Module 12 — Maritime English for GMDSS
1The lesson in plain words
SMCP reduces ambiguity, but clear speech and correct data still matter.
What are SMCP for?
They provide controlled vocabulary to reduce ambiguity, but they do not repair wrong data or replace a clear message.
What do you do with an identity or word?
Spell it with the applicable phonetic alphabet and read an MMSI digit by digit for accurate copying.
What do the closing words mean?
OVER invites a reply; OUT ends the exchange. SAY AGAIN requests repetition and REPEAT emphasises important information.
What must a clear message carry?
Make identity, position, time, danger and requested help easy to copy; if you forget the formal phrase, speak clearly.
2Step by step
Build and check an SMCP message
- 1
Decide whether the communication is distress, urgency, safety, or routine.
The category guides the phrase and action.
- 2
Choose the formal phrase if it expresses the intended action.
The wrong phrase cannot repair incorrect data.
- 3
Spell the identity or word with the applicable alphabet.
It helps the listener copy names and identities.
- 4
Send coordinates and numbers at a pace that permits copying.
That pace permits accurate transcription.
- 5
Confirm the expected response and correct misunderstandings.
Checking prevents the message from remaining unclear.
- WARNING
- THIS IS VESSEL [ALFA BRAVO CHARLIE]
- MY POSITION IS [degrees] DEGREES [minutes] DECIMAL [fraction] MINUTES [hemisphere], AT [UTC] UTC
- WARNING [information]
- REQUEST [action]
- SAY AGAIN [field]
- REPEAT [important part]
- OVER
3Key data
- SMCP markers
- INSTRUCTION, ADVICE, WARNING, INFORMATION, QUESTION, ANSWER, REQUEST, INTENTION
- SAY AGAIN
- Requests repetition
- REPEAT
- Emphasises important information
- OVER
- Invites a reply
- OUT
- Ends an exchange
- MMSI
- Read digit by digit
- Position
- Include UTC
- Appendix 14
- Spelling alphabet and figure code
4Key points
- 1
SMCP reduces ambiguity; clear language remains necessary.
- 2
Radiotelephony is slow and distinct; make data easy to copy.
- 3
OVER expects a reply; OUT ends the exchange.
- 4
Marker, message, response: the content must be understood.
5Frequent mistakes
Wrong: "If I use SMCP, a wrong coordinate no longer matters."
Right: SMCP reduces ambiguity, but it cannot correct wrong coordinates, identities, or services.
Wrong: "REPEAT is forbidden and OVER and OUT is the correct formula."
Right: REPEAT has SMCP uses; OVER invites a reply and OUT ends the exchange.
Wrong: "OVER and OUT mean the same thing."
Right: OVER expects a reply; OUT is used when the exchange has ended.
6Exam keys & interpretation
Exam keys
- If you see «OVER and OUT», separate them: OVER invites a reply; OUT ends.
- For repetition, distinguish SAY AGAIN from REPEAT: requesting is not emphasising.
- With coordinates or an MMSI, look for copyable reading, UTC, and separated digits.
How to read it
- Think of SMCP as a shared lane: it orders the message but cannot repair wrong data.
- If you forget the formal phrase, give clear emergency information and check what is copied.
7Go deeper: GOC exam level
The detail behind each step for the General Operator's Certificate: the rules, the radio technique and worked cases.
Before you press the PTT
- 1Listen first: never interrupt distress, urgency or safety traffic.
- 2Check that the channel or frequency and the mode are right.
- 3Think the message through: addressee, your identity, situation, the key data and the action required.
- 4Press the PTT, pause very briefly, and speak at a moderate pace.
- 5Use short sentences, one idea per sentence.
- 6Say names, numbers, positions, times and units clearly.
- 7End with OVER if you expect a reply, OUT if the exchange is finished.
- 8If you make a mistake, correct it explicitly; never trust the other station to "work it out".
The order of a radiotelephone call
| Step | Example |
|---|---|
| 1. Station called | TARRAGONA RADIO / MV ALTAIR |
| 2. Own identity | THIS IS MV BOREAL, CALL SIGN ..., MMSI ... |
| 3. Reason / message marker | REQUEST / INFORMATION / WARNING ... |
| 4. Content | Position, situation, data or request |
| 5. Close | OVER / OUT |
For routine calls, ITU-R M.1171 (current version M.1171-1) is the operational reference, incorporated by reference in the Radio Regulations.
Procedure words
| Proword | Use |
|---|---|
| THIS IS | Identifies the transmitting station |
| OVER | I have finished this turn and expect a reply |
| OUT | Exchange finished, no reply expected |
| ROGER | I have received your last transmission |
| WILCO | I have understood your instruction and will comply |
| SAY AGAIN | Repeat your message, or the part indicated |
| REPEAT | SMCP: "Repeat", then the important part again to safeguard it ("draft 12.6, repeat, WUN TOO DECIMAL SIX metres") |
| I SAY AGAIN | Radiotelephone procedure: I repeat my last transmission or the part indicated |
| MISTAKE … CORRECTION | SMCP: say "Mistake", then "Correction" and the corrected part |
| STAND BY | Wait; I will call you back / stay available |
| NOTHING HEARD | No reply was received to the call |
IMO SMCP message markers
| Marker | Announces |
|---|---|
| QUESTION | I am going to ask something |
| ANSWER | A reply to a question |
| REQUEST | I ask for an action or service |
| INFORMATION | I give information |
| WARNING | I warn of a danger |
| ADVICE | I recommend an action |
| INSTRUCTION | I give an instruction, when I have the authority to do so |
| INTENTION | I state what I intend to do |
Phrases to practise
| Situation | Standard phrase |
|---|---|
| Ask for position | What is your position? |
| Give position | My position is ... |
| Ask for course and speed | What is your course and speed? |
| Give course | My course is ... degrees. |
| Give speed | My speed is ... knots. |
| Ask for a repeat | Say again. |
| Correct an item | Correction. ... |
| Warn | Warning. You are running into danger. |
| Ask for help | I require assistance. |
| Medical help | I require medical assistance. |
| Change channel | Change to VHF channel ... |
| Wait | Stand by on VHF channel ... |
| Weak signal | Your signal is weak. |
| Not understood | I cannot understand you. |
| Abandon | I am abandoning ship. |
| Person in water | Man overboard. |
STCW requires officers of the watch to understand and use the SMCP; these phrases complement the current IMO SMCP (resolution A.918(22)). When language difficulties remain, the International Code of Signals offers another structured fallback.
Spelling and reading data
| A ALFA | B BRAVO | C CHARLIE | D DELTA | E ECHO | F FOXTROT |
| G GOLF | H HOTEL | I INDIA | J JULIETT | K KILO | L LIMA |
| M MIKE | N NOVEMBER | O OSCAR | P PAPA | Q QUEBEC | R ROMEO |
| S SIERRA | T TANGO | U UNIFORM | V VICTOR | W WHISKEY | X X-RAY |
| Y YANKEE | Z ZULU |
- Read MMSIs and other identifiers digit by digit.
- Give positions as latitude and longitude with hemisphere; if the position is not current, give its time.
- Give courses in degrees, adding TRUE when the context needs it; speeds in knots; operational times in UTC where the procedure requires it.
Saying figures and using Q-codes
The IMO SMCP (resolution A.918, section 2.2) gives a modified pronunciation for figures that survives noise, and says numbers are spoken digit by digit ("course two-seven-zero" becomes "TOO SEVEN ZEERO").
| Figure | SMCP pronunciation | Figure | SMCP pronunciation |
|---|---|---|---|
| 0 | ZEERO | 5 | FIFE |
| 1 | WUN | 6 | SIX |
| 2 | TOO | 7 | SEVEN |
| 3 | TREE | 8 | AIT |
| 4 | FOWER | 9 | NINER |
| Decimal point | DECIMAL (or POINT) | 1000 | TOUSAND |
Q-codes (ITU-R M.1172) are three-letter abbreviations still met on the air and in exams; as a question they end with a question mark.
| Code | Meaning |
|---|---|
| QRM | I am being interfered with |
| QRN | I am troubled by static (atmospheric noise) |
| QRT | Stop sending |
| QRU | I have nothing for you |
| QRV | I am ready |
| QRZ | Who is calling me? |
| QSL | I acknowledge receipt |
| QSY | Change to another frequency |
| QTH | My position is |
Read-back and verification
| Problem | Protocol |
|---|---|
| Missed an item | SAY AGAIN + name the part |
| Gave a wrong item | MISTAKE, then CORRECTION + the right item |
| Critical instruction | Read back the essential data |
| Doubtful position | Ask for latitude, longitude and time again |
| Doubtful identity | Spell it, repeat call sign or MMSI |
| Doubtful channel | Repeat the channel number and wait for confirmation |
A routine call moved to a working channel
ALTAIR, ALTAIR, ALTAIR. THIS IS BOREAL, BOREAL, BOREAL. OVER. BOREAL. THIS IS ALTAIR. OVER. ALTAIR. CHANGE TO VHF CHANNEL 72. OVER. BOREAL. VHF CHANNEL 72. ROGER. OUT.
GOC exam check
VTS tells you to reduce speed to 8 knots. You understand and will comply. What do you reply?
- ROGER
- WILCO
- RECEIVED
- STAND BY
Show the answer
B. WILCO
Why: WILCO means understood and will comply. ROGER only confirms receipt and does not promise to comply.
You end a transmission and expect no reply. Which proword do you use?
- OVER
- STAND BY
- OUT
- NOTHING HEARD
Show the answer
C. OUT
Why: OUT closes the exchange with no reply expected. OVER means you have finished your turn and expect a reply.
How is a course of 095 spoken using SMCP figure pronunciation?
- ZEERO NINER FIFE
- ZERO NINE FIVE
- ZEERO NINER FIVE
- NINETY-FIVE
Show the answer
A. ZEERO NINER FIFE
Why: SMCP speaks figures digit by digit: 0 as ZEERO, 9 as NINER and 5 as FIFE. ZEERO NINER FIVE gets the last figure wrong; plain ZERO NINE FIVE ignores the SMCP forms.
Another ship, with no authority over you, wants to recommend that you alter course to starboard. Which SMCP marker should it use?
- INSTRUCTION
- INFORMATION
- INTENTION
- ADVICE
Show the answer
D. ADVICE
Why: ADVICE marks a recommendation. INSTRUCTION is only for a station with authority, such as a VTS or RCC where applicable.
Which Q-code means I am troubled by static (atmospheric noise)?
- QRM
- QRN
- QRT
- QSY
Show the answer
B. QRN
Why: QRN is static. QRM is interference from other stations, a common near miss.
You just gave your position with a wrong minute value. How do you put it right under SMCP?
- SAY AGAIN
- REPEAT
- MISTAKE, then CORRECTION
- STAND BY
Show the answer
C. MISTAKE, then CORRECTION
Why: SMCP: say MISTAKE, then CORRECTION followed by the right item. SAY AGAIN asks the other station to repeat, and REPEAT only safeguards an important part; neither corrects your error.
What is the correct order for opening a radiotelephone call?
- Station called, THIS IS, own identity
- THIS IS, own identity, station called
- Own identity, station called, OVER
- Message marker, station called, own identity
Show the answer
A. Station called, THIS IS, own identity
Why: The station called comes first, then THIS IS and your own identity, then the reason and content. Starting with your own name puts the order backwards.
Through heavy interference you think you heard change to channel seven-two. What do you do?
- Change to Channel 72 and call on it
- Change to Channel 12 and call on it
- Answer ROGER and wait on the same channel
- Repeat the channel and wait for confirmation
Show the answer
D. Repeat the channel and wait for confirmation
Why: With a doubtful channel, repeat the number and wait for confirmation instead of guessing. ROGER would confirm something you have not clearly received.
BOREAL is 5 NM off Tarragona at 1500 UTC. On Channel 16 the ship ALTAIR calls you to discuss a crossing situation. How do you answer?
- ALTAIR, THIS IS BOREAL. CHANGE TO CHANNEL 13. OVER.
- BOREAL, THIS IS ALTAIR. CHANGE TO CHANNEL 13. OUT.
- ALTAIR, THIS IS BOREAL. GO AHEAD ON CHANNEL 16. OVER.
- ALTAIR, THIS IS BOREAL. CHANGE TO CHANNEL 70. OVER.
Show the answer
A. ALTAIR, THIS IS BOREAL. CHANGE TO CHANNEL 13. OVER.
Why: Name the station called, identify yourself and move the exchange to Channel 13, the bridge-to-bridge navigational safety channel, ending with OVER because you expect a reply. Staying on 16 ties up the distress and calling channel, and Channel 70 is for DSC only.
Same scenario: on the working channel you want to tell ALTAIR that you will pass astern of her. Which SMCP message marker do you use?
- INSTRUCTION
- ADVICE
- INTENTION
- WARNING
Show the answer
C. INTENTION
Why: INTENTION announces what you are going to do yourself. INSTRUCTION is the trap: it is for a station with authority over the other, and ADVICE would recommend an action to ALTAIR rather than state your own.
8Full lesson & sources
Open the full lesson (diagrams and official references)
Use IMO Standard Marine Communication Phrases to reduce ambiguity. Say identities and coordinates clearly, including degrees, minutes, decimal points and hemisphere. Use UTC and read MMSIs digit by digit. The radiotelephony spelling alphabet and figure code are in ITU Radio Regulations Appendix 14; miscellaneous abbreviations and Q-codes are in ITU-R M.1172.
SAY AGAIN requests repetition. REPEAT can emphasize important information and is explicitly used in SMCP; it is not forbidden at sea. OVER expects a reply; OUT ends the exchange. The eight message markers are INSTRUCTION, ADVICE, WARNING, INFORMATION, QUESTION, ANSWER, REQUEST and INTENTION. Plain, understandable emergency information remains essential when a speaker cannot use the standard phrases perfectly.
Clarity is a safety function
Radio traffic at sea happens over noise, between people with different first languages, often under stress. The IMO Standard Marine Communication Phrases (SMCP) are a small, fixed vocabulary designed so that a Greek officer and a Filipino officer understand each other through static. They remove ambiguity, but they cannot fix bad data: a perfectly phrased message with a wrong coordinate still sends the rescue to the wrong place. If you cannot remember the standard phrase in an emergency, plain, simple English is still far better than silence.
Use the formal tools carefully
ITU Radio Regulations Article 32.6 asks for radiotelephony to be slow and distinct. In practice: a short pause after pressing the PTT so the first syllable is not cut off, one idea per sentence, and numbers spoken digit by digit. Article 32.7 points to the phonetic alphabet and figure code in Appendix 14 and to ITU-R M.1172, and recommends SMCP where appropriate. ITU and SMCP pronounce some figures differently. Know which one you are using: SMCP pronounces 0 to 9 as ZEERO, WUN, TOO, TREE, FOWER, FIFE, SIX, SEVEN, AIT, NINER, and 1000 as TOUSAND.
| Proword | Means | Typical mistake |
|---|---|---|
| SAY AGAIN | Repeat your message, or the part I name | Saying REPEAT when asking for a repeat |
| CORRECTION | The item I just gave was wrong; here is the right one | Correcting silently and hoping the listener notices |
| ROGER | I have received your message | Using it to mean “I will do it” |
| WILCO | I have understood and will comply | Saying it without reading back a critical item |
| OVER | My turn is finished, I expect a reply | Saying “OVER and OUT”, which is a contradiction |
| OUT | The exchange is finished | Ending a call that still needs an answer |
Coordinates and identities
Say a position the way someone can write it down: “MY POSITION IS FOWER WUN DEGREES TOO TOO DECIMAL FOWER MINUTES NORTH, ZEERO ZEERO AIT DEGREES FOWER TREE DECIMAL WUN MINUTES WEST, AT WUN TOO WUN ZEERO UTC.” Read an MMSI digit by digit (224 123 456 is “TOO TOO FOWER, WUN TOO TREE, FOWER FIFE SIX”) and spell names with the phonetic alphabet: ALTAIR is ALFA LIMA TANGO ALFA INDIA ROMEO.
Now a read-back that catches an error. You say: “CHANGE TO VHF CHANNEL SEVEN TOO.” The other ship replies: “CHANNEL SEVEN SEVEN, ROGER.” You answer: “NEGATIVE. CHANNEL SEVEN TOO. I SAY AGAIN, SEVEN TOO.” Without the read-back you would both have spent the next minute calling on different channels. With a position or a channel instruction in a MAYDAY, that minute matters.
Message markers
SMCP markers go in front of a sentence and say what kind of sentence it is: QUESTION, ANSWER, REQUEST, INFORMATION, WARNING, ADVICE, INSTRUCTION, INTENTION. Compare “You should alter to starboard” with “ADVICE. Alter course to starboard” and “INSTRUCTION. Alter course to starboard”. A ship can give ADVICE to another ship; usually only a VTS or other authority can give an INSTRUCTION. The marker tells the listener whether the next sentence is an order, a suggestion or information.
Here is a vague call put into SMCP. Vague: “I think maybe you are heading a bit towards us.” SMCP: “ALTAIR, THIS IS BOREAL. WARNING. YOU ARE RUNNING INTO DANGER. MY POSITION IS TOO MILES ON YOUR PORT BOW. QUESTION. WHAT ARE YOUR INTENTIONS? OVER.”
Sources: IMO SMCP A.918(22); ITU RR 2024, Articles 32.6–32.7; ITU RR Appendix 14; ITU-R M.1172.
Official references · 2026-09-09
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