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.