47 CFR § 80.1087 - Ship radio equipment - Sea area A1.
This section contains the additional equipment requirements for ships that remain within sea area A1 at all times.
(a) In addition to meeting the requirements of § 80.1085, ships engaged on voyages exclusively in sea area A1 must be provided with a radio installation capable of initiating the transmission of ship-to-shore distress alerts from the position from which the ship is normally navigated, operating either:
(1) On VHF using DSC; or
(2) Through the polar orbiting satellite service on 406.0-406.1 MHz (this requirement may be fulfilled by the EPIRB required by § 80.1085(a)(6), either by installing the EPIRB close to, or by allowing remote activation from, the position from which the ship is normally navigated); or
(4) On HF using DSC; or
(b) The VHF radio installation, required by § 80.1085(a)(1), must also be capable of transmitting and receiving general radiocommunications using radiotelephony.