If you have a VHF radio with Digital Selective Calling (DSC), pay attention. The Coast Guard has issued a Marine Safety Alert Warning that any DSC-equipped VHF that has an Automatic Channel Switching mode (and that includes most DSC radios) "may create an unintended hazard by automatically switching from a working channel that might be in use at the time to Channel 16 when when the VHF radio receives a DSC distress alert, distress-alert acknowledgement, or other DSC call where a VHF channel number has been designated." The agency goes on to emphasize that this could happen without an operator's knowledge and could result in him/her believing he/she was on a working channel when in fact that was not the case. It could also happen in the midst of crucial transmissions.
The Coast Guard "strongly recommends" disabling the automatic channel switching feature, if your radio is so equipped. (International regulations published in 2004 require all DCS VHFs to have this disabling function, and FCC regulations require all DSC-equipped VHFs certified after March 25, 2009 to have it.) If your radio does not have this function, the Coast Guard advises you not to use it for crucial communications like ship-to-bridge traffic. In any case, it further recommends anyone using a DSC-equipped VHF to constantly monitor it to ensure the unit is on the intended channel.
The Coast Guard has also published on its web site a list of manufacturers of DSC-equipped VHF radios that are affected. To view the list or learn more about the advisory, go to the U.S. Caost Guard web page (www.uscg.mil), type in "alerts" in the seach box in the upper right-hand corner, click on the link "USCG: Safety Alert and Recalls," click on the "Safety Alerts" link, and at the top of the page, click on "most current" under "safety Alerts."