47 CFR §80.477

1. (a)AMTS coast stations may communicate with fixed platform stations located in the offshore waters of the Gulf of Mexico, with ship stations, and with land units in accordance with § 80.123.
2. (b)AMTS licensees in the offshore waters of the Gulf of Mexico may use AMTS coast and ship station frequencies on a secondary basis for fixed service communications to support offshore AMTS operations.
3. (c)AMTS service may be provided to any vessel within communication service range of an AMTS station even though the vessel may not be operating within the confines of a served waterway.
4. (d)AMTS licensees may use AMTS coast and ship frequencies on a secondary basis for fixed service communications to support AMTS deployment in remote fixed locations at which other communications facilities are not available.