to get rid of the fly. The majority of the time, they make a quick move right at the boat just when you think you are going to grab them. I have yet to find out how to keep from doubling over the rod when this happens or how to lift the fish out from under the boat without putting a large bend in the rod. I feared that the first fish was going to break my rod but it held up great. We landed 5 musky on that rod the first day and they were probably between 32-36" weighing around 8-12lbs. Here are a couple of pictures of the fight and the fish. (Greg Reeves)
Thanks for all the responses. To clarify: I don’t condone bending a rod in a “U” shape! I did it in my excitement and haste to get the largest trout I’d even hooked to net and release it. And I don’t condone lifting a fish out of the water unless it’s a 3” bluegill like I caught yesterday. I used 2 lbs as an arbitrary number for discussion purposes thinking that it is unlikely to exert more than 1/10 the fishes weight while fighting. From the responses based on actual fishing experience and the weight-at-the-end-of-rod experiments it seems most people will not be able to sustain a force equal to about 1 LB at the tip so maybe a 2 lbs “surge” might be expected occasionally. And certainly, lowering the rod angle relieves a lot of stress. I looked at several 8 foot 8 wts and they all had about the same stress peak in the butt section with a one pound load ~200,000 oz/in^2. That’s actual bent stress. And my deflection calculations agree favorably with the test that Bob Norwood conducted, though he didn’t say which rod he used. I took an average of three different 8 wts. Since no one has mentioned failures with big fish, then a value of 1 lb. force at the tip may well be a good number for an 8 wt and a value not likely exceeded on any rod because of human limitations. (Al Baldauski) The most pressure you can put on a fish is with a hand line, a straight line to the fish (ALA Old Man And The Sea) The most pressure you can put on a fish is not by rearing back on the rod but in lowering the tip of the rod. tarpon have been landed with 6 wt. rods but not by letting the fish fight the bend of the rod. Salt fishermen know that if you are ever going to land a tarpon you must not let it rest. fighting it with the rod held vertically will let the fish rest and would never be landed. You must lower the rod tip and put as much pressure on the fish as your terminal tackle will allow. The point is you can land a fish with any rod. A rod is designed to present the bait and for a trout rod, to protect tippets not to land the fish. In my view it doesn't matter what kind of weights you can lift with a rod. I am interested in accuracy, tracking, recovery, things that are important to me in delivering the bait to the target. Designing a rod to lift weights so you can use it use the rod bend to fight a fish in my view is counterproductive. (Dave Norling) I agree with you, but in the heat of the moment you would like to have some reserve so that if you forget that it’s not a broomstick in your hands you don’t break the rod you’ve spent so many hours on. I think your point that most people can’t exert much more that 1 LB at the tip for very long implies that most people are naturally lowering the rod tip and reducing stresses. The point of most “abuse” is, as I’ve inadvertently proved, is in single-handedly trying to net a fish. You can’t design a rod that fishes well AND survives a 180 degree bend. (Al Baldauski) There’s a very good reason that Tuna rods where about 5-6' long, leverage. Pool cues should be that stiff. On the upper Manistee river where small, difficult fish are the rule, the weapons of choice are usually 6'3" to 7'6" for #3-5. The current favorite being 7' #4, after all it is hopper season. If I was "mousing" on a certain inland stream, fed from a certain inland lake, the rod would be a #10-12 and the tippet #20. Rising fish can strike hard, and when hooked they do have a certain attitude. Due to the amount of logs available for cover, they are lost or landed quickly. There is little time for contemplation or the usual niceties, this is brute force trout fishing. (Peter McKean)
Here is one for all of the physicists on the list. Just to clarify, rods made of bamboo, fiberglass, graphite, boron, carbon fiber, etc. designed to have the same deflection will all recover or return to straight at a different rate. (Greg Reeves) That's relatively easily explained by the difference in area moment of inertia, of the objects, and the differing MOE. For a cantilever beam (which is essentially what a fly rod is) the formula:
where E is the MOE and I is the area moment of inertia which is a property of the cross section. Different cross sections, and different MOE's for all those materials. Clear as mud? ;-) (Mark Wendt) Your equation doesn't address the question of recovery rate. If they are "all designed to have the same deflection" then the rods will deflect similarly under the same loading (line wt and line out and acceleration) as your equation implies but they will have differing recovery rates based on different masses and internal friction. (Al Baldauski) Gee Greg... Are there any physicists on the list? Or, do you have to be a physicist to think? Or, was that meant to insult all the non-physicists on the list. Designed to have the same deflection...hmmmm Mark, Or is a fly rod more like this? (Jerry Foster) Jeez Jerry, that's almost as bad as the eye charts I had to look at last week, You must have some pretty good vision to read that... ;-) Besides, I was trying to give the simplest reason why. Now yer gonna make me get out my diffy Q books again. <VBSEG> (Mark Wendt) "Just to clarify, rods made of bamboo, fiberglass, graphite, boron, carbon fiber, etc. designed to have the same deflection will all recover or return to straight at a different rate. " Doesn't matter what any of those recovery rates are. Who cares? We make rods out of bamboo. The point is moot. (Jerry Drake) Wouldn't most agree that bamboo 'recovers' more slowly than graphite/carbon given identical tapers? Graphite can be real fast stuff. Glass rods, in my experience, can vary widely. S-glass, E-glass, Howald woven/spiral, etc. Some are so noodly I can time my pulse watching the tip shake. Bamboo has a strength of feel (for lack of a better phrase and maybe that's just good enough) that the others just don't have, IMHO. That, for me, explains the resurgence in interest in fishing cane. So I don't think the point is moot so much as it is one of personal preference. I don't hold anything against the other guys, we just fish differently and I can't even profess pureness myself, since until I replace all my plastic wands with bamboo, I'll fish those. I like to fish. Just don't get to do it as much as I'd like. Amen to that, right? (Bob Brockett) The result of my deepest reflection And that's all I've got to say about that...... (Peter McKean) The result of my deepest reflection And it is usually behind me. Sometimes the deflection is caused by the small fish (think chub) is flying overhead into the bushes behind me. (Gordon Koppin) We need to determine the launch velocity of that chub. Based on the deflection of the rod and the time factor of the return spring minus the dampening, of course... (Mark Wendt) Your deep inflection "Which accounts for my look of dejection." (Steve Dugmore) And may well cause an insurrection. (Mark Wendt) Ha! I was going to say finish with "And a cast off by more than a fraction." But I thought better and didn't say that. !^) (Bob Brockett) "no thanks to poor taper selection" (Steve Dugmore) "one likely excuse selection" (Gary Young) Final version The result of my deepest reflection
I have always tended to stay away from deflection calculations, as the mathematics of multiple simultaneous variables is beyond my applied math skills. perhaps you are able put it in a form that I can grasp. (Peter McKean) I think I will chicken out here and give you this reference. I think it pretty much covers the topic. Please... get back to me with questions, comments. (Jerry Foster)
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