No DSC Acknowledgement on MF/HF During a Medical Evacuation
MV Sagar Kanya, a 32,000 GT bulk carrier, is on passage from Paradip to Mombasa. At 0340 IST on 14 June she is in position 12°28′N 071°55′E, about 235 nm west of Kochi - Sea Area A3, but with marginal MF/HF coverage and no confirmed Inmarsat log-in after a recent terminal reset. The master has declared a distress situation: a crew member has suspected acute appendicitis; the nearest suitable port is over 36 hours away. The GOC operator sends an MF DSC distress alert on 2187.5 kHz with nature 'medical assistance' and position, then waits. At 0345 no DSC acknowledgement is received. An HF DSC alert on 8414.5 kHz is also sent, with no immediate acknowledgement. The second officer reports a nearby merchant vessel about 40 nm away on AIS, but no VHF contact. The master asks whether to repeat MF DSC, go straight to 2182 kHz voice, or try Inmarsat C.
1. Outline the operator's actions from 0345 to 0400 and explain why each step is taken.
Read the worked answer
At 0345 the five-minute wait after the initial MF DSC alert has expired. The operator should:
- Keep the MF/HF DSC watch on 2187.5 kHz and the RT watch on 2182 kHz.
- Repeat the MF DSC distress alert once on 2187.5 kHz, still with distress priority, correct position and nature 'medical assistance'. A repeat is justified because the first alert may have been missed or not acknowledged; it is not a false alert.
- Listen for five minutes on 2187.5 kHz after the repeat. Do not immediately abandon DSC for voice; a coast station or ship may acknowledge by DSC.
- At about 0350, if there is still no acknowledgement, transmit the voice MAYDAY on 2182 kHz using the full call and distress message. Voice is the fallback when DSC acknowledgement has not been received.
- Continue to keep watch on 2182 kHz and 2187.5 kHz; try VHF Ch 16 to the nearby vessel only if it does not delay the MF/HF distress traffic.
- Inform the master and start the radio log.
2. Should an Inmarsat C distress alert be sent now? Explain the priority and any risk of conflicting alerts.
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Inmarsat C is a valid GMDSS distress alerting system in Sea Area A3, but the terminal is described as not confirmed logged in after a reset. The operator should first restore log-in and check the LES/ocean region. If the MF/HF DSC and voice attempts remain unanswered, sending an Inmarsat C distress alert with the same position and nature is appropriate; it gives a second path to an RCC and does not depend on MF/HF propagation. It should not be sent as a substitute for the required MF/HF procedures before those have been tried, and it should not be delayed for hours. Duplicate alerts are acceptable in a genuine distress; RCCs can correlate them. The risk is confusion if the position or nature differs, or if a false alert is later found; therefore use the same data and log the time. If the Inmarsat C terminal cannot log in, do not spend critical minutes on it while the voice Mayday is unanswered.
3. State the minimum contents of the Mayday call and explain why each element matters in marginal coverage.
Read the worked answer
Use the standard distress message: MAYDAY MAYDAY MAYDAY; THIS IS SAGAR KANYA, SAGAR KANYA, SAGAR KANYA; CALL SIGN [if known]; MMSI [if known]; POSITION 12°28′N 071°55′E; NATURE OF DISTRESS: medical assistance, suspected acute appendicitis; ASSISTANCE REQUIRED: medical advice/evacuation; PERSONS ON BOARD: [number]; INTENTION: proceeding toward Kochi / request instructions; OVER. Each element matters: identity lets rescuers and ships know who is transmitting; position drives SAR plotting; nature decides the response (medical evacuation vs tow); persons on board helps prioritise; intention prevents conflicting actions. In marginal MF/HF coverage, speak slowly, repeat the position, and if no reply, repeat on another HF distress frequency such as 8 291 kHz voice after checking the DSC watch. Use the correct distress frequency for the band.