Effective communication is critical in maritime emergencies. This guide explains key protocols, including the definitions of emergency signals, the appropriate use of radio prefixes, and the procedures for distress, urgency, and safety communications. It also explores the history and development of maritime communication systems to provide context and understanding of their evolution.
Maritime communication has its roots in the use of visual and auditory signals, such as flags, bells, and foghorns, to convey messages between ships or to shore. The late 19th century saw the invention of wireless telegraphy, revolutionizing communication by enabling the transmission of Morse code via radio waves.
In 1904, Guglielmo Marconi's invention of the radio made it possible for ships to send distress signals across vast distances. The SOS signal, introduced in 1905, became the first standardized distress call in maritime history. This was later replaced by MAYDAY, introduced in 1923 by Frederick Stanley Mockford, a senior radio officer at Croydon Airport in London. The term derives from the French phrase "m’aider" (help me).
The Global Maritime Distress and Safety System (GMDSS), introduced in the late 20th century, marked a significant step forward. GMDSS integrates various communication technologies, ensuring seamless distress communication worldwide.
Effective communication is crucial in maritime emergencies. To ensure clarity, the Global Maritime Distress and Safety System (GMDSS) categorizes emergency scenarios into three distinct levels: Distress, Urgency, and Safety, each with its corresponding protocols and radio prefixes. This structured approach ensures that critical messages are prioritized and acted upon accordingly.
A Distress situation occurs when a vessel or individual is in grave and imminent danger, requiring immediate assistance. The universally recognized radio prefix for such situations is MAYDAY. When this call is broadcasted, it overrides all other radio transmissions, ensuring that the message receives the highest priority.
Examples of distress situations include:
A vessel sinking.
A person overboard.
A fire on a ship.
The skipper's authority is required to make a MAYDAY call. Such a call may also be initiated on behalf of another vessel unable to send its own distress signal.
An Urgency situation pertains to messages concerning the safety of a vessel or person, though the threat is not immediate. For instance, a vessel might be disabled or someone on board may require urgent medical attention. The radio prefix associated with this level of urgency is PAN PAN, repeated three times at the beginning of the message.
Urgency messages take priority over all transmissions except distress signals and are typically sent on VHF Channel 16 or MF 2182 kHz.
A Safety communication involves notifications of navigational hazards or meteorological warnings that could affect the safety of vessels in a given area. The prefix SÉCURITÉ (pronounced “SAY-CURE-E-TAY”) is used to indicate such messages.
These are often issued by Coast Guard Centers or Coast Radio Stations and may include updates about dangerous weather conditions, floating debris, or changes in navigational markers.
Broadcasting a distress call is a critical responsibility. Crews should be trained to follow the MAYDAY message format, and the instructions should be displayed near the radio for quick reference.
Preparation: Ensure that the radio and main battery are powered on, and set the device to HIGH POWER (25 watts) on VHF Channel 16 or MF 2182 kHz.
Transmission: Press and hold the transmit button and state clearly:
MAYDAY, MAYDAY, MAYDAY
Identify your vessel: "THIS IS [vessel name, repeated three times]"
Repeat your vessel name once, followed by its callsign or MMSI number.
Provide your position (latitude and longitude, or a recognizable location).
State the nature of the distress (e.g., sinking, fire).
Specify the help required and the number of people on board.
Add any additional helpful information (e.g., launching liferafts, firing distress signals).
End with OVER.
Wait for Acknowledgement: After transmitting, listen for a response. Repeat the call if no acknowledgement is received.
If you hear a MAYDAY call, stop all transmissions to avoid interference and note down the details. Acknowledge the call only if the nearest Coastguard station or another capable vessel has not already done so.
The acknowledgement should follow this format:
"MAYDAY [vessel name, repeated three times]"
"THIS IS [your vessel or station name, repeated three times]"
"RECEIVED MAYDAY."
If a distress call is heard but not acknowledged, it is your duty to relay the message. Use the phrase MAYDAY RELAY, followed by your vessel’s name and the original message details.
A MAYDAY call enforces general radio silence on the distress frequency. This is controlled by the station managing the distress traffic, which may broadcast:
SEELONCE MAYDAY: General silence imposed by the controlling station.
SEELONCE DISTRESS: Used by another station if necessary to maintain silence.
When the emergency resolves or conditions permit limited communication, the controlling station may relax the silence using the term PRUDONCE, indicating restricted working.
Once the situation is entirely resolved, the distress communication is terminated with the phrase SEELONCE FEENEE.
Modern radios with DSC capabilities streamline distress signaling. The steps typically involve:
Briefly pressing the red Distress button.
Selecting the nature of the distress (e.g., collision, fire) from the menu if time permits.
Pressing and holding the button for 5 seconds to transmit the alert.
DSC automatically sends the vessel’s position and time. If no acknowledgement is received from a Coastguard or Radio Station, the alert is repeated every four minutes until a response is obtained.
Accidental activation of a distress signal must be rectified immediately to avoid unnecessary deployment of rescue resources. Announce a cancellation on VHF Channel 16, including:
Your vessel’s name and MMSI number.
The statement: “Cancel my Distress Alert of [date/time].”
The PAN PAN prefix is used for situations requiring urgent assistance without immediate danger. Example:
"PAN PAN, PAN PAN, PAN PAN."
"ALL STATIONS, ALL STATIONS, ALL STATIONS."
"THIS IS YACHT SEABIRD, SEABIRD, SEABIRD."
"[Position details]."
"[Nature of problem, e.g., dismasted and dragging anchor]."
"Require urgent tow. OVER."
Urgency signals are handled similarly to distress calls but take a lower priority. Once resolved, the urgency signal must be canceled.
The SÉCURITÉ prefix precedes navigational or weather warnings. Typically announced on distress channels, these messages are transmitted on designated working frequencies.
An example might include:
"SÉCURITÉ, SÉCURITÉ, SÉCURITÉ."
"THIS IS [station name]."
"ALL STATIONS, ALL STATIONS, ALL STATIONS."
"[Details about the hazard or warning]."
MSI encompasses vital updates, including navigational warnings, weather reports, and safety alerts. These are distributed via:
Navtex (MF, 518 kHz and 490 kHz) for coastal coverage up to 300 miles.
SafetyNet using Inmarsat satellites for greater offshore ranges.
Coastguard stations may also broadcast MSI over VHF in coastal areas.
Maritime emergency communication is a cornerstone of safety at sea. Understanding the protocols for MAYDAY, PAN PAN, and SÉCURITÉ calls, as well as the proper use of DSC and other systems, can save lives. Mariners should regularly train in these procedures and ensure their equipment is operational, contributing to a safer maritime environment for all.
