Module 5 - Routine Calls
The Shape of a Complete Routine Call
What you will learn
Use a repeatable call lifecycle from preparation to restored watch, while adapting the channel route to the station and whether its MMSI is known.
A successful call is more than an opening phrase. It begins before PTT with a channel and message plan, moves through contact and useful traffic, and ends only when the listening arrangement has been restored.
With a known vessel MMSI, MCA guidance uses an Individual DSC call with routine priority and a proposed inter-ship channel. After acknowledgement, the conversation starts on that accepted channel. With an unknown MMSI, make a brief low-power voice call on Channel 16, then move to an appropriate inter-ship channel after contact.
A coast station using DSC controls its working voice route: send an Individual DSC routine call to the published MMSI, accept the acknowledgement, move to the indicated channel and wait for the coast station's voice call. A marina or harbour call instead follows its current published local service procedure.
Across all three routes, the human factors are the same: prepare, listen, identify, leave reply space, confirm any channel move, exchange only useful information, read back critical instructions and restore the required watch when complete.
Worked example
Known-MMSI routine inter-ship call to agree a meeting position.
- 1Select the saved MMSI, routine priority and an appropriate inter-ship working channel; transmit the DSC call.
- 2Wait for acknowledgement and confirm the accepted working channel.
- 3Listen on that channel, make the identified voice call and exchange the concise meeting information.
- 4Read back the position or time if it is operationally critical, close with OUT and restore the watch.
Sense check: No routine voice traffic should be spoken on Channel 70, and a known-MMSI DSC route should not need an unnecessary Channel 16 voice call.
| Stage | Operator action | Failure to avoid |
|---|---|---|
| Prepare | Station, identity, purpose and current channel route | Improvising a long message while transmitting |
| Listen | Check the route is clear and note higher-priority traffic | Talking over an existing exchange |
| Call | Identify the called station and own vessel briefly | Giving all detail before acknowledgement |
| Move | Accept or agree the correct working channel and confirm the display | Using Channel 70 for speech or staying on 16 |
| Exchange | Give concise facts and read back critical instructions | Guessing an unreadable group |
| Close | Use the correct proword, release PTT and restore the watch | Leaving the set on an unintended channel |
Choose the route before choosing the words
You need a routine conversation with another yacht. Its MMSI is saved and an appropriate inter-ship channel has been selected from the current plan.
1. Select digitally
Send an Individual DSC routine call to the known MMSI and propose the suitable inter-ship channel.
2. Move after acknowledgement
Confirm the accepted voice channel on the display; do not try to speak on Channel 70.
3. Exchange and restore
Make the short voice call, close cleanly and restore the required listening watch.
Sense check: At every stage you should be able to name the channel, its purpose and what event permits the next move.
Common mistake or limitation
- Memorising one opening but not planning the acknowledgement, channel move or closing.
- Making a Channel 16 voice call even though a routine DSC call to the known MMSI has been accepted.
- Ending the conversation but forgetting to restore the required listening watch.
Recap
- The station type and known or unknown MMSI determine the contact route.
- Preparation, reply space and a confirmed working-channel move protect the shared system.
- The call is not complete until critical instructions are understood and the watch is restored.
Optional quick check
Section 5 of 10
A known-MMSI routine DSC call is acknowledged on the proposed inter-ship channel. What follows?
Sources and factual review
Reviewed 20 August 2026 - Compass Revision editorial review.
Continue studying Routine Calls
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