A 75-year-old mystery has been solved, and the families of 80 American sailors lost at sea will now have closure: the U.S.S. Grayback has finally been found.

It was hidden from discovery all this time by a single errant digit.

The mystery began on Jan. 28, 1944, when the Grayback, one of the most successful American submarines of World War II, sailed out of Pearl Harbor for its 10th combat patrol. By late March it was more than three weeks overdue to return, and the Navy listed the submarine as missing and presumed lost.

After the war, the Navy tried to piece together a comprehensive history of the 52 submarines it had lost. The history, issued in 1949, gave approximate locations of where each submarine had disappeared.

The Grayback was thought to have gone down in the open ocean 100 miles east-southeast of Okinawa. But the Navy had unknowingly relied on a flawed translation of Japanese war records that got one digit wrong in the latitude and longitude of the spot where the Grayback had probably met its end.