The Red Distress Button: Will It Work?

Attention all vessel examiners: According to a Coast Guard District 5 report, the majority of recreational boats have their VHF radios configured incorrectly. You can easily tell if a marine VHF radio has the feature called Digital Selective Calling (DSC) by checking to see there is a big red button marked "distress." Most people will expect to be able to press that button in an emergency. But will that button work when you need it? The red distress button will not summon help as intended unless the radio has been programmed with a MMSI number (similar to a boat's phone number) and connected to a GPS (or the radio may have a built-in GPS).

If boaters aren't sure if they have set up their DSC, turn on the VHF and the startup screen usually shows the MMSI. Eventually it should show GPS Lat/Long, or sound a warning that no GPS is connected. If the boater needs an MMSI number, one can be obtained from the FCC.

In the Great Lakes It is important that boaters who wish to travel into Canadian waters do NOT use the free MMSI service from BoatUS (or any provider other than the FCC). Only registrations from the FCC are shared with other countries, so pressing the red distress button in Canadian waters will not work properly with a free MMSI from BoatUS. You can tell if the MMSI will work in Canada if it ends in zero. As Canadian waters are so close, there is a strong case to be made that all boaters in our area of operations should obtain MMSI numbers from the FCC that will work in Canada. These numbers end in zero.

If you buy a used boat, the MMSI stays with the boat, not with the prior owner. If you find a radio that has been programmed correctly with an MMSI, ask if the current owner did this, or if the MMSI came from a past owner. When boat ownership is transferred the new owner needs to file a change of address with the FCC. This provides important information in a search and rescue situation: it tells the Coast Guard who is calling when the distress feature is used.

Some boaters will erroneously say that without the MMSI programmed a distress call will still work, "it will just send zeroes to the Coast Guard" instead of the boat’s MMSI. This is false, DSC radios will NOT send mayday using the red button without an MMSI. The red "DISTRESS" button will not signal distress.

It is the position of the US Coast Guard that boaters should have a VHF radio even though recreational boats are generally not required by law to have one and a radio is not required for a VSC. New fixed marine VHF radios should all have the red DSC distress button. According to NAVCEN, “The Coast Guard urges, in the strongest terms possible, that you take the time to interconnect your GPS and DSC-equipped radio. Doing so may save your life.”

Resources/Tools:

• A printable US Coast Guard PDF pamphlet about MMSI numbers: https://www.dco.uscg.mil/Portals/9/CG-5R/SARfactsInfo/MMSIpamphlet.pdf
• The end of this YouTube video explains how to get an MMSI through the FCC: https://youtu.be/8W4ntoOWZ-s?t=218
• FCC Help: How to apply for a new license (this will include an MMSI) https://www.fcc.gov/wireless/support/knowledge-base/universal-licensing-system-uls-resources/applying-new-license
• Look up an MMSI ending in zero to see if it is properly registered to the current vessel owner: https://wireless2.fcc.gov/UlsApp/UlsSearch/searchShip.jsp
• Instructions for changing ownership of an MMSI when a vessel is sold (click “Vessel Transfer”): https://www.fcc.gov/wireless/bureau-divisions/mobility-division/maritime-mobile/ship-radio-stations/maritime-mobile
• NAVCEN page about Digital Selective Calling (DSC): 
• https://www.navcen.uscg.gov/digital-selective-calling
• The DSC system is discussed in Ch. 2 of AUXCOM

Activity Idea:

• Bring in a handheld VHF that has a properly programmed MMSI and built-in GPS. Demonstrate how a VSC would check that the GPS and MMSI are valid. (Note GPS won't work indoors but may work if held in a window.)