A man speaking broken English cried through the radio. Something about an attack. Shots fired. Grenades launched. Pirates. Aboard the U.S.S. Peleliu, the officers in charge expected such distress calls. On that day, Aug. 8, the ship was stationed in the Gulf of Aden, a strip of water between Yemen and Somalia known among seafarers as Pirate Alley. The hijacking was 10 miles from the Peleliu, close enough for the ship to send out rescue teams. Steering one vessel was Jonathan Johnston, a 24-year-old Navy lieutenant junior grade. He maneuvered toward the Gem of Kilakarai, the cargo ship from Singapore...