Prior to the development of the Global Maritime Distress and Safety System maritime radio communications depended on shipborne radiotelegraph and radiotelephone systems. The GMDSS was first developed by the International Maritime Organisation in the late 1960s. The IMO Convention on the Safety of Life at Sea, to which Ireland is a signatory, was amended to include the GMDSS and that amendment was implemented on a phased basis for merchant ships from 1 February 1992. Furthermore, two EU directives Council Directive 97/70/EC setting up a harmonised safety regime for fishing vessels of 24 metres in length or over and Council Directive 98/18/EC on safety rules and standards for passenger ships, in respect of newly built national passenger ships of 24 metres and above on domestic voyages, extended the provisions of chapter IV of the SOLAS Convention (GMDSS) to both classes of vessel.
In 1996 the report of the fishing vessel safety review group recommended that radio rules be introduced for all fishing vessels. These recommendations provided for the installation of GMDSS radio installations on board all fishing vessels, to a greater or lesser degree depending on the length of the vessel, and the operating area of each fishing vessel.
All of the fishing industry representative groups were represented on the review group and the recommendations of the group were implemented in Irish law by the Fishing Vessel (Radio Installations) Regulations, 1998 (S.I. No. 544 of 1998).
The GMDSS uses both terrestrial and satellite radio communication systems. It provides for electronic distress, urgency and safety alerting and radio watchkeeping. When a vessel needs to send a distress alert it can immediately transmit the identity of the vessel, the position of the vessel and the fact that the vessel is in distress, all at the push of a button.
This transmission can be made on very high frequency with a range of approximately 30 nautical miles, on medium frequency with a range of approximately 150 miles or on high frequency with a range of thousands of miles depending on the frequency band.
The GMDSS also requires ships to carry emergency position indicating radio beacons. These devices can be activated either manually or automatically. When activated the devices transmit the identity of the EPIRB/vessel and the COSPAS-SARSAT satellite system, through which the EPIRB operates, computes the position of the EPIRB. All of the information is then quickly and automatically routed to a marine rescue co-ordination centre. Ireland, in complying with the IMO SOLAS Convention, has installed GMDSS radio communications equipment at its coastguard radio stations for the reception of distress, urgency, safety and routine communications from ships of all flags within its waters.
It is recognised that there have been problems with the GMDSS, in particular the problem of the transmission of false distress alerts. However, it must be said that the serious efforts which have been made, and which continue to be made, are helping to reduce the number of such incidents.