What flag is raised when a ship is leaving port?

When a ship is leaving port, the flag typically raised is the "Q" flag, also known as the Quebec flag, which is a blue and yellow flag. This flag indicates that the ship is requesting permission to enter port and is often used to signal that the vessel is ready for inspection by port authorities. Additionally, other flags may be flown to signify the ship's nationality or specific messages, but the Q flag is standard for departure.