GMDSS - GLOBAL MARITIME DISTRESS AND SAFETY SYSTEM |
VERIFIED ANSWERS AND QUESTIONS - MOST RECENT
EDITION 2026/2027
Q1. What does GMDSS stand for?
Global Maritime Distress and Safety System.
Q2. What is the main purpose of GMDSS?
To provide automatic and reliable distress alerting and communication
between ships and shore, and to ensure rescue authorities are notified quickly.
Q3. Which IMO convention introduced GMDSS?
SOLAS Convention (Safety of Life at Sea), 1974, Chapter IV.
Q4. When did GMDSS become fully mandatory?
1 February 1999 for all SOLAS ships.
Q5. What system did GMDSS replace?
The Morse code radio telegraphy system (500 kHz).
Q6. Which organization coordinates GMDSS development at the UN level?
IMO (International Maritime Organization).
,Q7. Which body assigns radio frequencies for GMDSS?
ITU (International Telecommunication Union) through the Radio Regulations.
Q8. Which two organizations produce GMDSS technical standards?
IMO (performance standards) and ITU (technical characteristics).
Q9. GMDSS covers how many sea areas?
Four sea areas: A1, A2, A3 and A4.
Q10. Name the three general communications functions of GMDSS.
Distress, urgency and safety communications.
Q11. What are the nine functional requirements of GMDSS?
1) Ship-to-shore distress alerts, 2) Shore-to-ship distress alerts, 3) Ship-to-ship
distress alerts, 4) Search and rescue coordinating communications, 5) On-scene
communications, 6) Locating signals, 7) Maritime safety information, 8)
General radio communications, 9) Bridge-to-bridge communications.
Q12. What is a distress alert?
A notification, initiated by a ship or a person, indicating the ship or person is in
distress and requires immediate assistance.
Q13. What is an urgency message?
A message concerning the safety of a ship, aircraft or person, e.g. a medical
emergency or a ship in need of assistance but not in grave danger.
Q14. What is a safety message?
,A message containing information concerning navigational or meteorological
warnings, or other safety-related information.
Q15. Which satellites are used by the Inmarsat portion of GMDSS?
Geostationary (GEO) satellites about 35,786 km above the equator.
Q16. Name the satellite systems recognized for distress alerting in GMDSS.
Inmarsat (GEO) and Cospas-Sarsat (LEO/GEO) EPIRBs.
Q17. What is the basic philosophy of GMDSS compared to the old system?
GMDSS alerts the nearest rescue authority automatically with position
information, instead of waiting for a nearby ship to hear a Morse call.
Q18. Which ships must carry GMDSS equipment?
All passenger ships and all cargo ships of 300 GT and upwards on international
voyages (SOLAS).
Q19. What document certifies a ship's GMDSS compliance?
The ship's Safety Radio Certificate and the associated Record of Equipment
(Form R).
Q20. What is the minimum radio operator requirement under GMDSS?
At least two persons holding GMDSS General Operator's Certificates (GOC), or
one GOC holder plus a Restricted Operator's Certificate (ROC) holder, per sea
area requirements.
, === 2. SOLAS & Regulatory Framework
Q21. Which chapter of SOLAS covers radiocommunications?
Chapter IV – Radiocommunications.
Q22. What does SOLAS Chapter IV require regarding radio equipment?
It prescribes the functional requirements, equipment carriage, performance
standards and availability requirements of radio installations.
Q23. Who approves radio installations on SOLAS ships?
The flag State Administration, through classification societies or its own
inspectors.
Q24. What is the Radio Regulations document?
An ITU treaty that governs the use of radio frequencies and procedures for all
radio stations, including maritime.
Q25. What frequency band is VHF maritime radio?
156–174 MHz.
Q26. What frequency band is MF maritime radio?
415–535 kHz (distress 2182 kHz in the 2 MHz band).
Q27. What frequency band is HF maritime radio?
4–27.5 MHz (4, 6, 8, 12, 16 and 22 MHz maritime bands).
Q28. What is the priority of distress communications?
VERIFIED ANSWERS AND QUESTIONS - MOST RECENT
EDITION 2026/2027
Q1. What does GMDSS stand for?
Global Maritime Distress and Safety System.
Q2. What is the main purpose of GMDSS?
To provide automatic and reliable distress alerting and communication
between ships and shore, and to ensure rescue authorities are notified quickly.
Q3. Which IMO convention introduced GMDSS?
SOLAS Convention (Safety of Life at Sea), 1974, Chapter IV.
Q4. When did GMDSS become fully mandatory?
1 February 1999 for all SOLAS ships.
Q5. What system did GMDSS replace?
The Morse code radio telegraphy system (500 kHz).
Q6. Which organization coordinates GMDSS development at the UN level?
IMO (International Maritime Organization).
,Q7. Which body assigns radio frequencies for GMDSS?
ITU (International Telecommunication Union) through the Radio Regulations.
Q8. Which two organizations produce GMDSS technical standards?
IMO (performance standards) and ITU (technical characteristics).
Q9. GMDSS covers how many sea areas?
Four sea areas: A1, A2, A3 and A4.
Q10. Name the three general communications functions of GMDSS.
Distress, urgency and safety communications.
Q11. What are the nine functional requirements of GMDSS?
1) Ship-to-shore distress alerts, 2) Shore-to-ship distress alerts, 3) Ship-to-ship
distress alerts, 4) Search and rescue coordinating communications, 5) On-scene
communications, 6) Locating signals, 7) Maritime safety information, 8)
General radio communications, 9) Bridge-to-bridge communications.
Q12. What is a distress alert?
A notification, initiated by a ship or a person, indicating the ship or person is in
distress and requires immediate assistance.
Q13. What is an urgency message?
A message concerning the safety of a ship, aircraft or person, e.g. a medical
emergency or a ship in need of assistance but not in grave danger.
Q14. What is a safety message?
,A message containing information concerning navigational or meteorological
warnings, or other safety-related information.
Q15. Which satellites are used by the Inmarsat portion of GMDSS?
Geostationary (GEO) satellites about 35,786 km above the equator.
Q16. Name the satellite systems recognized for distress alerting in GMDSS.
Inmarsat (GEO) and Cospas-Sarsat (LEO/GEO) EPIRBs.
Q17. What is the basic philosophy of GMDSS compared to the old system?
GMDSS alerts the nearest rescue authority automatically with position
information, instead of waiting for a nearby ship to hear a Morse call.
Q18. Which ships must carry GMDSS equipment?
All passenger ships and all cargo ships of 300 GT and upwards on international
voyages (SOLAS).
Q19. What document certifies a ship's GMDSS compliance?
The ship's Safety Radio Certificate and the associated Record of Equipment
(Form R).
Q20. What is the minimum radio operator requirement under GMDSS?
At least two persons holding GMDSS General Operator's Certificates (GOC), or
one GOC holder plus a Restricted Operator's Certificate (ROC) holder, per sea
area requirements.
, === 2. SOLAS & Regulatory Framework
Q21. Which chapter of SOLAS covers radiocommunications?
Chapter IV – Radiocommunications.
Q22. What does SOLAS Chapter IV require regarding radio equipment?
It prescribes the functional requirements, equipment carriage, performance
standards and availability requirements of radio installations.
Q23. Who approves radio installations on SOLAS ships?
The flag State Administration, through classification societies or its own
inspectors.
Q24. What is the Radio Regulations document?
An ITU treaty that governs the use of radio frequencies and procedures for all
radio stations, including maritime.
Q25. What frequency band is VHF maritime radio?
156–174 MHz.
Q26. What frequency band is MF maritime radio?
415–535 kHz (distress 2182 kHz in the 2 MHz band).
Q27. What frequency band is HF maritime radio?
4–27.5 MHz (4, 6, 8, 12, 16 and 22 MHz maritime bands).
Q28. What is the priority of distress communications?
