46 C.F.R. § 27.205 What are the requirements for internal communication systems on towing vessels?
Title 46 - Shipping
(a) You must ensure that your vessel is fitted with a communication system between the engine room and the operating station that— (1) Consists of either fixed or portable equipment, such as a sound-powered telephone, portable radios, or other reliable method of voice communication, with a main or reserve power supply that is independent of the electrical system on your towing vessel; and (2) Provides two-way voice communication and calling between the operating station and either— (i) The engine room; or (ii) A location immediately adjacent to an exit from the engine room. (b) Twin-screw vessels with operating-station control for both engines are not required to have internal communication systems. (c) When the operating-station's engine controls and the access to the engine room are within 3 meters (10 feet) of each other and allow unobstructed visual contact between them, direct voice communication is acceptable instead of a communication system.
Title 46: Shipping
PART 27—TOWING VESSELS
Subpart B—Fire-Protection Measures for Towing Vessels
§ 27.205 What are the requirements for internal communication systems on towing vessels?