For nearly 75 years, the circumstances surrounding the sinking of the U.S.S. Eagle PE-56, a World War II Navy ship, eluded historians and relatives of the lost sailors. Even its location was unknown.

This week, searchers announced that the missing warship had been discovered five miles off the coast of Maine and 300 feet beneath the surface of the Atlantic Ocean, in a rocky warren. 

A team of eight civilian divers found the wreckage of the ship, which the Navy had initially ruled was destroyed by a boiler explosion. But over five decades later, a historian convinced the Navy that the Eagle 56 was the last American warship sunk by a torpedo from a German submarine. 

The searchers grappled with 40-degree water temperatures and visibility as low as five feet while locating and surveying the ship’s wreckage, which is protected under federal law because it is a war grave. Forty-nine of the ship’s 62 crew members were killed.

“When you see a four-inch deck gun, you know you’re not dealing with a fishing boat,” said Ryan King, a member of the technical dive team that discovered the ship. 

The Eagle 56 sank on April 23, 1945, off the coast of Cape Elizabeth while towing a practice target for bombers from the nearby Naval Air Station Brunswick. The ship was part of a class of submarine chasers built by the Ford Motor Co. to combat German U-boats in World War I, but saw their first substantial action in World War II.