Mayday! Mayday! The internationally recognized distress call for mariners and aviators; however, if no one hears the call, help will not be dispatched. The U.S. Coast Guard has been taking steps to make sure that their ships and shore stations do hear the call, whenever and wherever it is sounded, and are able to respond effectively. The service has been busy for quite some time installing an advanced new state-of-the-art command, control, and communications system known as Rescue 21.
For several decades the Coast Guard relied primarily on VHF-FM line-of-sight communications to receive distress calls from mariners. That system uses antennas mounted on towers known as high-level sites to increase the range of the system – which, unfortunately, was still plagued with some coverage gaps. The system also lacked any direction-finding capability, forcing responders to depend upon locations provided by the caller. Far too often, though, the positions provided were inaccurate, which meant that lengthy (and expensive) searches were needed to locate a vessel in distress. The lack of direction-finding capability also removed at least one way to rapidly identify a hoax distress call because there was no way to correlate the caller’s information with the direction from which the call was coming.
Another problem was that this legacy system uses analog recording equipment, which degrades clarity and offers no means for “cleaning up” a garbled transmission. The importance of possessing a “degarbling” capability was exemplified in the case of the sailing vessel Morning Dew. In the early morning hours of 29 December 1997, the Morning Dew – with a father, two sons, and a nephew on board – struck the rock jetty at the entrance to the harbor of Charleston, South Carolina. Ultimately all four passengers perished.
Too Little, Too Late – What Might Have Been
A post-incident investigation determined that the local Coast Guard station did hear someone calling the Coast Guard, but the transmission was mostly unintelligible, and the station’s personnel could not determine the location of the transmission. Coast Guard watch standers radioed a response, but received no clear additional transmission. A replay of the recording of the original transmission did not help at the time – but in a later review of the tapes, with the full circumstances of the incident known, the word “Mayday” could be made out. One can only wonder if the outcome would have been less tragic if the Coast Guard’s watch standers had had a digital communications system available with the ability to clean up the recording.
Rescue 21 addresses all of the equipment shortfalls identified in the Morning Dew case, and more. The system includes, among other subsystems and capabilities: direction-finding equipment; multiple voice/data channels; protected communications for government operators; a tracking system for Coast Guard assets; a digital voice recording capability with enhanced playback; and, if the source transmitter is properly registered, the ability to quickly provide information about the specific vessel, its current position, and other situational data. In the words of Coast Guard Commandant Admiral Thad Allen, “Rescue 21 is helping the Coast Guard take the ‘search’ out of search and rescue.”
The installation of Rescue 21 systems is still ongoing, but unit sets already have been deployed to 11 Coast Guard regions – enough, in other words, to permit Allen to truthfully declare that the system is now “operationally ready.” The system – which uses a total of 350 communication towers – eventually will be installed at 46 Coast Guard sector commands and 220 stations. However, full implementation, originally scheduled for 2006, is now scheduled for 2011.
The views expressed herein are those of the authors and are not to be construed as official and/or reflecting the views of the commandant or of the U.S. Coast Guard.