Module 5 - Routine Calls
Unanswered, Garbled and Repeated Calls
What you will learn
Respond proportionately to silence or unreadable speech without blocking the channel, inventing missing information or escalating a routine call to a false priority.
A failed call is a diagnosis problem. Leave reply space, verify the station and set, repeat briefly when justified and use the specific published fallback only when its conditions apply.
If there is no answer, release PTT and wait. Check the station name, channel, volume, squelch, power, antenna path, distance, opening hours and whether the station is expected to monitor. A second brief call after a real interval may be reasonable; continuous or rapid repetition prevents replies and adds interference.
For an unknown-MMSI inter-ship voice call, current MCA guidance says to call briefly on Channel 16 using low power first, move to an inter-ship channel if answered, and try Channel 13 for bridge-to-bridge communication if there is no response. That is a bounded navigation-communication fallback, not a general second channel for marinas or social traffic.
For a garbled response, use SAY AGAIN and identify the missing word, group or instruction where possible. Do not infer a berth, position, channel or direction. If you notice your own spoken error, use CORRECTION and provide the corrected information; do not leave both versions unresolved.
Worked example
Harbour control's reply contains an unreadable waiting area and you also misstated your draught.
- 1Ask: 'SAY AGAIN waiting area. OVER.' Do not guess from a place name heard earlier.
- 2After the repeat, read the waiting area back.
- 3Then say: 'CORRECTION, draught one decimal eight metres' and wait for confirmation if required.
Sense check: The final shared understanding should contain one verified waiting area and one corrected draught, not two competing versions.
Reassess before repeating
An unidentified ship does not answer your brief low-power Channel 16 call. Relevant bridge-to-bridge navigation communication is still needed.
1. Leave a reply interval
Release PTT, listen and confirm the call was clearly identified on the intended channel.
2. Check the path
Verify controls, power, antenna, range and whether the ship is likely to be maintaining the expected watch.
3. Use the bounded fallback
Try Channel 13 for the relevant bridge-to-bridge communication, while continuing safe navigation independently of any reply.
Sense check: A radio call never transfers collision-avoidance responsibility, and an unanswered routine call does not itself create distress priority.
Common mistake or limitation
- Repeating immediately without leaving enough time for the other station to answer.
- Using Channel 13 as a universal alternative for any unanswered routine call.
- Guessing an unreadable operational group or leaving an own-message error uncorrected.
Recap
- Wait, listen and check the complete path before repeating.
- Channel 13 is the specific unknown-MMSI bridge-to-bridge fallback after an unanswered Channel 16 attempt.
- Use targeted SAY AGAIN for received uncertainty and CORRECTION for your own error.
Optional quick check
Section 9 of 10
A marina reply is clear except for the berth number. What is the safest radio response?
Sources and factual review
Reviewed 20 August 2026 - Compass Revision editorial review.
Continue studying Routine Calls
This public lesson is part of Revision Module 5. Full revision access adds the guided Learn, Practise and Test flow, flashcards and revision progress.