It's more than 40 years since one of Australia's worst naval disasters, the collision between HMAS Melbourne and an American warship, the USS Frank E. Evans. The training accident killed 74 American sailors. It also ruined the career of a promising Australian Navy captain. John Stevenson was court martialled, even though it was accepted widely then that as captain of HMAS Melbourne he'd done nothing wrong. Now the Australian Government has admitted for the first time that he was treated unfairly.