Captain
The captain of a ship at sea is in absolute command of that vessel even if higher-ranking persons are aboard. If higher-ranking persons give orders to the nautical captain, such persons are very careful to say what they want done rather than specifying how the orders are to be carried out, because even higher rank does not give them the right to interfere in how a captain runs the ship.
Onshore, a Harbourmaster, as the equivalent "chief" of a port, was sometimes titled "Captain" if he had merchant marine or naval rank and professional service in command at sea.
Within our own Colorado Rogues we also have a Madam of The House who is in charge of the House and all the assorted Colorado Rogues Guilds on the Island.
The officer who is ranked immediately below the Captain of a ship is designated the Chief Mate, or First Mate.
There are 2 types of Captains. Colorado Rogues Captains and Visiting Captains.