Maritime Training

1. Global Maritime Distress
and Safety System
(GMDSS)

2. Basic Concept of the GMDSS
The fundamental difference between the old
and the new distress system is that the new
system is shore centred/coordinated and
moves emphasis from ship to ship alerting
to ship to shore alerting. The new system is
quicker, simpler and, most importantly, more
efficient and reliable than the old manual Morse
Code and radiotelephone alerting system.
GMDSS is specifically designed to automate a
ship’s radio distress alerting function, and
consequently, remove the requirement for
manual (human) watch-keeping on distress
channels.

3. The basic concept of the system is that
search and rescue authorities ashore, as well
as shipping in the immediate vicinity of the
ship in distress, will be rapidly and
automatically alerted to a distress situation so
that they can assist in a co-coordinated SAR
operation with minimum delay. The system
also provides for urgency and safety
communications, and the promulgation of
maritime safety information (MSI) including-
navigational and meteorological warnings and
forecasts, and other urgent safety information
to ships. In other words, every ship, fitted
appropriately for GMDSS, is able, irrespective
of the area in which it operates, to perform
those communication functions, which are
essential for the safety of the ship itself and
of other ships operating in the same area.

4. Before

5. Now

6. Now

7. The GMDSS Equipment

8. Rescue
co-ordination
centre
Coast
earth
station
Local user
terminal/mission
control centre
Rescue
co-ordination
centre
Coast
station
HF, MF, VHF
Coast
station
HF, MF, VHF
National/international
networks
INMARSAT COSPAS
SARSAT
National/international
networks
General radiocommunications
e.g. medical advice, VTS,
ship reporting etc. Navigational
warnings
Meteorological
warnings
SAR
information
Maritime safety information (MSI)
www.jojoeland.com

9. Functional requirements
 The GMDSS regulations (chapter IV
of the International SOLAS
Convention), require that every
GMDSS equipped ship shall be
capable of;

10. 1. Distress alerting – Ship to shore
 EPIRB
 Digital Selective Calling (DSC)
 INMARSAT

11. 2. Distress alerting – Shore to ship

12. 3. Distress alerting – Ship to ship

13. 4. Search and Rescue Co-ordinating
Communications

14. 5. On-Scene Communication

15. 6. Locating

16. 7. Transmission/Reception of Maritime
Safety Information

17. 8. General Radiocommunications

18. 9. Bridge-to-Bridge Communications

19. Application
The GMDSS applies to vessels subject
to the SOLAS Convention - that is:
 Commercial vessels of 300 Gross
Registered Tons (GRT) and above,
engaged on international voyages.
 The GMDSS became mandatory
for such vessels
as at February 1, 1999.

20. 1 February 1992 – ships may comply with
the GMDSS requirements
1 August 1993 – ships must comply
with satellite EPIRB and NAVTEX
requirements
1 February 1995 – ships built on or
after this date must fully comply with
the GMDSS requirements
1 February 1999 – ships must
comply with the GMDSS
requirements

21. Equipment vs Operational
requirements
 The major difference between the
GMDSS and its predecessor systems
is that the radio communications
equipment to be fitted to a
GMDSS ship is determined by the
ship's area of operation, rather
than by its size.

22.  Because the various radio systems
used in the GMDSS have different
limitations with regards to range and
services provided, the new system
divides the world's oceans into 4
areas:
 Sea Area 1
 Sea Area 2
 Sea Area 3
 Sea Area 4

23. GMDSS Sea Area 1
 This area of GMDSS is within the
radiotelephone coverage of at least
one VHF coast station in which
continuous DSC alerting is available.
Such area could extend typically 30
– 50 nautical miles from the coast
station.

25. GMDSS Sea Area 2
 This area of GMDSS is an area
excluding sea area A1, within the
radiotelephone coverage of at least
one MF coast station in which
continuous DSC alerting is available.
Such area could extend typically
about 50 – 400 nautical miles from
the coast station

27. GMDSS Sea Area 3
 This area of GMDSS is an area
excluding sea area A1 and A2, within
the radiotelephone coverage of at
least one HF coast station in which
continuous DSC alerting is available.
This area lies between about
latitudes 70º North and South.

29. GMDSS Sea Area 4
 This area of GMDSS is an area
outside sea area A1, A2 and A3.