USS Indianapolis Shark Attack: The Deadliest Shark Encounter in History

The USS Indianapolis shark attack is one of the most terrifying survival stories in military history. In the summer of 1945, nearly 900 American sailors were thrown into the pitch-black Pacific Ocean. What followed was four days of unimaginable horror. Sharks circled constantly. Men went mad from thirst. And nobody came to rescue them. The world didn’t even know they were missing.

It started just after midnight on July 30, 1945. A Japanese submarine fired two torpedoes into the USS Indianapolis. The first ripped off the ship’s starboard bow. The second ignited 3,500 gallons of aviation fuel. The explosions split the ship in two. The vessel sank in just 12 minutes , still traveling at 17 knots. Around 900 men made it into the water. They had almost no lifeboats. Many had no life jackets at all.

The ship had just delivered components for the atomic bomb dropped on Hiroshima. That mission was so secret that almost nobody knew where the Indianapolis was headed. And that secrecy would cost hundreds of men their lives.

According to historical records, three separate stations received the ship’s distress signals , and none of them acted. One commander was drunk. Another had ordered his men not to disturb him. A third thought the signal was a Japanese trap. So the men floated. And the sharks came.

The USS Indianapolis Shark Attack: What the Survivors Saw

The sharks arrived almost immediately. Survivor Loel Cox described the experience in chilling detail. “We were losing three or four each night and day,” he recalled. “You were constantly in fear because you’d see ’em all the time. Every few minutes you’d see their fins , a dozen to two dozen fins in the water.”

The primary killers were oceanic whitetip sharks. These open-ocean predators are among the most dangerous sharks on Earth. They don’t need to be provoked. They are bold, persistent, and relentless. Tiger sharks also joined the feeding. Survivor testimonies describe both large, powerful sharks and smaller, faster ones that bit repeatedly without retreating.

Boatswain’s Mate Eugene Morgan witnessed something almost impossible to believe. “We had a cargo net that had Styrofoam things attached to keep it afloat,” he testified. “There were about 15 sailors on this, and suddenly, 10 sharks hit it and there was nothing left.”

Ensign Twible tried to organize “shark watches.” He kept men clustered together. Larger groups had a better chance. Sailors would beat and kick at the fins to drive them away. It worked , sometimes. But exhaustion wore men down. Those who drifted from the group were often taken.

The sharks weren’t the only killer. Survivor Dick Thelen described men gulping saltwater out of desperation. “Within two hours foam comes to your mouth, your eyeballs pop out, you’re totally insane,” he said. Hallucinations spread through the groups. Men fought each other. Some swam toward imaginary islands. Others simply slipped beneath the surface and didn’t come back up.

Four Days of Terror: The USS Indianapolis Shark Attack Timeline

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The men were not discovered for four agonizing days. On August 2, a passing U.S. naval aircraft spotted the survivors by accident. The pilot had no idea what he was looking at. He radioed for help immediately. By then, of the roughly 900 men who entered the water, only 316 were still alive.

The National Park Service notes that the Indianapolis now rests three miles below the ocean surface. It is the Navy’s deepest confirmed shipwreck. The wreck was only located in 2017, after naval historian Dr. Richard Hulver identified a landing craft that had spotted the ship the night it went down. That clue narrowed the search to a 600-square-mile section of open ocean.

The wreck site is now protected under the Sunken Military Craft Act. It is considered a war grave. The ship’s incredible preservation three miles down offers researchers a rare chance to study the sinking in detail. For decades, the only accounts came from survivor testimonies. Now the wreckage can corroborate those stories.

The exact number of men killed by sharks remains unknown. Some survivors never saw a single shark. Others watched their friends disappear in explosions of blood and foam. The National WWII Museum acknowledges the uncertainty. The popular image of hundreds of men being devoured is almost certainly an exaggeration , but the reality was still catastrophic.

The Science Behind the USS Indianapolis Shark Attack

Modern science has added new weight to the survivor testimonies. In April 2025, a peer-reviewed study published in Frontiers in Fish Science documented something remarkable. Researchers observed at least nine oceanic whitetip sharks and five tiger sharks simultaneously scavenging the same carcass off Kailua-Kona, Hawaii. The two species showed no aggression toward each other. They simply fed together.

These are the exact two species implicated in the Indianapolis disaster. The study suggests that both species could have co-fed on victims in the water without conflict. It paints a deeply unsettling picture of what those four days must have looked like from below the surface.

The Florida Museum of Natural History identifies oceanic whitetips as responsible for numerous unrecorded human fatalities. They are most dangerous in exactly the conditions the Indianapolis survivors faced , open ocean, no land nearby, victims unable to leave the water.

The sharks were doing what sharks do. They had no malice. But for the men floating in the Pacific, that made it no less terrifying.

The Cover-Up and the Captain’s Fate

The aftermath of the sinking carried its own dark chapter. Captain Charles McVay III survived the disaster. He was then court-martialed for failing to order a timely abandon-ship order. Incredibly, the Navy called the Japanese submarine commander who sank his ship as a witness against him.

McVay was convicted. The Navy later suspended his sentence. But hate mail from grieving families haunted him for decades. In 1968, he took his own life. He was found holding a toy sailor in his hand.

In 2000, Congress passed a resolution exonerating McVay. The Navy officially amended his record. But for many survivors, justice came far too late. The men who floated in shark-infested waters for four days deserved better. Their captain deserved better. The USS Indianapolis shark attack remains a wound in American military history , one that has never fully healed.