( CNN ) -- Silent and shadowy , two hulks lie under the Gulf of Mexico 's warm waters , unmoved since their deadly encounter 72 years ago during World War II . Now , the future has come to take a closer look . From July 6 to 14 , the 211-foot research ship Exploration Vessel Nautilus conducted dives to the final resting places of the American steamer SS Robert E. Lee and the German U-boat U-166 , about 45 miles south of the Mississippi River delta . The Robert E. Lee was torpedoed by the U-166 while ferrying victims of other U-boat attacks from Trinidad to New Orleans . The sub succumbed to depth charges fired from an escort ship . These doomed ships are now separated by only two miles of seabed . The Nautilus is operated by the Ocean Exploration Trust , a research group founded in 2008 for the purpose of carrying out `` pure ocean exploration , '' according to the group 's website . The ship carries 17 permanent crew members and a rotating , 31-member Corps of Exploration composed of scientists , engineers and other special personnel . It also holds two remotely operated vehicles , Hercules and Argus , which collect data and samples from deep beneath the ocean 's surface . The purpose of the Nautilus ' mission to the twin shipwrecks was to perform forensic archeological documentation to more clearly understand their demises , said Ocean Exploration Trust spokeswoman Susan Poulton . By the time the team was finished , it had conducted high-resolution mapping of the area and created 3-D images of the wrecks . Assisted by the recent findings , archeologists have been able to supplement what they already knew about the attack , Poulton added . `` On July 30th , 1942 at 10:30 p.m. , a torpedo from U-166 hit the [ Robert E. Lee ] , which took about 15 minutes to sink . One officer , nine crewmen , and 15 passengers died as the vessel went down , '' according to an article on the Nautilus Live website . `` Once the torpedo was sighted , the passenger ship 's armed escort vessel , PC-566 , dropped several depth charges . ... those depth charges sank the U-boat with all hands . '' Fifty-two crew members went down with the U-boat , according to an article on the U.S. Coast Guard 's website . This sort of Nazi incursion into American waters was perhaps more ubiquitous than modern Americans believe . `` Historians say U-boats sank at least 50 American ships in the Gulf , one in the very mouth of the Mississippi River . Americans managed to sink only one U-boat in the Gulf of Mexico , '' said Poulton . The nature of these wrecks as war graves is not taken lightly by the researchers on the Nautilus , according to Poulton , who quoted the founder of the Ocean Exploration Trust , Robert Ballard , as saying , `` Many souls were lost on these wrecks and others , but now they are teeming with corals and undersea creatures . It 's the amazing tapestry of life . '' The Nautilus will continue its expedition in the Gulf by examining the effects of the Deepwater Horizon oil spill and is expected to complete its cruise in early October . The mission 's progress can be tracked live at the Nautilus Live website . Researchers in Hawaii find lost Japanese WWII megasub . Megayacht 's mission to uncover WWII battle cruiser 's final moments .
Two WWII shipwrecks lie two miles apart in the Gulf of Mexico . Two is a German U-boat that sank an American steamer . Nazis sank One German ships in the the Gulf of Mexico during the war . Exploration Vessel Nautilus conducted dives in July to learn more about 1942 incident .