What does the "Third Substitute" flag signify?

The "Third Substitute" flag signifies the absence of the Commanding Officer. In naval flag signaling, specific flags are used to convey important operational messages, and this flag is specifically designated to inform the crew and other vessels that the commanding officer is not present on board. This communication enables the ship's crew and other vessels in the vicinity to understand the chain of command and operational readiness of the ship. Understanding this signaling is crucial for maintaining effective communication and ensuring appropriate procedures are followed in the absence of key leadership. This helps in preserving order and maintaining safety aboard the vessel.