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
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:
- 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.
- Distress signal "MAYDAY", spoken
- The words "THIS IS", spoken once.
- Name of vessel in distress (spoken
three times) and call sign or boat registration number, spoken once.
- Repeat "MAYDAY" and name of vessel,
- 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.
- Nature of distress (sinking, fire
- Kind of assistance desired.
- Number of persons onboard.
- Any other information which might
facilitate rescue, such as length or tonnage of vessel, number of persons needing medical attention, color hull, cabin, masks,
- 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.
THIS IS BLUE DUCK-BLUE DUCK-BLUE DUCK WA1234
LIGHT BEARS 185 DEGREES MAGNETIC-DISTANCE 2 MILES
STRUCK SUBMERGED OBJECT
NEED PUMPS-MEDICAL ASSISTANCE AND TOW
ADULTS, TWO CHILDREN ONBOARD
ONE PERSON COMPOUND FRACTURE OF ARM
ESTIMATE CAN REMAIN AFLOAT TWO HOURS
BLUE DUCK IS
THIRTY TWO FOOT CABIN CRUISER-WHITE HULL-BLUE DECK HOUSE
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.
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.