BRENTWOOD, Tenn. (AP) — The small boat lurched. First upward, to the crest of the oncoming wave. Then down into the valley between each 15-foot swell.

Each time the nose of the small fishing vessel plunged forward, its passengers' feet lifted off the ground. And when the bow slammed into the wall of water ahead, their bodies crashed back to the deck, jarring their tailbones and bruising their legs.

"Life jackets! Life jackets!" the captain yelled.

What began as a memorable deep sea excursion for two Brentwood Academy students and two faculty members in Costa Rica had been upended. And the hour...