MADEIRA BEACH - As they craned their necks upward, a small group of tourists noticed something was wrong with the two teenage girls parasailing together Thursday afternoon. The girls were drifting 200 to 250 feet in the air - not over the Gulf of Mexico as they should have been, but over the beach. And they were headed inland. Then the same group, made up mainly of Midwesterners, noticed the line that had connected the pair to a boat was dragging along the surface of the Gulf. It had snapped. Some heard the girls scream. Jon Shoemaker, a 34-year- old...