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What is GMDSS?

The Global Maritime Distress and Safety System (GMDSS) has achieved major improvements in maritime safety and communications. GMDSS is an automated ship to shore distress alerting system that relies on satellite and advanced terrestrial communications links. The system also provides some limited ship to ship communications capabilities, as well as items specific to Search & Rescue activities such as EPIRBs and SARTs.  

Every ship subject to the communications act or the safety convention must comply with GMDSS. These vessels include:

  • All passenger ships regardless of size

  • Cargo ships of 300 gross tons and upward

For more information about the GMDSS=>                 FCC-GMDSS=>     
Marine Equipment Directive=>                        International Maritime Organization=>

GMDSS is a system based on the linking of Search and Rescue (SAR) authorities ashore with shipping in the immediate vicinity of a vessel in distress or in need of assistance. The primary purpose of GMDSS is to automate and improve emergency communications for the world's shipping industry. GMDSS uses a number of frequencies, modes and systems to accomplish this mission. The Global Marine Distress and Safety System (GMDSS) uses both satellite and terrestrial radio systems because each system has its own individual limitations with respect to geographical coverage and services it can provide.

The Basic concept of GMDSS is to alert SAR authorities ashore and vessels in the vicinity of a distress so they can assist in a coordinated search and rescue operation with minimum delay. EPIRBs and other radio systems are used to 'raise the alarm' in an emergency, and some EPIRBs also provide approximate location information. SARTs, on the other hand, greatly improve the ease and speed of locating and rescuing the survivors, by displaying an Internationally recognized signature on the radar screens of passing vessels or aircraft. No specialist equipment needs to be carried by the receiving craft, so any passing vessels or aircraft will be able to react to the SART's signal, reducing the all-important time-to-rescue dramatically.

GMDSS rules state that all registered vessels above 300 gross tonnes must carry at least one SART, and those above 500 gross tonnes at least two SARTs.

SARTs have proved themselves invaluable in rapidly locating survivors so much so that SOLAS requirements now specify SARTs to also be fitted to life-rafts in Ro-Ro ferries from July 2004. The new legislation calls for a SART to be fitted to one in every four liferafts, but it is anticipated that in due course this will be extended to include every liferaft (after all, which liferaft would you want to be in?)

The IMO GMDSS Handbook provides an explanation of the principles upon which the GMDSS is based, the radio-communication requirements and recommendations for its implementation, the operational performance standards and technical specifications to be met by GMDSS equipment, and the procedures for and method of operation of the various radio services which form the GMDSS and the Master Plan for the GMDSS.



All information SevenStar Electronics Ltd 2002-18