Maritime Safety Information Under the GMDSS

Background The GMDSS makes specific requirements with regard to radio equipment, and ships must be able to carry out several different functions, one of which is the ability to TRANSMIT and RECEIVE Maritime Safety Information (MSI)

Maritime Safety Information (MSI) Navigational reports Meteorological reports Weather Forecasts Messages of General Importance

MSI is transmitted via the ff: NAVTEX Inmarsat EGC system Radio Telex (NBDP) Radio telephony (Safety Messages)

Navtex system MSI

The NAVTEX System Navtex system could reach up to a distance 600 nm offshore. 518 kHz is the International navtex frequency 24 Navtex stations in one NAVAREA The 24 stations are divided into 4 groups consisting of 6 transmitting stations. Every group is allowed one hour transmission time. (10mins/4 hours)

Navareas There are 16 Navareas worldwide. Navtex stations are geographically separated. Every Navtex station has its own identification character (A-Z). Navtex stations coverage is shown in the ITU “List of Radio Determination and Special Service Stations” The Navtex coordinator in each Navarea decides which MSI messages the system is to broadcast.

Navtex Stations Worldwide Click to play video

The Navtex Coordinator Coastguard Buoyage authority Electronic Navaids Offshore Operator Government dept. Ship reports NAVAREA co-ordinator National Coordinator Ice Monitoring meteorological offices Initial distress message SAR co-ordinator Navigational warning co-ordinator Meteorological message co-ordinator NAVTEX coordinator Transmitter

Building up a Navtex message ------------------------------------------------------------ ZCZC B1 B2 B3 B4 Message Origin ……. …………………….. NNNN -------------------------------------------------------------

The Subject Indicators (B2) A = Navigational Warnings (cannot be rejected by the receiver) B = Meteorological Warnings (cannot be rejected by the receiver) C = Ice Reports D = Search and Rescue information (cannot be rejected by the receiver) E = Meteorological Forecasts F = Pilot Service Messages G = DECCA Messages H = LORAN Messages I = OMEGA Messages J = SATNAV Messages K = Other Electronic Navaid Messages (messages concerning radio navigation services) L = Navigational Warnings for mobile drilling rig movements (cannot be rejected by the receiver) V = Amplifying navigational warning information initially announced under “A” Z = No messages on hand

------------------------------------------------------------ ZCZC PB68 NETHERLANDS COASTGUARD GALE WARNING NR. 55 180630 FEB DOVER THAMES – SOUTH 8 OTHER DISTRICTS – NO WARNINGS NNNN ------------------------------------------------------------- ------------------------------------------------------------ ZCZC GL67 RIGMOVE. SOUTHERN NORTHSEA. “CHARLES ROWAN” AT 54-19N 02-07.7E CANCEL THIS MESSAGE 121020 Z FEB 25 NNNN ------------------------------------------------------------- ------------------------------------------------------------ ZCZC GA20 ORKNEY ISLANDS LOTHER ROCK RACON 58.44N 02.49W TEMPORARILY OFF AIR NNNN -------------------------------------------------------------