33 U.S.C. § 1203 — Radiotelephone requirement

(a) Except as section 1206 provides, these must have a radiotelephone operable from the navigation bridge, or a dredge’s main control station: (1) every power-driven vessel at least 20 meters long while navigating; (2) every vessel of at least 100 gross tons, measured under section 14502 of title 46 or an alternate tonnage under section 14302 as prescribed under section 14104, carrying one or more passengers for hire while navigating; (3) every towing vessel at least 26 feet long while navigating; and (4) every dredge and floating plant working in or near a channel or fairway in a way likely to restrict or affect other vessels’ navigation. The radio must send and receive in the 156–162 megahertz band, using emission classes the FCC designates after consulting other responsible agencies, for exchanging navigational information. (b) The radio must be carried on those vessels, dredges, and plants on United States navigable waters, including all waters of the territorial sea described in Presidential Proclamation 5928 of December 27, 1988.