Fly Casting Instructor - the physics of fly casting
|Fly casting Rule 1
Fly casting is a relatively simple physical skill that depends on obeying a few fundamental rules and achieving good timing. If you develop bad habits eradicating them is difficult but if you understand the principles of efficient fly casting from the start the process of learning to cast a fly becomes easier. There are no bad students, only bad instructors. A fly fishing instructor must be able to communicate the essentials of fly casting physics clearly so that the student understands and practices good technique. Style is an individual choice. We are each physically different and you may wish to cast in an unorthodox style but the physics of efficient fly casting must be complied with. This and other pages on fly casting instruction are about what makes a cast work, the essential fundamentals that a good fly fishing instructor must emphasize. I will also mention tips that my experience suggests make it easy for most people to become good fly casters with the minimum of effort. First I am going to remind you of the three essential rules for fly casting. Every perfect cast used these principles whether the fly fisherman was conscious of them or not!
Rule 1. Start with straight (or organised) line.
If the line is not organised rod movement is wasted to straighten and tension it and your effort is not only wasted, you have now got the rod in the incorrect place to start the cast. Always start with the line organised and this of course applies whether your line is on the water, in the air or formed into a roll casting D loop. Remember that the cast does not start until the fly moves. The simplest organized line is of course a straight line on the water surface with the rod tip low and tight to it. I have used the word “organised” to include the starting point for roll casts which is a curved line, but it is still organised.
Question – What happens if you start a cast with slack line?
Answer – The line will jerk when it eventually tightens and will be unable to make the cast correctly. Note that because an overhead or straight line cast is actually two casts, (a forward cast plus a back cast) continuing with the forward cast if the back cast line has not straightened also causes a jerk that results in untidiness, a tailing loop or slack line in the delivery.
Rule 2. Every positive casting stroke should be a smooth acceleration of the rod tip followed by a stop.
The accelerating stroke bends the rod against the line's resistance, loading it like a spring. Whilst the rod is accelerating the bend deepens (increases), when movement of the rod stops the rod recovers and straightens, it is the precise stop that transfers the stored energy in the spring (rod) to the line to rapidly increase line speed and hence casting distance. That is why descriptions "like flicking paint off a brush" may be applied to casting but be careful to understand that casting is not a “flick”, a long smooth exponential acceleration to the “stop” gives the smoothest casts. The better the "stop" the better it goes.
Question – Why does the rod have to accelerate smoothly?
Answer – If not the will line will not remain straight and tight and the cast will be less than perfect. The rod must be pulling all of the line (accelerating) throughout a cast. The cast stops when the rod movement stops for instance with the stop at the end of the back cast.
Question – What is a stop?
Answer – A stop is a physical state that is described perfectly, it is a “stop”. Not a slow down, not an over hard snap followed by vibration of the rod tip, a stop is just a precise dead stop. By relaxing the grip immediately after the stop the angler will reduce vibration in the rod tip and prevent shock waves traveling down the line.
|Fly casting Rule 3
Rule 3. The line follows the rod tip and when the rod stops the line projects in the direction that the rod tip was going in when the stop occurred.
The direction that the line takes is produced by movement the rod tip. If you want your line to go in a straight line - make the rod tip move in a straight line, the direction and path of the line is controlled by the direction of the rod tip and the same thing goes for circles or parts of circles, ellipses or other shapes that will support continuous motion for the duration of a casting stroke. Stop the rod and the line will attempt to follow the direction of the tip as the rod straightens.
Question - Why does bending the wrist cause problems sometimes?
Answer – Wrists make circular movements so using your wrist too much means that the rod tip path is curved, it is therefore impossible for the line to travel straight with a narrow loop. It will instead produce a wide curved loop. If during the back cast the rod is stopped whilst the tip is going downwards the line will be cast downwards. The line does not "fall", it is cast to the ground – very bad technique but all too common.