The steering part has long been automated. Captains are still on board ships to make decisions and to serve a management and diplomatic role. They're there to be the line-boss of the people repairing the engines and doing maintenance. They are the human responsible for port paperwork, and are in many ways the fall guys should something happen. They can fulfil both those roles because automation and that most of the paperwork and diplomacy can be done remotely though it still needs a human present for the important bits.
The Navigator used to be a position, and sometimes still nominally is, but it's now an officer position for management reasons and not because of a high degree of specialized skill.
The Navigator used to be a position, and sometimes still nominally is, but it's now an officer position for management reasons and not because of a high degree of specialized skill.