(Part 1)

While the exception of the EPIRB, all distress modes are two-way (i.e. the alert is sent and the alert is acknowledged). The EPIRB is a one-way system; the alert is sent but not acknowledged. Other than EPIRB, alert and acknowledge procedures use essentially the same format.

Voice distress procedures

In voice radio certain procedural words are used as an alarm signal. MAYDAY indicates a distress; MAYDAY RELAY indicates a distress relay and MAYDAY receivedindicates a distress acknowledgement. Normally the frequency used to initiate the distress alert is the frequency used to acknowledge the alert and becomes the control frequency. Coast stations or rescue units may request a change in frequency to facilitate better communications but the distress unit must agree. A coast station hearing 2182 alarm signal or MAYDAY should impose SILENCE on the distress frequency so that the distress message can be heard. Vessels hearing SILENCE MAYDAY should maintain silence on the frequency until the distress is ended or SILENCE FINI is received.

DISTRESS	MAYDAY, MAYDAY, MAYDAY
	This is… (name and call sign of distress)
	DISTRESS INFORMATION(position, etc.)

RELAY	MAYDAY, MAYDAY, MAYDAY
	This is… (relay ship or station) MAYDAY RELAY NAME AND CALL SIGN OF SHIP IN DISTRESS
	DISTRESS INFORMATION(as received)

ACK	MAYDAY, MAYDAY, MAYDAY
	NAME AND CALL SIGN OF SHIP IN DISTRESS
	This is… (acknowledging station) RECEIVED, MAYDAY

Procedures for acknowledging a distress using NBDP telex are the same as voice radio except substitute DE for THIS IS and RRR for RECEIVED.

DSC Distress Procedure

The DSC alert concept uses two distress formats. DISTRESS and DISTRESS RELAY or ACKNOWLEDGE. Menu driven formats are used to ensure the required information is entered. Complete each entry according to the menu. Select the proper frequency for sending the alert and enter a telecommand for follow-up communications. It is important to note that each DSC alert frequency has a companion voice and telex frequency. If no telecommand is given, the assumption is that communications will be in voice.

Sending DSCs are programmed to automatically repeat an alerting sequence for several minutes. HF DSC alerts are transmitted on 8414.5 and at least one other HF frequency. The second HF DSC frequency should be one that will best reach the nearest DSC coast station.

DSC distress alerts are intended to be acknowledged only by a coast station or RCC. A ship receiving a DSC alert must stop any transmission capable of interfering with distress traffic and monitor the appropriate companion frequency and 2182. If a coast station does not acknowledge after about 3 minutes, a “distress relay” should be sent to the nearest RCC. This should be done via INMARSAT or coast radio station working frequency, not on DSC. The purpose in not relaying via DSC is not to interfere with the alert, which may be in the process of being received by the coast station. When relaying a distress, transmit all information exactly as received. If your ship is in position to assist, notify the coast station or RCC and contact the ship in distress using the companion working frequency.

RECEIVING A DISTRESS ALERT (RADIO)

Because radio propagation can carry HF signals over very long distances, a distress alert sent by HF DSC can trigger alarms across thousands of miles. To limit alerts to their own area and to minimize false alerts, it is important that strict procedures be used when receiving a distress alert:

1.Allow a coast stations to acknowledge. Set a watch on the appropriate companion frequency and 2182.

2.If the distress is not acknowledged by a coast station after 3 minutes, acknowledge the distress using 2182 and Ch 16 (not DSC) and inform the nearest RCC. Monitor companion frequencies for distress traffic.

3.If after acknowledging on 2182 and Ch 16, the distress alert persists on DSC, the regional RCC may ask you to acknowledge the alert to silence the alarm. Use the individual call format to acknowledge and notify the RCC via INMARSAT or coast radio.

CANCELING A DISTRESS ALERT (RADIO)

DSC Stop the DSC (if still transmitting) and broadcast to “all stations” as follows:

“ALL STATIONS, ALL STATIONS, ALL STATIONS...”

“THIS IS... (name, call sign, MMSI and position) “...

“CANCEL MY DISTRESS ALERT DATE, TIME (UTC)”...

“THIS IS...(name, call sign and MMSI number)”.

NOTE:Message must be transmitted on all appropriate radiotelephone frequencies corresponding to the DSC frequencies used in the alert.

2182-Stop the alarm (if still transmitting) and broadcast to “all stations” as follows:

“ALL STATIONS, ALL STATIONS, ALL STATIONS...”

“THIS IS...(name, call sign and position)”...

“CANCEL MY AUTO ALARM ON 2182KHZ, DATE, TIME”...

“THIS IS... (name and call sign)”.