Re: Cracking the whip
The crack in the cast happens when the rythym is off between the forward cast and the backcast. You haven't put enough umph in the backcast and the line stalls in the air and when you make that sudden change of direction to get your fly to the target it snaps the end of the leader because it isn't moving in any direction. The speed of the forward cast and it's plane should equal the backcast.
The tempo is 1..2..1..2. You pause slightly between the forward and back cast and try not to give it a burst of speed when you present the fly.