( CNN ) -- A World War II German U-boat , sunk during the Battle of the Atlantic more than 72 years ago , has been discovered off the coast of North Carolina , the National Oceanic and Atmospheric Administration announced Tuesday . The German sub , the U-576 , was found at the bottom of the Atlantic 30 miles off Cape Hatteras and just 240 yards from an American merchant ship , the merchant tanker Bluefields , which was part of a 24-ship U.S. convoy heading from Virginia to Key West , Florida , on July 14 , 1942 . `` This is not just the discovery of a single shipwreck , '' said Joe Hoyt , chief scientist of NOAA 's Office of Marine Sanctuaries expedition , which found the vessels . `` We have discovered an important battle site that is part of the Battle of the Atlantic . These two ships rest only a few hundred yards apart and together help us interpret and share their forgotten stories . '' The story of U-576 is the more tragic of the two wrecks . Bluefields did not sustain any casualties during the sinking , but all 45 crew of the U-boat were lost . Commanding U-576 that July day was Kapitanleutnant Hans-Dieter Heinicke . According to documents from the Monitor National Marine Sanctuary , where the wrecks rest , Heinicke had radioed back to commanders in occupied France on July 13 to say the U-boat was damaged and heading back to Germany after a month-long patrol without success against Allied shipping . A U-boat and its American prey haunt Gulf of Mexico . As U-576 began that journey home , it ran across convoy KS-520 , with 19 merchant vessels and five escorts , on the afternoon of July 14 , according to the documents . Heinicke , who was on his fifth U-boat patrol with relatively little success against Allied shipping , saw a chance for redemption . `` In spite of his damaged ship , Heinicke decided to attack at all costs , '' a history from the sanctuary reads . `` However , at 4:00 pm just before he could fire his torpedoes , one of the Coast Guard cutters picked up a sonar contact . The Coast Guard crew dropped three depth charges , followed by five more 10 minutes later . '' But Heinicke pressed his attack , firing off four torpedoes about 4:15 p.m. `` The U-576 sank the Nicaraguan-flagged freighter Bluefields and severely damaged two other ships . In response , U.S. Navy Kingfisher aircraft , which provided the convoy 's air cover , bombed U-576 while the merchant ship Unicoi attacked it with its deck gun , '' the NOAA release reads . The sub sank in minutes . Two NOAA research vessels , the Okeanos Explorer and SRVX Sand Tiger , participated in the search for the wrecks , which were found and verified in August , NOAA said . The wreck site is considered a war grave and protected by international law . `` Few people realize how close the war actually came to America 's shores , '' David Alberg , superintendent of NOAA 's Monitor National Marine Sanctuary , said in a statement . `` As we learn more about the underwater battlefield , Bluefields and U-576 will provide additional insight into a relatively little-known chapter in American history . '' Zeroing in on what caused Civil War submarine 's sinking .
German U-576 attacked convoy off Cape Hatteras in 1942 . U-boat sank tanker Bluefields , but was sunk by Allied planes , ship . The USS Indianapolis ( or the ) was a battleship that served during World War II and later became an aircraft carrier.