It was April 28, 1944, six weeks before D-Day, and Vincent Ricciardi, an engineer, was in the midst of Exercise Tiger, one of the most secretive training missions of the war. In preparation for the Normandy beach landing, a convoy of eight transporters sped toward a rocky beach in southwest England, where they were to practice maneuvers under live fire. But nine German warships sailing from Chambourd, France, had found the training group and let loose a flurry of torpedo fire. Before it was over, 749 servicemen lost their lives.