A lot of argument goes into when a haul starts. Get the finish right instead.

What the instructor says

• The haul stops with the rod hand. Almost simultaneously is what everyone who hauls well does; where it starts is personal. The tip rebounds after the hand stops.
• An equal 18 inch haul. Both stops at 18 inches, about the same length, even at 50 feet where one hand would carry it; hands merely separating on the back cast is not a haul.
• Parallel to the rod. Out to the side, the line drags across a guide at close to right angles and the efficiency is gone; slack at the finger means the rod is already unbending.

Putting it to work

1. Cast 50 feet with a haul on the pickup, five or six reps, rod in hand until told; good loops will not save flawed mechanics.
2. Film the line hand: both stops at 18 inches, no slack, no sideways drift.
3. For the teaching question, teach real students first, then say this is how I do it; what the haul buys you is on the double haul card.

Source

From the FFI CI walkthrough series by Dayle Mazzarella (Chapter 3 — FFI Casting Instructor Certification Tasks, Fly Fishing Coach International), lesson 12, 00:03:56. See the video library and the task pages for the exam wording; terms follow the FFI Fly Casting Definitions.