(CNN)The USS Eagle PE-56 was supporting Navy training exercises off the coast of Maine when an explosion tore it in half in April 1945.
Only 13 people survived, and 49 officers and crew members went down with the ship.
For 75 years, no one knew exactly where the submarine hunter -- and its crew -- rested at the bottom of the ocean.
But in June 2018, a team of eight wreck divers working with the Smithsonian Channel finally located it about six miles from Maine's shore.
The group of divers, known as the Nomad Exploration Team, spent four years searching for the wreck until they stumbled upon it with the help of sonar technology from Garry Kozak.
"When we found her initially and found subsequent pieces later on, we were just in absolute awe and there was an incredible amount of respect for the sailors who are still entombed with the Eagle 56," Ryan King, one of the divers, told CNN.
The wreckage sits more than 250 feet below the surface, King said.
The ship's steel plating is starting to rust away, but the site has been designated a war grave "and has all the protections associated with that," King said.
Finding the shipwreck was a challenge: Diving off the coast of Maine means that it's cold and visibility is often less than 20 feet.
"It's not a wreck that's in shallow waters. It's significantly deeper than recreational diving," King said. "Decompression on these dives will last 1.5 to 2 hours, sometimes longer."
The sinking was originally thought to be an accident
The USS Eagle PE-56 was the last American warship sunk off the East Coast during World War II, according to the Smithsonian Channel.
The US Navy originally dubbed the April 23, 1945, sinking an accident from a boiler explosion, but many survivors reported seeing a Nazi U-boat at the time.
Naval historian Paul Lawton and archivist Bernard Cavalcante's research proved the initial assessment inaccurate, and in 2003, the Navy reclassified the sinking as a combat loss. It also recommended that Purple Hearts be awarded to the 49 dead and 12 survivors. The reclassification made the USS Eagle PE-56 the Navy's largest single combat loss in New England waters.