The United States Coast Guard is the sole source of the information on this page (sailontide.com specifically disclaims any and all responsibility or liability for the accuracy or updating of this information); for more info see:
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RADIO INFORMATION FOR BOATERS
Radios That You Need
Before you purchase anything else, make sure you have a VHF marine radio. A VHF marine radio is the single most important radio system you should buy. It is probably also the most inexpensive. 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.
Radio Watchkeeping Regulations
If you have a VHF-FM radio, there are certain regulations in place for monitoring/listening to your radio. Please read our radio watchkeeping section for more information.
Mayday! Mayday! Mayday!...Sending a distress call
You may only have seconds to send a distress call. Here's what you should do:
Procedure for Digital Selective Calling (DSC) Radio: DSC MAYDAY
Procedure for VHF Channel 16 MAYDAY:
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 three times.
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, spoken once.
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 etc.).
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, etc.
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:
MAYDAY-MAYDAY-MAYDAY
THIS IS BLUE DUCK-BLUE DUCK-BLUE DUCK WA1234 MAYDAY THIS IS BLUE DUCK
CAPE HENRY LIGHT BEARS 185 DEGREES MAGNETIC-DISTANCE 2 MILES
STRUCK SUBMERGED OBJECT
NEED PUMPS-MEDICAL ASSISTANCE AND TOW
THREE 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
OVER
Repeat at intervals until an answer is received.
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 to do if 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.
Frequencies You May 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.
Boater Calling Channel (VHF Channel 9)
The Federal Communications Commission established VHF-FM channel 9 as a supplementary calling channel for noncommercial vessels (recreational boaters) at the request of the Coast Guard. A ship or shore unit wishing to call a boater would do so on channel 9, and anyone (boaters included) wishing to call a commercial ship or shore activity would continue to do so on channel 16. Recreational boaters would continue to call the Coast Guard and any commercial facility on channel 16.
The purpose of the FCC regulation was to relieve congestion on VHF channel 16, the distress, safety and calling frequency. FCC regulations require boaters having VHF radios to maintain a watch on either VHF channel 9 or channel 16, whenever the radio is turned on and not communicating with another station.
Since the Coast Guard generally does not have the capability of announcing an urgent marine information broadcast or weather warning on channel 9, use of channel 9 is optional. We recommend boaters normally keep tuned to and use channel 16 in those waters unless otherwise notified by the Coast Guard.
Procedure for Calling A Ship by Radio
You may use channel 16 to call a ship or shore station, but if you do so, you must, must be brief! We recommend this same procedure be used over channel 9, if channel 9 is used as a calling channel.For example:
Blue Duck: "Mary Jane, this is Blue Duck" (the name of the vessel or MMSI being called may be said 2 or 3 times if conditions warrant)
Mary Jane: "Blue Duck, this is Mary Jane. Reply 68" (or some other proper working channel)
Blue Duck: "68" or "Roger"
Global Maritime Distress & Safety System
VHF maritime channel 70 (156.525 MHz) is authorized exclusively for distress, safety and calling purposes using digital selective calling (DSC) techniques. No other uses are permitted.
Channel 70 is used to send distress alerts, safety announcements and for calling purposes under the Global Maritime Distress and Safety System (GMDSS). Many vessels are now equipped with DSC capability and are using channel 70 for this purpose. It is essential that this channel be protected.
Storm Warnings?
The Coast Guard announces storm warnings and other urgent marine information broadcasts on VHF channel 16 and 2182 kHz before making the broadcasts on VHF channel 22A and 2670 kHz respectively. Storm warnings and forecasts are also made byNOAA Weather Radio.
MAYDAY Radio Checks and other Hoaxes
*A growing number of boaters unsuccessful in getting a radio check on VHF channel 16 are calling MAYDAY to get a response. Every hoax, including MAYDAY radio checks, is subject to prosecution as a Class D felony under Title 14, Section 85 of the U.S. Code, liable for a $5000 fine plus all costs the Coast Guard incurs as a result of the individual's action. Since hoaxes can lead to loss of life, the Coast Guard and Federal Communications Commission will work closely together, using when necessary FCC equipment capable of identifying the electronic signature of the offending radio. We ask your cooperation in helping us and the FCC remove hoaxes from the VHF radiotelephone distress, safety and calling channel 16.
Radio Checks
Radio checks with the Coast Guard Communications Stations on DSC and HF radiotelephone are allowed.
Federal Communications Commission (FCC) Radio License Information
An FCC ship station radio license is no longer required for any vessel travelling in U.S. waters which uses a VHF marine radio, radar or EPIRB, and which is not required to carry radio equipment. A license is necessary however for any vessel required to carry a marine radio, on an international voyage, or carrying an HF single sideband radiotelephone or marine satellite terminal. FCC license forms, including applications for ship and land station radio licenses, can now be downloaded from the FCC website.
Satellite Communications
Currently the Inmarsat Organization, an international organization established by treaty, is the sole provider of worldwide maritime mobile satellite communications offering emergency calling capability. Coverage is available between about 70 deg N latitude and 70 deg S latitude. Other mobile satellite systems are also becoming available, but these systems in general do not offer an emergency calling capability.
For More Information...
Cellular Telephones
Coast Guard high seas radio distress watchkeeping schedules
Coast Guard Telecommunications
Coast Guard VHF Coverage in Your Area
Maritime Safety Broadcast Information
National Weather Service Marine Product Information Dissemination (this link leads outside the USCG)
Rules which require listening to your VHF marine radio
VHF Marine Radio Channels and Frequencies
For general boating safety information questions...
CG Boating Safety
Hours of operation: Monday through Friday
8:00 AM to 5:00 PM EST
Excluding government holidays
Infoline: 1-800-368-5647
For Text Telephone service: 1-800-689-0816
email at: uscginfoline@gcrm.com
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DSC DISTRESSThe following procedures were adapted from the International Telecommunications Union, Radio communications Study Group Recommendation M.541, Operational Procedures for the use of Digital Selective-Calling (DSC) Equipment in the Maritime Mobile Service.
Operating procedures may vary somewhat among different radios, depending upon how the radio is designed, how the radio's software is configured, and how the DSC processor is connected to the radio transceiver.
Transmission of DSC distress alert
A distress alert should be transmitted if, in the opinion of the Master, the ship or a person is in distress and requires immediate assistance.
A DSC distress alert should as far as possible include the ship's last known position and the time (in UTC) when it was valid. The position and the time may be included automatically by the ship's navigational equipment or may be inserted manually.
The DSC distress alert is transmitted as follows:
1. tune the transmitter to the DSC distress channel (4125.0 kHz on HF, channel 70 on VHF)
2. if time permits, key in or select on the DSC equipment keyboard
the nature of distress,
the ship's last known position (latitude and longitude),
the time (in UTC) the position was valid,
type of subsequent distress communication (telephony),
in accordance with the DSC equipment manufacturer's instructions;
3. transmit the DSC distress alert
4. prepare for the subsequent distress traffic by tuning the transmitter and the radiotelephony receiver to the distress traffic channel in the same band, i.e. 2 182 kHz on MF, channel 16 on VHF, while waiting for the DSC distress acknowledgment.
NOTE - Some maritime MF radiotelephony transmitters shall be tuned to a frequency 1700 Hz lower than 2187.5 kHz, i.e. 2185.8 kHz, in order to transmit the DSC alert on 2187.5 kHz.
Actions on Receipt of a Distress Alert
Ships receiving a DSC distress alert from another ship should normally not acknowledge the alert by DSC since acknowledgment of a DSC distress alert by use of DSC is normally made by coast stations only.
Only if no other station seems to have received the DSC distress alert, and the transmission of the DSC distress alert continues, the ship should acknowledge the DSC distress alert by use of DSC to terminate the call. The ship should then, in addition, inform a coast station or a coast earth station by any practicable means.
Ships receiving a DSC distress alert from another ship should also defer the acknowledgment of the distress alert by radiotelephony for a short interval, if the ship is within an area covered by one or more coast stations, in order to give the coast station time to acknowledge the DSC distress alert first.
Ships receiving a DSC distress alert from another ship shall:
1. watch for the reception of a distress acknowledgment on the distress channel (2187.5 kHz on MF and channel 70 on VHF);
2. prepare for receiving the subsequent distress communication by tuning the radiotelephony receiver to the distress traffic frequency in the same band in which the DSC distress alert was received, i.e. 2182 kHz on MF , channel 16 on VHF;
3. acknowledge the receipt of the distress alert by transmitting the following by radiotelephony on the distress traffic frequency in the same band in which the DSC distress alert was received, i.e. 2182 kHz on MF, channel 16 on VHF:
"MAYDAY",
the 9-digit identity of the ship in distress, repeated 3 times,
"this is",
the 9-digit identity or the call sign or other identification of own ship, repeated 3 times,
"RECEIVED MAYDAY".
NOTE - Ships out of range of a distress event or not able to assist should only acknowledge if no other station appears to acknowledge the receipt of the DSC distress alert.
Distress Traffic
On receipt of a DSC distress acknowledgment the ship in distress should commence the distress traffic by radiotelephony on the distress traffic frequency (2182 kHz on MF, channel 16 on VHF) as follows:
1. "MAYDAY",
2. "this is",
3. the 9-digit identity and the call sign or other identification of the ship,
4. the ship's position in latitude and longitude or other reference to a known geographical location,
5. the nature of distress and assistance wanted,
6. any other information which might facilitate the rescue.
Transmission of a DSC Distress Relay Alert
A ship knowing that another ship is in distress shall transmit a DSC distress relay alert if
the ship in distress is not itself able to transmit the distress alert,
the Master of the ship considers that further help is necessary.
The DSC distress relay alert is transmitted as follows:
1. tune the transmitter to the DSC distress channel (4207.5 kHz on HF, channel 70 on VHF),
2. select the distress relay call format on the DSC equipment, key in or select on the DSC equipment keyboard:
All Ships Call or the 9-digit identity of the appropriate coast station,
the 9-digit identity of the ship in distress, if known,
the nature of distress,
the latest position of the ship in distress, if known,
the time (in UTC) the position was valid (if known),
type of subsequent distress communication (telephony);
transmit the DSC distress relay call,
3. prepare for the subsequent distress traffic by tuning the transmitter and the radiotelephony receiver to the distress traffic channel in the same band, i.e. 4125.0 kHz on HF and channel 16 on VHF, while waiting for the DSC distress acknowledgment.
Acknowledgment of a DSC Distress Relay Alert Received From a Coast Station
Coast stations, after having received and acknowledged a DSC distress alert, may if necessary, retransmit the information received as a DSC distress relay call, addressed to all ships, all ships in a specific geographical area, a group of ships or a specific ship.
Ships receiving a distress relay call transmitted by a coast station shall not use DSC to acknowledge the call, but should acknowledge the receipt of the call by radiotelephony on the distress traffic channel in the same band in which the relay call was received, i.e. 4125.0 kHz on HF, channel 16 on VHF.
Acknowledge the receipt of the distress alert by transmitting the following by radiotelephony on the distress traffic frequency in the same band in which the DSC distress relay alert was received:
1. "MAYDAY",
2. the 9-digit identity or the call sign or other identification of the calling coast station,
3. "this is",
4. the 9-digit identity or call sign or other identification of own ship,
5. "RECEIVED MAYDAY".
Acknowledgment of a DSC Distress Relay Alert Received From Another Ship
Ships receiving a distress relay alert from another ship shall follow the same procedure as for acknowledgment of a distress alert, given above.
Cancellation of an Inadvertent Distress Alert (Distress Call)
A station transmitting an inadvertent distress alert shall cancel the distress alert using the following procedure:
1. Immediately transmit a DSC "distress acknowledgment" in accordance with Recommendation ITU-R M.493, 8.3.1 e.g. with own ship's MMSI inserted as identification of ship in distress. (NOTE: This feature is not yet generally available on DSC-equipped radios)
2. Cancel the distress alert aurally over the telephony distress traffic channel associated with each DSC channel on which the "distress call" was transmitted.
3. Monitor the telephony distress traffic channel associated with the DSC channel on which the distress was transmitted, and respond to any communications concerning that distress alert as appropriate.
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