*Question E1A11:
[97.5] What licensing is required when operating an amateur station aboard a US-registered vessel in international waters?*  

*Correct Answer is  B: Any FCC-issued amateur license*  

### AI Response: (may contain errors)  

To operate an amateur station aboard a US-registered vessel in international waters, the correct licensing requirement is:

**Correct Answer: B: Any FCC-issued amateur license**

### Explanation of the Correct Answer:
- **Any FCC-issued amateur license**: When operating in international waters, you are still subject to the regulations of the country that registered your vessel. For US-registered vessels, any amateur radio license issued by the FCC is valid, regardless of class. This means that even a Technician class license is sufficient.

### Explanation of Incorrect Answers:
- **A: Any amateur license with an FCC Marine or Aircraft endorsement**: This is incorrect because there is no specific requirement for a marine or aircraft endorsement to operate an amateur station on a vessel. The standard amateur license suffices.

- **C: Only General class or higher amateur licenses**: This is incorrect as well. There is no restriction that requires a General class or higher license for operation in international waters on a US-registered vessel. Any amateur license is acceptable.

- **D: An unrestricted Radiotelephone Operator Permit**: This is also incorrect. While a Radiotelephone Operator Permit is required for certain commercial operations, it is not necessary for amateur radio operations on a vessel.

### Summary:
- **Key Point**: Any FCC-issued amateur license is valid for operating on a US-registered vessel in international waters.
- **Regulatory Reference**: This is based on the FCC's rules regarding amateur radio operation and the recognition of licenses in international waters.

This understanding is crucial for the Extra Class exam and ensures compliance with regulations while operating in international waters.