Which operational code refers to coming alongside while underway?

The operational code that refers to coming alongside while underway is indeed ROMEO. This signal is significant in maritime operations, particularly when vessels need to communicate intentions regarding maneuvering and formation changes. The ROMEO flag is used to indicate that a ship is bringing another vessel alongside, often for purposes such as refueling, transferring personnel, or cargo operations while both ships are moving. This operational code is critical for ensuring safe and effective coordination between vessels in such maneuvers, as it helps prevent misunderstandings during complex operations at sea.

In contrast, the other codes serve different purposes. FIVE does not pertain to underway operations, while FOXTROT is used for indicating port and starboard vessel alignment. KILO, on the other hand, generally refers to a specific operational situation that does not involve coming alongside. Understanding these distinctions helps clarify the roles that each operational code plays in maritime communication and navigation.