Who must be in physical control of the station apparatus of an amateur station aboard any vessel or craft that is documented or registered in the United States?

FCC Part 97 rules dictate that an amateur station must always have a designated control operator whenever it is transmitting. If the station is located on a US-documented or registered vessel, the person in physical control of the transmitting apparatus must be a legally authorized amateur radio operator. This authorization requires either an FCC-issued amateur license or a foreign license recognized for alien reciprocal operation in the US. The operator does not necessarily have to be the specific person named on the amateur station's license, as long as they hold the proper amateur credentials. Distractors suggesting a Marine Radio license or a restricted Radiotelephone Permit are incorrect because those credentials govern commercial and marine mobile operations, which are entirely separate from amateur radio regulations.