On 16 July 1945, the Portland class heavy cruiser CA-35, the USS Indianapolis, departed San Francisco for the island of Tinian to deliver parts for the first atomic bomb to be dropped on Japan. After successfully delivering the parts, the Indianapolis set off for the Philippines to participate in exercises for the upcoming planned invasion of Japan. Because of her secret mission, neither the 3rd nor the 5th Fleet were tracking her. Furthermore, she set off alone because naval intelligence deemed the waters between the Marianna’s and the Philippines safe.
On 30 July 1945, the USS Indianapolis was struck by a torpedo fired by Japanese submarine I-58. 300 of the 1200 crewmembers died in the initial attack and 900 abandoned ship into the oil slick and shark infested waters. A distress call was sent but none of the three stations that heard it acted on it. For four days and three nights, the survivors endured dehydration, saltwater and oil poisoning, hallucinations and madness, hypothermia, and numerous shark attacks.
On 2 August, a PV-1 Ventura spotted the survivors when the bombardier was rubbing his stiff neck (from changing an aerial) and glanced in their direction. They called it in and soon a PBY Catalina dropped rubber life rafts, water, and lifejackets to the remaining survivors. The pilot violated his patrol orders and landed to pick up stragglers after he watched in horror a shark attack consume one of the Indianapolis’ crew. Several hours later the destroyer escort USS Cecil J Doyle arrived on her captain’s own authority after hearing the PBYs desperate calls for assistance.
Only 317 of the Indianapolis’ 1197 crew members survived.