Puget Sound Fleet 5 C34 Owners Ė
A couple years ago, I had to replace my VHF radio after accidentally hitting the 12V DC power with 120V shore power. (Yes, turn things off when messing behind the panel). The new radio I bought, the cheapest at WM at the time, had a feature called ďDSCĒ. After reading the manual, I discovered DSC, among other features, provided unique identification of my vessel when the distress button was pressed. All that was required was to enter a MMSI number into the VHF radioís static memory. I also found I already had a MMSI number on my FCC station license. You can also be assigned a MMSI number from an organization such as BoatUS. Step one was complete, theyíll know Craig on Espresso was sinking, but where? The VHF also had a NMEA 0183 input that would allow Lat/Lon data from a GPS to be included with the distress call, but I rarely used the old black & white Garmin unit at my Nav table, so I didnít pursue getting them interconnected.
Last spring, I got real serious about interconnecting all the NMEA capable equipment on my boat and invested in a new chartplotter and more capable VHF. Iíll focus on just my chartplotter and VHF interfacing.
I picked up a Garmin 492 on closeout, it being superseded by a unit that supported XM satellite weather. I also purchased a Uniden UM525 Loud Hailer. Thereís a plethora of chartplotters on the market and many VHF options, I just want to share the opportunities when you can connect them together. Both devices both input and output NMEA data. Iíll list a bunch of web links at the end of this.
Among its many features, the Uniden UM525 will not only use DSC for distress transmit and receive signaling, but will allow directed calling of other VHF stations to their MMSI number. You can build a directory of friendsí boats MMSI numbers and save them by boat name. If the radio receives a DSC call, it will automatically switch channels, if desired. Lastly, when a DSC call is received, it will put an alert on the NMEA data bus. The Uniden also uses GPS information for more than distress Lat/Lon. Itís capable of automatically picking US or Canadian channels and displaying the appropriate local time. It will also repeat from the GPS, course and speed information.
The Garmin 492ís DSC features allow an alarm to display on the screen and emit an alarm tone. It will log and display the calling vesselís position. You can then display the caller on your chart and/or create a waypoint.
DSC need not be only used in an emergency. Itís limited only by the range of your VHF. You can use it to directly contact another vessel without trying to hail it on channel 16 or the VTS channels. If you have AIS installed and integrated to your chartplotter, the MMSI number is included in the AIS data stream. You could contact that approaching tug and verify its course.
Rescue 21 is an initiative by the Coast Guard to upgrade their facilities to more quickly and accurately respond to emergencies. For more information, see: http://www.piersystem.com/go/doc/21/141255/http://seattletimes.nwsource.com/html/localnews/2003725556_coastguard29m.html
I donít intend to endorse any specific product, just encourage you to take advantage of existing capabilities on your equipment and consider these features when you need to replace or upgrade your gear. Of course, Iím open to share my experiences with other boat networking topics.
C34 #1150 Espresso
DSC Ė Digital Selective Callinghttp://www.boatus.com/husick/c_dsc.asphttp://www.navcen.uscg.gov/MARCOMMS/gmdss/dsc.htmhttp://www.navcen.uscg.gov/marcomms/gmdss/dscworks.htm http://www.boatsafe.com/nauticalknowhow/dig0101.htmhttp://www.ybw.com/ybw/vhf/dsc.html