Emergency communications

Emergency communications include distress, urgency and safety messages.

4.10.3.1 Distress alert, distress message and distress relay

The distress alert is an automated form of distress signal and indicates that a ship, aircraft or other vehicle, or a person, is in grave and imminent danger and requires immediate assistance. It may contain all or some of the information contained in the distress message.

The distress alert may be sent using DSC on one or more of the frequencies dedicated exclusively to the purpose, or by satellite (see annex A6).

Messages concerning safety of life and navigation should be transmitted in a standard form containing the following information, whichever mode of transmission is used:

• name of ship;

• call sign of ship;

• maritime mobile service identity (MMSI) of ship;

• position of ship;

• nature of distress (or other emergency);

• type of assistance required (if appropriate);

• any other information that may help those whose assistance is required.

The master should order the relaying of a distress message whenever it is clear that the ship in distress cannot transmit the message itself, or if further help is thought to be necessary. The master should make clear in the relay message that his own ship is not in distress by using the prefix 'MAYDAY RELAY'.

4.10.3.2 Urgency messages

An urgency message is one containing urgent information relating to a ship, aircraft or person. For example:

man overboard;

Guidance to na sir?

• lost propeller;

• permanent loss of power;

• announcing and identifying medical transports;

• communications concerning medical advice.

The urgency signal should only be sent on the authority of the master.

If using terrestrial communications, the urgency announcement should be made on one or more of the DSC distress frequencies contained in annex A6. The actual urgency message which follows should be sent on one or more of the radio telephony/telex frequencies for follow-up distress traffic.

If using satellite communications, it should be noted that ship earth stations only have 'distress' and 'routine' priority levels. Inmarsat has therefore devised a system of two-digit codes for urgency and safety communications. Not all coast earth stations accept all the codes.

Safety messages

A safety message is one containing an important navigational or meteorological warning. As well as the items listed in section 3.7.2, information reports concerning the position of buoys and the working of lighthouses and other aids to navigation can be made.

When transmitting safety messages, the safety message format should be used using the same frequencies and procedures as for urgency messages.

Emergency over

Whenever the emergency is clearly over, it should be cancelled by a broadcast to 'all stations'.

Date: 2016-04-22; view: 708