When fly casting, the rod must bend and unbend. This sounds simple and actually is if you incorporate the fundamentals properly. With spin or bait casting it is the weight if the lure that greatly assists bending (loading) the rod. With fly fishing it is the weight of the fly line that does the job. In order to utilize the complete weight of the fly line, the caster must eliminate all slack in the line before and during the casting motion.
The first step in accomplishing this is to eliminate slack prior to setting the rod into motion. Stripping line in prior to making the cast is the most common method. Letting the current of the water pull the line taut is another. Once the slack is eliminated the casting stroke can begin. Unwanted slack can also be introduced during the casting stroke phase. Typically this is caused by deceleration of the casting stroke. Deceleration usually occurs near the end portion of the stroke but it can also happen somewhere earlier. Smooth acceleration finished with a crisp stop is critical for maintaining proper tension. Any deviation will cause an erratic amount of tension.
If you do not apply this principle the rod never bends or unbends (unloads). Essentially it is akin to waving around with a two-by-four piece of lumber. You can get away with flailing the line and fishing this way but you will be limited to rudimentary casts and miss many opportunities that require advanced casting skills.
Unloading the rod is critical to successful casting. By stopping the casting motion at the appropriate time the caster enables the transfer of motion/energy from the rod to the fly line. Resulting with the fly line hurling through the air with proper velocity to reach the target and with precision to hit the target.
It’s hot and sunny. You are on a small mountain stream lined with rhododendron. Finally after a half-mile hike you arrive to the deep plunge pool that’s become a familiar friend. There under the rhododendron branch in the shade lays a nice sized trout casually sipping any meal that floats by. You look back to check for back casting interference and luckily you have a shot. It’s tight but as long as you make a tight loop you should get by. You cast a tight loop back flawlessly and proceed with a needle like loop on the forward cast. Nice and tight right under the branch. You only have a short drift but if all goes well it should be enough. Bang! There he is game on. After a short but sweet fight you release a beautiful wild Brown trout for another day.
– Eliminate slack in the fly line before making the cast.
– Maintain tension in the fly line throughout the cast by smoothly accelerating.
– Stop the stroke crisply to avoid introducing slack caused by deceleration.