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Mayday Mayday Mayday

Rule No1 in an emergency - Keep Calm
Knowing your boat inside out, the emergency procedures and a touch of common sense will save your life.

Radio Information for Boaters

Which radio do I need

 A VHF marine radio nowadays is inexpensive, so its worth considering to buy one. The Lm25 license is a bit heavy for most of us , and may put you off.  If you plan to travel more than a few miles offshore, plan to purchase an MF/HF radiotelephone or mobile satellite telephone, an emergency position indicating radio beacon, or EPIRB, and a second VHF radio or cellular telephone as well. Mobile satellite telephones are becoming more common and more inexpensive. The mobile satellite will provide easier and clearer communications than the MF/HF radiotelephone, but the HF radiotelephone will receive high seas marine weather warnings.


Mayday! Mayday! Mayday!


Sending a distress call


You may only have seconds to send a distress call. Here's what you do.

Transmit, in this order:

  1. If you have an MF/HF radiotelephone tuned to 2182 kHz, send the radiotelephone alarm signal if one is available. If you have a VHF marine radio, tune it to channel 16. Unless you know you are outside VHF range of shore and ships, call on channel 16 first.
  2. Distress signal "MAYDAY", spoken three times.
  3. The words "THIS IS", spoken once.
  4. Name of vessel in distress (spoken three times) and call sign or boat registration number, spoken once.
  5. Repeat "MAYDAY" and name of vessel, spoken once.
  6. Give position of vessel by latitude or longitude or by bearing (true or magnetic, state which) and distance to a well-know landmark such as a navigational aid or small island, or in any terms which will assist a responding station in locating the vessel in distress. Include any information on vessel movement such as course, speed and destination.
  7. Nature of distress (sinking, fire etc.).
  8. Kind of assistance desired.
  9. Number of persons onboard.
  10. Any other information which might facilitate rescue, such as length or tonnage of vessel, number of persons needing medical attention, color hull, cabin, masks, etc.
  11. The word "OVER"

Stay by the radio if possible. Even after the message has been received, the Coast Guard can find you more quickly if you can transmit a signal on which a rescue boat or aircraft can home.

For example:


Repeat at intervals until an answer is received.

What do you do if you hear a distress call?

If you hear a distress message from a vessel and it is not answered, then you must answer. If you are reasonably sure that the distressed vessel is not in your vicinity, you should wait a short time for others to acknowledge.

MF/HF Radiotelephone

Your VHF radio is intended mainly for short range communications, generally 5-10 miles, and at least 20 miles to a USCG station.  To communicate at longer ranges, you will normally need a satellite telephone or an MF/HF marine radiotelephone.  Marine radiotelephone equipment normally operates between 2 - 26 MHz using single sideband emissions. MF/HF marine radiotelephones can also be used to receive high seas weather broadcasts, and by using a computer and a special interface provided by some coast stations, can provide Internet email.

What do you do if you are out of range of other vessels, and no one responds to your distress call?

Tune your HF radiotelephone to an HF channel guarded by the Coast Guard, and repeat your mayday call. Activate your EPIRB.

What Frequencies Can I Use?

See the High Frequency Radiotelephone Channels webpage.  HF radiotelephone channels are normally limited to operational, business, safety or public correspondence purposes.

Radiotelephone alarm signal

This signal consists of two audio tones transmitted alternatively on the distress frequency 2182 kHz. It is not used over VHF marine radio in the United States, although it may be used on VHF in Canada. This signal is similar in sound to a two-tone siren used by some ambulances. When generated by automated means, it shall be sent continuously as practicable over a period of not less than 30 seconds nor more than 1 minute. The purpose of the signal is to attract attention or to activate automatic devices giving the alarm. Cargo ships ceased guarding this frequency on February 1, 1999.

The radiotelephone alarm signal is used only in a distress, including when a person has been lost overboard and the assistance of other vessels is required.

The radiotelephone navigation warning signal, a single 2200 Hz tone transmitted twice per second, is used to announce a storm or similar warning.


Other standard marine distress signals

Channel   Ship      Ship      Use 

Number    Transmit  Receive 



 01A      156.050   156.050   Port Operations and Commercial.   

                              VTS in selected areas. 

 05A      156.250   156.250   Port Operations.  VTS in Seattle 

 06       156.300   156.300   Intership Safety 

 07A      156.350   156.350   Commercial 

 08       156.400   156.400   Commercial (Intership only) 

 09       156.450   156.450   Boater Calling.  Commercial and Non-Commercial. 

 10       156.500   156.500   Commercial 

 11       156.550   156.550   Commercial.  VTS in selected areas. 

 12       156.600   156.600   Port Operations.  VTS in selected areas. 

 13       156.650   156.650   Intership Navigation Safety  

                              (Bridge-to-bridge).  Ships >20m 

                              length maintain a listening watch  

                              on this channel in US waters. 

 14       156.700   156.700   Port Operations.  VTS in selected areas. 

 15          --     156.750   Environmental (Receive only).  Used  

                              by Class C EPIRBs. 

 16       156.800   156.800   International Distress, Safety and  

                              Calling.  Ships required to carry 

                              radio, USCG, and most coast  

                              stations maintain a listening watch  

                              on this channel. 

 17       156.850   156.850   State Control 

 18A      156.900   156.900   Commercial 

 19A      156.950   156.950   Commercial 

 20       157.000   161.600   Port Operations (duplex) 

 20A      157.000   157.000   Port Operations 

 21A      157.050   157.050   U.S. Government only 

 22A      157.100   157.100   Coast Guard Liaison and Maritime  

                              Safety Information Broadcasts.   

                              Broadcasts announced on channel 16. 

 23A      157.150   157.150   U.S. Government only 

 24       157.200   161.800   Public Correspondence (Marine Operator) 

 25       157.250   161.850   Public Correspondence (Marine Operator) 

 26       157.300   161.900   Public Correspondence (Marine Operator) 

 27       157.350   161.950   Public Correspondence (Marine Operator) 

 28       157.400   162.000   Public Correspondence (Marine Operator) 

 63A      156.175   156.175   Port Operations and Commercial.   

                              VTS in selected areas. 

 65A      156.275   156.275   Port Operations 

 66A      156.325   156.325   Port Operations 

 67       156.375   156.375   Commercial.  Used for Bridge-to-bridge communications in lower  

                              Mississippi River.  Intership only. 

 68       156.425   156.425   Non-Commercial 

 69       156.475   156.475   Non-Commercial 

 70       156.525   156.525   Digital Selective Calling (voice communications not allowed) 

 71       156.575   156.575   Non-Commercial 

 72       156.625   156.625   Non-Commercial (Intership only) 

 73       156.675   156.675   Port Operations 

 74       156.725   156.725   Port Operations 

 77       156.875   156.875   Port Operations (Intership only) 

 78A      156.925   156.925   Non-Commercial 

 79A      156.975   156.975   Commercial 

 80A      157.025   157.025   Commercial 

 81A      157.075   157.075   U.S. Government only - Environmental protection operations. 

 82A      157.125   157.125   U.S. Government only 

 83A      157.175   157.175   U.S. Government only 

 84       157.225   161.825   Public Correspondence (Marine Operator) 

 85       157.275   161.875   Public Correspondence (Marine Operator) 

 86       157.325   161.925   Public Correspondence (Marine Operator) 

 87       157.375   161.975   Public Correspondence (Marine Operator) 

 88       157.425   162.025   Public Correspondence in selected areas only. 

 88A      157.425   157.425   Commercial, Intership only.