Which SELCAL number type is typically used by a ship station?

The SELCAL number type typically used by a ship station is a 5 digit SELCAL. This system allows for the identification of a ship by a unique code that consists of five letters, each representing a specific combination of signals that can be sent and decoded.

5 digit SELCAL codes are specifically designed to facilitate the process of alerting a ship station to a communication from an aircraft or a shore station, ensuring efficient communication at sea.

The use of a 7 digit SELCAL, while it could theoretically exist, is not recognized in standard maritime practices. A 9 digit SELCAL code, which you mentioned, is identical to the Maritime Mobile Service Identity (MMSI), and this level of code is not used specifically for SELCAL communications. Similarly, a 4 digit SELCAL would be insufficient to support the requirements of identifying ships accurately in seafaring operations.

Understanding these distinctions is vital for effective communication and safety in maritime operations, as the correct identification method plays a crucial role in operational readiness and emergency responses.