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Rod Design - The Casting System

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I am going to point it out again. The fly rod, line, and caster are a "Casting System". One caster likes a rod, another does not. One caster can not cast the rod, another can. Not only is the bamboo a variable, so is the line choice, and obviously the casters physical abilities. In my opinion there is no unique taper design that will satisfy all casters with their physical abilities. Obviously the rod design taper is important, but it is not the be all and end all in my opinion.  (Frank Paul)

I agree with all your points

Now in all you say, what is the one part of this system that the maker has total control?

Someday, if we continue to evolve, someone can walk into a rodmaking studio and walk out with a rod tuned to them. A rod based on the performance criteria put forth by the buyer and further refined by the maker to take into account casting style, personal physic.....

We are a long way away and will never get there if, maintain that the best rods have already been made. Or throw up our hands and say there's so much i can't control.

The only control we have is the bamboo on the bench in front of us, variable as it may be. And how pretty the finished product is. (Jerry Foster)

I come at this from a very different direction than Frank, but his conclusions are exactly the same as mine. There is no Holy Grail, every taper is a compromise. We have been doing this for over 100  years. Rod tapers are skinny at the tip, and fat at the butt. There are only so many ways to get from one end to the other. Tapers have been designed by geniuses, dopes,  crackpots, drunks, and by accident. If the Grail was there, would we not possess it? IMHO, the greatest design aid we have are the taper archives.

Ray G. I have built one of the Bremond flat stress tapers. It's not my cup of tea, but is very interesting. The taper is steep and the rod is hollow built. It casts sort of the same with a variety of line weights, but you can pick the speed you like by varying line weights.  It's hard to explain that, but the rod flexes the same way all the time, but it flexes more and slower the more you load it.

NOT tweak a taper?? Sorry, but I reserve that ONLY for Garrison, who I believe to have been one of the geniuses. I can't  believe you posted something that I so totally disagree with.  (Tom Smithwick)

Would a roll cast (spey) best exemplify the power of the spring (mainly)?

Could the arm, body, be considered a series of levers also.

Don't forget timing, coordination, many women, maybe half my size and strength, can outcast me by a long shot. (no pun)  (Jerry Foster)

I am not sure the roll cast is best in this regard, but this cast is clearly when the rod is used as a elastic member. Just think of using a broom stick to make a roll cast  :-[ .

When we looked at the human arm we considered only the serial combination of wrist, forearm, upper arm, and the rotational shoulder. We did not consider body motion.

Oh yes, we all know that many women can be super casters because the issue of timing involves the casting stroke power supplied during the process.  (Frank Paul)

Honest question..

What determines loop size? (Jerry Foster (7/25/2016))

What determines loop size?

Hi Jerry - I think you have heard the answer from a couple sources, It is mostly up to the caster, but taper does play a role. As far as the fine points of loop shape, the best source of information I know of is at this site.

It is worth poking around the entire site if you want some things to think about.  (Tom Smithwick)

The junk that has to pass through it.  I'll never put a too-small tip top on a steelhead rod again.  Haven't made that mistake in a long time.  I'd also add that if you fish freezing rivers, a larger tip top will clear of ice quicker.  For you blizzard buzzards out there.  You know who you are...    #!^)  (Bob Brockett)

I should have clarified..., "line loop." (Jerry Foster)

Sorry, Jerry, I see my mistake now.  For some reason, I immediately thought of the top size. (Bob Brockett)

My belief is that a number of factors go into your line loop.  One would be line speed.  You need to generate enough speed to keep the line in the air, ie, overcome gravity.  That will depend on how much line you're throwing.  Another big factor is the size of your arc.  As fly casters, we all understand that the motion is different than bait casting for instance.   
    
I always learned the idea of push-push-push-snap, pull-pull-pull-snap.  If you want to open up your loop, subscribe a wider arc with the tip.  Very useful when throwing weighted flies, lead shot, etc.
  
Those are a couple factors, I'll leave it there and will be interested to watch and see where this discussion goes. (John Jazwa)

That's a good question.I suppose line speed and time you leave in the back cast before you start the forward cast? (Tony Young)

That certainly has bearing on it.but not until later? (Jerry Foster)

It's a hard think for me to really quantify because when I cast if I don't like the result I generally just either speed up the line a bit on the back cast or wait longer for the back cast to straighten out before I start forward again. It's casting timing thing I think. (Tony Young)

I intended to add, but got sidetracked by something else happening in the background here, that rods do not throw tailing loops, nor tight narrow loops, nor wide open loops - the caster does. (Peter McKean)

As far as differences in rods, a "soft" rod would tend to flex more, and the tip would subscribe a larger arc than a "stiff" rod, arm motion, etc.  being the same.  Thus, a more open loop with the exact same motion.

Therefore, the importance of the caster's sensitivity to and input to the rod.  Some casters have a stroke which is natural to them, and they prefer or are even limited to particular rod actions.  There are other casters who can pick up any rod and bring out its best!!! (John Jazwa)

Casting technique! (Peter McKean)

The loop is formed when the forward cast stops and the transfer of energy travels from that point of maximum deflection down the rod through the tip and then down the line. My two cents worth.  (Dave Norling Jr)

A very interesting conversation and a lot of good points brought up.  In some ways I think everyone is correct. At short to medium distance a tight loop can be made by a good caster with pretty much any rod. However, there is a definite rod design component to forming great loops. In fact, with every rod I design one of the criteria I judge the rod on is loop formation.  Like pretty much every other part of casting or rod design I don't think it's possible to fully understand every component of it. A good example of this is the idea that a quick stop forms a tight loop. While I agree that this is true to a point, especially on short to medium distances, we also have to consider what happens to the tip after the stop. A couple of years ago while casting in the Hardy Cup tournament a friend took a pic of me casting. He snapped the photo just after my forward stop.  At this instant, the rod was stopped at an upward angle, probably around 10 o'clock, but the tip, becasue of the abrupt stop, had continued movement because of momentum and was bent to the point where the tip top was pointing to the ground. At the point the loop is literally 8 feet wide, but as the tip recovered it formed at least a semi-nice loop. And this was with a short 6'11", very powerful, extremely hollow built rod. Imagine how an 8'6" or 9' solid built rod would have bent after the same stop.

So, I think the best way to answer the original question would to be say what percent of loop formation is the caster and how much is the rod. My guess would be at short to medium distances 85% caster and 15% rod. On longer casts I would say maybe 65% caster and 35% rod.  Just my thoughts. (Mike McFarland)

Rod tip path.

A function of both the caster and the Rod design. (Gary Young)

I was beginning to wonder if the rod had anything to do with it.

OKAY, let's refine it a little more..

What determines the top of the loop? (Jerry Foster)

Top of the loop is the extension of the path (vector) from rod tip position at start of road loading to rod tip position at point of maximum deflection Bottom (lowest point) of the loop is the position of the rod tip at maximum recoil at end of casting stroke.

Bottom (average) of the loop is the extension of the path (vector) from rod tip position at maximum deflection to rod tip position at rod recovery to straight. (Stephen Dugmore)

Another note about the loop.  It is where the velocity of the line overtakes the Rod tip and begins the incremental conversion of kinetic energy of the forward moving line into stored strain energy in the Rod (reloading the spring).  The completion of this conversion on an incremental basis occurs at the bottom of the loop.  The tighter the loop the more efficient the conversion. (Gary Young)

Years ago I thought I remembered a post from Darry Hayashida that expressed his belief that you could design a Rod that will almost always throw a tight loop.  I went back into the archives and found the post:

I think that the caster does have influence on the tip path but maybe not as much if you have a Rod that flexes "correctly" at the right location.  I have not built this geometry so I do not know how well it works.

So the top of the loop would be formed during the forward cast as the Rod is bend back and the tip is transitioning to an unloaded state. (Gary Young)

Top of the loop?

The direction of travel of the tip of the rod, and the resultant force applied to the line. This force is a vector, and the direction of the vector is a resultant of force magnitude and direction of travel.

I do not mean to be critical of Darryl Hayashida, but his rod which will "always throw a tight loop " presupposes that it is used by a competent operator who is aiming for a tight loop; if wielded by someone like me it could throw anything from a Turk's Head knot right through to cat's cradles! (Peter McKean)

There is no such rod as one that always throws a tight loop.  It depends on line speed, path of the rod tip, skill of the caster, what is on the leader & other factors.  Give me that rod & I will show you it will throw an open loop.  Each casting situation is different when you are on the water. (Bret Reiter)

I must add to this, that I've fished with Peter and regardless of what he say's I found his casting style to be very smooth and efficient. Didn't cast long, there's never really the need but it was controlled and good to watch. (Tony Young)

I agree that the caster is in control of the physics.. I think the same about accuracy..

However, isn't it interesting that we are talking about human control when this is the one time during the cast when the rod is under absolutely no external influence.

Snapping our wrists introduces a rotary component to the cast.

Rod speed (rod deflection) is also a factor. While the tip is straightening it scribes a couple of arcs. The slower the rod, the longer these arcs, the greater the loop size the rod wants to throw naturally. (Jerry Foster)

Maybe at first it is easier to take the cast out of it a bit. Think of a bow and arrow cast, one in which the angler is holding the fly in his drawing hand, i.e. a straight line from fly to tip top. Lets assume you give it enough juice to throw forward whatever line you have out of the tip top and dissipate perfectly with full extension in the front. Does that change our perception any? I think this is the spring part of the cast that ECP used to talk about.

Back to the other part: the lever. My own take is that the loop height (and shape) is controlled by the angler. I think this because I've watched talented casters create identical loops (well, as near as I could tell after watching hundreds of casts) with very different rods. They adjust to the nature of the rod. I think we like certain rods more than others because, for an angler's given stroke and skill set, each rod either facilitates or hinders making the desired loops for that angler. The loop height and shape are controlled by the angler, as Jerry stated, by manipulating several factors: overall rod speed, amount of acceleration, the abruptness of the stop, cushioning / dropping the rod, any kind of twist or out of plane movement intentional or otherwise, and so on. That said, I think the main loop height determinant is the change in height (I don't want to say deflection since you can do this with a large wooden beam that isn't really bending) from the path of the tip top at the moment that the angler stops supplying forward motion to where it stops "deflecting". Back to the spring, which is determined by the taper. This has to be factored in, too. The spring has to be managed to manipulate that delta in rod tip height. Good casters can quickly learn and adjust to this springiness and differences in springiness between rods. Bad casters tend to overpower the spring in some rods (tailing loop) and underpower others (improper loading).

Back to a little experiement. Holding your elbow tight and stiff as you can and your wrist, too, give your rod a tiny back and forward false cast with a quick stop. You will get a loop of 2-3 inches. Keeping everything as tight and abrupt, as you can, a little more juice this time. The tip will dip more and the loop will be a little taller, maybe 10", and the line will go a little farther. One more time with as much juice as you can keeping everything tight and abrupt. Now your loop will be 18" or more and flying 30ft. Watch the tip top. It will dip even more this last time. A "normal" cast with more variables under the control of the angler allows the creation of open loops, v-loops, curves, etc.

Hope that made any sense at all. (Chris Moore)

The shape of the line moving forward is a direct relationship to the tip path from the end of the line at the time the rod tip starts moving forward. if your line is straight at the beginning of the forward cast the straighter the path of the tip the tighter the loop. the shape of your cast can then control the loop shape. you can open it up for heavy flies and tighten it up in the wind. its not the rod action that only influences the motion required by your hand controlling the tip of the rod.  (Jeff Clyma)

When you say "no human influence", that may be true in a sense for a very brief point in time; but it has to be realised that the rod, rod tip and line have reached this point in time entirely due to the external agency of the caster.

The path of travel, speed, rate of stopping, strength, angular displacement, weight of line in the air and all the things that define the rod status at that point of "no human interference" are all provided by human action.

I just fail to see that there can be any cast, any loop or anything else associated with propelling line that can be considered without reference to the person or the apparatus controlling the rod. (Peter McKean)

It's a zen and the art of flycasting thing. I don't even like to think about it much because it's like knowing when to strike when nymphing. If you nymph a lot you often find yourself striking before the indicator moves if you're using one and wonder just how you knew that, but only momentarily because to think too much about it just ruins the timing. I know that's a spooky thing to say but it's true. What happens when you try to think about gear changes when using a manual car? Or climbing a set of stairs looking at your feet, or you try to put your socks on the wrong foot first? Who knows why you strike when you do when you do enough of it but it works. The moment you explain it you lose it until you forget it again.

I'm not a casting instructor but maybe it's worth mentioning that personally, I think that if you're having timing issues with your casting, slow down and cast short. Look at the back cast and when you've thrown the line back STOP, don't just slow the cast down, STOP it, wait till the the line straightens behind you and do the forward cast. The forward cast is easy to know when to make the back cast because you see the line but also STOP the cast when you've thrown the line forward too. When you get that right cast a little longer. Within a few mins you don't need to look behind you and you've got it nailed but it's a casting thing, not a rod thing.

I'm not sure the tip has to describe the same path in both directions necessarily though it helps if it does. You do various spey casts by swinging the tip in an arc and they work well. Depends on the cast you're doing.

What I do know is that I've used some real junk over the years and I think you can make any flyrod cast well enough given time to get to know it. A nice rod doesn't take very long to get to know which is why it's a nice rod. (Tony Young)

The previous sentence, "I agree that the caster is in control of the physics.."

I agree that all you say is true and has been set up by the caster, but at the exact time after the stop the rod is on its own. It will unload (un-spring) and keep accelerating the line (I hope), by it's own rules. The shape we put in it. (Jerry Foster)

Agreed! (Peter McKean)

One of the top casting instructors in the world is Michael Malone, of Camarillo, California. He teaches that it is the speed and direction of the rod and how suddenly the caster stops the forward motion of the rod, then how much he drops the rod tip down.

A fast acceleration of the rod on the forward cast throws a tighter casting loop than a slower acceleration.

A very sudden stop of the rod (with the butt end of the blank at the top of the arc and the tip flexing from "11 o'clock to 1 o'clock" - the actual tip path depends on rod taper, strength, line mass & momentum, wind, and other factors) will send a tighter loop than a not-so-sudden stop.

If the caster drops the rod 2" immediately after the stop, he will send a tighter loop than if he drops the rod tip 4" (or more).

There is more to it when one starts hauling and double hauling, but go work with that for now.

I agree that a fast taper rod casts a tighter loop than a slow taper rod. Anyone can go check that. A skilled caster can still throw a pretty good distance cast even with a slow action rod, but not as far as he can with a fast taper rod. (Casey)

I'm not sure that I agree with that bit (that even a good caster can aiways throw a greater distance with a fast taper than with a less fast taper). (Peter McKean)

Rodcasters forum? I was asking about the rods relationship to the loop.. I understand the caster has control. But surely all those hours you spent carving that special pattern into the cane means something? (Jerry Foster)

Mike McFarland has said the rod makes a dif especially for long casts. I won’t argue the point but most of the casts I do are inside of 50', lots shorter usually and I cast doing the full STOP at the forward and back cast and like the results I get.

I don't consider myself to be a good caster, a gorilla waving a stick really but I think I could get good results with anything that isn't complete and total rubbish because I've fished with lots of junk over the years and it all seems to be able to be made to work.

The nice rods are nice rods because they're good tapers. But the whole rod is a good taper, not just the tip or some juju magical point that will cure all that ails ya. 

The reason as people have said is that it's a timing thing to do with the caster, not the rod. You could likely make nice loops using a car aerial or broom stick or a metronome set right if you tried. Not long casts I grant you, but aerials and broomsticks aren't made to fish with.

Personally, I never concern myself that much with what the tip of the line is doing during the cast, I'm more concerned with what the weight part of the line is doing because it's the only part you can really feel on the back cast to cue you for the forward cast, the belly in the case of a DT and thick part of a WF, the rest is just going along for the ride. Get the weighty part of the line doing what it should be doing at the right speed at the right stage of the tip motion and you've good good loops. Practice is the only answer to good casting. Wax on, wax off kind of thing.

I don't know why you're asking this but if you're looking for the answer to your own casting having loops you don't want, it's a practice thing. If you're looking to find something within your rods that will be an infallible answer to bad loops for anybody who casts the rod it's a forlorn hope. 

Casting action wise I believe most people do something of an oval or rounded corner triangle, not a strict back and forth motion. Slightly outside of vertical on the back cast, straight in the forwards. I've watched some bloody good casters doing their thing while fishing and that's common. It's why tips unwind in one direction relative to the butt if your ferrules are a little loose, so I don't really think trying to straighten that up is all that much help. (Tony Young)

Funny you mention broom sticks & ariels!! Reminds me of 95% of the graphite rods I've cast. (Bret Reiter)

Me too.

I did mean broom sticks but there are graphite rods that are so stiff they just aren't fun to cast. There is a #10 graphite rod I won that I used for Mahi Mahi when I lived in Perth. It is one of the real junk rods of which I wrote but it was a boat rod, they don't last long sometimes, and it was for casting into wind of the kind you don't usually have to deal with for trout and fish a bit quite larger than any trout ever was ever built too. Still own it in fact, this rod doesn't even have a brand name. But you can make it work on a boat in a swell with wind from any quarter given the time to understand it.

The worst trout rod I ever used was a Diawa fiberglass rod that my dad bought when I was 12. We bought it at a petrol station when we were at Khancoban. Must have paid at least $7 for it. He still has it. Straight neoprene grip absolutely guaranteed to cause blisters on your thumb. I used it fishing at Brumby's Creek a few years back when I visited and din't have my own tackle with me, he must have been mad with me at the time :-) and it's actually worse than I remembered it being. It's hard to believe rods were made that badly and people actually paid money for them. (Tony Young)

Someone suggested that we read from Howell's book, did I miss something?, so I re-read the passage. I continue to say what I always say about that book. "What a Lovely Book". 

Here are couple of articles (1 & 2) also relating to loops and rods in general. (Jerry Foster)

Further thoughts:

A single rod will behave differently under different dynamics so there cannot be a particular loop size associated with a particular rod. I think most people would agree loop size is determined by the tip path and the closer that is to a straight line the tighter the loop. By straight line we mean the least variation from highest point of tip path to lowest point.

For purposes of limiting variables let's assume that the hand does not move up or down or forward or back during the casting stroke but simply rotates around a fulcrum.

If we take a broom stick - i.re a rod that effectively doesn't bend – then the loop size generated by that rod is determined by the length of the arc it travels through. A wider arc will make a bigger loop and a narrower arc a tighter loop. The same rod therefore doesn't consistently cast the same loop size. The length of the rod compounds the variations possible.

If the same length of line was required to be cast using 2 different arcs, then clearly our broomstick rod would have to be accelerated differently too (greater acceleration for the shorter arc). And the acceleration can only come from the caster. So, the caster determines the loop size.

If we take a rod that bends under the same circumstances, then the variables change in that tip can now bend into the desired straight-line tip path. But it requires a precise relationship between 1) the varying accelerations of the cast (because they need to vary), 2) the timing of those accelerations and 3) the way the rod bends. Again, the accelerations come from the caster.

So, if you want to divorce the caster from the equation then you have to standardise everything else in order to make comparisons between how different rods behave i.e. standardise accelerations, timing of accelerations, travel arc,  length of rod etc.  And depending on what standardisations are chosen different rods will perform better or worse than others in terms of loop formation.

And we haven't introduced hand movement to the equations.

So ultimately the choice of rod and the way a rod forms loops under particular conditions becomes personal to the caster - which is great. It would be miserably boring making rods if it weren't.

The one factor in a rod that makes loop size larger across all rods, and that can be designed to reduce is 'tip bounce'. Any rod that has excessive tip bounce is likely to make casting a tighter loop that much more difficult. (Stephen Dugmore)

Good Synopsis Steve. 

And thanks for all the info, everyone... 

And thanks to the better casters.."the Borg".. those who assimilate flyrods. 

I sit in envy at the rodmakers events as I watch all the good casters make music with any rod the pick up. Theirs is not a process of taking control of the rod but one attuning to it. To feeling the rods rhythm. Sometimes it takes one cast, sometimes it takes 3, more. Why? Obviously, the rods have a different architecture. The question at hand here was "loops." I am looking at loops, not as a caster but, as a rod designer. What aspect of the rod can I change to affect the area in question (loops). Tony. If I can quantify it, I can build a set of test rods (3) to test the theory, And If you ever run into me again you are free to cast the rods and verify to your own feel what is what. 

I was looking for things like.. If I change the amplitude of the tip deflection peak, If I change the duration of the same peak, if I change the location of the same. (Jerry Foster)

I'm not saying that modification to the tip or whatever won’t make a difference, but I am saying that without timing the rod wont work. To use DH's magic numbers, I'm sure that for his style and rod in question which was probably a Sir D or similar what he came up with was an improvement on the entire rod taper. I could cast huge loops and make wind knots with it if I didn't time the cast right. But I'll cast any rod anybody ever hands me, I like to try rods out and I'd be extremely happy to see what you'd done, and I'd approach it all with an open mind to it.  (Tony Young)

Could you give a brief explanation the terminology you are using? I think I get it, but just to be clear...

Amplitude of tip deflection peak, duration, location. Are these from DynaRod? How would they translate to a "stress graph" for those who use them? (Chris Moore)

Yes, some of this is from dynarod. 

First about stress graphs.  

If you mentally replace the 200,000 line with, "1Degree", and subdivide the rest into 10th's of degrees you get an approximation of an incremental deflection curve. 

Rough 

All of Max's software is still based on stress. It has to be,.the stress causes bend. But he updated Garrisons model. Max's is based on a moving beam (dynamic) with a rotary component. You don't have to look at, or design on this layer(the stress curve only layer). If I can see the end result (deflection) I don't need to see the intermediary results (stress) any more. 

Terminology 

Stress and deflection charts..tips on left butts on right. from left to right the tip goes up to some value (it's amplitude), it stays there for so long (duration) and goes downward headed right, so we have a base duration component that can be adjusted also, (slope). And finally, it's centered location from the tip, 5", 10",20". 

Because I was talking about rod design and loop size i thought maybe these were the areas of the rod people would key in on. (Jerry Foster)

There is a section of Jack Howells "The Lovely Reed" that talks about 'Designing the Rod Tip'.  This might be of some interest to you all and might aid the discussion. (Paul Julius)