Module 13 — Radio log, publications and station management
What must be recorded and when: licence, manuals, publications, equipment tests, false alerts and inspection readiness.
The radio log is the legal memory of the GMDSS station. It documents that the watch has been kept, equipment has been tested and distress, urgency and safety traffic has been handled correctly. In any incident or inspection, what is not written has not happened.
What must be logged
Typical entries
Each entry contains at least: UTC time, equipment or frequency, category (routine / safety / urgency / distress), parties involved, message summary and operator signature. Corrections are made by a single line through the wrong text plus operator signature; never with correction fluid or erasure.
Mandatory publications on board
Inspection readiness
All documentation must be accessible, up to date and legible. Battery tests, DSC functional tests, EPIRB checks and position verifications must appear in the log at the required frequency. Inspectors typically start with the licence, operator certificates and the latest log entries — the first filter of an inspection.
Mandatory onboard publications
The manual and SOLAS IV/V require carrying: the IMO GMDSS Manual 2024 itself, the NAVTEX Manual, the International SafetyNET Services Manual, the Iridium SafetyCast Service Manual, ITU List IV (Coast Stations), ITU List V (Ship Stations) and IAMSAR Manual Volume III (SOLAS V/2). Add the ship station licence, operator certificates under ITU RR Article 47 and the applicable frequency-allocation tables.
MMSI and administrative data (6.6)
The MMSI is a nine-digit number identifying the ship; the first three digits (MID) denote nationality. Group MMSIs start with 0; coast-station IDs with 00; AIS-SARTs with 970; AIS-equipped EPIRBs with 974; MOB devices with 972. The coding is not trivia: it determines how to filter and interpret what arrives by DSC or AIS.
Radio log content
Record: distress alerts transmitted and received, urgency and safety messages, periodic tests (DSC, reserve source of energy, EPIRB, SART), faults and repairs, watch handovers, battery use, relevant MSI. Traceability must allow reconstruction of what happened, when, with which equipment and under which procedure.
Visible operating guidance
Part 5 recommends that the distress operating guidance (Figure 23 of the manual) be displayed on the bridge alongside the DSC frequencies and procedures. It is not decoration: under stress an operator reads better than recalls.
Inspections and renewal
Annual inspections verify licence, certificates, maintenance, log, EPIRB/SART self-tests, reserve-battery test and the record of weekly DSC tests. An inspection will spot an empty log long before an electronic fault: the record is the proof that the system is operated, not just installed.
ITU publications in detail
Beyond the GMDSS Manual 2024 and IAMSAR Vol. III already cited, the ship must keep up to date: ITU List IV (List of Coast Stations and Special Service Stations, RR No. 20.7) for CRS frequencies and schedules; ITU List V (List of Ship Stations and MMSI Assignments, RR No. 20.8) for ship identification by MMSI and call sign; ITU List VIIA (List of Call Sign and Numerical Identities, Article 19) for call-sign allocations; the ITU Manual for Use by the Maritime Mobile and Maritime Mobile-Satellite Services; the NAVTEX Manual; the SafetyNET and SafetyCast Services Manuals; and the Admiralty List of Radio Signals Vol. 5 (NP285), the day-to-day operational reference for MSI, DSC, RMSS and coast procedures.
MMSI, call sign and log retention
The MMSI takes its first three digits (MID) from nationality under RR Article 19 and ITU-R Recommendation M.585; the prefixes already described encode function (00 coast-station group, 0 coast station, 111 SAR aircraft, 970 AIS-SART, 972 MOB, 974 EPIRB-AIS, 99 AtoN). The call sign is an alphanumeric string with the country's ITU prefix and a national suffix; both the MMSI and the call sign appear on the ship station licence. The radio log is retained for at least two years and kept available to the administration (common practice accepted by most flags; check the flag's exact period) and must be produced for any inspector or SAR authority that asks for it.
Entry templates (exam-style samples)
Ship station licence content
The licence issued by the flag administration (in Spain the Secretaría de Estado de Telecomunicaciones and/or DGMM by split) must include: ship name, call sign, MMSI, type of service (maritime), authorised emissions with their class (J3E, G3E, F1B, etc.) and bands, equipment list (VHF-DSC, MF/HF-DSC, Inmarsat C, Iridium, 406 EPIRB with HEX ID, AIS, NAVTEX), authorised power, validity and any particular conditions. It must be displayed visibly at the ship's radio station and produced on inspection. An expired licence or a mismatch with the equipment actually installed is an immediate finding at PSC/FSC inspection.
STCW Bridge Watch Lens
Decide applicability before manoeuvring: Rules 4-10 apply in any visibility, Rules 11-18 only when vessels are in sight, and Rule 19 governs radar-only encounters in restricted visibility.
Build the traffic picture with sight, hearing, radar/ARPA and chart context. Do not let AIS or one isolated bearing replace systematic observation.
After manoeuvring, keep monitoring bearing, range, CPA/TCPA and passing distance until the other vessel is finally past and clear.
Exam Focus
Identify the vessel types first, then the relative bearing, then whether one vessel is overtaking. Misclassifying the encounter is the usual exam failure.
If two rules seem to conflict, check the order carefully: overtaking duties still apply, and Rule 2 still requires ordinary seamanship.
Key Takeaways
An unwritten record does not legally exist.
Every entry needs UTC time, equipment, frequency, parties and signature.
False alerts must be logged with their cancellation and cause.
Licence and operator certificates are what every inspector checks first.
Mandatory publications: GMDSS Manual, NAVTEX Manual, SafetyNET/SafetyCast Manuals, ITU List IV/V, IAMSAR Vol. III.
MMSI has coded format: 970 AIS-SART, 972 MOB, 974 EPIRB-AIS, groups start with 0.
The radio log captures alerts, tests, faults, handovers and relevant MSI.
The distress operating guidance (Figure 23) must be displayed on the bridge.
Specific ITU publications: List IV, List V, List VIIA and the ITU Maritime Mobile Service Manual.
ALRS Vol. 5 (NP285) is the day-to-day reference for MSI, DSC and coast procedures.
Call sign and MMSI appear on the licence; the first three MMSI digits (MID) encode nationality.
The radio log is retained at least two years and must be produced on inspection or SAR request.
Key entry templates: weekly DSC test, MSI received, cancelled false alert, fault with backup arrangement.
Ship station licence lists: name, call sign, MMSI, emissions (J3E/G3E/F1B), equipment with HEX ID, power, validity.
The licence is displayed visibly at the radio station; expiry is an immediate inspection finding.
Common Mistakes
Skipping the daily test log because nothing failed.
Incomplete entries: missing UTC time, frequency or operator.
Correcting with fluid or erasure rather than line + signature.
Out-of-date publications, or unofficial photocopies instead of originals.
Confusing the ship station licence with the operator certificate: they are separate documents.
Not logging weekly DSC tests and being caught during an inspection.
Reducing 'documentation' to certificates and forgetting the operational manuals (NAVTEX, SafetyNET).
Not updating IAMSAR Vol. III or the GMDSS Manual to the current edition.
Carrying an out-of-date ALRS Vol. 5: CRS frequencies and schedules change edition by edition.
Confusing List IV (coast) with List V (ship) when looking up an MMSI.
Destroying radio logs before the flag's required retention period has elapsed.
Cancelling a false alert without logging the cause and cancellation time in the radio log.
Leaving the ship station licence out of date after an equipment change (new beacon, new HEX ID).
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