Hauling primarily increases line speed - it does not necessarily increase rod loading. There are lots of quite complicated physics arguments related to this.

 

Cheers James, the increase in line speed. I can get my head around that. Probably couldn't explain in writing though. I may have a go at some point.

Sean

 

Is this not about momentum? If you have two lines travelling in the same trajectory, but one is faster than the other, then it must place more load on the rod?

 

Chris,

Q: If there are two indentical objects and one is travelling at 10m/s and one is travelling at 20m/s - which one has the greater force acting on it?

A: Neither; they both have zero force acting as they are not accelerating. (and it's this force that bends the rod).

Ok, so the one going faster had a higher force acting on it in order to accelerate it to the higher speed then. Nope, not necessarily - it might of had a lower force applied for a longer time. Like I said it gets complicated.

A perfect haul will be applied late when the rod is unloading.

 

To increase line speed, you will need to apply a force to it. Unless the rod is completely rigid, I don't see how you can do that without also loading the rod.

 

Yes you're right. However if you haul when the rod is unloading there isn't any increase in rod bend, just (perhaps) a delay in the unload that the casual observer would not see.

 

Hauling does have a loading effect of the rod, but so does the back and forth movement of the rod, have a loading effect. Loading the rod is a side issue to hauling, whose main purpose is to increase the line speed in the "unload" stage. The haul is performed as the rod passes the vertical, which by that stage, the rod begins it's unloading, thus more speed, a tighter loop, less wind resistance due to the tighter loop...result...more distance.

 

I disagree that the rod starts to unload as it passes verticle , the rod can't unload until it is decelerated enough that the line is traveling faster than the rod. I would say that this begins with the the caster stopping the rod hand and ends when the line passes over the rod tip at the point when the rod becomes straight before it counter flexes.

Sorry if this is a little complicated for some, but I have to dash of to the river and don't have time to simplify my explanation.

Sean , on the whole hauling increasing line speed but there is also an amount of extra load added to the rod however. I believe that this is and should be negligible for a good haul to work the caster should decrease the work done by the casting hand. Allowing the haul to produce most of the energy in the line.

Two simple experiments.

1 lay a line on the ground and give it a pull/ haul. What happens to the line?

2 Fix the line to something solid,this simulates an increase in inertia, gently pull on the line. What happens to the rod?

To some degree both of these experiments will show you what happens when you haul.

 

Something that I have been thinking quite hard about over the past few weeks...
There is a chance that the rod starts unbending past the vertical but still has the same loading from the line...
If we first assume that that for a given load acting on the rod by the line the maximum bending is going to occur when rod and line are at 90degs to each other. As the angle between the rod and line starts to close (I.E. a the rod passes through the vertical on the casting stroke) then even though the force acting on the rod remains the same because it's acting at under 90degs the actual bending force is reduced and therefore the rod will start to unbend...
To illustrate this, hold the fly line in your had and pull on the rod at 90deg. Now start to close the angle between the rod and line and see how much harder you need to pull to maintain the same bend in the rod.
Obviously the above ignores the effect of increasing acceleration of the cast past the vertical (which would add more bending force to the rod) and of the effect of gravity making the line drop 'behind' the stroke (which would decrease the amount of bending force on the rod).
Please feel free to pull this apart, I'd be interested to hear thoughts on the above...

Andy

 

Hello andy i am not a techy with the computer, maybe someone could film a fisherman doing a double haul cast, and then slow down the film!!!

 

I started practising distance casting this past winter and as a help I have had photographs taken at several shots per second of my own cast stroke and I know for a fact that maximum bend takes place well after the rod has passed vertical.

Whether this is also the maximum load is another matter and I haven't the instrumentation to prove anything.

Also regarding the haul: even a late haul takes place over a large part of the stroke. It has to: the left hand haul on a distance cast is over several feet and as such starts quite early and has finished just as the rod starts to unload. When people talk about a late haul it means that it is left as late as possible but "as late as possible" still means that it starts well before the vertical.

 

It both increases line speed and loads the rod, if you slow down a haul you can clearly see the extra loading on the rod at the point of the haul as it suddenly flexes more. To time a haul to the exact point of maximum load would create such a really sudden loading of the rod/acceleration of the line, it will shock the entire system leading to a messy forward cast negating any benefits of the haul.

 

Check this out...

Fish, Flies & Water [blog] » 500fps Fly Casting (Hi-Res + Data)

Andy

 

This one's getting like the old joke about how the centipede thought about which leg went first ......... and couldn't walk for thinking after .

All you can do with this is engage in ' Paralysis through Analysis .'

So learn Double haul and you'll never go back to Single - whatever the physics may happen to be !

Less theorising - more practise !

Best wishes

Steve P

 

Less theorising - more practise !

Best wishes

Steve P

It is possible that some us may be doing both...

Andy

 

The late Tom White explains it like this. He said that learning to double haul is like owning a chainsaw that you have been using for a while and then someone comes alone and shows you how to start up the saw! Double haul casts line with little effort and less energy.

BTW, don't forget about the guy that cast most of his line without a rod, by hauling with his hands.

 

Hauling does bend the rod

Yes, hauling adds to line speed and does add loading of the rod.
This can be demonstrated by casting without moving the rod hand. By correctly hauling, with no rod hand movement, false casting can be demonstrated. And does the the hauling cause the rod to bend? Yes, it does.
Try it for yourself.
Regarding hauling, it has to be done to coincide with the highest speed of the line and rod tip. This should coincide with the rod butt passing the vertical. If the haul is completed before the rod tip reaches the highest speed it is inefficiently being applied and in badly timed (early) instances can lead to our old friend the tailing loop.
People who start the haul as they start the forward cast often believe that hauling adds nothing to the performance of the cast. And it probably dosen't because when the rod tip is at it's fastest the haul has nothing to add. I talk from experience!
Rusty:wine:

 

Yes, hauling adds to line speed and does add loading of the rod.
This can be demonstrated by casting without moving the rod hand. By correctly hauling, with no rod hand movement, false casting can be demonstrated. And does the the hauling cause the rod to bend? Yes, it does.
Try it for yourself.
Regarding hauling, it has to be done to coincide with the highest speed of the line and rod tip. This should coincide with the rod butt passing the vertical. If the haul is completed before the rod tip reaches the highest speed it is inefficiently being applied and in badly timed (early) instances can lead to our old friend the tailing loop.
People who start the haul as they start the forward cast often believe that hauling adds nothing to the performance of the cast. And it probably dosen't because when the rod tip is at it's fastest the haul has nothing to add. I talk from experience!
Rusty:wine:

Thank you rusty. Probably the easiest to understand, and the most factually correct explanation yet.

 

Hi, pretty much every article I've read regarding the Double haul. Eludes to the fact that hauling increases the load on the rod. Yet none of them tell you how or why rod load is increased.

Is this a fact or not.

If someone could explain in simple terms, how hauling increases rod load. That would be good.

Sean

The haul puts more bend into the rod during the loading move therefore more potential energy which when released on the unloading move increases the line speed As i am not from a mechanical or physics background I am sure there will be arguments about this.

Brian

 

Well I've got both a mechanical and physics backround, low level , and that explains it nicely

 

is it easier to think of loading as just bending the rod?, when you pull on the line, and the line is extended enough to be a weight to pull on, the rod has to bend, as it would with the line tied to a fence post.

 

Frank has it right.

A haul does produce additional rod loading.

We all agree that hauling increases line speed. In order to increase line speed, the object to which the line is attached must resist the pull. This Newton's third law of motion. For every action, there is an opposite and equal reaction. This resistance of the rod tip to this extra energy added to the cast causes the rod to bend a bit more.

The haul does two things. The first is to increase line velocity and the second is to lessen mass. We commonly think of increased line velocity but also in pulling some line in, we remove some line; and this removes the amount of line mass that is aerialized. How can the double haul increase the distance of the cast if we remove line from the cast with the haul?

We increase distance because kinetic energy is Mass x Velocity squared = MxV2. Energy is what determines how far the cast will go and by increasing velocity we more than compensate for a slight loss in line mass. This extra energy allows to then shoot line which compensates for the slight amount of line removed during the haul.

It is not momentum (MV) that determines how far a cast will go, it is the kinetic energy in the cast (MVV). What momentum does is to determine the DIRECTION of the cast. Momentum has a direction component and energy does not.

What slows down the is air resistance or drag. It so happens that drag is also a squared function of velocity (V). This is why it is so hard to add that last bit of distance to a cast. The first 10 feet requires much less energy than the final 10 feet. To add that last 10 feet we must increase the energy in the cast and the velocity enough to overcome the squared velocity function of drag over the entire length of the cast. The fact that both KE and aerodynamic drag (FD) are both proportional to V2 is one of the beautiful symmetries of physics.

As to the timing of the haul, it should be during the maximum acceleration phase or maximum rod loading phase of the cast, right before the stop.

Recall that I have shown that the haul adds load to the rod, which causes the rod to bend just a bit more to resist the added energy in the line which is pulling on the rod tip. When the rod bend a bit more, the effective rod length shortens and the rod tip gets closer to the casting hand. If this rod shortening occurs during unloading, it will cause a dip or wave in the straight line path and an inefficient cast. If it it occurs too early, it will causes a dip in the rod tip path, which causes a concave rod tip path, which causes a tailing loop. So timing is critical so that the additional bend in the rod is added smoothly to the point of maximum bend to preserve the straight line rod tip path.

Consider the following articles on casting and the double haul by espert casters and scientists.

http://www.nytimes.com/2006/01/07/sports/othersports/07outdoors.html?_r=1

"Now you are ready for the double haul," Jaworowski said as he demonstrated. "With your line hand, you add in a fast crisp pull as you begin your back cast and then pull once again on the forward cast. The goal is acceleration and then a sudden stop. While the motion of your rod hand serves to flex the rod, pulling down on the line with your other hand puts pressure on the rod tip and bends it even more."

The Biomechanics of Fly Casting by Al Kyte, Ed.Dr., Univ. of California and Gary Moran Ph.D. University of San Francisco

"The most effective haulers pulled the line back for greater distance than the other casters primarily during the final, accelerated stages of loading. Thus they stopped the haul and released the line father back as well (figure 10)."

Double Hauling by Bruce Richards

"When a short, sharp haul is made in the middle of this long stroke, tailing loops are the result. It only makes sense that a poorly-timed, sharp haul will cause the rod tip to collapse into a concave pathway, thus making the line 'tail'."

 

Frank has it right.

A haul does produce additional rod loading.

We all agree that hauling increases line speed. In order to increase line speed, the object to which the line is attached must resist the pull. This Newton's third law of motion. For every action, there is an opposite and equal reaction. This resistance of the rod tip to this extra energy added to the cast causes the rod to bend a bit more.

The haul does two things. The first is to increase line velocity and the second is to lessen mass. We commonly think of increased line velocity but also in pulling some line in, we remove some line; and this removes the amount of line mass that is aerialized. How can the double haul increase the distance of the cast if we remove line from the cast with the haul?

We increase distance because kinetic energy is Mass x Velocity squared = MxV2. Energy is what determines how far the cast will go and by increasing velocity we more than compensate for a slight loss in line mass. This extra energy allows to then shoot line which compensates for the slight amount of line removed during the haul.

It is not momentum (MV) that determines how far a cast will go, it is the kinetic energy in the cast (MVV). What momentum does is to determine the DIRECTION of the cast. Momentum has a direction component and energy does not.

What slows down the is air resistance or drag. It so happens that drag is also a squared function of velocity (V). This is why it is so hard to add that last bit of distance to a cast. The first 10 feet requires much less energy than the final 10 feet. To add that last 10 feet we must increase the energy in the cast and the velocity enough to overcome the squared velocity function of drag over the entire length of the cast. The fact that both KE and aerodynamic drag (FD) are both proportional to V2 is one of the beautiful symmetries of physics.

As to the timing of the haul, it should be during the maximum acceleration phase or maximum rod loading phase of the cast, right before the stop.

Recall that I have shown that the haul adds load to the rod, which causes the rod to bend just a bit more to resist the added energy in the line which is pulling on the rod tip. When the rod bend a bit more, the effective rod length shortens and the rod tip gets closer to the casting hand. If this rod shortening occurs during unloading, it will cause a dip or wave in the straight line path and an inefficient cast. If it it occurs too early, it will causes a dip in the rod tip path, which causes a concave rod tip path, which causes a tailing loop. So timing is critical so that the additional bend in the rod is added smoothly to the point of maximum bend to preserve the straight line rod tip path.

Consider the following articles on casting and the double haul by espert casters and scientists.

When Less Is More: Subtleties of the Double Haul Cast - New York Times

"Now you are ready for the double haul," Jaworowski said as he demonstrated. "With your line hand, you add in a fast crisp pull as you begin your back cast and then pull once again on the forward cast. The goal is acceleration and then a sudden stop. While the motion of your rod hand serves to flex the rod, pulling down on the line with your other hand puts pressure on the rod tip and bends it even more."

The Biomechanics of Fly Casting by Al Kyte, Ed.Dr., Univ. of California and Gary Moran Ph.D. University of San Francisco

"The most effective haulers pulled the line back for greater distance than the other casters primarily during the final, accelerated stages of loading. Thus they stopped the haul and released the line father back as well (figure 10)."

Double Hauling by Bruce Richards

"When a short, sharp haul is made in the middle of this long stroke, tailing loops are the result. It only makes sense that a poorly-timed, sharp haul will cause the rod tip to collapse into a concave pathway, thus making the line 'tail'."

I've just finished reading this (I started at half six) I am going to sleep on it reply in the morning(Look in a Book)

 

was this ever in dispute

 

Thanks Chaps, excellent explanations, some simple. Others not so. All have merit. Even Senpai Parton with his "Do, not think" philosophy.

Than you all for your help.

Sean

 

Here's my explanation to a 12 year old
Imagine someone pushing you on a swing, and you kick your legs at the right point in the swing you go faster (=higher). That kick is like a haul, it puts more energy into the system translating to greater speed. If you kick at the wrong time it is largely ineffective, timing is everything
-A.

 

just had a thought, if a haul didnt compress the rod tip where would that bloody tailing loop be coming from when you haul too hard, too early?

 

I've been fishing for a number of years now, i've never felt the need to double haul or look at the physics behind it. But this thread has been interesting. I think i will still be sticking with my own style of casting as it seems to catch fish.

 

Chris,

Q: If there are two indentical objects and one is travelling at 10m/s and one is travelling at 20m/s - which one has the greater force acting on it?

A: Neither; they both have zero force acting as they are not accelerating. (and it's this force that bends the rod).

Ok, so the one going faster had a higher force acting on it in order to accelerate it to the higher speed then. Nope, not necessarily - it might of had a lower force applied for a longer time. Like I said it gets complicated.

A perfect haul will be applied late when the rod is unloading.

your explanation assumes that the "model system" has achieved Vmax, in reality, due to the forces acting upon the line, the casting stroke , the flex in the rod and the haul it is more likely that there is either an acceleration or a deceleration involved and that the zero forces scenareo only occurs momentarily throughout the process

 

There are plenty of videos and still pics of truly accomplished casters (Paul Arden, Lasse Karlsson etc.) who haul right through the stop and sometimes well into the counterflex. Being as the rod is actually straightening as they're hauling it's hard for me to think that hauling is about increasing load (although I'm not saying it doesn't). Much simpler to regard it as directly increasing line speed.

---------- Post added at 12:25 AM ---------- Previous post was at 12:22 AM ----------

your explanation assumes that the "model system" has achieved Vmax

Hi - I was just trying to make the point that you can't infer any force history just by looking at instantaneous velocity.

 

Picture 345 « Album 1 « Gallery 11 « Gallery | BFCC - Home Of Uk Fly Casting

Here's an example of a certain Chuckfluffer's haul timing - if you look he still has hold of the line yet the rod has passed the straight position.

 

Please excuse my ignorance. How often is double hauling required when fishing stillwaters?

 

hello from my experience not that often, unless say farmoor the fish are out in the windlanes feeding a bit far than norm, or if using a sinker and booby or shooting head casting far can be productive. anyway it is only another method with fly line. in case anyone replies this i dont do now like in the early days am no expert was a method many people took up. if i did this today after a short time would have too much back pain (work accident) so decided to give up using my heavier gear. happy for w/f6 d/t 6 and under. some good and interesting replies to this thread. happy easter to all