What daily and weekly GMDSS equipment checks are required under SOLAS and how does the OOW document them?

A. GMDSS MAINTENANCE REQUIREMENTS — SOLAS IV/15: SOLAS requires vessels to maintain GMDSS equipment in efficient working order. DAILY CHECKS (OOW responsibility each watch): (1) VHF: check DSC controller has current GPS position (confirm position and time on display); check battery charge indicator if applicable; (2) NAVTEX: verify receiver is on and printing — check for recent messages; (3) INMARSAT-C: confirm terminal is logged into the satellite — signal strength indicator; check for unread SafetyNET or MSI messages; (4) EPIRB: visual check — correct in bracket, hydrostatic release intact, LED status light; (5) SART: visual check — in bracket, no damage, activation indicator; (6) VHF CH 16 WATCH: confirm radio on and monitoring Ch 16 continuously; WEEKLY CHECKS: (1) DSC TEST ON VHF: send a DSC test call to coastguard (or an agreed vessel) — NOT a false distress — this confirms DSC controller is transmitting and being received; (2) VHF RADIO CHECK: radio check on Ch 16 with nearest coast station or vessel to confirm transmitter power; (3) EPIRB SELF-TEST: press test button — LED confirms operation (does not transmit MAYDAY signal); (4) BATTERY STATUS: check battery indicators on all GMDSS equipment; RECORDS: all GMDSS maintenance and tests must be recorded in the GMDSS LOG (or Radio Log) — time, nature of test, result, name of officer.

B. GMDSS checks are required only during annual survey. Daily checks are not mandated by SOLAS — they are optional best practice.

C. GMDSS daily checks are the Radio Officer's responsibility. Modern vessels without a dedicated Radio Officer are exempt from GMDSS daily test requirements.

D. The EPIRB self-test should be conducted daily. Each self-test broadcasts a full 406 MHz signal lasting 30 seconds to confirm the beacon is operational.

A. DSC DISTRESS ALERT — VHF PROCEDURE: DSC (Digital Selective Calling) on VHF Channel 70 is the primary GMDSS distress alerting mechanism. PROCEDURE: (1) ENSURE POSITION IS UPDATED: the DSC controller must have a current GPS position input (most modern sets auto-update from GPS). Verify the position shown is current; (2) OPEN THE DSC CONTROLLER: navigate to the distress function — typically a protected button (lift cover or press and hold to prevent accidental activation); (3) SELECT NATURE OF DISTRESS: most DSC controllers allow selection of distress nature — UNDESIGNATED, FIRE, FLOODING, COLLISION, GROUNDING, LISTING, SINKING, DISABLED AND ADRIFT, ABANDONING SHIP. If time permits, select the correct nature; (4) TRANSMIT: press/hold the distress button for the required duration (typically 5 seconds with button confirmation). The controller transmits the DSC distress call on Ch 70 — this broadcasts your MMSI, position, time, nature of distress to all vessels in range and to coast stations; (5) SWITCH TO CH 16: immediately after DSC transmission, switch VHF to Ch 16 and transmit the voice MAYDAY message; (6) MAYDAY VOICE: "MAYDAY MAYDAY MAYDAY — THIS IS [vessel name × 3] — MAYDAY [vessel name] — POSITION [lat/lon] — [NATURE OF DISTRESS] — [POB] — [ANY OTHER RELEVANT INFO] — OVER"; (7) AWAIT ACKNOWLEDGEMENT: coast stations and vessels will acknowledge on Ch 16.

B. The DSC distress alert is transmitted on Ch 16. Tune the VHF to Ch 16, press the distress button, and speak the MAYDAY message directly.

C. Voice MAYDAY on Ch 16 must be transmitted first — then the DSC alert follows. The voice call alerts nearby vessels who may not be monitoring DSC.

D. DSC distress is only for MF/HF radio. VHF uses the traditional voice MAYDAY on Ch 16 only — VHF DSC is not a required GMDSS function.

A. NAVTEX — SYSTEM AND OOW USE: NAVTEX (Navigational Telex) is an automated system that broadcasts maritime safety information (MSI) on 518 kHz (international) and 490 kHz (national language) using NBDP (Narrow Band Direct Printing). WHAT IT PROVIDES: (1) NAVIGATIONAL WARNINGS (B messages): hazards to navigation — wrecks, buoy off station, new obstructions, pilot areas, lights changed; (2) METEOROLOGICAL WARNINGS (W messages): gale warnings, storm warnings, weather bulletins; (3) PILOT SERVICE MESSAGES (P messages); (4) ICE REPORTS (I messages); (5) SAR INFORMATION (D messages): distress messages, SAR operations in the area; (6) SUBFACTS and NAVFACTS: submarine exercise areas and other military notifications. HOW IT WORKS: NAVTEX stations broadcast on a schedule. Each station has a unique letter identifier. The NAVTEX receiver is programmed to receive messages from stations covering your sea area. Messages not relevant to the vessel's area can be filtered. OOW DUTIES: (1) Ensure NAVTEX is switched on and printing; (2) Check the NAVTEX receiver is set to receive messages from stations in the current sea area; (3) READ ALL MESSAGES as they print; (4) Bring significant messages (navigational warnings, gale warnings, SAR in the area) to the master's attention; (5) CHART PLOT: plot navigational warnings on the chart/ECDIS; (6) Do NOT ignore NAVTEX messages — they contain safety-critical information.

B. NAVTEX operates on VHF Ch 68 and provides local port information for vessels within 20nm of the coast. It is only relevant when approaching port.

C. NAVTEX is a backup to weather fax and provides only meteorological information. Navigational warnings are only available through the vessel's AIS.

D. NAVTEX messages should be collected and reviewed once per watch. Urgent messages are highlighted in red and require immediate action; all others can wait.