Which Coast Guard frequency corresponds to communications with civilian vessels?

The frequency used for communications with civilian vessels is the one designated for this purpose by the International Maritime Organization (IMO) and the U.S. Coast Guard. In this case, the correct answer is associated with a designated calling frequency used primarily for ship-to-ship and ship-to-shore communications, particularly for distress and safety communications in international waters.

Option 22A is set aside specifically for non-commercial maritime communications and serves as an alternative for vessel-to-vessel communications that do not fit into other categories. This frequency allows for communications that may not involve emergency situations, focusing instead on general vessel traffic and information sharing.

On the other hand, frequency 16 (156.800 MHz) is the international hailing and distress frequency, which is crucial for emergency situations and initial contact before switching to another working frequency. While frequency 13 is used more for vessel navigation purposes such as bridge-to-ship communications, it does not serve the broader scope of general civilian vessel communications as effectively as 22A. Lastly, frequency 11 is primarily for maritime mobile service play a different role and is not designated for this type of communication.

Thus, the context of maritime communication suggests that 22A is the most appropriate choice for civilian vessel communications, as it