This story appears in the August 2016 issue of National Geographic magazine.
On July 26, 1945, the heavy cruiser U.S.S. Indianapolis landed on Tinian Island in the northern Pacific and delivered components for the atomic bomb that 11 days later would be dropped on Hiroshima. World War II was almost over. But for the crew of the Indy, the worst of the war was yet to come. Four days later, en route to the Philippines, the ship was torpedoed by a Japanese submarine. The ship sank in 12 minutes, taking some 300 men down with it. The remaining 900 men were set adrift for the better part of five grueling days. Only 317 survived. It was the worst disaster at sea in U.S. naval history.
It was also perhaps the U.S. Navy’s most shameful debacle. The stranded sailors died in many ways, all horrible: injury, hypothermia, saltwater poisoning, shark attack—even homicide, when men began slipping into hallucinatory madness, stabbing and drowning shipmates they mistook for enemies. But most of those deaths had the same ultimate cause: the Navy’s failure to notice the Indianapolis was overdue at its next port of call and its failure to investigate. No search party was dispatched; the survivors were rescued only after a passing plane spotted them. To deflect blame, the Navy court-martialed the ship’s captain, Charles McVay, for failing to elude the attack—the only U.S. captain court-martialed for losing a ship in the war. He later committed suicide. After a campaign to clear his name, McVay was exonerated in 2000, and the Indy survivors had something to celebrate at last: their story told truly.

1,000 mi
United
States
1,000 km
San Francisco
July 16, 1945
Departed carrying components and nuclear material for atomic bombs
N
Hawaii (U.S.)
July 19, 1945
Refueled
Pearl Harbor
PACIFIC
OCEAN
July 26, 1945
Delivered the cargo in record time, taking only 9 days to travel more than 5,000 miles
July 28, 1945
Departed for Leyte Gulf in the Philippines
Tinian
Guam
Philippine
Sea
July 30, 1945, 12:05 a.m.
Hit by two torpedoes from the Japanese submarine I-58, it sank in 12 minutes
August 2, 1945
Survivors were sighted by a patrol plane and rescue operations began. Only 317 men were saved out of a ship’s complement of 1,200.
Matthew W. Chwastyk, NGM Staff
Source: NAval History and Heritage Command, U.S. Navy

July 16, 1945
United
States
Departed carrying components and nuclear material for atomic bombs
Korea
San Francisco
PACIFIC
OCEAN
China
July 26, 1945
Delivered the cargo in record time, taking only 9 days to travel more than 5,000 miles
July 19, 1945
Refueled
Hawaii
(U.S.)
Philippine
Sea
Pearl
Harbor
Tinian
Guam
July 28, 1945
Departed for Leyte Gulf in the Philippines
July 30, 1945, 12:05 a.m.
Hit by two torpedoes from the Japanese submarine I-58, it sank in 12 minutes
1,000 mi
1,000 km
August 2, 1945
Survivors were sighted by a patrol plane and rescue operations began. Only 317 men were saved out of a ship’s complement of 1,200.
Matthew W. Chwastyk, NGM Staff
Source: NAval History and Heritage Command, U.S. Navy
The Indianapolis’s covert mission set the stage for the horrors the crew would face. The unescorted ship sped to its destination of Tinian carrying the components of the new secret weapon that U.S. commanders hoped would force Japan’s capitulation.