some excellent analysis by Steve and Tim Rajeff via Fly Casting Forum
as a reminder, here’s the generally accepted definition of Drift taken from The Sexyloops Fly Casting Model-
Drift: To position (or reposition) the rod between casting strokes.
Moving the rod (tip) to adjust Casting Arc, Stroke Length or Casting Plane. Drift applies little or no force on the line.
although not a necessity for every casting situation, we’ll see from the second part of the definition above that this technique should be well engrained and in every fly angler’s bag of tricks.
some purists will state that it’s not needed even for the longest casts but i can’t think of a serious distance caster that doesn’t drift… besides, without going into the specialised world of distance casting, simply put, drifting makes a lot of casts easier and cleaner. something we all aspire to, specially when fishing. why miss out ?
apart that it negates creepy creeping and greatly reduces tailing loops, parallel drifting promotes (actually necessitates) a greater involvement of the whole arm and its joints which leads to fluidity and smoothness for both the caster and line path. pretty darn good results considering how easy and effortless this action is.
if drifting isn’t part of your repertoire do yourself the favour of practicing and keeping it in a near-to-access part of your casting brain. it will come in handy. promise !
THE TWO KINDS OF DRIFT
The puzzle of every teacher is how to introduce drift without ruining the short stroke that has been taught. The best answer to this is to teach drift way after the student is thoroughly grounded in casting and hauling etc..The interesting thing about drift is that first of all there are two ways to drift and second, drift adds so much power and control when distance is on the menu.
The first type of drift ordinarily discovered by the caster is rotary drift – produced by angular motion of the rod from wrist action. This drift can be found in any length of stroke and tends to open up the loop in both directions.
This wrist generated angular drift is frequently followed by a tailing loop as well.
The other kind of drift is what I call the parallel drift. This will be seen in many illustrations of casting strokes and is the gem of the drift game. I don’t see it as much as the rotary drift and the reason is that it is hard to do from a mechanical standpoint. Every caster starts out wanting to cast with the wrist and one reason for that is that it is less effort to rotate the rod from the wrist than to put out the foot pounds needed to move the whole rod back, by the use of hand movement, thus adding a few inches or a foot or more to the space available for loading the rod on the forecast. The hand has to be out by the shoulder and moving from a point a foot or so in front of the head to a point as much as six inches or a foot behind the head, depending on how limber the caster is. This requires work and requires rotating the wrist forward, rather than back in order to keep the rod moving parallel to itself as the forearm is moving and rotating backward.
There are various degrees of this motion available depending on how far out from the body the cast is being made. For accuracy casts with the rod side foot forward the hand will be beside the head and moving back and forth in a plane that misses the ear, just barely. For great power, with an open stance, the rod might be outside of the shoulder in the baseball throwing motion used for great distance. In either case conscious effort to make the rod run back parallel to itself is needed . The wrist will resist cocking so far forward while the hand is moving backward. There will be instances where after the limit of parallel drift has been reached some rotary drift will be added to the back cast. This can get the rod back almost horizontal and in a position to come forward with the leading elbow motion that helps produce line speed. While the elbow is leading the hand forward the rod is moving forward parallel to itself before finally going into rotary motion again, leading to the final tip snap.
So, the parallel backward drift is mirrored on the leading elbow forward stroke.
This parallel drift will loosen up the arm and shoulder joints in time and should be approached gradually. It is amazing how the body wants to return to bending the wrist back rather than to perform the arduous parallel drift maneuver. But in time, the very pleasing results from this move will produce a conditioned response. If I do this uncomfortable parallel drift I will have a great back cast and forward cast.
The final dividend from the parallel drift is that it allows the caster to feel the tug of the line better, because the rod is closer to perpendicular to the line. The closer the rod is to ninety degrees from the line the easier it is to feel the line straighten out. Sometimes you can drift a little more with the wrist as you feel the line straighten if there is enough speed on the back cast.