Broadcast on VHF CH 70 by a person or vehicle in grave and imminent danger, and requiring immediate assistance.

A Distress alert transmits the following information on VHF CH 70:

The vessel’s MMSI
The vessel’s position (either from an interfaced GPS or manually entered by the operator)
The UTC time indicating the time when the latest position was updated
The nature of the Distress (it remains 'undesignated' in the case of Undesignated Distress Alert)

The vessel's position and UTC time indicating the time when the latest position was updated that are transmitted within a Distress Alert is very important information for any rescue operation. So, if VHF radio is not interfaced with GPS or the automatic GPS-entered position is not valid, the position and time should be updated manually. The recommended minimum time period between updates is no more than 4 hours.

Practise on the VHF radio simulator

Press the Menu softkey
Press the Posn softkey
Press the Posn softkey
Enter Latitude and Longitude using the keypad and N,S,E,W softkeys when available
Press the E key
Enter UTC time (24-hour format) using the keypad
Press the E key

Entering position and time manually

Normally broadcast to ALL STATIONS and received by all within the VHF range of the station transmitting the alert.

Normally, it is expected that only a CRS will acknowledge the DSC Distress Alert by DSC and will act as the coordinator for the rescue, which would probably include other vessels in the vicinity.

Following on from the DSC Distress Alert, the station in distress will broadcast a Distress Message by voice on VHF CH 16 .

MAYDAY, MAYDAY, MAYDAY

THIS IS (Name of the vessel in distress spoken 3 times)

MAYDAY

(MMSI of the vessel in distress), (Name of the vessel in distress), (Call sign of the vessel in distress)

POSITION (Vessel's position) AT (Time of vessel's position in UTC)

(Type of accident)

IMMEDIATE ASSISTANCE REQUIRED

(Number of people onboard - Other information that could help SAR services such as weather conditions, an activated EPIRB etc.)

OVER

Pattern of a Distress Call and Message

MAYDAY, MAYDAY, MAYDAY

THIS IS Sailboat Spinaker, Spinaker, Spinaker

MAYDAY

278054321, Spinaker, call sign Sierra 5 Lima 1 2

POSITION 45⁰ 36' North 013⁰ 32' East AT 0545 UTC

The mast has broken and the engine is not strong enough to prevent us from grounding on a rocky shore

IMMEDIATE ASSISTANCE REQUIRED

5 persons on board and due to strong winds we can only remain on board for approximately two zero minutes

OVER

An example of a Distress Call and Message

A Distress message must not begin from MAYDAY, MAYDAY, MAYDAY, if a Distress Call and Message have already been sent. The Distress message in this situation has to begin with MAYDAY .

There are three types of Distress Alert.

Undesignated Distress Alert

This is enabled either by pressing a single push-button or pair of push- buttons, normally covered by a protective flap, for a short period of time, usually 5 seconds.

To be used only when there is no time to compose an alert because:

the position and time that will be transmitted is not checked and corrected to be up-to-date,
the alert will not include information relating to the nature of distress (string "Undesignated" is sent).

Practise on the VHF radio simulator

The DISTRESS button is located under a protective cover that must be slid back before the button can be pressed.
To send the call, press and hold down the DISTRESS key for 5 seconds. A countdown to the transmission will be displayed. Release the key at any time during this countdown to abort the transmission.

Broadcast of an Undesignated Distress Alert. A subsequent DSC Acknowledgement is displayed from the CRS 002780200 (MRCC Koper , Slovenia).

Designated Distress Alert

This is enabled by programming the DSC Controller to include further information relating to the nature of distress and to update the time and position manually if necessary. The Designated Distress Alert is then broadcast by either pressing a single push-button or pair of push-buttons for 5 seconds after programming.

The following are internationally recognized Natures of Distress:

Fire/Explosion
Flooding
Collision
Grounding
Listing/Capsizing
Sinking
Disabled & Adrift
Abandoning
Man overboard
Undesignated (same as an unprepared Undesignated Distress Alert)

Practise on the VHF radio simulator

If the position and time displayed are not up-to-date, you should change them following the procedure already explained above. Then you can follow this by setting up a Distress Alert
The DISTRESS button is located under a protective cover that must be slid back before the button can be pressed
Press the DISTRESS button to access the Distress Alert screen
If the position indicated on the display is not up-to-date:

press a softkey indicating position

Enter Latitude and Longitude using the keypad and N,S,E,W softkeys when available
Press the E key

If time indicated on the display is not up to date:

Press a softkey indicating time
Enter UTC time (24-hour format) using the keypad
Press the E key

Press the lowest softkey to scroll through natures of distress and select the most appropriate one
To send the call, press and hold the DISTRESS key for 5 seconds. A countdown to the transmission will be displayed. Release the key at any time during this countdown in order to abort the transmission.

The setting up and broadcast of a Designated Distress Alert indicating 'a collision' as the nature of distress. A subsequent DSC Acknowledgement is displayed from the CRS 002780200 (MRCC Koper, Slovenia).

Distress Relay

This is only broadcast when a station learns that:

Another person/vehicle is in Distress and is unable to transmit the Distress Alert itself, for example red flares sighted at night or
The person/vehicle in Distress is beyond the VHF range of a CRS, for example in GMDSS Sea Area A2, A3 or A4, and you have acknowledged his DSC Distress Alert or subsequent Distress Call and Message by voice.

MAYDAY RELAY, MAYDAY RELAY, MAYDAY RELAY

THIS IS (MMSI of the vessel), (Name of the vessel spoken 3 times), (Call sign of the vessel)

RECEIVED THE FOLLOWING MAYDAY FROM (MMSI of the vessel in distress), (Name of the vessel in distress), (Call sign of the vessel in distress)

MESSAGE BEGINS

(message received from the vessel in distress or details of the distress)

MESSAGE ENDS

OVER

Pattern of a Distress Relay Call and Message

MAYDAY RELAY, MAYDAY RELAY, MAYDAY RELAY

THIS IS Ferryboat Catherine, Catherine, Catherine

MAYDAY

278054321, Spinaker, call sign Sierra 5 Lima 1 2

POSITION 45⁰ 36' North 013⁰ 32' East AT 0545 UTC

The mast has broken and the engine is not strong enough to prevent us from grounding on a rocky shore

IMMEDIATE ASSISTANCE REQUIRED

5 persons on board and due to strong winds we can only remain on board for approximately two zero minutes

OVER

An example of a Distress Relay Call and Message

When a DSC Distress Alert is received by a CRS, there should be an immediate DSC acknowledgement from them. If the DSC Distress Alert goes unacknowledged, the DSC Controller will automatically repeat the broadcast at approximately 4½ minute intervals. A repeat broadcast can also be made manually by first cancelling the Distress Alert and re-programming the DSC Controller before once again pressing the Distress button(s) for 5 seconds. When a DSC Distress Alert acknowledgement is broadcast, this automatically stops the repeat of the Alert. The information contained in the acknowledgement includes:

MMSI of the acknowledging CRS,
MMSI of the station in Distress.

Any subsequent RT Distress Call and Message broadcast on VHF CH 16 will be acknowledged by voice by both the CRS and any vessels in the vicinity under the control of the CRS.

Reception of a Distress Alert

After the reception of a Distress Alert on VHF CH 70, a Distress Message on VHF CH 16 must be listened to. Then wait for a CRS to acknowledge the call and for any following voice communication on VHF CH 16. If your own vessel is able to assist, acknowledge the call by RT on VHF CH 16.

If a Distress Alert is not followed by an RT broadcast on VHF CH 16 or acknowledgment by any other station, acknowledge the call by RT on VHF CH 16 and proceed with voice communication on VHF CH 16 and try to notify the shore authorities by any means.

MAYDAY

(MMSI of the vessel in distress), (Name of the vessel in distress 3 times), (Call sign of the vessel in distress)

THIS IS (MMSI of the vessel), (Name of the vessel spoken 3 times), (Call sign of the vessel)

RECEIVED MAYDAY

Pattern of acknowledgment of a Distress Call on RT

Practise on the VHF radio simulator

After the reception of a Distress Alert press the softkey OK to cancel the ringing and to clear the display. Press the softkey

and

for more information about Distress Alert.

Reception of a Distress Alert

Control of communication on VHF CH 16

During distress, silence on VHF CH 16 is automatically imposed. So, radio communication on VHF CH 16 should be controlled. This control is achieved by all stations voice broadcasting on VHF CH 16 using some procedure words.

SEELONCE MAYDAY means that the VHF CH 16 may only be used by the vessel in distress and the responding authority (and any other vessels that ask for assistance in handling the emergency). It is used by the responding authority when another vessel is interfering with the distress on VHF CH 16.

SEELONCE DISTRESS means that the VHF CH 16 may only be used by the vessel in distress and the responding authority (and any other vessels that ask for assistance in handling the emergency). It is used by any vessel when another vessel is interfering with the distress on VHF CH 16.

PRUDONCE means that the VHF CH 16 may be also used for restricted radio working. It is used by the responding authority when initial distress problems have been dealt with and it is expected that distress will not be over soon.

SEELONCE FEENEE means that distress is over and normal radio working can be resumed on VHF CH 16. In most cases it is used by a CRS.

All messages to control radio communication on VHF CH 16 have the same pattern. However, different procedure words are used for different situations.

MAYDAY

ALL STATIONS, ALL STATIONS, ALL STATIONS

THIS IS (Name of the vessel or the responding authority spoken 3 times)

(Date and time in UTC)

(MMSI of the vessel in distress), (Name of the vessel in distress), (Call sign of the vessel in distress)

(procedure word)

OUT

Pattern of a Call and Messages to control radio communication on VHF CH 16

MAYDAY

ALL STATIONS, ALL STATIONS, ALL STATIONS

THIS IS RCC KOPER, RCC KOPER, RCC KOPER

21 November at 0615 UTC

278054321, Spinaker, call sign Sierra 5 Lima 1 2

SEELONCE FEENEE

OUT

An example of a Call and Messages to announce that the distress is over

Cancelling a False Alert

If a DSC Distress Alert is broadcast in error, the Alert must be stopped from being repeated by either pressing a Cancel or Stop push-button or by switching off the VHF DSC radio (though it should be switched back on after a few seconds). An all stations voice broadcast should then be made on VHF CH 16, cancelling the alert and indicating that it was transmitted in error.

ALL STATIONS, ALL STATIONS, ALL STATIONS

THIS IS (MMSI of the vessel), (Name of the vessel spoken 3 times), (Call sign of the vessel)

POSITION (Vessel's position) AT (Time of vessel's position in UTC)

CANCEL MY DISTRESS ALERT OF (Original date and time of distress alert in UTC)

OVER

Pattern of a Call and Message to cancel a false Distress Alert

ALL STATIONS, ALL STATIONS, ALL STATIONS

THIS IS 278054321, Spinaker, Spinaker, Spinaker, call sign Sierra 5 Lima 1 2

POSITION 45⁰ 36' North 013⁰ 32' East AT 0550 UTC

CANCEL MY DISTRESS ALERT OF 21 November at 0545 UTC

OVER

An example of a Call and Message to cancel a false Distress Alert

Last modified: Saturday, 25 April 2020, 7:50 PM