47 CFR 80.956 - Required frequencies and uses.
(a) Each VHF radiotelephone installation must be capable of transmitting and receiving G3E emission as follows:
(1) Channel 16 - 156.800 MHz-Distress, Safety and Calling; and
(2) Channel 6 - 156.300 MHz - Primary intership.
(b) The radiotelephone station must have additional frequencies as follows:
(1) Those ship movement frequencies appropriate to the vessel's area of operation: Channel 11 - 156.550 MHz, Channel 12 - 156.600 MHz, or Channel 14 - 156.700 MHz.
(2) The navigational bridge-to-bridge frequency, 156.650 MHz (channel 13).
(3) Such other frequencies as required for the vessel's service.
(4) One channel for receiving marine navigational warnings for the area of operation.
(c) Every radiotelephone station must include one or more transmitters, one or more receivers, one or more sources of energy and associated antennas and control equipment. The radiotelephone station, exclusive of the antennas and source of energy, must be located as high as practicable on the vessel, preferably on the bridge, and protected from water, temperature, and electrical and mechanical noise.