Ship or submarine captains command the operations of a ship or submarine and its crew. They implement orders by planning exercises and maneuvers to carry out missions. Captains direct daily operations and plan tactics. As part of a naval staff, they direct the planning of fleet operations exercises.
Executive/Staff officers are second in command on a ship or submarine. They issue orders and instructions to assist the ship’s captain and command the vessel in the captain’s absence. They also manage administrative and maintenance activities.
Department heads manage major functional areas on a ship such as engineering, navigation/operations, or combat systems. They plan and coordinate the department’s activities and conduct drills to evaluate the department’s performance in emergency or combat situations. They also train new officers in seamanship and leadership.
Ship and submarine officers usually begin their careers as division officers on vessels. They command a division of 10 to 50 Sailors, stand watches in a variety of functional areas, and plan work schedules.