What is Global Maritime Distress and Safety System or GMDSS and its details?

Which types of vessel GMDSS apply to:

  • GMDSS will apply to all Cargo Ship of 300 GT and above, and
  • To all passenger ship regardless of size on international voyage.

GMDSS is largely but not fully automated system. The GMDSS emphasizes the ability to alert SAR authorities ashore as well as shipping in the vicinity in order to receive a rapid co-ordinated response to distress situations.

Functional Requirements of GMDSS equipments :-

  1. Transmission of ship to shore distress alert by at least two separate and independent means, each using a different radio communication.
  2. Reception of shore – to ship distress alerts.
  3. Transmission and reception of Ship to ship distress alert.
  4. Transmission and reception of SAR (Search and rescue) coordinating communication.
  5. Transmission and reception of on-scene communication (At the point distress location)
  6. Transmission and reception of signals for locating.
  7. Transmission and reception of MSI (Maritime safety Information).
  8. Transmission and reception of general radio – communication to and from shore based radio system or networks; and
  9. Transmission and reception of bridge to bridge communications.


GMDSS divides the world’s oceans into four “sea areas”, designated A1 through A4.

About the author

Amit Sharma

Graduated from M.E.R.I. Mumbai (Mumbai University), After a brief sailing founded this website with the idea to bring the maritime education online which must be free and available for all at all times and to find basic solutions that are of extreme importance to a seafarer by our innovative ideas.

1 Comment

  • Man Overboard is a distress situation. Even the RT message will be Distress message . Information given that RT message will be Urgency is absolutely wrong. Students following this in GOC examination will fail. Request you to correct this. You may consult ITU manual for maritime mobile & maritime mobile satellite services.
    Thanking you

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