Two torpedoes combined to sink the Indianapolis in 12 minutes. 883, about a fourth of the 1,196 men on board, died in the attack. The rest of the crew, nearly all without lifeboats, floated in the water until the rescue was completed five days later. The resue came after they were spotted by pilot Lt. Wilber (Chuck) Gwinn and copilot Lt. Warren Colwell. They suffered from lack of food and water, but the worst hazard came from constant shark attacks. Only 316 men survived. 
Captain Charles Butler McVay III survived. In November, 1945, he was court-martialed and convicted of "hazarding his ship by failing to zigzag." Several circumstances of the court-martial were controversial: there was overwhelming evidence that the Navy itself had placed the ship in harm's way, the Japanese submarine commander (brought to the trial from the recently-conquered country of Japan) testified that zigzagging would have made no difference , and although 700 navy ships were lost in combat in World War II, McVay was the only captain to be court-martialed. 
Just over fifty years after the tragedy, Hunter Scott (12 years old at the time) was instrumental in raising awareness of the miscarriage of justice carried out at the captain's court-martial. Source: Detroit News, April 23, 1998
In October of 2000 Congress passed a resolution that Captain McVay's record should reflect that "he is exonerated for the loss of the USS Indianapolis." President Clinton also signed the resolution. 
See USS Indianapolis for other Navy ships of the same name.