Describe the EPIRB — how it works, how it activates, and what the OOW's responsibilities are regarding EPIRB maintenance and use.

A. EPIRB — EMERGENCY POSITION INDICATING RADIO BEACON: WHAT IT IS: an EPIRB transmits a distress signal on 406 MHz to the COSPAS-SARSAT satellite network, which relays the signal to a Local User Terminal (LUT), which passes it to Mission Control Centres (MCC) and then to SAR coordinators (MRCC). It also transmits on 121.5 MHz as a homing signal for SAR aircraft. HOW IT ACTIVATES: (1) MANUALLY: operated by hand — remove from bracket, arm, and activate; (2) AUTOMATICALLY HYDROSTATIC: the hydrostatic release releases the EPIRB from its bracket when submerged to a depth of 1-4 metres — the EPIRB floats free and activates automatically. This means it will activate if the vessel sinks. (3) AUTOMATIC FLOAT-FREE: modern EPIRBs combine hydrostatic release with automatic activation when floating; REGISTRATION: the EPIRB must be registered with the national maritime authority (in UK, MCA). Registration links the MMSI/beacon ID to vessel name, owner, contacts, and SAR information. Unregistered EPIRBs cause unnecessary SAR callouts; OOW RESPONSIBILITIES: (1) MONTHLY INSPECTION: verify EPIRB is in its bracket, hydrostatic release intact, battery expiry date not exceeded, self-test indicator light correct; (2) BATTERY: battery must be renewed by expiry date (marked on the EPIRB); (3) ANNUAL CHECK: typically at annual survey; (4) IN EMERGENCY: manually activate EPIRB before abandoning ship if time permits. The automatic hydrostatic release is a backup — manual activation is faster; (5) FALSE ACTIVATION: if EPIRB activates accidentally, cancel immediately on DSC/radio and notify coastguard.

B. The EPIRB transmits on VHF Ch 70 and is received by local coast radio stations. It does not use satellites and only works within 50nm of the coast.

C. EPIRB maintenance is the radio officer's responsibility. The OOW has no role in EPIRB inspection or deployment decisions.

D. The EPIRB should only be activated by the master — the OOW does not have authority to activate EPIRB even in a genuine emergency.

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.