SafetyNET and Reception of Maritime Safety Information
What the exam tests here
MSI is the GMDSS broadcast of navigational and meteorological warnings, forecasts and SAR information. It reaches ships by NAVTEX in coastal waters, by SafetyNET (Inmarsat Enhanced Group Call) in ocean areas, and by VHF/MF broadcasts from coast stations in A1 and A2. The exam tests the choice of system and the correct receiver settings.
How SafetyNET works
SafetyNET uses the Enhanced Group Call facility of Inmarsat. Messages are addressed either to a fixed geographic area (a NAVAREA or METAREA, or a circular area defined by a centre point and radius) or to a group of ships. Priority levels are distress, urgency, safety and routine. Receivers print the message automatically and store it. An EGC-only receiver can be fitted where full Inmarsat-C is not carried, but the terminal must still be logged in to the correct ocean region.
Navareas and metareas
NAVAREA VIII is coordinated by India (National Hydrographic Office, Dehradun) and METAREA VIII by the India Meteorological Department. A ship must know which navarea she is in so that she can check that she is receiving the correct broadcasts, and must log in to the ocean region covering her position.
Operator checks
- Confirm the terminal is logged in to the correct ocean region.
- Confirm the correct navareas and metareas are selected.
- Confirm GPS position input is live.
- Read and file received MSI; do not simply leave it unread on the printer.
Worked example
A vessel sails from the Indian Ocean into the Pacific. The Inmarsat-C has been logged in to the Indian Ocean region; shortly after the boundary the printer goes quiet. The cause is the ocean region, not a faulty printer: re-select the Pacific region and confirm log-in, then check that the new navarea's broadcasts are arriving.
Traps
- Assuming NAVTEX and SafetyNET are alternatives everywhere; they cover different areas.
- Leaving the terminal logged in to the wrong region so MSI and shore-to-ship alerts are missed.
- Not reading the MSI that is printed, which is an inspection finding as well as a safety risk.