Step 1: Establish the A-B Line
Run a straight A-B line parallel to the pool, at least 4 feet from the water's edge and at least two-thirds the length of the pool. Point A must be to the left of point B. Measure the full A-B line and record it on your A-B measuring sheet. The example line is 20 feet long. Draw your A-B line along the bottom of the pool sketch.