GMDSS Sea Areas A1–A4
Understand how the sea areas are defined and how shore and satellite coverage relates to the GMDSS requirements.
Read the sea areas guide →ℹ️
Study GMDSS with confidenceFor working seafarers and cadets
GMDSS Expert explains maritime radio equipment, distress and safety communications, sea areas, and the knowledge assessed in General Operator’s Certificate (GOC) training. Use the guides to refresh a topic, prepare for an exam, or build a clear understanding of shipboard radio systems.
The learning material is organised around IMO Model Course 1.25 and relevant IMO, SOLAS, STCW and ITU publications. Each guide links to the sources used.
IMO Model Course 1.25
GOC training framework
GOC training framework
Deck officers
Operational refresh
Operational refresh
Maritime cadets
Structured study
Structured study
GMDSS topics
Equipment and procedures
Equipment and procedures
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GMDSS study guidesDSC Distress Alert
Review the purpose of a DSC distress alert and the communication that follows its receipt.
Read the DSC guide →EPIRB, Radar SART and AIS-SART
Compare these alerting and locating devices and learn the role each plays in search and rescue.
Compare the devices →GOC Exam Preparation
Plan your revision of GMDSS equipment, radio communications, regulations and practical skills.
Open the GOC study guide →Sources and Method
See how the learning guides use IMO, SOLAS, STCW and ITU publications, with links to primary sources.
Read the source policy →📝
Practice and equipmentGMDSS Self-Practice Test
Check your understanding of core GMDSS topics with a self-paced knowledge test.
Start the GMDSS test →SAILOR / CES-6000 Practice
Explore a focused practice tool for the SAILOR 6000 series radio interface.
Open CES-6000 practice →📚
What the GOC course coversCore areas of GMDSS competence
Radio equipment
VHF, MF and HF radio, DSC, NAVTEX and recognised mobile satellite services.
Distress and safety communications
Distress, urgency and safety communications, alerting, locating and SAR coordination.
Maritime safety information
Receiving and using MSI, including NAVTEX and satellite-based broadcasts.
Regulations and publications
SOLAS Chapter IV, STCW requirements, ITU Radio Regulations and relevant documentation.
Routine communications
Ship-to-ship and ship-to-shore radio communications and communication planning.
GMDSS sea areas
How A1, A2, A3 and A4 relate to available GMDSS services and equipment.
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