Module 18 - Signals & Communications
Position, Phonetics, Read-back and Radio Log
What you will learn
Prepare, transmit, read back and hand over safety-critical position, identity, channel and time information without losing its reference or currency.
Radio accuracy is a crew system. Written positions, standard phonetics, grouped numbers, read-back and a short UTC log reduce memory errors when navigation and emergency tasks compete.
Prepare position before the call. Latitude and longitude must include degrees, minutes, decimals if used, and North or South, East or West; give the time and datum if relevant. Alternatively give an unambiguous bearing and distance from a charted feature. Read from a written position when possible, and have another crew member compare it with the display or chart before transmission.
Use the international phonetic alphabet for call signs, ambiguous names, and letters that matter. Speak numbers clearly and in an order the receiver can write. Break a long message into short groups, pause for acknowledgement, and read back safety-critical instructions, coordinates, channels, and times. If the read-back is wrong, correct the specific item and obtain a fresh confirmation.
Maintain a radio log during significant traffic. Record UTC or the clearly stated time basis, station, channel, call priority, position, message, instructions, acknowledgements, and actions. Logging is not paperwork for its own sake: it prevents a relief watch from repeating an obsolete instruction and gives the skipper a timeline when distress, traffic, and navigation demands compete.
The handover should identify who controls the radio exchange, who controls the vessel, the current working channel, the last message sent and received, what response is expected, and the time for the next call. If the operator becomes overloaded, say ‘stand by’ when appropriate, stabilise the vessel, and return with an accurate message rather than improvising numbers while losing situational awareness.
Worked example
The written position is 50° 42.6′ N 001° 12.4′ W at 2214 UTC and the vessel call sign is MABC2.
- 1Cross-check the coordinate digits, North/West directions and time against the chart or independent display.
- 2Use the international phonetic alphabet for MABC2 and speak the coordinate groups slowly enough to be written.
- 3Read back any corrected digit, channel or time and obtain confirmation rather than assuming silence means agreement.
- 4Log the station, priority, channel, position, instruction, acknowledgement and resulting action.
Sense check: The log preserves both the value and its time; a correct coordinate without currency can still mislead the response.
| Log field | Example | Why retain it |
|---|---|---|
| Time basis | 2214 UTC | Preserves currency and sequence |
| Station/channel | HMCG / working channel | Allows reliable handover |
| Position/message | Checked coordinates and condition | Separates fact from later inference |
| Instruction/action | Update at 2230 / person assigned | Closes the communication loop |
Hand over a live Coastguard exchange
The radio operator must leave to help with a casualty after receiving a new working channel and a request for an updated position at 2230 UTC.
1. Write and read back
Record the channel, time, coordinate directions and instruction, then read back the safety-critical parts.
2. Handover
Name the controlling station, last sent and received messages, next expected action and who controls the vessel.
3. Update from evidence
At the due time, give a freshly checked position and state the time basis rather than repeating an old display value.
Sense check: The replacement operator can continue the exchange without asking the Coastguard to reconstruct the yacht's last message.
Common mistake or limitation
- Coordinates without North/South, East/West and a clear time basis are incomplete.
- Do not read from memory when a written and cross-checked position is available.
- A read-back must resolve the uncertain digit, word, channel or instruction; merely continuing the exchange preserves the error.
- A radio handover that omits the next call time or current channel leaves the relief operator without the live task.
Recap
- Write and cross-check the position before transmitting when time permits.
- Use standard phonetics and clear number groups for ambiguous identity and data.
- Read back safety-critical coordinates, channels, times and instructions.
- Log and hand over the live exchange with its next action.
Optional quick check
Section 16 of 18
A Coastguard read-back gives 001° 21.4′ W instead of 001° 12.4′ W. What should the operator do?
Sources and factual review
Reviewed 20 August 2026 - Compass Revision editorial review.
Continue studying Signals & Communications
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