U.S. Coast Guard should announce plans to declare Sea area A1,
where ships are within range of at least one VHF coast station with continuous
DSC alerting available (about 20–30 miles from the coast).
Areas of operation for the GMDSS
According to the range of various systems of radiocommunications constituting the GMDSS to make it possible that a ship at sea can always contact a shore-based radio station (normally an MRCC), sea areas are defined as follows:
Sea area A1 : Within range of at least one VHF coast
station with continuous DSC alerting available (about 20–30 miles from the
Sea area A2 : Beyond
area A1, but within range of at least one MF coast station with continuous DSC
alerting available (about 150–200 miles from the coast).
Sea area A3 : Beyond the first two areas, within
coverage of an Inmarsat geostationary satellite in which continuous alerting is
available (approximately between latitudes 70º North and 70º South).
Sea area A4 : The remaining sea area outside A1, A2 and
A3 (i.e. the polar regions) and covered
by at least one HF coast station providing a continuous DSC alerting service.
The VHF range in sea area A1 is calculated by the height of
the coast stations’ antennas (assuming 4 metres for a ship’s
antenna) and can vary from 15 to 60 nautical miles or even more. Many MRCCs
serving sea area A1 has several remote sites to cover a long coastline.
The concept of sea areas is fundamental, since GMDSS
equipment carriage requirements are based not on the size of a ship but on the
sea area(s) in which it operates.
Completion of Rescue 21 project
With the completion of Rescue 21 in the United States soon
to be achieved, it is considered appropriate to announce plans for declaration
of Sea Area A1 in the U.S. The possible target date would be 31 December 2012.
This decision affects regulatory matters involving non-SOLAS
vessels required to be VHF equipped but operating under a waiver delaying the
requirement to be DSC capable.