NIMASA GMDSS GOC Exam study guide
NIMASA GMDSS GOC Exam · Work through your exam, one topic at a time.
The GMDSS General Operator's Certificate (GOC) is the radio-operator qualification required of seafarers who carry out distress, urgency and safety communications on ships fitted to the Global Maritime Distress and Safety System. In Nigeria it is examined under the maritime administration's oversight and is the certificate that lets a holder stand watch on the radio equipment of SOLAS-class vessels and act as the ship's radio operator. The NIMASA GMDSS GOC Exam study guide has 10 sections and about 3,110 words.
01GMDSS general principles
The Global Maritime Distress and Safety System is a SOLAS Chapter IV system built around functional requirements, not a single radio. It provides six functions: distress alerting, SAR coordination, locating, maritime safety information, general radiocommunications, and bridge-to-bridge communications.
315 words, about 2 min02Carriage requirements and functional elements
SOLAS IV requires ships to have equipment for six functions: distress alerting, SAR coordination, locating, MSI reception, general radiocommunications and bridge-to-bridge communications. Equipment must be type-approved and surveyed.
332 words, about 2 min03Radio propagation, frequencies and basic radio theory
Frequency and wavelength are related by λ = c/f. VHF (156–174 MHz) is essentially line-of-sight, so antenna height dominates range.
293 words, about 1 min04VHF and MF/HF radiotelephony including DSC
VHF Ch16 is the voice distress, safety and calling channel; Ch70 is the DSC channel and must never carry voice. Ch13 is intership navigation safety; Ch06 is ship-to-ship.
320 words, about 2 min05Inmarsat and satellite communication services
Inmarsat provides geostationary satellite communications for A3, generally between about 70°N and 70°S. Inmarsat-C is a store-and-forward, data-only terminal used for distress alerting, EGC/SafetyNET reception, two-way messaging and polling.
301 words, about 2 min06Maritime Safety Information: NAVTEX, SafetyNET and MSI reception
Maritime Safety Information includes navigational warnings, meteorological warnings and forecasts, SAR information and other urgent safety information. SOLAS requires ships to receive MSI for the areas they sail.
322 words, about 2 min07Distress, urgency and safety communications procedures
Distress is grave and imminent danger requiring immediate assistance: MAYDAY, spoken three times. Urgency concerns safety of a ship or person but no immediate grave danger: PAN PAN.
303 words, about 2 min08Emergency position indicating radio beacons and search and rescue radar transponders
The 406 MHz EPIRB is a float-free satellite distress beacon detected by COSPAS-SARSAT. It transmits a unique beacon ID (usually linked to the vessel's MMSI) and, with GNSS, a position.
317 words, about 2 min09Batteries, power supplies, antennas and equipment maintenance/fault finding
GMDSS batteries are usually lead-acid or VRLA. Capacity is in ampere-hours (Ah); usable capacity is reduced by age, temperature and discharge rate.
308 words, about 2 min10Radio regulations, licensing, watchkeeping and interference
Ship radio stations are licensed by the national administration-in Nigeria, NIMASA-and the ship must carry the licence, call sign and MMSI assignment. The GOC certificate authorises the holder to operate the GMDSS equipment and handle distress, urgency and safety traffic; it is not a ship licence.
299 words, about 1 min