looking up at the surface, where a hull floats in silhouette against the daylight. there's a commotion, and a water ski drops into view. then another one. pale legs churn the water. following the skis effortlessly, closing in on the turbulent wake. closing in on the wake, crossing it. closing in on the thrashing figure. the class, paired up, is drifting down; sparky offering encouragement as they descend. andrews and crosby are already disappearing, swimming away with strong kicks. the sandpiper's hull, alone above us, as the shark rises with dreadful certainty, attracted by the erratic sounds of ed's hasty search. the twin hulls of a catamaran's hull, the muffled, eerie sound of drumming, as the water carries the tempting "thud- thud-thud" sound down to the deep. looking up at the scattered hulls of the sailboats, the turbulence from the low-flying chopper making a vast circular pattern of irregular vibrations. looking up at pontoons, wreckage, wind turbulence on the surface, the heavy "thud-thud-thud" of chopper blades. marge ducking under the bulk of the shark, shoving off with panicky reserves of strength, swimming away underwater, while the shark takes a massive crunching bite out of a submerged hull. the inverted mast of one of the wrecked boats is snagged on the rocks on the bottom. the mast bends under the strain, but holds the raft stuck fast.