Distress Signal - Maritime Distress Signals

Maritime Distress Signals

Distress signals at sea are defined in the International Regulations for Preventing Collisions at Sea and in the International Code of Signals. Mayday signals must only be used where there is grave and imminent danger to life. Otherwise, urgent signals such as pan-pan can be sent. Most jurisdictions have large penalties for false, unwarranted or prank distress signals.

Distress can be indicated by any of the following officially sanctioned methods:

• Transmitting a spoken voice Mayday message by radio over very high frequency (shorter range VHF) channel 16 (156.8 MHz) and/or high frequency (longer range HF) on 2182 kHz
• Transmitting a digital distress signal by activating (or pressing) the distress button (or key) on a marine radio equipped with Digital Selective Calling (DSC) over the VHF (channel 70) and/or HF frequency bands.
• Transmitting a digital distress signal by activating (or pressing) the distress button (or key) on a Inmarsat-C satellite internet device
• Sending the Morse code group SOS by light flashes or sounds
• Burning a red flare (either hand-held or aerial parachute flare)
• Emitting orange smoke from a canister
• Showing flames on the vessel (as from a burning tar barrel, oil barrel, etc.)
• Raising and lowering slowly and repeatedly both arms outstretched to each side
• Making a continuous sound with any fog-signalling apparatus
• Firing a gun or other explosive signal at intervals of about a minute
• Flying the international maritime signal flags NC
• Displaying a visual signal consisting of a square flag having above or below it a ball or anything resembling a ball (round or circular in appearance)
• Launching distress rockets

In addition, a distress can be signaled using automated radio signals such as a Search and Rescue Transponder (SART) which responds to 9GHz radar signal, or a Emergency Position-Indicating Radio Beacon (EPIRB) which operates in the 406 MHz radio frequency. EPIRB signals are received and processed by a constellation of satellites known as COSPAS-SARSAT.

A GPIRB is an EPIRB that is equipped with a global positioning system (GPS) sensor which enables the distress signal to incorporate the latitude and longitude position of the party in distress.

A DSC radio distress signal can include the position if the lat/long are manually keyed into the radio or if a GPS-derived position is passed electronically directly into the radio.

A Mayday message consists of the word "mayday" spoken three times in succession, which is the distress signal, followed by the distress message, which should include:

• Name of the vessel or ship in distress
• Her position (actual, last known or estimated expressed in lat./long. or in distance/bearing from a specific location)
• Nature of the vessel distress condition or situation (e.g. on fire, sinking, aground, taking on water, adrift in hazardous waters)
• Number of persons at risk or to be rescued; grave injuries
• Type of assistance needed or being sought
• Any other details to facilitate resolution of the emergency such as actions being taken (e.g. abandoning ship, pumping flood water), estimated available time remaining afloat

In North America, marine search and rescue agencies in Canada and the United States also recognize certain other distress signals:

• Sea marker dye
• White high intensity strobe light flashing at 60 times per minute

A floating man-overboard pole or dan buoy can be used to indicate that a person is in distress in the water and is ordinarily equipped with a yellow and red flag (international code of signals flag "O") and a flashing lamp or strobe light.