The unthinkable has happened; your boat, you and your crew are in grave and imminent danger. To raise the alarm, you sent a distress call by voice on VHF Channel 16. That distress call, with “Mayday” spoken three times followed by your vessel’s identification information, alerted your potential rescuers to immediately standby for the distress message which will contain all the pertinent details to aid in your rescue.
It is critical that you remember as many of the particulars that are needed for the Mayday message, so it can be transmitted coherently. The mnemonic “MIPDANIO” gives you a crutch to lean on when it’s difficult to focus your thoughts in an emergency.
Keep this acronym posted by your VHF radio or write it down on a notepad prior to broadcasting your Mayday, as it will guide you through the distress message:
M – Mayday
I – Identity
P – Position
D – Distress
A – Assistance
N – Number
I – Information
O – Over
During an actual emergency, your Mayday message will unfold as follows:
Mayday – Say Mayday just once to begin the distress message.
Identity – Broadcast the vessel’s name preceded by a descriptor to better identify the type of boat. For example: “sailing vessel Morning Star” or “motor yacht Diana’s Dream.” The vessel’s radio call sign and Maritime Mobile Service Identity (MMSI) number, also spoken once, complete the identification portion of the message.
Position – Your latitude and longitude are the easiest position locators to give, as they can be read right off the GPS display. However, until the listener plots these coordinates on a chart they may be of little value. Instead, it can be preferable to use a familiar charted landmark as a point of reference. First give the direction from the landmark to your vessel, followed by name of the landmark and then the distance to your vessel. “My position is one-two-seven degrees true from the Miami safe water buoy, seven point six nautical miles,” is the proper format. These descriptions give the search vessel or helicopter the information needed to set out on their rescue mission.
Distress – There’s no need for a lengthy explanation, just a short description such as “sinking”, “taking on water” or “on fire.”
Assistance – In most cases, “request immediate assistance” is sufficient. Additional information, such as a request for pumps or a tow can be helpful.
Number – The number of people on board that need to be rescued.
Information – Give any other information pertinent to a rescue. That can be actions being taken, such as “abandoning to a liferaft,” or a brief description of the boat’s features (the color of the hull, number of masts, monohull or multihull).
Over – The procedural word “over” concludes the distress message, and also means a response is expected.
What do you do if you hear a distress call?
The International Telecommunication Union (ITU), which sets the Radio Regulations by international treaty, states the following rules: If it is likely that a coast radio station (such as the Coast Guard) will have received the message, you should allow five minutes for them to respond before doing so yourself. If you are in a position to offer effective assistance, you should acknowledge the message. Unless you are acknowledging and assisting, you must maintain radio silence on any channel being used for distress communications.
If the Coast Guard does not respond in the duly allotted time and you can offer help, acknowledge the call to the vessel in distress, let them know where you are, your boat speed and your estimated time of arrival.
The station in control of the distress radio traffic may transmit the procedural words: “Seelonce Mayday” (from the French), to remind any boaters in range not to break radio silence. Once the need for radio silence has ended, they will announce: “Seelonce Feenee.”
Sometimes a Mayday will go unheard by search and rescue authorities due to a poor quality signal or too great a distance from the vessel in distress. In such a case, when it is clear that the call was not acknowledged you can act as a relay to the Coast Guard or all ships in range. The Mayday relay call begins with the words “Mayday Relay” spoken three times, plus the name and call sign of your vessel. It is followed by repeating the exact Mayday message from the vessel in distress. This can only be done verbatim if you wrote down the distress message.
The next article of this series will cover the use of the Digital Selective Calling (DSC) distress alert as part of the Global Maritime Distress and Safety System (GMDSS).
The VHF Radio Distress Call: Digital Selective Calling (DSC)
Capt. Jeff Werner is a 23 year veteran of the yachting industry. In addition to working as a captain on private and charter yachts, both sail and power, he is a certified instructor for the RYA, MCA, USCG and US Sailing.
