How many men died when the USS Indianapolis sank?

Of about 1,195 men aboard, an estimated 879 died and 316 survived, according to the U.S. Naval History and Heritage Command and the National WWII Museum. Roughly 300 died in the torpedo strike and sinking itself; most of the remaining losses occurred among the estimated 880-900 men who went into the water and were not rescued until August 2-3, 1945.

Did sharks really kill most of the men in the water?

No. While sharks were present and did attack some survivors, historians who have reviewed the record, including Seth Paridon, formerly of the National WWII Museum, in reporting by National Geographic and analysis in Naval History Magazine, conclude that most deaths came from blast wounds, dehydration, salt poisoning, exhaustion, and drowning, not shark bites. The "worst shark attack in history" framing largely traces back to the 1975 film Jaws rather than to survivor testimony.

Why wasn’t the USS Indianapolis reported missing sooner?

Two separate failures compounded each other. First, at least three Navy radio stations received SOS signals from the sinking ship but none acted on them, as documented by HistoryNet. Second, Navy procedure at the time did not require arrival reports for combatant warships, so no command was tracking whether Indianapolis had reached Leyte Gulf on schedule. The Navy's own court of inquiry found the Tacloban operations officer, Lieutenant Stuart Gibson, responsible for not flagging the ship as overdue, and he was formally reprimanded.

When and how was the wreck of the USS Indianapolis found?

On August 19, 2017, a search team funded by Microsoft co-founder Paul Allen, operating from the research vessel R/V Petrel, located the wreck about 5,500 meters (18,000 feet) deep in the Philippine Sea, as reported by USNI News. The team combined historical records with underwater search vehicles to pinpoint the site more than 72 years after the sinking.

USS Indianapolis: The Secret Mission and the Disaster That Followed

A secret atomic-bomb delivery, a torpedo attack, and a distress call three radio stations ignored, the real, verified story of the USS Indianapolis in July 1945.

A Secret Cargo Bound for Tinian

On July 16, 1945, USS Indianapolis left San Francisco's Hunters Point Naval Shipyard carrying a classified cargo: components for the "Little Boy" uranium bomb, including a large share of the world's available enriched uranium-235. A lead-lined cylinder was welded to the deck of the flag lieutenant's cabin and guarded around the clock; most of the roughly 1,195 men aboard had no idea what they were transporting, only that the mission was urgent.

The ship covered the run to Pearl Harbor and on to Tinian at a pace fast enough to set a record for the route, arriving on July 26, 1945. After the cargo was unloaded, Indianapolis sailed on to Guam and then set out, unescorted, for Leyte Gulf in the Philippines to join a training squadron ahead of the planned invasion of Japan. Eleven days after the delivery, on August 6, 1945, the components she had carried were used in the atomic bombing of Hiroshima.

Torpedoed Just After Midnight

Shortly after midnight on July 30, 1945, the Japanese submarine I-58, commanded by Mochitsura Hashimoto, fired a spread of six torpedoes at Indianapolis in the Philippine Sea. Two struck, one near the bow and one amidships, igniting a fuel tank and a powder magazine. The ship rolled over and sank in about twelve minutes, too fast for most life rafts to be launched and, according to later Navy findings, too fast to get a clean, complete distress signal off the air before power failed.

Roughly 300 men went down with the ship or died in the initial explosions. The remaining crew, some 880 to 900 men, went into the water with whatever life jackets, floater nets, and small rafts they could reach, not nearly enough for that many sailors to have on hand at once.

Four Days Adrift: What Actually Killed the Men

Popular culture, largely through the shark-attack monologue in the 1975 film *Jaws*, has fixed the Indianapolis story in the public mind as history's worst mass shark attack. The documented record is more complicated. Seth Paridon, a historian formerly with the National WWII Museum who has researched the sinking extensively, put it directly: "Did they eat some of the corpses? Absolutely. Did they bite some of the survivors? For sure ... but it wasn't to the degree that the myth makes it out to be." Some survivors, including the ship's senior medical officer, reported seeing few or no sharks at all during the ordeal, while others described repeated attacks, the experience clearly varied by location in the scattered, miles-long float of survivors.

Naval History Magazine's review of the record concludes that the majority of the roughly 580 men who died after entering the water were killed by wounds from the torpedo blasts, exhaustion, and above all severe dehydration and its effects, men who drank seawater developed hypernatremia (salt poisoning), suffered hallucinations, and in some documented cases drowned or attacked other sailors they mistook, in their delirium, for the enemy. Survivor Harlan Twible, a young officer who organized a group of men to keep them together and alive, recalled the psychological toll years later: "We tried to keep the men thinking that they would be saved, but there was no way in God's green earth that I knew we were gonna be saved." Rescue did not come until August 2, when a routine Navy patrol plane happened to spot the survivors by chance, not because anyone had realized the ship was overdue.

The Distress Call No One Answered

For decades the Navy's public position was that Indianapolis went down too fast to send any distress signal at all. Records declassified later showed that was not true: at least three radio stations picked up SOS transmissions from the sinking ship within roughly a half hour of the torpedo strike, and none acted on them. At the naval facility in Tacloban, radioman Clair Young received the message and personally delivered it to the senior officer present, Commodore Jacob Jacobson, whose recorded response was simply "no reply at this time." Aboard the harbor examination vessel LCI-1004, sailor Russell Hetz logged two SOS transmissions from Indianapolis roughly eight and a half minutes apart, but his crew judged it implausible that a heavy cruiser could sink that quickly and dismissed the calls as a possible Japanese deception. At a third station, seaman Don Allen said his commanding officer had left standing orders not to be disturbed; tugs were briefly sent to investigate on Allen's own initiative before being recalled.

Separately from the missed radio calls, standing Pacific Fleet procedure at the time held that arrival reports were not required for combatant warships, only for auxiliary and cargo vessels, so no one at the Philippine Sea Frontier command was tracking whether Indianapolis had actually reached Leyte on schedule. The Navy's own court of inquiry later found that Lieutenant Stuart B. Gibson, the operations officer at Tacloban's port director office, had failed to flag that Indianapolis was overdue and had not received a new movement report; he was formally reprimanded by Fleet Admiral Chester Nimitz. Captain Charles McVay, the ship's commanding officer, was court-martialed and convicted of failing to steer an evasive zigzag course, even though I-58's own commander, Hashimoto, testified that zigzagging would not have saved the ship. McVay was posthumously exonerated by a joint resolution of the U.S. Congress in October 2000, after a campaign that included research by a sixth-grade student, Hunter Scott.

Finding the Wreck, 72 Years Later

Indianapolis lay undiscovered for more than seven decades. On August 19, 2017, a team funded by Microsoft co-founder Paul Allen and operating from the research vessel R/V Petrel announced they had located the wreck roughly 5,500 meters (about 18,000 feet) down in the Philippine Sea, between Guam and Palau. The team used newly available historical records, including the position of the ship that had rescued survivors, which narrowed the likely sinking location, along with autonomous and remotely operated underwater vehicles to search the sea floor and confirm the find.