MARITIME COMMUNICATIONS
Communications are a critical but often weak link in the Search and Rescue
(SAR) system. Distress and safety communications include distress, urgency, and
safety calls and messages. Boaters in distress have a variety of methods,
ranging from sophisticated electronic devices to waving a piece of cloth, for
alerting the SAR system.
VHF-FM-FM Radios (fixed and handheld)
Very High Frequency (VHF-FM) radios are the most common of all maritime
communication devices. The U.S. Coast Guard and the New Jersey Marine Services Bureau monitor VHF-FM channel 16
twenty-four hours a day.
- VHF-FM radios have a useful range of 20-25 miles, based on “line-of-sight”.
- The height of the radio antennae is an important consideration and determines
the range of the radio.
- The hand-held units are portable with short antennae; the range is limited to
5 miles. At a minimum, VHF-FM radios should have channels 16, 09, 06 and 22.
Additionally, channels 24-28 and 84-88 are for contacting marine operators and
channels WX-1-3 are the NOAA weather channels.
VHF-FM with Digital Selective Calling (DSC)
There are new Medium Frequency (MF) and High
Frequency (HF) radiotelephone services available to mariners as part of the new Global
Maritime Distress and Safety System (GMDSS). The service is expected to begin in
2006. The new DSC service will allow mariners to instantly send an automatically
formatted distress alert (mayday) to the Coast Guard or other rescue authority
anywhere in the world.
When interfaced with the Long Range Aids to Navigation (Loran) or Global
Positioning System (GPS), the transmission automatically sends the latitude and
longitude of the vessel.
To use the DSC system, recreational boaters need to obtain a Maritime Mobile
Service Identity (MMSI) number through major marine retail stores using the
Federal Communications Commission (FCC) form 605.
CB Radios
Citizen Band radios provide two-way communications at an affordable cost.
Maximum output is limited to 4 watts Double Side Band or 12 watts Single Side
Band. The U.S. Coast Guard does not monitor the emergency CB channel. CB radios
should be used to supplement the VHF-FM radios, not replace them.
Communicating a Distress CallVHF-FM Channel 16 is the hailing and distress frequency. Contact communications
between boaters may take place on channel 16, but boaters may not stay on
channel 16 for non-emergency conversations. Emergency communications on the
VHF-FM radio should be transmitted on channel 16. If an emergent situation is
discovered, all boaters should immediately put on a life jacket.
VHF-FM Radio or Citizen Band RadioAnnouncement procedure: Say Mayday, Mayday, Mayday; this is the vessel
___________, I repeat this is the _________, again the ________ (state the name
of your vessel three times).
State your call sign. Then begin your message. Say "Mayday, the vessel
___________, (state your position - preferably latitude and longitude or by
geographical reference), the nature of your emergency, a description of your
vessel and the number of people on board your boat.
Say again the name of your vessel and your call sign. Stay calm and speak
slowly. Then UNKEY the microphone (release the button) and wait for a response.
If you get no response after a minute or so, repeat the entire broadcast. Get
life jackets on everyone, gather emergency supplies, get your flares and any
other signaling devices ready.
STAY CALM - you, as Captain, need to set the example for your passengers. If
you hear a MAYDAY, stay off the radio and record the information given in the
broadcast. Once a mayday call is issued, the code of "Silence" goes into effect.
VHF-FM radio equipped with DSCBy activating the DSC system, no voice transmission is required to alert the SAR
system.
Once alerted, the SAR system will communicate directly with the unit activating
the DSC emergency broadcast. Standard voice communications will be used by the
SAR system to obtain amplifying information from the vessel in distress.
Cellular Phone
Boaters using cellular phones to communicate a distress call need to inform 911
dispatchers of the same information as if calling from a VHF-FM radio. The 911
system is arranged to give emergency response personnel a physical address of
the caller. This is not possible when using a cellular phone, and a very
detailed description of the location must be relayed from the boater.
One of the major drawbacks of using a cell phone in an emergency situation, when compared to a VHF-FM radio, is that a cell phone call is only heard by one person whereas everyone with in range of the VHF-FM transmission can hear the call.
Personal Location Beacons (PLB/EPIRB)
These units will enable rescuers to identify your location when a radio or cell phone will not reach emergency services. They work by accessing satellites and identifying your geographical position and giving that information to the nearest emergency services.
As of February 1, 2009, the National Oceanic and Atmospheric Administration no longer uses its satellites to monitor the 121.5 MHz frequency used by older analog boater distress beacons.
NOAA and the U.S. Coast Guard, which responds to maritime distress calls, will instead limit their watch to newer digital signals coming across the 406 MHz frequency. Analog beacons have been banned from sale for the past two years.
For recreational boaters, EPIRBs are not mandatory equipment, but they are considered a good idea.
Anyone calling for help with an older EPIRB might still get help if their signal is picked up by a passing airplane because 121.5 MHz remains an aviation distress channel, but there is no guarantee.
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