VHF/MF/HF voice procedure

Distress procedure
Distress communications rely on the use of terrestrial MF, HF and VHF radio
communications and communications using satellite techniques. Distress
communications shall have absolute priority over all other transmissions. The following
terms apply:
− The distress alert is a digital selective call (DSC) using a distress call format, in the
bands used for terrestrial radio communication, or a distress message format, in
which case it is relayed through space stations.
− The distress call is the initial voice or text procedure.
− The distress message is the subsequent voice or text procedure.
− The distress alert relay is a DSC transmission on behalf of another station.
− The distress call relay is the initial voice or text procedure for a station not itself in
distress
The distress call shall be sent on the distress and safety frequencies designated in the
MF, HF and VHF bands for radiotelephony. The distress alert or call and subsequent
messages shall be sent only on the authority of the person responsible for the ship,
aircraft or other vehicle carrying the mobile station or the mobile earth station. It shall
be transmitted with full carrier power (VHF - 25W, MF/HF – full power)
Transmissions by radiotelephony shall be made slowly and distinctly, each word being
clearly pronounced to facilitate transcription. The phonetic alphabet and figure code in
appendix 14 of the RR and the abbreviations and signals in accordance with the most
recent version of Recommendation ITU-R M.1172 should be used where applicable.
Ship-to-ship distress alerts are used to alert other ships in the vicinity of the ship in
distress and are based on the use of DSC in the VHF and MF bands. Additionally, the
HF band may be used. Ship stations equipped for DSC procedures may transmit a
distress call and distress message immediately following the distress alert in order to
attract attention from as many ship stations as possible. Ship stations not equipped for
DSC procedures shall, where practical, initiate the distress communications by
transmitting a radio telephony distress call and message on the frequency 156.8 MHz
(VHF channel 16).
The radiotelephone distress signal consists of the word MAYDAY. The distress call
sent on the frequency 156.8 MHz (VHF channel 16) or on MF/HF shall be given in the
following form:

MAYDAY MAYDAY MAYDAY

THIS IS
SHIP’S NAME SHIP’S NAME SHIP’S NAME
CALL SIGN
MMSI

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The distress message which follows the distress call should be given in the following
form:
MAYDAY; SHIP’S NAME; CALL SIGN;MMSI
− the position, given as the latitude and longitude, or if the latitude and
longitude are not known or if time is insufficient, in relation to a
known geographical location;
− the nature of the distress;
− the kind of assistance required;
− any other useful information

Distress Relay
A station in the mobile or mobile-satellite service which learns that a mobile unit is in
distress (for example, by a radio call or by observation) shall initiate and transmit a
distress alert relay and/or a distress call relay on behalf of the mobile unit in distress
once it has ascertained that any of the following circumstances apply.
− on receiving a distress alert or call which is not acknowledged by a coast station
or another vessel within five minutes
− on learning that the mobile unit in distress is otherwise unable or incapable of
participating in distress communications, if the master or other person
responsible for the mobile unit not in distress considers that further help is
necessary
However, a ship shall not transmit a distress alert relay to all ships by DSC on the VHF
or MF distress frequencies following receipt of a distress alert sent by DSC by the ship
in distress.
When an aural watch is being maintained on shore and reliable ship-to-shore
communications can be established by radiotelephony, a distress call relay is sent by
radiotelephony and addressed to the relevant coast station or rescue coordination
centre on the appropriate frequency.

The distress call relay sent by radiotelephony should be given in the following form:
MAYDAY RELAY MAYDAY RELAY MAYDAY RELAY
ALL STATIONS ALL STATIONS ALL STATIONS
THIS IS
SHIP’S NAME SHIP’S NAME SHIP’S NAME
CALL SIGN
MMSI
(all identifications of the relaying vessel)

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This call can be addressed to all stations or to an individual station. This call shall be
followed by a distress message which shall, as far as possible, repeat the information
contained in the original distress alert or message or the observations done by the
relaying station:
Following received on Channel 16 at time in UTC
MAYDAY; SHIP’S NAME; CALL SIGN;MMSI
(All identifications of the vessel in distress)
− the position, given as the latitude and longitude, or if the latitude and
longitude are not known or if time is insufficient, in relation to a
known geographical location;
− the nature of the distress;
− the kind of assistance required;
− any other useful information

or

following observed
MAYDAY; Unidentified trawler

(If the station in distress cannot be identified, originate the distress message as well,
using, terms such as ―Unidentified trawler‖ to refer to the mobile unit in distress.)
− the observed position, given as the latitude and longitude, or if the
latitude and longitude are not known or if time is insufficient, in relation
to a known geographical location;
− the nature of the distress
− the kind of assistance required;
− any other useful information
Acknowledgement
Acknowledgement of receipt of a distress alert, including a distress alert relay, shall be
made in the manner appropriate to the method of transmission of the alert and within
the time-scale appropriate to the role of the station in receipt of the alert.
When acknowledging receipt of a distress alert sent by DSC, the acknowledgement in
the terrestrial services shall be made by DSC, radiotelephony or narrow-band direct-
printing telegraphy as appropriate to the circumstances, on the associated distress and
safety frequency in the same band in which the distress alert was received, taking due
account of the directions given in the most recent versions of the RR Art.32.
In areas where reliable communications with one or more coast stations are
practicable, ship stations in receipt of a distress alert or a distress call from another
vessel should defer acknowledgement for a short interval so that a coast station may
acknowledge receipt in the first instance.

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When acknowledging by radiotelephony the receipt of a distress alert or a distress call
from a ship station or a ship earth station, the acknowledgement should be given in the
following form:

MAYDAY
SHIP’S NAME and CALL SIGN or MMSI
(of the vessel in distress)
THIS IS
SHIP’S NAME and CALL SIGN
(of the acknowledging vessel)
RECEIVED MAYDAY

Ship stations in receipt of a distress call sent by radiotelephony on the frequency

156.8 MHz (VHF channel 16) shall, if the call is not acknowledged by a coast station
or another vessel within five minutes, acknowledge receipt to the vessel in distress and
use any means available to relay the distress call to an appropriate coast station or
coast earth station.
However in order to avoid making unnecessary or confusing transmissions in
response, a ship station, which may be at a considerable distance from the incident,
receiving an HF distress alert, shall not acknowledge it but shall observe the distress
frequency in the band in which the distress alert was sent and shall, if the distress
alert is not acknowledged by a coast station within five minutes, relay the distress alert,
but only to an appropriate coast station or coast earth station.
A ship station acknowledging receipt of a distress alert sent by DSC should, in
accordance with the following.
− In the first instance, acknowledge receipt of the distress alert by using
radiotelephony on the distress and safety traffic frequency in the band used for
the alert, taking into account any instructions which may be issued by a
responding coast station.
− If acknowledgement by radiotelephony of the distress alert received on the MF
or VHF distress alerting frequency is unsuccessful, acknowledge receipt of the
distress alert by responding with a digital selective call on the appropriate
frequency.
However, unless instructed to do so by a coast station or a rescue coordination centre,
a ship station may only send an acknowledgement by DSC in the event that:
− no acknowledgement by DSC from a coast station has been observed; and
− no other communication by radiotelephony or narrow-band direct-printing
telegraphy to or from the vessel in distress has been observed; and
− at least five minutes have elapsed and the distress alert by DSC has been
repeated.

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A ship station in receipt of a shore-to-ship distress alert relay or distress call relay
should establish communication as directed and render such assistance as required
and appropriate.

Distress Traffic and on scene communication

On receipt of a distress alert or a distress call, ship stations and coast stations shall
set watch on the radiotelephone distress and safety traffic frequency associated with
the distress and safety calling frequency on which the distress alert was received.
Distress traffic consists of all messages relating to the immediate assistance required
by the ship in distress, including search and rescue communications and on-scene
communications. The distress traffic shall as far as possible be on the frequencies
contained in the RR Article 31.
For distress traffic by radiotelephony, when establishing communications, calls shall
be prefixed by the distress signal MAYDAY.
The rescue coordination centre responsible for controlling a search and rescue
operation shall also coordinate the distress traffic relating to the incident or may appoint
another station to do so.

On-scene communications are those between the mobile unit in distress and assisting
mobile units, and between the mobile units and the unit co-ordinating search and
rescue operations. Control of on-scene communications is the responsibility of the unit
co-ordinating search and rescue operations. Simplex communications shall be used
so that all on-scene mobile stations may share relevant information concerning the
distress incident. If direct-printing telegraphy is used, it shall be in the forward error-
correcting mode.
The preferred frequencies in radiotelephony for on-scene communications are 156.8
MHz and 2182 kHz. The frequency 2174.5 kHz may also be used for ship-to-ship on-
scene communications using narrow-band direct-printing telegraphy in the forward
error correcting mode. In addition to 156.8 MHz and 2182 kHz, the frequencies 3023
kHz, 4125 kHz, 5680 kHz, 123.1 MHz and 156.3 MHz may be used for ship-to- aircraft
on-scene communications.
The selection or designation of on-scene frequencies is the responsibility of the unit
co-ordinating search and rescue operations. Normally, once an on-scene frequency is
established, a continuous aural or teleprinter watch is maintained by all participating
on-scene mobile units on the selected frequency.

MAYDAY
SHIP’S NAME and CALL SIGN
(for example vessel in distress)
THIS IS
SHIP’S NAME and CALL SIGN
5
 (assisting vessel)
Calling reason

The rescue coordination centre co-ordinating distress traffic, the unit co-ordinating
search and rescue operations or the coast station involved may impose silence on
stations which interfere with that traffic. This instruction shall be addressed to all
stations or to one station only, according to circumstances. In either case, the following
shall be used:
In radiotelephony, the signal SEELONCE MAYDAY

SHIP’S NAME, CALL SIGN or ALL STATIONS

SEELONCE MAYDAY

Until they receive the message indicating that normal working may be resumed, all
stations which are aware of the distress traffic, and which are not taking part in it, and
which are not in distress, are forbidden to transmit on the frequencies in which the
distress traffic is taking place.
When distress traffic has ceased on frequencies which have been used for distress
traffic, the station controlling the search and rescue operation shall initiate a message
for transmission on these frequencies indicating that distress traffic has finished.
In radiotelephony, the message should consist of:

MAYDAY
ALL STATIONS ALL STATIONS ALL STATIONS
THIS IS
SHIP’SNAME SHIP’S NAME SHIP’S NAME
CALL SIGN
MMSI
the time of handing in of the message in UTC
SHIP’S NAME, CALL SIGN and MMSI
(of the mobile station which was in distress)
SEELONCE FEENEE

False Alert
A station transmitting an inadvertent distress alert or call shall cancel the transmission.
An inadvertent DSC alert shall be cancelled by DSC, if the DSC equipment is so
capable. The cancellation should be in accordance with the most recent version of
Recommendation ITU R M.493. In all cases, cancellations shall also be transmitted by

6
radiotelephony.
An inadvertent distress call shall be cancelled by radiotelephony in accordance with
the procedure described below.
Inadvertent distress transmissions shall be cancelled orally on the associated distress
and safety frequency in the same band on which the distress transmission was sent,
using the following procedure:

ALL STATIONS ALL STATIONS ALL STATIONS

THIS IS
SHIP’S NAME SHIP’S NAME SHIP’S NAME
CALL SIGN
MMSI
PLEASE CANCEL MY DISTRESS ALERT OF time in UTC.

Canellation of False distress alerts

Urgency procedure
Urgency communication include
− Medico- and medical transport calls,
− urgent communication relating extreme weather conditions and
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 − support communications for search and rescue operations.
Urgency communications shall have priority over all other communications, except
distress.
The following terms apply:
− The urgency announcement is a digital selective call using an urgency call
format in the bands used for terrestrial radio communication, or an urgency
message format, in which case it is relayed through space stations.
− The urgency call is the initial voice or text procedure.

− The urgency message is the subsequent voice or text procedure.

In a terrestrial system, urgency communications consist of an announcement,

transmitted using DSC, followed by the urgency call and message transmitted using
radiotelephony. The announcement of the urgency message shall be made on one or
more of the distress and safety calling frequencies specified in the RRs, using both
DSC and the urgency call format, or if not available, radio telephony procedures and
the urgency signal. Announcements using DSC should use the technical structure and
content set forth in the most recent version of Recommendations ITU-R M.493 and
ITU-R M.541.
Ship stations not equipped for DSC procedures may announce an urgency call and
message by transmitting the urgency signal by radiotelephony on the frequency
156.8 MHz (channel 16), while taking into account that other stations outside VHF
range may not receive the announcement.
In the maritime mobile service, urgency communications may be addressed either to
all stations or to a particular station. When using DSC techniques, the urgency
announcement shall indicate which frequency is to be used to send the subsequent
message and, in the case of a message to all stations, shall use the ―All Ships‖ format
setting.
Urgency announcements from a coast station may also be directed to a group of
vessels or to vessels in a defined geographical area.
The urgency call and message shall be transmitted on one or more of the distress and
safety traffic frequencies. However, in the maritime mobile service, the urgency
message shall be transmitted on a working frequency:
− in the case of a long message or a medical call; or
− in areas of heavy traffic when the message is being repeated.
An indication to this effect shall be included in the urgency announcement or call.
The urgency signal consists of the words PAN PAN. The urgency call format and the
urgency signal indicate that the calling station has a very urgent message to transmit
concerning the safety of a mobile unit or a person. Communications concerning
medical advice may be preceded by the urgency signal. Mobile stations requiring
medical advice may obtain it through any of the land stations shown in the List of Coast

8
Stations and Special Service Stations.
Urgency communications to support search and rescue operations need not be
preceded by the urgency signal.

9
The urgency call should consist of:

PAN PAN PAN PAN PAN PAN

ALL STATIONS ALL STATIONS ALL STATIONS
THIS IS
SHIP’S NAME SHIP’S NAME SHIP’S NAME
(or coast station name)
CALL SIGN
MMSI
followed by the urgency message or followed by the details of the channel to
be used for the message in the case where a working channel is to be used.

In radiotelephony, on the selected working frequency, the urgency call and message
consists of:

PAN PAN PAN PAN PAN PAN

ALL STATIONS ALL STATIONS ALL STATIONS
THIS IS
SHIP’S NAME SHIP’S NAME SHIP’S NAME
(or coast station name)
CALL SIGN
MMSI
the text of the urgency message

The urgency call format or urgency signal shall be sent only on the authority of the
person responsible for the ship, aircraft or other vehicle carrying the mobile station or
mobile earth station. The urgency call format or the urgency signal may be transmitted
by a land station or a coast earth station with the approval of the responsible authority.
Ship stations in receipt of an urgency announcement or call addressed to all stations
shall not acknowledge. Ship stations in receipt of an urgency announcement or call of
an urgency message shall monitor the frequency or channel indicated for the message
for at least five minutes. If, at the end of the five-minute monitoring period, no urgency
message has been received, a coast station should, if possible, be notified of the
missing message. Thereafter, normal working may be resumed.
Coast and ship stations which are in communication on frequencies other than those
used for the transmission of the urgency signal or the subsequent message may
continue their normal work without interruption, provided that the urgency message is
10
not addressed to them nor broadcast to all stations.
When an urgency announcement or call and message was transmitted to more than
one station and action is no longer required, an urgency cancellation should be sent
by the station responsible for its transmission.
The urgency cancellation should consist of:

PAN PAN PAN PAN PAN PAN

ALL STATIONS ALL STATIONS ALL STATIONS
THIS IS
SHIP’S NAME SHIP’S NAME SHIP’S NAME
(or coast station name)
CALL SIGN
MMSI
PLEASE CANCEL URGENCY MESSAGE OF time in UTC

Medical Transport
The term ―medical transports‖, as defined in the 1949 Geneva Conventions and
Additional Protocols, refers to any means of transportation by land, water or air,
whether military or civilian, permanent or temporary, assigned exclusively to medical
transportation and under the control of a competent authority of a party to a conflict or
of neutral States and of other States not parties to an armed conflict, when these ships,
craft and aircraft assist the wounded, the sick and the shipwrecked.
For the purpose of announcing and identifying medical transports which are protected
under the above mentioned Conventions, the procedure of urgency announcement,
call and message is obligatory. The urgency call shall be followed by the addition of
the single word MAY-DEE-CAL, in radiotelephony.
When using DSC techniques, the urgency announcement on the appropriate DSC
distress and safety frequencies shall always be addressed to all stations on VHF and
to a specified geographical area on MF and HF and shall indicate ―Medical transport‖
in accordance with the most recent version of Recommendations ITU-R M.493 and
ITU-R M.541
Medical transports may use one or more of the distress and safety traffic frequencies
for the purpose of self-identification and to establish communications. As soon as
practicable, communications shall be transferred to an appropriate working frequency.
The use of the signals described above indicates that the message which follows
concerns a protected medical transport. The message shall convey the following data:

− call sign or other recognized means of identification of the medical transport;

− position of the medical transport;
− number and type of vehicles in the medical transport;

11
 − intended route;
− estimated time en route and of departure and arrival, as appropriate;
− any other information, such as flight altitude, radio frequencies guarded,
languages used and secondary surveillance radar modes and codes.

The use of radio communications for announcing and identifying medical transports is
optional; however, if they are used, the provisions of the RRs and particularly of the
Articles 30-33 shall apply.

Safety procedure
Safety communications include

− navigational and meteorological warnings,

− urgent information,
− ship-to-ship safety of navigation communications,
− communications relating to the navigation, movements and needs of ships and
− weather observation messages destined for an official meteorological service.

Safety communications shall have priority over all other communications, except
distress and urgency

The following terms apply:

− the safety announcement is a digital selective call using a safety call format in
the bands used for terrestrial radio communication or a safety message format,
in which case it is relayed through space stations;
− the safety call is the initial voice or text procedure;
− the safety message is the subsequent voice or text procedure

In a terrestrial system, safety communications consist of a safety announcement,

transmitted using DSC, followed by the safety call and message transmitted using
radiotelephony, narrow-band direct-printing or data. The announcement of the safety
message shall be made on one or more of the distress and safety calling frequencies
using either DSC techniques and the safety call format, or radiotelephony procedures
and the safety signal.
However, in order to avoid unnecessary loading of the distress and safety calling
frequencies specified for use with DSC techniques:

− safety messages transmitted by coast stations in accordance with a

predefined timetable should not be announced by DSC techniques;
− safety messages which only concern vessels sailing in the vicinity should be
announced using radiotelephony procedures

In addition, ship stations not equipped for DSC procedures may announce a safety

12
message by transmitting the safety call by radiotelephony. In such cases the
announcement shall be made using the frequency 156.8 MHz (VHF channel 16), while
taking into account that other stations outside VHF range may not receive the
announcement.
In the maritime mobile service, safety messages shall generally be addressed to all
stations. In some cases, however, they may be addressed to a particular station. When
using DSC techniques, the safety announcement shall indicate which frequency is to
be used to send the subsequent message and, in the case of a message to all stations,
shall use the ―All Ships‖ format setting
In the maritime mobile service, the safety message shall, where practicable, be
transmitted on a working frequency in the same band(s) as those used for the safety
announcement or call. A suitable indication to this effect shall be made at the end of
the safety call. In the case that no other option is practicable, the safety message may
be sent by radiotelephony on the frequency 156.8 MHz (VHF channel 16)
The safety signal consists of the word SECURITE.
The safety call format or the safety signal indicates that the calling station has an
important navigational or meteorological warning to transmit. Messages from ship
stations containing information concerning the presence of cyclones shall be
transmitted, with the least possible delay, to other mobile stations in the vicinity and to
the appropriate authorities through a coast station, or through a rescue coordination
centre via a coast station or an appropriate coast earth station. These transmissions
shall be preceded by the safety announcement or call. Messages from ship stations,
containing information on the presence of dangerous ice, dangerous wrecks, or any
other imminent danger to marine navigation, shall be transmitted as soon as possible
to other ships in the vicinity, and to the appropriate authorities through a coast station,
or through a rescue coordination centre via a coast station or an appropriate coast
earth station. These transmissions shall be preceded by the safety announcement or
call

The complete safety call should consist of:

SECURITE SECURITE SECURITE

ALL STATIONS ALL STATIONS ALL STATIONS
(or individual called station, three times)
THIS IS
SHIP’S NAME SHIP’S NAME SHIP’S NAME
(or coast station name)
CALL SIGN
MMSI
followed by the safety message or followed by the details of the channel to be
used for the message in the case where a working channel is to be used.

13
In radiotelephony, on the selected working frequency, the safety call and message
should consist of:

SECURITE SECURITE SECURITE

ALL STATIONS ALL STATIONS ALL STATIONS
(or individual called station, three times)
THIS IS
SHIP’S NAME SHIP’S NAME SHIP’S NAME
(or coast station name)
CALL SIGN
MMSI
the text of the safety message

Ship stations in receipt of a safety announcement using DSC techniques and the ―All
Ships‖ format setting, or otherwise addressed to all stations, shall not acknowledge.
Ship stations in receipt of a safety announcement or safety call and message shall
monitor the frequency or channel indicated for the message and shall listen until they
are satisfied that the message is of no concern to them. They shall not make any
transmission likely to interfere with the message

Intership navigation safety communications

Intership navigation safety communications are those VHF radiotelephone
communications conducted between ships for the purpose of contributing to the safe
movement of ships. The frequency 156.650 MHz is used for intership navigation safety
communications.
Port operation and ship movement communication
Radio traffic belonging port operation and ship movement service is a radio traffic
regarding the safety of navigation. Calls for this service do not contain the safety signal
e.g.:

Hamburg Pilot
this is
Moby Dick / TFKA
I will arrive at your position in about two hours
Over

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Use of other frequencies for safety
Radio communications for safety purposes concerning ship reporting communications,
communications relating to the navigation, movements and needs of ships and weather
observation messages may be conducted on any appropriate communications
frequency, including those used for public correspondence. In terrestrial systems, the
bands 415-535 kHz (see RR Article 52), 1606.5-4000 kHz (see RR Article 52), 4000-
27500 kHz (see RR appendix 17), and 156-174 MHz (see RR appendix 18) are used
for this function. In the maritime mobile-satellite service, frequencies in the bands 1530-
1544 MHz and 1626.5-1645.5 MHz are used for this function as well as for distress
alerting purposes.

Routine communication
Routine communications are communications which do not require any priority.

Calling a subscriber (ship to shore)

After announcing the coast station by DSC and receiving their acknowledgement
including the working frequencies, the coast station will call the ship station as soon as
possible on the specified frequency like e.g.
Moby Dick / TKFA 251 725 110
this is
Lyngby Radio
How do you read me?

The ship station replies and supplies the coast stations with the necessary details

Lyngby Radio
this is
Moby Dick / TKFA 251 725 110
I read you loud and clear. I have a phone call to Hamburg
country code 49
area code 40
telephone number 2006570

15
 my accounting code (AAIC) is IS01
over

The coast station replies as follows:

Moby Dick / TKFA

this is
Lyngby Radio
I understood, I shall call your party

When the subscriber ashore is on the line, the coast station will inform the ship
station to start talking:

Moby Dick / TKFA

this is
Lyngby Radio
your party is on the line, go ahead please

After finishing the conversation the coast station will inform the ship station about the
appropriate duration to be paid:

Moby Dick / TKFA

this is
Lyngby Radio

It was a 5 minutes call. I have no more traffic for you.

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 Phone call from ashore (shore to ship)
After receiving a DSC announcement from a coast station the ship station
has to acknowledge the receipt by DSC as soon as possible and tune to the
working frequencies which were given in the coast stations announcement.
Then the coast station will call the ship station on the mentioned working
frequency:

Moby Dick / TKFA 251 725 110

this is
Lyngby Radio
How do you read me?

The ship station replies to the coast station:

Lyngby Radio this is

Moby Dick / TKFA
251 725 110
I read you loud and clear.
over

The coast station will inform the ship station as follows e.g.

Moby Dick / TKFA

this is
Lyngby Radio

I have a phone call from Hamburg for the master, stand by I will connect you

When the subscriber ashore is on the line, the coast station will inform the
ship station to start talking:

Moby Dick / TKFA

this is
Lyngby Radio
your party is on the line, go ahead please

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