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

The USS Grayback has finally been found. It was hidden from discovery all this time by a single errant digit.

The mystery began on 28 January 1944, when the Grayback, one of the most successful American submarines of the Second World War, sailed out of Pearl Harbour for its 10th combat patrol.

By late March, it was more than three weeks overdue to return, and the US Navy listed the submarine as missing and presumed lost