GOC GMDSS Exam study guide
GOC GMDSS Exam · Work through your exam, one topic at a time.
The General Operator's Certificate (GOC) is the GMDSS radio operator credential that lets a qualified person operate the radio installation on a vessel subject to the Global Maritime Distress and Safety System carriage requirements. It is held by deck officers and dedicated radio operators who may need to transmit distress, urgency and safety traffic, keep a radio watch, and manage the ship's radio log. The GOC GMDSS Exam study guide has 9 sections and about 3,420 words.
01Distress, Urgency and Safety Communications Procedures
Every GMDSS transmission sits in one of three priority bands. Distress (highest) uses MAYDAY on radiotelephony, SOS on Morse, and DSC category Distress with a nature-of-distress code and, where fitted, a position.
418 words, about 2 min02GMDSS System Architecture
The GMDSS is built around functional requirements , not specific equipment. A vessel must be able to transmit ship-to-shore distress alerts, receive shore-to-ship alerts, transmit and receive distress and safety communications, transmit and receive MSI, and transmit and receive general radiocommunications.
349 words, about 2 min03Sea Areas and Carriage Requirements
Sea Area A1 is within radiotelephony coverage of at least one VHF coast station with continuous DSC alerting. A2 is beyond A1 but within MF coast-station coverage with continuous DSC alerting.
350 words, about 2 min04VHF and MF/HF Radiotelephony and DSC Operations
VHF channel 16 is the radiotelephony distress, safety and calling channel; channel 70 is reserved for DSC and must never carry voice. MF distress and calling is 2182 kHz with DSC on 2187.5 kHz.
353 words, about 2 min05Satellite Communications: Inmarsat and Other GMDSS Services
Satellite services provide alerting and communications where terrestrial systems cannot reach, especially in Sea Area A3. Inmarsat geostationary satellites support voice, data and distress alerting through ship earth stations, and the system includes a dedicated distress function that routes an alert to a rescue coordination centre.
345 words, about 2 min06Maritime Safety Information: NAVTEX, EGC/SafetyNET and Reception
Maritime Safety Information includes navigational warnings, meteorological warnings and forecasts, search and rescue information, and other urgent safety information. The GMDSS requires a vessel to be able to receive MSI throughout its voyage.
311 words, about 2 min07EPIRBs and SART/AIS-SART
An Emergency Position-Indicating Radio Beacon transmits a distress alert via satellite (COSPAR-SARSAT) and provides a homing signal for rescue units. Modern EPIRBs are activated manually or automatically by water immersion when the vessel sinks, and float free from their bracket.
335 words, about 2 min08Radio Propagation, Antennas and Electromagnetic Compatibility
VHF is essentially line-of-sight, with range extended by antenna height and atmospheric conditions. MF ground-wave gives reliable short-to-medium range; skywave at night can extend it but is less predictable.
327 words, about 2 min09Power Supplies, Batteries, Maintenance, Fault-Finding and Testing
GMDSS equipment is supplied from the ship's main and emergency sources, with a reserve source (usually a battery) independent of the generators, capable of supplying the distress and safety functions for the required period. Know that the reserve source must be able to supply the required load and that its capacity is tested regularly.
632 words, about 3 min