Approximately 60 yrs ago a certain science teacher tried to make me understand levers. It appears I didn’t listen very well.
My problem has to do with exactly how a short tug with the line hand, when co-ordinated with the speed up and stop portion of the cast, causes the rod tip to bend further and thus loading the rod with extra energy to cause additional casting speed of the line
following the abrupt stop.
My present muddled thinking is that a tug on the line would tend to straighten the candy cane bend ?!!. Of course I know this cannot be true. I just wish I could understand the mechanics of how it works.
I would be very grateful for any help that knowledgeable readers could provide.
Here’s a simple way to see the mechanics of what happens when you haul. Lay out 30 or 40’ of line. Hold the rod straight up (12 o’clock), Look at the rod tip and without doing a back cast just haul on the line and watch the tip. Try a short haul vs. a long haul. You can easily see how a haul effects the cast & the rods action.
I think what you’re missing is that a fly rod is more than just a lever
It’s really a combination of a lever and a spring.
EDROB -
First of all, welcome to the FAOL Bulletin Board, and greetings from SE Idaho.
Always nice to see new folks from Canada make an appearance here. Haven’t been to your part of Alberta, but you live in one of the beautiful Provinces of Canada and not far from some of the best mountain country the Canadian Rockies have to offer.
Now, for your question. GREAT question. Can’t wait to see what folks have to offer in the way of answers, explanations, guesses, opinions, etc. which abound here, almost all offered with a friendly and helpful attitude. Since I haven’t learned how to haul on the forward cast ( can put a decent haul into the backcast ), maybe some comments will help me get past my own present limitations ??
For what it is worth ( and this is in the “guess” category ), it seems to me the difference is that a fly rod is not a stiff like a lever and it is the combination of flex and speed that make the difference ?? Also, the additional stress put on the blank during the haul would move energy down deeper into butt end adding to a stronger rebound when the rod tip stops - kind of like a springboard in diving, where the higher the jump immediately preceding the dive adds to the height the diver will achieve at the beginning of the dive ??
Anyway, welcome, and thanks for the question.
John
P.S. Someone is bound to tell you that the “new guy brings the donuts” - but it won’t be me.
First the fly rod is a simple flexable lever, it responds to and acts and reacts as a lever. This action and reaction is set by the tapper of the rod and all elements acting upon its movement. All elements include, weight and make up of the rod, diamiter, guides, line, flie and down to the weight of the grip and the reel acting as a counter weight. Frankely seeing the reaction does not explaine the the dyamanics involved. The application of energy and how the lever reacts to it, is dertermined by were the energy has the greatest ‘effect’ upon the on the lever at the point of greatest application. In the case of a person throwing a fly rod there are two dominate points of energy application, the grip and the tip. The gip is the point a person is most awear. The tip on the other hand, being a number of feet away, is less directly understood. If I stand by your side and wisper in your ear, its likely your going to have a clear understanding of what I said. However if I stand across a crowded room and wisper, likely not so much. By drawing the line with your line hand your adding energy directly to the line. The line which is resisting the movement is drawing against the rod tip, while the tip is drawing against the line. The rod will only deflect to the point it becomes equil to and then over comes the resistance of the line. As you press forward with the rod adding force to the lever you are continualy incressing the ratio of force verses resistence and the line is drawn in the direction of force applied. If you are drawing line while pressing forward with the rod, you are both incressing the force on the line while decressing the lines resistence as there is less line behind the point of force application, the rod tip. At this point the line is actualy moveing faster than the rodtip itself. As long as the energy being applied against the resistance of the line is greater than the static reflex of the blank, the rod will remain in a retracted postion. That is till the forces equalize which is in this instence, right after the stop portion.
Yeah man, what he said!
Mike. 
Yeah I was going to say that exact thing. 
PS I used to live in Fawcett Alberta 147 north of Edmonton. Finally saw the light and moved to BC. Welcome to the board. Lots of us Canucks here.
Here is a nice video clip of Joan Wulff teaching the Double Haul.
http://www.midcurrent.com/video/clips/wulff_dynamics_17.aspx
It’s a small part of JOAN WULFF’S DYNAMICS OF FLY CASTING
Randy and Mato -
Thanks much for the links.
John
I have had that argument with several different “Master Certified Casting Instructors”. One swore all it did was load the rod deeper, the other was just as convinced that it did not; it just speeded up the line some. Another thought all it did was to take out the slack and yet another said he thought it might some of each, depended on ‘how and when ya did it’. Can it be done wrong? Yes. I know one very good caster who busted five rods due to incorrect timing of the ‘haul’.
Actually, one of them went on to write a big book on how to do it. 
I dont know what i do but i think all my hauling effort is complete before i stop the rod—im working on getting it harder and more intense closer to the stop----but not after the stop.
I always thought of it as storing more energy(assuming the rod will have the reserve strength to handle it) into the spring (rod)—i’ve already loaded the rod by stroking forward and if i could run forward like a javelin thrower i could get more energy into the act (not practical)—the haul bends the rod deeper and stores a little more energy before you transfer it all to the line by stopping abruptly.
another link
http://www.sexyloops.com/beginners/doublehaulbasic.shtml
Thanks to all reponders. I am still struggling with hauling mechanics but perhaps should explain that my immediate aim is to improve my regular cast, however I would like to further define my confusion about the haul.
I cannot understand how a tug (haul) with the line hand can cause the rod to bend (load) further than it did on the forward cast as a result of the accelerating rod movement and the restraining weight of the line. In my thinking the tug action would tend to unbend(?) the rod.
I always thought a fly-fishers silent mutter of ABRACADABRA was designed to allow time for the back-cast to straighten but now I am thinking the haul is actually MAGIC.
Man GREAT info. Thanks for the vids. Like trying to tye a fly I need to see it done. Saves me days of error.
Just a quick note on hauling.
The term hauling is generally applied to the process of adding line velocity to the cast by applying a force using the off (or non-casting) hand. By pulling the line through the guides just before the stop is accomplished, additional acceleration is added to the cast over and above what is generated by the motion of the rod tip. Hauling is generally used for distance casting when you just can’t generate enough velocity to accomplish a long cast with rod motion alone. Hauling in the back cast is used in these conditions to aerialise more line for the same purpose. When hauling in both directions, it is generally called double hauling.
Sometimes casters will automatically haul even on shorter casts. This allows them to use a shorter arc under normal distances and many find this less fatiguing for a long day of fishing.
The following figure shows the haul as it is used in long distance casting. Note that the haul is generally timed to add acceleration on top of the maximum acceleration of the cast and motion after the stop is initiated is actually follow through. The haul can actually be thought of as adding length to the casting stroke because the effect would be the same.
Discussions often center around the idea that the haul adds velocity by storing more energy in the rod by increased deflection. While some added deflection does occur, the contribution to the line velocity is mainly to the motion of the line caused directly by the haul and not by any added energy stored in the rod. This is the same as in a normal cast, the majority of the energy comes directly through rod translation and rotation and only a small amount is stored and recovered from the rod deflection directly. You can prove this to yourself by having someone hold your line on the back cast and you holding the rod vertical. Have them release the line without you moving the rod and you will see how much energy is actually stored in the rod.
You can read more on my website in:
http://www.hatofmichigan.org/uploads/Mechanics_of_Fly_Casting.pdf through
http://www.hatofmichigan.org/uploads/Mechanics_of_Fly_Casting_5.pdf
or you can use them to cure your insomnia – your choice – they will work for either.
Bob
Awesome link Mato
Thanks a bunch!
I think this really goes the heart of a fly cast versus a spin cast. The distance achived by any cast is relative to the energy stored in the system. The system in this case being the rod, line and lure. The more energy stored and released in the cast, the further the cast will go. The energy can either be kinetic (energy due to objects in motion) or potential (energy stored at rest) In a spin cast the energy is in the heavy lure moving quickly as propelled by the lever of the fairly stiff rod. In a fly cast there is almost no weight to the fly so there is very little energy in the fly. Instead energy is in two places during a fly cast. Kinetic energy is in the line since it is heavy (relative to the fly) so the faster and heavier the line, the more energy it has and the further it will go. Potential energy is stored in the rod and as it unflexes (as you make the STOP) the potential energy is converted to kinetic energy (movement) in the line.
To understand why your rod flexs more when you pull on the line try this: Tie the end of your fly line to a tree. Pull on the line. The rod bends more. You just stored potential energy in the rod. When you untie the line from the tree and pull on the line it will do the same thing. This is due to the inertia that the line has. Inertia is the property matter has that resists changes in movement (things at rest like to stay at rest, things that are moving liek to stay moving in the same direction). So the line doesn’t want to move so it pulls back just like the tree did, you just happen to be strong enough to make it move (added kinetic energy to the line instead of potential energy to the rod) so it feels very different.
Hope this helps.
Thanks again for responses. I would like to ask ORRISMA if he would agree with my following interpretation.
On the forward cast the pull portion of the line-hand haul ,with the correct timing and duration, should overcome the kinetic energy possessed by the line.
This will result in the rod starting to lose its potential energy (begin to straighten or unload ) but before this can happen the line release portion of the haul is initiated and the increased kinetic energy of the line and fly is RE-APPLIED
This results in a further loading/bending of the rod that now has increased potential energy than before the haul.
The abrupt stop of the rod immediately following the haul release will result in the normal perfect tight loop but with the added benefit of distance and force to combat a headwind.
So am I correct in saying that the reason the rod bends further after a haul is due to a second application of the lines kinetic energy brought about by the release portion of the haul/tug by the line hand causing the rod to bend further ?
Your hoped for response is “by George he has got it” spoken in a perfect John Cleese accent; of course it could also be “the man is an idiot -sell him a parrot-”
EDROB,
You can help your understanding faster if you forget about energy terms and go back to simple old F=MA. The acceleration of a fly line is a function of the force applied to it and it’s mass. It’s final velocity is a function of the distance over which this force is applied. This distance is the length of the casting stroke. Hauling is a method of applying a force over an additional distance with your other hand. This also adds velocity. Once you get that down, you can start thinking about work and kinetic energy and how they are equal.
Let go of thinking about the energy that is stored and recovered in the rod. This is not the big actor here and is more about feel and comfort. You can cast perfectly well with a dead stiff rod (or broomstick as JC does it) which does not store any energy whatsoever. You may not like it, but it is easy to do.
If you must jump straight to energy, the kinetic energy in the fly line is equal to 1/2 MV^2 which is also equal to the work done on the flyline during the cast. This work is the rod tip load times the rod tip path length plus the force of your off hand times the length of the haul. The distance over which the rod recovers is much smaller than the total travel of the rod tip and the haul distance so it’s work contribution is also substantially less.
Again - read Mechanics of Flycasting 1-5
Bob
Another simple way to look at this question is the old “equal and opposite reaction” law. (Bobinmich’s post with the pic above shows this very well)
Since the fly line has weight to it, as you accelerate it, energy is transferred into the line, therefore, while it is moving, it has energy stored in it (it has some at rest too, but we’ll ignore that here). Due to the physics of the aforementioned law, energy will be transferred into something else in order to change the direction of the line. So, the greater the angle of the rod tip to the moving fly line, the more energy that will be transferred and stored in the rod.
As an experiment, try this:
Pull 10-20 feet (or more if you have the room) of fly line through the guides, and lay your fly rod rig somewhere on the floor (preferably a carpeted or soft floor). Lay the fly line out in a straight line perpindicular (90 degrees) to the rod tip. Now, holding the fly rod’s handle in place on the floor with one hand, tug on the line pulling it back toward the reel and observe what the rod’s tip does. Repeat the experiment several times, pulling harder as you go. How does the behavoir of the rod tip change?
Next, repeat the same experiment, but with the line laying straight out from the tip guide (parallel to the direction the rod is pointed). What happens to the rod tip when you tug on the line? (this should be obvious)
Imagine the rod’s tip is nothing more than a pulley. Then the physics involved in the force/energy transfer is nothing more than a simple entry-level college statics problem.