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Importance of Reliable Marine Communications and Empowering Maritime Industry

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Effective communication is paramount within any industry, and the maritime sector is no exception. The safe and efficient movement of goods and personnel across international waters hinges upon a robust and standardized communication infrastructure.

This article provides an overview of marine communications, exploring the established protocols, emerging technologies, and their significance for global trade and maritime safety.

Duplex and Simplex Modes of R/T Operation

The majority of radiotelephone public correspondence and commercial radio traffic is operated on a duplex basis using paired working frequencies, i. e., transmission and reception are simultaneous, using two different frequencies so that it is just like an ordinary phone call. Simplex operation is used in ship-to-ship communication using one frequency; each person needs to say “over” and release the “press-to-talk” button before they can receive.

General Procedures

Calls to coast stations should be made on the appropriate working channel whenever possible. At other times, 2182 kHz (MF) or channel 16 (VHF) should be used. On HF, the paired calling frequency should be used. The ITU List of Coast Stations should be consulted for further details.

All ships making international voyages in Region 1 should be able to use the ship-to-shore working frequency 2045 kHz and the intership frequency. However, these frequencies shall not be used for working between stations of the same nationality. Instead, the nationality authorized frequencies should be used. In regions 2 and 3, ships making international voyages should be able to use the intership frequencies 2635 kHz and 2638 kHz.

When transmitting certain expressions, unusual name and words, figures or abbreviations, the International Phonetic Alphabet should be use. This is shown in Table 1.

Table 1. International Phonetic Alphabet and Figure Code
Code wordSpoken as
AAlphaAL FAH
BBravoBRAH VOH
CCharlieCHAR LEE or SHAR LEE
DDeltaDELL TAH
EEchoECH OH
FFoxtrotFOKS TROT
GGolfGOLF
HHotelHOH TELL
IIndiaIN DEE AH
JJulietJEW LEE ETT
KKiloKEY LOO
LLimaLEE MAH
MMikeMIKE
NNovemberNO VEM BER
OOscarOSS CAR
PPapaPAH PAH
QQuebecKEH BECK
RRomeoROW ME OH
SSierraSEE AIR AH
TTangoTANG GO
UUniformYOU NEE FORM or OO NEE FORM
VVictorVIK TAH
WWhiskeyWISS KEY
XX-RayECKS RAY
YYankeeYANG KEY
ZZuluZOO LOO
0NadazeroNAH-DAH-ZAY-ROH
1UnaoneOO-NAH-WUN
2BissotwoBEES-SOH-TWO
3TerathreeTAY-RAH-TREE
4KartefourKAR-TAY-FOWER
5PantativePAN-TAH-FIVE
6SoxisixSOK-SEE-SIX
7SettesevenSAY-TAY-SEVEN
8OktoeightOK-TOH-AIT
9NovenineNO-VAY-NINER
Decimal pointDecimalDAY-SEE-MAL
Full stopStopSTOP

In practice, difficult names or words should be spoken and then spelt phonetically and then spoken again. All figures should be repeated, e. g., “eighteen miles, I say again 18 (one eight) miles”.

Speak slowly and clearly at all times. In case of communication/language difficulties, refer to IMO Standard Marine Communication Phrases.

The Q-code abbreviations are often employed by coast stations, ship stations and other types of station to aid communications. The full list of Q-Codes used in Maritime Mobile and Maritime Mobile-Satellite Services.

The Q-Code abbreviations, plus complementary information, are put in the form of a question when followed by the signal RQ (spoken as “ROMEO QUEBEC”). Some abbreviations may be given an affirmative or negative sense by adding the signals C (positive) or NO (negative) (spoken as “CHARLIE” or “NO”).

Many of the Q-Codes for the maritime mobile service have meanings similar to signals appearing in the Code of Signals (INTERCO).

R/T Call & Reply Frequencies

Internationally, 2182 kHz and VHF channel 16 are used for call and reply (calls being less than 1 minute), and by coast stations to announce traffic lists, weather bulletins, etc. For information on communications with the various coast stations, consult the ITU List of Coast Stations. Radiotelephone operation at HF and VHF is also subject to the channel plans established in Appendices 16 and 18, respectively, of the ITU Radio Regulations (see the ITU Manual for Use bye the Maritime Mobile and Maritime Mobile Satellite-Services).

The HF frequencies generally authorised for ship stations to call coast stations in the duplex (i. e., paired-frequency) mode of operation are:

  • 4125*kHz;
  • 6215*kHz;
  • 8255*kHz;
  • 12290*kHz;
  • 16420*kHz;
  • 18795*kHz;
  • 22060*kHz;
  • 25097*kHz.

The frequencies 4125 kHz, 6215 kHz, 12290 kHz and 16420 kHz are also designated as simplex mode radio-telephone distress and safety traffic frequencies (see article R/T Distress Calls, Mayday Procedures & Terrestrial Communications“NON-DSC Terrestrial Distress Communications”). Use of these frequencies for other purposes is therefore allowed only on the condition that harmful interference to distress, urgency and safety communications shall not occur.

The frequencies 4125 kHz and 6215 kHz may in addition be used for and reply purposes by coast and ship stations on a simplex basis provided that the power does not exceed 1 kW. In addition, the frequency 4125 kHz is also authorised for common use in the United States by coast stations and ship stations for radiotelephone communications on a simplex basis with the power limit of 1 kW.

Calling Procedures

Once the chosen frequency is established, the ship station operator should ensure that proceeding with the call is not likely to cause interference to transmissions already in progress. If, by chance, interference is caused then the transmission must cease as request. The station making the request should indicate the time needed to complete its traffic.

Traffic Lists

For ship to shore communications it is the ship which usually establishes communication. Coast stations with traffic for ships transmit their call in the form of a traffic list which consists of the names and call signs, in alphabetical order, of the ships for which they have traffic on hand.

Traffic lists are sent at fixed times. For this reason, ship should monitor local stations on MF or VHF and/or HF according to the information given in the ITU List of Coast Stations and relevant national publications.

If, after the name or call sign, the Q-Code QTC is sent, this indicate that the coast station has a telegram for the ship. Similarly, the Q-Code QTJ indicates that there is a telephone call for the ship.

In both cases the ship waits the end of the traffic list and then call the coast station and asks for its traffic.

Working Procedures

When making a call to a coast station on 2182 kHz the ship station operator should indicate the reason for the call and the intended working channel for the subsequent traffic, e. g.,

SINGAPORE RADIO (up to 3 times)
 
THIS IS
 
MUNDOGAS ATLANTIC (up to 3 times)
 
CALL SIGN LIMA ECHO ECHO NOVEMBER
 
I HAVE A TR FOR YOU ON CHANNEL 23
 
OVER

When calling on a VHF working channel, the ship should indicate which channel it is calling on.

If the station being called does not reply to a call sent three times at 2 minutes intervals, the ship should stop calling for a further period of 3 minutes.

When reply to a call, the coast station may ask the ship to go immediately to a working frequency, in which case the ship should then re-establish contact with the coast station. If the ship is given a turn number, the ship should go to the working frequency and wait for the coast station to call. Once contact is established, names or call signs need only be used once.

When a called station is unable to accept traffic immediately, it may indicate the waiting time, with a reason if the delay exceeds 10 minutes.

When a station receives a call without being certain for which the call is intended, it shall not reply until the call has been repeated. Alternatively, if the call is intended for it but the called station is uncertain who is calling, it shall replay immediately, asking for a repetition , e. g.,

STATION CALLING MUNDOGAS ATLANTIC
 
PLEASE REPEAT YOUR CALL
 
OVER

During communications between ships and coast stations, the coast station controls the working. In communications between ships, the called ship station controls the working.

Ships stations whose operation is not continuos should not close before:

  1. Finishing all operations relating to distress, urgency or safety.
  2. Receiving or transmitting, as far as is practicable, all traffic known to be available.

When arriving in port and intending to close down, ship stations should so advise the local station.

On-board Communications

Normally conducted on VHF channels 15 or 17; or in UHV in the bands between 450 and 470 MHz. Transmitter power output is limited to 1 W on VHF; 2 W on UHF.

Call should take the form of the following examples.

From the Controlling Station (Bridge):

ATLANTIC ALPHA (or BRAVO, tc,) (×3)
 
THIS IS
 
ATLANTIC CONTROL (×3)

From the Sub Station

ATLANTIC CONTROL (×3)
 
THIS IS
 
ATLANTIC ALPHA (×3)

Pilot Services

A ship calling a pilot service should use, in order of preference:

  1. A VHF channel (usually a working channel);
  2. An MF R/T working frequency;
  3. 2182 KHz to determine working frequencies.

Communications in the Port Operations Service are restricted to those relating to the safe movements of ships, operational handling and, in an emergency, the safety of persons.

Specific details of pilot and port operations services and their frequencies are available in the ITU List of Coast Stations and other publications produced by national Administrations and service providers.

R/T Commercial Working(1.25)

An exercise in commercial working which includes a simulated distress situation is recommended for the GMDSS examination.

The following section gives an example exercise where the examiner will take the part of both the vessel in distress and the local coast station. The candidates will each assume they are on a different ship in the vicinity on the incident and must respond accordingly whilst at the same time keeping a log.

The practice working described includes more than learning about distress operations. Candidates need to be able to send a transit report (TR), make R/T link call, receive a traffic list, receive a weather bulletin, etc.

Operational Watchkeeping Procedures

Commercial working exercise should allow the candidate to gain experience in the complete sequence of operations involved in sending a TR, making link call, calling the coast station on 2182 MHz or a VHF channel with call details and the intended working channel or frequencies, etc.

Commercial Working Exercise

SINGAPORE RADIO (up to 3 times)
 
THIS IS
 
MUNDOGAS ATLANTIC (up to 3 times)
 
CALL SIGN LIMA ECHO ECHO NOVEMBER
 
I HAVE A TR AND A LINK CALL FOR YOU CHANNEL 16
 
PLEASE
 
OVER

The coast station would then reply:

(a)
 
MUNDOGAS ATLANTIC
 
THIS IS SINGAPORE RADIO
 
ROGER
 
CHANGE THE CHANNEL 27
 
OVER

Or:

(b)
 
MUNDOGAS ATLANTIC
 
THIS IS SINGAPORE RADIO
 
ROGER
 
CHANGE THE CHANNEL 27
 
STANDBY YOU ARE TURN NUMBERTWO
 
OVER

The reply would be:

  • ROGER GOING UP (now change to the working channel);

When on channel 27, either call the coast station

[(a) above]

SINGAPORE RADIO (up to 3 times)
 
THIS IS
 
MUNDOGAS ATLANTIC (up to 3 times)
 
How do you read me
 
OVER

Or [(b) above], stand by until Singapore Radio calls again.

When the coast station asks for the TR, reply:

SINGAPORE RADIO
 
THIS IS MUNDOGAS ATLANTIC
 
MY TR BEGINS,
 
CALL SIGN LIMA ECHO ECHO NOVEMBER
 
I AM IN POSITION
 
BOUND FOR
 
END OF MY TR,
 
OVER

The coast station then acknowledges receipt of the TR and, if a link call has been request, will ask for the telephone number.

Then reply:

SINGAPORE RADIO
 
THIS IS MUNDOGAS ATLANTIC
 
MY LINK CALL NUMBER IS…,
 
I SAY AGAIN…
 
MY ACCOUNTING CODE IS (….)
 
OVER

The coast station may then give instructions to STANDBY while the call is connected and will then reply that the telephone call has been connected, read back the number (N. B.; the telephone number should be verified before completing the connection), and give the instruction GO AHEAD.

The reply then is:

ROGER GOING AHEAD (The call now takes place).

When the call is completed, inform the coast station so:

SINGAPORE RADIO
 
THIS IS MUNDOGAS ATLANTIC
 
THAT IS THE END OF MY LINK CALL,
 
OVER

The coast station then REPLIES, giving details of the call duration, which should be confirmed before signing off, i. e.

INGAPORE RADIO
 
THIS IS MUNDOGAS ATLANTIC
 
I AGREE 3 MINUTES
 
I HAVE NO FURTHER TRAFFIC, THANKYOU,
 
OUT

The call details should then be recorded (the radio log may be used for the exercise, although in practice computer systems are often used to record details of chargeable calls).

At some stage of the exercise the coast station can announce the traffic list on channel 16, e. g.:

ALL STATIONS (×3)
 
THIS IS SINGAPORE RADIO
 
LISTEN FOR MY TRAFFIC LIST ON CHANNEL 24
 
STANDBY

Then change on to the broadcast frequency, receive the list and the information (again, the log can be used for the purposes of the exercise).

Author
Author photo - Olga Nesvetailova
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Literature
  1. General operator’s Certificate for The Global Maritime Distress and Safety System, Course + Compendium, Model Course IMO 1.25, Printed by PMS UK Ltd London, 2004.
  2. European Radiocommunications Committee ERC Decision of 10 March 1999 on the harmonised examination syllabi for General Operator’s Certificate (GOC) and Restricted Operator’s Certificate (ROC)(ERC 99 01).
  3. IMO GMDSS-Handbook, London, U. K., 2004.
  4. Norcontrol Capella GMDSS Simulator, Technical documentations, Kongsberg Maritime Ship Systems, Norway, 2005.
  5. INMARSAT MARITIME COMMUNICATIONS HANDBOOK – INMARSAT – London, U. K, 2005.
  6. Seafarers’ Training, Certification and Watchkeeping CODE 1995 (STCW Code 95, published by IMO, London, 1996), – Part A Mandatory standards regarding provisions of the annex to the Convention Chapter IV Standards regarding radio personnel.
  7. Seafarers’ Training, Certification and Watchkeeping CODE 1995 (STCW Code 95, published by IMO, London, 1996), – Part B Mandatory guidance regarding provisions of the STCW and its annex; Chapter IV Guidance regarding radiocommunication and radio personnel.
  8. V. Pipirigeanu, M. Udrea, Introducere in GMDSS – Sistemul Mondial de Primejdie si Siguranta Maritima, Ed. Europolis, Constanta, 2002.
  9. Graham D. Lees, William G. Williamson, Handbook for Marine Radio Comunication, e d. LLOYD S OF LONDON PRESSLTD., 2004.
  10. ITU Manual for Use by The Maritime Mobile and Maritime Mobile Satellite Services, 2006.
  11. IAMSAR Manual – International Aeronautical and Maritime Search and Rescue Manual, 2001.
  12. C/S G.003 – Introduction to Cospas-Sarsat System, (G3OCT28.99D Issue 5 – Rev 1 October 1999), C/S Documents published by Cospas-Sarsat in Handbook of Regulations on 406 MHz and 121,5 MHz Beacons, (1999);
  13. Tor R. Kristensen – An Introduction to GMDSS, revised GOC Edition, – 7th edition, Leknes, Norway, 2007.
  14. C/S T.001 – Specification for Cospas-Sarsat 406 MHz Distress Beacon, (T1OCT30.99D – Issue 3-Rev. 2 October 1999), Documents published by Cospas-Sarsat in Handbook of Regulations on 406 MHz and 121,5 MHz Beacons (1999).
  15. IMO SOLAS (SAVE OF LIVE AT SEA), Consolidated Edition, London, 2001.
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