Maritime Safety Information: NAVTEX, EGC/SafetyNET and Reception
What MSI covers
Maritime Safety Information includes navigational warnings, meteorological warnings and forecasts, search and rescue information, and other urgent safety information. The GMDSS requires a vessel to be able to receive MSI throughout its voyage. The two main delivery systems are NAVTEX on MF and EGC/SafetyNET via Inmarsat.
NAVTEX
NAVTEX transmits on 518 kHz in English using narrow-band direct printing, with a range of roughly 200 to 400 nautical miles. Each message carries a station identifier, a message type (such as navigational warning or meteorological warning), and a serial number. Receivers can be programmed to reject certain message types or stations. A common trap is thinking NAVTEX covers all sea areas; it is coastal and does not reach mid-ocean. Another is confusing the message-type codes and their priorities.
EGC/SafetyNET
EGC allows messages to be addressed to specific geographic areas or to all ships, and is used for MSI in areas beyond NAVTEX coverage, including A3 and A4 where satellite coverage exists. SafetyNET is the Inmarsat service for this. Traps include assuming EGC requires a NAVTEX receiver, or that EGC is available in A4 where Inmarsat does not reach.
Reception and records
Operators should ensure the MSI receiver is switched on, correctly programmed and monitored, and that received warnings are logged and acted upon. Some messages are mandatory and cannot be rejected.
Worked example
A vessel crossing the Atlantic in A3 with an Inmarsat terminal and no NAVTEX coverage relies on EGC/SafetyNET for weather and navigational warnings. A coastal vessel in A1 may rely on NAVTEX alone, provided it can receive the relevant stations.