Which of the following sets correctly lists the frequencies mandated to monitor in U.S. navigable waters?

• A. 2182 kHz, 156.8 MHz, 156.65 MHz (channel 13)
• B. 121.5 MHz, 2182 kHz, 243 MHz
• C. 138.78 MHz, 157.1 MHz, 123.1 MHz
• D. 156.8 MHz, 156.65 MHz, 243 MHz

Answer: (A)

Watching for distress and safety signals relies on three standard frequencies. The MF frequency at 2182 kHz is used worldwide for distress calls and calls between ships and coast stations on the medium-frequency band, so it’s a fundamental watch point for long-range communications. On the VHF band, Channel 16 at 156.8 MHz is the international distress, safety, and calling channel—boats and coast stations surface calls here to establish contact, especially in emergencies. Channel 13 at 156.65 MHz is the bridge-to-bridge channel used to manage and coordinate movements between vessels, particularly when passing or maneuvering near each other.

So the mandated monitoring set combines the MF distress/calling frequency with the two key VHF channels for distress, calling, and bridge-to-bridge communication. The other options mix in frequencies that aren’t required to be watched in U.S. navigable waters (such as older or nonstandard channels), so they don’t align with the required watch frequencies.