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GMDSS operational requirements
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General
The GMDSS enables a ship in distress to send an alert using various radio
systems. These systems are designed such that the alert has a very high probability of
being received by either shore rescue authorities and/or other vessels in the area.
Equipment performing GMDSS functions must be simple to operate and
(wherever appropriate) be designed for unattended operation.
Distress Alerts must be able to be initiated from the position from which
the ship is normally navigated (ie; the bridge).
EPIRBs are required to be installed close to, or capable of remote
activation from the position from which the ship is normally navigated.
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The SOLAS GMDSS regulations are structured such that all GMDSS ships are
required to carry a minimum set of equipment, with (basically) more equipment being
required the further the ship travels from land.
The SOLAS GMDSS regulations do not make particularly easy reading - a
simplified version of the equipment required to be carried for each sea area is detailed
below.
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GMDSS ships are required to carry the following minimum equipment:
A VHF radio installation capable of transmitting DSC on channel 70, and radiotelephony on channels 16,
13 and 6. (see Note 1). One SART if under 500 GRT, 2 SARTs if over 500 GRT. Two portable VHF transceivers for use in survival craft if under 500 GRT, three if over 500 GRT. A NAVTEX receiver, if the ship is engaged on voyages in any area where a NAVTEX service is provided. An Inmarsat EGC receiver, if the ship is engaged on voyages in any area of Inmarsat coverage where
MSI services are not provided by NAVTEX or HF NBDP (see note 2). A 406 MHz or 1.6 GHz EPIRB
Note 1 - Voice watch is effectively required on channel 16 until
further notice.
Note 2 - in practice, this means that all GMDSS A3 and A4
vessels are required to carry at least one Inmarsat C system.
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Every ship engaged on voyages exclusively in sea area A1 shall be provided
with the minimum equipment specified previously, with the option to replace the 406 EPIRB
with a VHF DSC EPIRB.
GMDSS VHF equipment
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Radio
equipment - Sea areas A1 and A2
Every ship engaged on voyages beyond sea area A1, but remaining within
sea area A2, shall be provided with the minimum equipment specified previously, plus:
Typical GMDSS A2 station
The ship shall, in addition, be capable of transmitting and receiving
general radiocommunications using radiotelephony or direct-printing telegraphy by:
A HF radio installation operating on working frequencies in the
(marine) bands between 1,605 kHz and 27,500 kHz. (This requirement is normally fulfilled
by the addition of this capability in the MF equipment referred to earlier).
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These vessels have two options to satisfy their GMDSS requirements. The
options allow a vessel to choose from the primary method to be used for ship-shore
alerting ;
Every ship engaged on voyages beyond sea areas A1 and A2, but remaining
within sea area A3 shall be provided with the minimum equipment specified previously,
plus either:
OR
An MF/HF radio installation capable of transmitting and receiving
on all distress and safety frequencies in the (marine) bands between 1,605 kHz and 27,500
kHz: using DSC, radiotelephony; and NBDP
An MF/HF DSC watchkeeping receiver capable of maintaining DSC
watch on 2,187.5 kHz, 8,414.5 kHz and on at least one of the distress and safety DSC
frequencies 4,207.5 kHz, 6,312 kHz, 12,577 kHz or 16,804.5 kHz; at any time, it shall be
possible to select any of these DSC distress and safety frequencies
A 406 MHz EPIRB
An Inmarsat ship earth station
Typical GMDSS A3 station
In addition, ships shall be capable of transmitting and receiving general
radiocommunications using radiotelephony or direct-printing telegraphy by an MF/HF radio
installation operating on working frequencies in the (marine) bands between 1,605 kHz and
27,500 kHz. This requirement is normally fulfilled by the addition of this capability in
the MF/HF equipment referred to earlier.
In practice, MF only transceivers are not
produced - all marine MF radio equipment is also fitted with HF facilities.
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In addition to carrying the equipment listed previously,
every ship engaged on voyages in all sea areas shall be provided with:
In addition, ships shall be capable of transmitting and receiving general
radiocommunications using radiotelephony or direct-printing telegraphy by an MF/HF radio
installation as described earlier.
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Confused ? Wait, there's more..!
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Means
of ensuring availability of ship station equipment
Regulation 15 of the SOLAS GMDSS regulations defines 3 methods to ensure
availability of GMDSS equipment at sea;
At sea electronic maintenance, requiring the carriage of a qualified
radio/electronic officer (holding a GMDSS First or Second class Radio-Electronics
Certificate) and adequate spares and manuals;
Duplication of certain equipment; or
Shore based maintenance
Ships engaged on voyages in sea areas A1 and A2 are required to use at
least one of the three maintenance methods outlined above, or a combination as may be
approved by their administration. Ships engaged on voyages in sea areas A3 and A4 are
required to use at least two of the methods outlined above.
And of course what all that means is that 99% of A3 GMDSS ships, along
with probably 100% of A1 and A2 GMDSS ships do not opt for at sea maintenance - they
either duplicate the equipment and use shore based maintenance (for A3 ships), or use
shore based maintenance only (A1 and A2 ships).
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Equipment
to be duplicated for area A3 vessels
GMDSS ships operating in A3 areas are required to provide the following
duplicated equipment;
Two complete VHF installations (including DSC), and either;
Two complete Inmarsat C systems and one MF radio system, or;
One complete Inmarsat C system and one complete MF/HF radio system
(including a scanning DSC receiver and NBDP equipment).
Many GMDSS ships opt for the latter option (1 Inmarsat C and
one MF/HF DSC system), on cost grounds. Unfortunately, this has proven to
be one of the underlying causes of the present extremely high false
alerting rate on some GMDSS systems.
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Power supply requirements
GMDSS equipment is required to be powered from three sources of supply:
ship's normal alternators/generators;
ship's emergency alternator/generator (if fitted); and
a dedicated radio battery supply.
The batteries are required to have a capacity to power the equipment for 1
hour on ships with an emergency generator, and 6 hours on ships not fitted with an
emergency generator.
The batteries must be charged by an automatic charger, which is also
required to be powered from the main and emergency generators.
Changeover from AC to battery supply must be automatic, and effected in
such a way that any any data held by the equipment is not corrupted (ie: "no
break").
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There are a number of different types of GMDSS qualifications, as follows:
First Class Radio-Electronic Certificate;
Second Class Radio-Electronic Certificate; and
GMDSS General Operator's Certificate
The First and Second Radio-Electronic Certificates are diploma and
associate diploma level technical qualifications. They are designed for Ship's
Radio-Electronic Officers, who sail on GMDSS ships which use the option of at-sea
electronic maintenance.
The GMDSS General Operator's Certificate is a non-technical operator
qualification, designed for Navigating Officers.
The GMDSS General Operator's Certificate is normally awarded after a ten
day course and examination.
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Continue to equipment requirements for Survival
Craft...
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Disclaimer: The equipment displayed on this page is provided solely
as representative samples.
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