ROD PLANE: The orientation of the rod from vertical to horizontal on either side of the caster.
LINE PLANE: Trajectory of the line. (For example — a high back cast followed by a low forward cast, maintaining 180 degrees between the two.)
CASTING PLANE: Many use this term in preference to the way I have used," LINE PLANE."
THE 180 DEGREE "RULE": (Applies to Line Plane.)
RULE OF ELEVENS : Subtraction of the X leader number from 11 to come up with the leader diameter in thousandths. (Example: 4X leader = 11-4= 7= .007 " dia.)
RULE OF 3's (or 4's): Division of the numerical fly hook size by either 3 or 4 to come up with the X number for the leader. (Example: # 12 hook. 12 divided by 3= 4=4X tippet)
RULE OF "30": Method of coming up with the approximate grain weight of the first 30' of a fly line by multiplying the fly line rating number ("size") by 30. (A very rough approximation for mid range fly lines.)
RULE OF "9’s": Rough calculation of the lb. test of a fly leader/tippet by subtracting the X number from 9. (Much less accurate in recent times because of wide variation in tippet material diameter/strength ratios.)
CASTING STROKE: The linear path taken by the hand during the cast.
RSP: Rod Straight Position. (The point at which the fly line can overtake the rod tip allowing the loop to begin to form.)
COUNTERFLEX: The flexion motion of the rod tip immediately after RSP.
REBOUND: The reverse motion of the rod tip immediately after Counterflex.
ROD HARMONICS: The first and second nodal vibration characteristics of a fly rod.
TIP TRAVEL: Total linear distance the rod tip moves in the direction of the cast. (This can be the product of; 1.) Stroke length, 2.) Casting arc, 3.) Body motion in the direction of the cast & a step by the caster in the direction of the cast.)
CREEP: Minimally accelerated, slow (usually unintended) motion of the rod tip opposite that of an unrolling or newly unrolled loop.
DRIFT: Movement of the rod tip (usually intended) in the direction of an unrolling loop. This can, 1.) increase the available stroke length for the next stroke, 2.) allow for repositioning of the hand/arm for the following stroke, 3.) provide the feeling of, "staying connected", 4.) provide increased, "hang time" for the above.
FOLLOW-THROUGH: Same as drift, but used more often to describe the action immediately following the forward (presentation) stroke.
TAILING LOOP: A loop characterized by the fly (upper) leg crossing over the rod (lower) leg. Most often resulting from a concave rod tip path during or between strokes.
STROKE LENGTH: The linear distance in the direction of the cast traveled by the hand.
CASTING ARC: Also called, "Casting angle". This is the angular change between the positions of the butt section of the rod from the beginning to that of the completion of the cast.
TRACKING: Technically, the property of the rod tip following a straight line in all planes. In common use, however, it is considered the property of the moving rod tip to deviate or not from right to left. (Good tracking would be no deviation.)
SLP: Straight Line Path of the rod tip. (Realizing that a perfect one would result in the line colliding with the rod tip......and the fact that the best, "elite" casters have a very slightly convex path of the rod tip).
MEND: In- the- air or on- the- water repositioning of the line after the cast.
LAYOUT: The position of the fly line and leader upon landing on the water or the ground.
SPEY CAST: (My definition, after much deliberation and discussion with expert Spey folks.) An aereolized, live line, change of direction roll type cast.
KICK: One use, is the sudden bucking of a level line at the conclusion of a cast. (Another use would be the description of rapid turnover of a fly leader beneath overlying brush.)
OVERHANG: Two uses. One is the fallen brush or bushes, mangroves, etc. which protrude from the bank.
In casting , it is used to describe the thin running line behind the fly line head.
DOUBLE AND SINGLE HAULS: Most writers and instructors define a single haul as a pull with the line hand on either the back cast or the forward cast, and a double haul as a pull on each. You should be aware that Joan Wulff and her "disciples" teach it differently. She looks at the single haul as a pull without giving back line, and a double haul as a pull followed by giving back of line on a single stroke, forward or back.
HIDDEN DRAG: Drag of a dry fly so slight as to escape the notice of the angler ... (But not the fish!)
Legs of the Loop: The legs of a fly line loop are commonly described as 1.) the FLY LEG and; 2.) the ROD LEG. I prefer those terms instead of "top leg" and, "bottom leg" respectively, because it assumes a vertical rod plane. Where, for example, is the "top" leg when casting with the rod parallel to the ground?
Note that a few mechanical engineers use the terms, "traveling leg" and, "stationary leg". These definitions suffer in the case of shooting line in which instance the term, "stationary" becomes a misnomer.
Mac Brown (CASTING ANGLES, P. 88) refers to the legs of a loop as the, "end line" and "main line". I preferred not to use "main" since at the start of the cast that limb of the loop is much smaller than the other (fly leg).......one interpretation of the word, "main" being, "greatest".