If you saw Jaws

or read it, you will remember the harrowing story Quint (Robert Shaw) tells of surviving the sinking of the cruiser Indianapolis. It was on this date in 1945 that the ship, which had carried the Hiroshima atomic bomb, was torpedoed by the Japanese. According to the U.S. Navy:

The ship capsized and sank in twelve minutes. Survivors were spotted by a patrol aircraft on 2 August. All air and surface units capable of rescue operations were dispatched to the scene at once, and the surrounding waters were thoroughly searched for survivors. Upon completion of the day and night search on 8 August, 316 men were rescued out of the crew of 1,199.

Shark attacks began with sunrise of the first day and continued until the survivors were removed from the water almost five days later.

The Navy web site includes oral histories with Indianapolis Captain McVay and Japanese submarine Captain Hashimoto. The Discovery Channel has a wealth of material.

The site dedicated to the Indianapolis is perhaps the best source.