What is the minimum requirement for vessels in international waters regarding radio equipment?

The minimum requirement for vessels in international waters regarding radio equipment is a Digital Selective Calling (DSC) system. DSC is a crucial safety feature that allows for automatic distress signaling and communication with rescue coordination centers and other vessels. It enhances the ability to send distress alerts, receive acknowledgments, and facilitate communication during emergencies.

In international maritime regulations, vessels must comply with the Global Maritime Distress and Safety System (GMDSS), which mandates the use of DSC-equipped radios for efficient and reliable communication, particularly in remote and high-seas environments. This requirement ensures that vessels can continuously monitor distress frequencies and respond rapidly to emergencies, thereby improving overall maritime safety.

The other options, although important in various contexts, do not meet the specific minimum requirement set forth for all vessels operating in international waters. Single sideband radios, VHF radios, and high-frequency radios may be used for communication, but they lack the automated distress capabilities and standardized operational protocols that DSC systems provide.