GMDSS — Mandatory marine safety communications

Updated 11 Oct 2019

Ship radio 75nhfhc2j

Regardless of whether or not a ship makes use of modern communications infrastructure and equipment for commercial and welfare reasons, it is obliged to do so for safety purposes under GMDSS (Global Maritime Distress and Safety System) which began in 1992.

Although it did not entirely replace radio, GMDSS was aimed at putting satellite technology at the heart of the safety communications system for maritime users. The advent of GMDSS saw a major change in the way all communications including commercial messages were handled on ships. It also ensured the demise of the dedicated radio officer.

Today, the GMDSS infrastructure and system is undergoing its first restructuring and, although the changes may not all be in place in the immediate future, the changes will see an initial opening-up of the allowed means of communication to new service providers.

Although probably responsible for saving many lives, the maritime communication system that existed prior to GMDSS suffered from a multitude of limitations. GMDSS is an international system that uses land-based and satellite technology and ship-board radio-systems to ensure rapid and automated alerting of shore-based communication and rescue authorities, in addition to ships in the immediate vicinity, in the event of a marine distress.

It was adopted by the IMO by way of amendments to SOLAS 1974 Chapter IV in 1988 and entered into force on 1 February 1992 with a phase-in period running until 1 February 1999, depending on ship type and size. With the phase-in period now well past, all ships are now subject to the full GMDSS carriage and maintenance requirements, which vary depending on ship type and area of operation.

A comprehensive review of GMDSS began in 2012 and in March 2016 at the Navigation, Communications and Search and Rescue sub-committee’s third meeting (NCSR 3) it was recommended that an agreed two-year modernisation plan should be got underway with a completion date in 2018. That was a year later than the initial date when the review was initiated and at the time of writing, in October 2019, that plan has still not been completed.

The outcome of the plan will feed into the review, which will require changes to Chapters VI and V of SOLAS. This will also take time and it is now expected that it will be 2024 before all the changes come into effect. One change, which is not directly linked to the review, is the ending of the Inmarsat monopoly and the recognition of Iridium as an approved satellite service provider. Currently there are no planned changes to the overall carriage requirements of GMDSS but that is no guarantee for the long term.

The integration of communication and navigation equipment that is being considered as part of the e-navigation project is seen as being desirable but with numerous hurdles to overcome. The e-navigation concept itself is still somewhat nebulous and its development direction is still unclear; in recent years the emphasis has been more on emissions reduction than safety related issues.

The GMDSS review has been wide ranging and has looked at existing and emerging technologies that could be incorporated into the system. As an example, the review has looked at the possible role of Automatic Identification System (AIS) in all its forms and emerging VHF Data Exchange System (VDES) technology. Bringing in these two services effectively links a future GMDSS with e-navigation but precisely how and to what extent remains to be seen.

A draft Modernization Plan of the GMDSS was completed at NCSR 4 in March 2017 and submitted to the MSC for approval. The aim is to eventually adopt a revised and updated SOLAS chapter IV, enabling the use of modern communication systems in GMDSS, while removing the requirement to carry obsolete systems, at the same time maintaining the requirements for ships to carry specified terrestrial and satellite radiocommunications equipment for sending and receiving distress alerts and maritime safety information, as well as for other communications.

Nothing in the plan at the moment will add to the carriage requirements but it will provide for the introduction of new services and systems, such as other terrestrial communications using digital technologies for broadcasting maritime safety and security-related information from shore-to-ship, and for enhanced and more reliable search and rescue capabilities by, for example, including the Cospas-Sarsat MEOSAR system.

The plan also proposes the review of related regulations in other SOLAS chapters, including SOLAS chapter III (life-saving appliances), particularly in relation to search and rescue transponders, and the incorporation of maritime security communications in SOLAS chapter IV. Because of the reach of GMDSS through SOLAS, other areas will also be affected. For example, as the means of permitted communication expands, so will the complexity and the training needed for operators to ensure mistakes are not made.

The scope of GMDSS and how it operates in practice even in its present form is vast and warrants a complete book in itself in the shape of the IMO-published GMDSS Manual. In this ShipInsight guide, only the basics and the equipment carriage and maintenance aspects are covered.

Under GMDSS, all oceangoing passenger ships and cargo ships of 300gt and above engaged on international voyages must be equipped with radio equipment and other communications equipment that conforms to international standards. A survey of GMDSS equipment is needed at regular intervals for the ship to be issued with and retain a valid Safety Radio Certificate. Surveys of radio installation on SOLAS ships should be carried out in accordance with the rules laid down in IMO Res. A.746(18) Survey Guidelines under the harmonised system of survey and certification R 8 (adopted by IMO), and SOLAS 1974 as amended, chapter I, part B.

The radio survey should always be performed by a fully-qualified radio surveyor who has adequate knowledge of the IMO’s relevant conventions and associated performance standards and appropriate ITU Radio Regulations. It is considered as very important that the responsible radio operators are properly instructed and trained in how to use the GMDSS radio equipment. The radio licence and certificate for the radio operator/operators should be checked during the survey.

Related Articles

Updated 11 Oct 2019


The Journal

Published every February the journal is now recognised as the highest quality publication that covers all aspects of maritime technology and regulation and a must read for the industry.

More Details