What is the title given to the commanding officer of a ship, regardless of their rank?

The title given to the commanding officer of a ship is "Captain," and this designation is used universally regardless of the officer's actual rank. In naval terminology, the term "Captain" refers to the officer who is in command of a vessel, which can include various ranks. For example, a Commander or even a Captain (in terms of rank) can serve as the commanding officer, but both would be referred to as the Captain of the ship.

Understanding this terminology is important, as it signifies the authority and responsibility that the individual holds over the ship's operations, crew, and mission. It also establishes a clear line of command, as sailors and other personnel onboard will refer to the commanding officer as Captain, fostering a sense of respect and order within the maritime environment.