Description:: I learned this cast from Vincenzo Penteriani, a great instructor of Robert Pragliola's interesting TLT school (Italian acronym for Total Casting Technique). The line takes a V shape, which serves as a minimum anchor point for immediately executing a roll cost.
Use: : to position the line for placing quite a bit of line right upstream of the fly with a fast roll cast. A great anti-drag maneuver in fast currents and little weirs, always upstream and in line with the current.
Execution: : after a wide, lazy loop and always after the forward stop, drop your casting elbow below your waist and then raise it again. The movement must be smooth but fast. The rod tip points straight up all the time.
If it doesn't come out right, it's because...