Section 121.602 - Internal communications systems(a) A vessel equipped with pilothouse control must have a fixed means of two-way communications from the operating station to the location where the means of controlling the propulsion machinery, required by § 121.620(a) , is located. Twin screw vessels with pilothouse control for both engines are not required to have a fixed communications system.(b) A vessel equipped with auxiliary means of steering, required by § 119.600 of this chapter, must have a fixed means of two-way communications from the operating station to the location where the auxiliary means of steering is controlled.(c) When the propulsion machinery of a vessel cannot be controlled from the operating station, an efficient communications system must be provided between the operating station and the propulsion machinery space.(d) When the locations addressed in paragraphs (a), (b), and (c) of this section are sufficiently close together, direct voice communications satisfactory to the cognizant OCMI is acceptable instead of the required fixed means of communications.(e) The OCMI may accept hand held portable radios as satisfying the communications system requirement of this section.