Spey casting dynamics

[Traditionalist]

the bit we differ is in power application, for me the lift, be that a spey cast or overhead supplies enough energy to complete the cast(the rod bending stores it) i don't add much forward, the line already has the momentum to carry itself.

you appear to be using energy to propel the line forward, i would argue that no matter how much extra effort you use forward it has very little effect and looses you control,

it comes as a shock to many that the momentum of the line itself is what gets it there, moving it forward with massive force is much the same as moving it forward with little....because its moving the same distance.

this sounds a bit weird but i could show you real easy.

The only thing that supplies any energy at all when casting is the person doing it. In order to cast further you need to apply more force.

The same thing applies when throwing a stone, in order to get it to fly farther you need to apply more force.

Momentum is mass times velocity.  You can not change the mass on a shooting head, you can only increase the velocity, and to do that you need to apply more force. Things are more complex if you are extending a full line as you also change the mass but the same principles apply.

Those basic facts are unassailable.

If you don't accept them for some reason or other, then we will simply have to agree to disagree.  I can't see any point at all in any further discussion unless one can agree on basic facts, and it seems we can't.

There are many more factors, variables, and conditions, at any given moment in a cast to be taken into consideration, but those basic factors always apply.

TL
MC

[Malcolm]

i have seen an 84 year old spey cast a 5 weight WF into the backing by shooting line, you have to shoot with a WF because too much line lifted and it collapses, Craig(buster) manages about 80' as would Malcolm, but with a DT you can lift way more line than the head of a WF, and i find a DT shoots not too bad, just a bit less than the average WF.
spey casting a WF needs critical balance, you pick up at exactly the same optimum weight point for the rod, less or more can catch you out, this is not an issue with a DT, you can cast any amount of head as long as you have enough weight to bend the rod, no advantage in distance competitions but when fishing you cast different distances with greater ease.

having said that i mostly use a triangle taper, best of both worlds.

Alan,

Distance casting with a spey line is a completely different topic to casting short distances, in heavy vegetation, with a heavy fly. It's just not relevant. Creating a D-loop with 60 feet or more of a double taper is useless: the D-loop would be snagged up.

The purpose of the Skagit is so that I can pick up 5 or 7 metres of line with a heavy fly and shoot another 5 to 10 metres of line. That's just not possible with a double taper. The heavy line creates too much resistance.  Before going any further would you try this: put a heavily leaded size 6 goldhead wooly bugger on your 5 weight, put 7 metres of line beyond the tip and spey/roll cast. The chances are the fly won't even leave the water. If it does it will be a wide open lob. Try the same thing on the same rod but this time with a size 12 line. Much easier.   

[Traditionalist]

this is indeed where we differ, throwing an object is one movement from a to b, a cast relies on the line already having momentum, movement continues from lift to lay and energy is contained from lift to lay,    you can make the loop unroll faster, you can force the rod to bend further, you can even force the rod through the air faster, this will only add 2' to a 70' cast because most of the energy you use to cast is imparted in the lift, and is more efficiently contained by perfect tracking and aerodynamic loop than any amount of force, this is not defying the laws of physics its understanding them,
if you try to force anything against air resistance you get diminishing returns,

the reason I'm still going on about it is that every casting instructor in the country bangs their head against the wall with this one, the 2 biggest misunderstandings with beginners is using too much force and trying to force the line to do it.

I agree that beginners using too much force, ( and applying it incorrectly anyway) is a major problem.  But that does not alter the basic facts.

The force required to propel any given mass 35 feet is considerably less than the force required to propel the same mass 70 feet.

How the force is applied, and the general efficiency of the cast will affect how the cast ends up,but to cast twice the distance still requires more force.

Momentum is mass times velocity.   When a line stops on the backcast for instance it has no momentum.  Movement is required for momentum. Momentum is achieved by applying force. The greater the force the greater the momentum.

The problem for beginners is the inappropriate use of too much force.

TL
MC

[Buanán]

A switch cast ( also called a "jump-roll"),  is just a variation on a dynamic roll cast;

http://www.letsflyfish.com/rollcastmovie.htm

Fly Casting DVD Video ROLL CAST / Switch Cast Excerpt from 'Casts that Catch Fish'

Switch Cast

Roll Cast vs Switch cast

has nothing to do with a "Switch rod" by the way, which can be used in various ways;

HD - "Switch Rod Casting Techniques"

TL
MC

Thanks Mike, it's a short roll cast that I'm doing with the heavier lines in very windy conditions. I'll be trying to sort out the switch/jump roll cast during this afternoons wander.

[Traditionalist]

Thanks Mike, it's a short roll cast that I'm doing with the heavier lines in very windy conditions. I'll be trying to sort out the switch/jump roll cast during this afternoon wander.

It's a problem nowadays just sorting out what is what with all these "defined" casts and descriptions. I don't think most people care much as long as whatever they do works for them. It is of course useful to watch various casts so that you have at least an idea of what you are trying to achieve.
When I first started there were basically two casts in trout fishing, overhead and roll casting. All the other stuff was just seen as variations. In the meantime I have lost count of the casts which are defined and described

TL
MC

[Traditionalist]

if you recall we were talking about the differences between double taper and weight forward lines, with a dt 70' is a longer cast than 35', with a dt the extra distance is shot rather than cast, no extra force is needed to let line shoot, if the aerialised head of the line is loading the rod all you need to do is alter trajectory.

I think we have been talking about different things and that is causing confusion. I think the above may be a typo?

The techniques for casting a full line are different to the techniques required when casting various heads, and this also depends on how they are cast.

However, if you want to shoot a head further you need more force to provide the momentum. Simply aerialising a head and letting it go wont propel it much  further than what you have aerialised.

A fully aerialised head is EXACTLY the same as a lead weight ( ignoring things like drag on the backing etc).  If you cast a lead weight, you need more force to make it go further. How you apply force is important, but you have to apply more force to cast further. There is no getting away from that.

TL
MC

[Traditionalist]

While I agree with you that many people vastly overestimate the force required to cast, and too much force is invariably detrimental.

Force is required to cast, and more force is required to cast further.

There is nothing else I can say if you don't accept that.

Force is defined as anything that causes an acceleration on an object when applied. Without an applied force an object can not accelerate. That is a physical fact, it can not be refuted.  Although you may of course refuse to believe or accept it.

TL
MC

[Traditionalist]

Very considerable problems can arise with these things.  The main reason that beginners have problems with applying too much force is that they confuse the application of force itself and the method of application, so they end up applying the force incorrectly.

They know intuitively that to make something go further ( a thrown stone for instance), more force is required, and they try to do the same thing when using a rod and line. There are some people who can cast intuitively, ( which means they instinctively know how to do it correctly), but the vast majority have to learn.  This is further complicated by the use of "general" language to describe things.

In order to describe things accurately the only safe way is to use mathematical concepts.  Most people think they know what acceleration is , but most actually don't. What they "know" is invariably some generalised conception of "going faster".

Acceleration however, is defined thus;

http://www.physicsclassroom.com/class/1dkin/u1l1e.cfm

Forces are defined thus;

http://www.physicsclassroom.com/Class/energy/u5l1aa.cfm

and there is a great deal more to it if one wishes to be precise.

This makes casual discussion of such things extremely difficult, and often results in confusion.

TL
MC

[Traditionalist]

the nature of these things :lol:

Mike im not saying force in not used, i was just saying if you arialise the head of a WF line you can shoot it to 70', no extra effort required than casting to 35' or whatever because you have only cast 35' and let go, the extra effort is letting it go rather than casting 35'...by not letting it go.

Well, I disagree. Simply aerialising a head wont allow you to shoot it to 70 feet. But there is little point in repeating things.

As this is apparently seen as crap I wont bother posting any more on it.

TL
MC

[Inchlaggan]

More crap follows, look away now.
Whist the physics quoted is correct in every respect, casting cannot be explained by basic application of force (energy).
Try this-
Take a piece of split shot and see if you can throw it 75 ft.
Stick in a rubber balloon, inflate the balloon, tie off and see if you can throw it 75ft.
Stick it in a cricket ball and see if you can throw it 75ft.
Stick it in a golf ball and see if you can hit it with a driver for 75ft.
Make it into a pellet and fire it from an break action air rifle, can it make 75ft?.
The energy (force) required to move that mass of lead 75 ft remains the same (gravity and air resistance being taken as constant) in all cases.
Of the above challenges the one that makes the 75 ft for the least input of energy on your part, is the air rifle.
Because you have used a tool.
Rod and line are a tool, rod acting as lever and spring, line carrying momentum through the complex process.
The energy required to propel that weight of fly and line that distance remains the same (the minimum), casting requires the expenditure of much more energy than the task requires, the design of lines and rods aim to reduce the energy expended by the angler to the minimum.
So DF or WF?