1. Maritime Safety Information Under the GMDSS

2. 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)

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

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

5. Navtex system MSI

6. 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)

7. 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.

11. Navtex Stations Worldwide
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12. 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

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

14. 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

15. ------------------------------------------------------------
ZCZC PB68
NETHERLANDS COASTGUARD GALE WARNING NR FEB DOVER THAMES – SOUTH OTHER DISTRICTS – NO WARNINGS
NNNN
ZCZC GL67
RIGMOVE. SOUTHERN NORTHSEA. “CHARLES ROWAN” AT 54-19N E CANCEL THIS MESSAGE Z FEB 25
NNNN
ZCZC GA20
ORKNEY ISLANDS
LOTHER ROCK RACON 58.44N 02.49W
TEMPORARILY OFF AIR
NNNN