World War II couldn’t destroy USS Independence. The light aircraft carrier survived three years of frantic combat in the Pacific Theater, where it weathered torpedo damage from enemy bombers and dueled with one of the Imperial Japanese Navy’s most fearsome warships. Neither could the atom bomb. The ship stayed afloat even after being pummeled by a pair of 21-kiloton atomic blasts while serving as a guinea pig during the Operation Crossroads nuclear tests. Now, it appears that even a long nap at the bottom of the Pacific Ocean was not enough to break Independence apart. According to a team from the National Oceanic and Atmospheric Administration, which recently surveyed the 11,000-ton carrier’s resting place off the coast of San Francisco, the vessel is still sitting upright and “amazingly intact” despite more than six decades at a depth of around 2,600 feet.
“After 64 years on the seafloor, Independence sits on the bottom as if ready to launch its planes,” NOAA scientist James Delgado said in a press release. “This ship fought a long, hard war in the Pacific and after the war was subjected to two atomic blasts that ripped through the ship. It is a reminder of the industrial might and skill of the ‘greatest generation’ that sent not only this ship, but their loved ones to war.”
Delgado, who also serves as maritime heritage director for NOAA’s Office of National Marine Sanctuaries, was the chief scientist on a recent mission that used an 18.5-foot underwater autonomous vehicle called Echo Ranger and three-dimensional sonar designed by Coda Octopus to chart Independence’s watery grave near California’s Farallon Islands. The images, captured as Echo Ranger swam 150 feet above the wreck, show the ship is still in surprisingly good condition even after being subjected to the shockwaves, heat and radiation of two atomic blasts. The carrier is listing slightly to starboard and has holes where its hangar bays once were, but large portions of its hull and flight deck are still intact. Images released by NOAA and Boeing, which built the Echo Ranger, even show what may be an airplane resting in one of the aircraft elevator hatches. “We imaged the same spot on that shipwreck multiple times,” Coda Octopus Technology President Blair Cunningham said in a video on the NOAA website. “That gives us very, very high definition.”
Nicknamed “The Mighty I,” Independence was the lead vessel in its class of aircraft carriers during World War II. After joining the U.S. Pacific fleet in 1943, it sustained severe damage from an enemy torpedo at the Battle of Tarawa and spent time in San Francisco undergoing repairs. It later participated in attacks against Japanese forces in the Philippines and at Okinawa, often acting as a nighttime reconnaissance and combat ship. Independence’s most famous action came at October 1944’s Battle of Leyte Gulf, where its nearly three-dozen aircraft had a hand in sinking Musashi, a Japanese battleship considered one of the most heavily-armed vessels of World War II.
After completing its tour of duty in late-1945, Independence got a front row seat to the beginning of the Atomic Age. It was one of more than 90 surplus and captured vessels assembled into a target fleet during Operation Crossroads, the United States’ famous atomic bomb tests at the Bikini Atoll in the South Pacific. On July 1, 1946, while dozens of reporters and scientists looked on, Independence and the rest of the dummy fleet were subjected to the punishing force of an airborne 21-kiloton blast. The carrier was only a half-mile away from the first detonation, which left part of the flight deck a smoldering hulk. Independence was then placed farther away from ground zero when a second test bomb—this time an underwater blast—ripped through the fleet on July 25.
The U.S.S. Independence was one of several ships that still remained afloat after the Bikini mushroom clouds had subsided. Shortly thereafter, the now-radioactive vessel was taken to Hunters Point Naval Shipyard in San Francisco, where scientists used it to study nuclear decontamination. The carrier was in danger of sinking, however, so in January 1951, the Navy towed it out to sea and scuttled it 30 miles off the coast of Half Moon Bay. Its exact location was unknown until 2009, when scientists confirmed that a blip on a U.S. Geological Survey sonar image was the famed aircraft carrier.
The Independence wreck site now sits within the Farallon Islands Radioactive Waste Dump, a swath of sea where the Navy deposited some 50,000 barrels of low-level radioactive waste between 1946 and 1970. The ship supposedly carried several barrels of waste when it was consigned to the deep, but the NOAA team says there is no reason to believe the hazardous cargo poses a threat to public safety. “Even if some of the radioactive materials ‘leaked’ or still ‘leak’ from the ship, this radioactivity will be diluted very quickly in the water reducing the concentration substantially,” UC Berkeley nuclear physicist Kai Vetter told Live Science. “In addition, the radiation emitted by the radioactive materials on the ship will not travel very far as the water is an excellent shield.”
The recent NOAA mission was part of a two-year effort to “locate, map and study” the estimated 300 shipwrecks that lie in the Gulf of the Farallones National Marine Sanctuary. “By using technology to create three-dimensional maps of the seafloor and wrecks like Independence, we can not only explore, but share what we’ve learned with the public and other scientists,” said Frank Cantelas, an archaeologist with NOAA’s Office of Ocean Exploration and Research. James Delgado said NOAA has no immediate plans to enter and explore the wreck firsthand, but he considers the carrier a vital piece of American history. “This ship is an evocative artifact of the dawn of the Atomic Age,” he told the San Jose Mercury News, “when we began to learn the nature of the genie we’d uncorked from the bottle.”