User:Delroland/sandbox

=Global Maritime Distress and Safety System Sea Areas= The Global Maritime Distress and Safety System (GMDSS) is an integrated communications system using satellite and terrestrial radiocommunications to ensure that no matter where a ship is in distress, aid can be dispatched. The GMDSS combines various subsystems - which all have different limitations with respect to coverage - into one overall system, and the oceans are divided into four sea areas. GMDSS sea areas serve two purposes: to describe areas where GMDSS services are available, and to define what radio equipment GMDSS ships must carry (carriage requirements). Prior to the GMDSS, the number and type of radio safety equipment ships had to carry depended upon its tonnage. With GMDSS, the number and type of radio safety equipment ships have to carry depends upon the GMDSS areas in which they travel.

In addition to equipment listed below, all GMDSS-regulated ships must carry a satellite EPIRB, a NAVTEX receiver (if they travel in any areas served by NAVTEX), an Inmarsat-C SafetyNET receiver (if they travel in any areas not served by NAVTEX), a DSC-equipped VHF radiotelephone, two (if between 300 and less than 500 GRT) or three VHF handhelds (if 500 GRT or more), and two 9 GHz search and rescue radar transponders (SART).

Sea Area A1
An area within the radiotelephone coverage of at least one VHF coast station in which continuous digital selective calling (Ch.70/156.525 MHz) alerting and radiotelephony services are available. Such an area could extend typically 30 nmi to 40 nmi from the Coast Station.

The United States presently has no A1 Sea Areas. The United States Coast Guard has implemented Rescue 21 to manage VHF communication along the coast of the United States. Rescue 21 is operational along the entire Atlantic, Pacific, and Gulf coasts of the continental United States as well as along the shores of the Great Lakes, Puerto Rico, Hawaii, and Guam.

Sea Area A2
An area, excluding Sea Area A1, within the radiotelephone coverage of at least one MF coast station in which continuous DSC (2187.5 kHz) alerting and radiotelephony services are available. For planning purposes, this area typically extends to up to 180 nmi offshore during daylight hours, but would exclude any A1 designated areas. In practice, satisfactory coverage may often be achieved out to around 400 nmi offshore during night time.

The United States presently has no declared A2 Sea Areas. The US Coast Guard has installed and is operating seven A2 Sea Area-capable coast stations, but those stations do not yet provide continuous coverage.

Sea Area A3
An area, excluding sea areas A1 and A2, within the coverage of an INMARSAT geostationary satellite in which continuous alerting is available. Ships travelling this area must carry either an Inmarsat F77, B or C ship earth station, or a DSC-equipped HF radiotelephone/telex, in addition to equipment required for an A1 and A2 Area.

Sea Area A4
The area outside that covered by areas A1, A2 and A3 is called Sea Area A4. Ships travelling these polar regions must carry a DSC-equipped HF radiotelephone/telex, in addition to equipment required for areas A1 and A2.

GMDSS Radio Equipment Required for U.S. Coastal Voyages
Presently, GMDSS-mandated ships operating off the U.S. coast must fit to Sea Areas A3 (or A4) regardless of where they operate. U.S. ships whose voyage allows them to always remain within VHF channel 16 coverage of U.S. Coast Guard stations may apply to the Federal Communications Commission for an individual waiver to fit to Sea Area A1 requirements. Similarly, those who remain within 2182 kHz coverage of U.S. Coast Guard stations may apply for a waiver to fit to Sea Area A2 requirements.

GMDSS Radio Equipment Required for Australia and New Zealand
Australia and New Zealand have designated their coastal waters as GMDSS Sea Area A3, thus GMDSS-mandated ships operating off the coast of Australia or New Zealand must fit to Sea Area A3 (or A4) requirements.