A vessel certified for service in Sea Area A3 is required to maintain a watch on:

A vessel certified for service in Sea Area A3 is required to maintain a watch on specific frequencies that are crucial for safety and communication purposes. The correct choice highlights the need for the vessel to monitor VHF Channel 70, MF Frequency 2187.5 kHz, HF on 8414.5 kHz, and an additional HF DSC frequency.

The monitoring of VHF Channel 70 is essential because it is designated for Digital Selective Calling (DSC) communication, which allows vessels to send distress signals and receive safety information. This channel acts as a primary medium for distress alerts and other critical maritime safety communications.

Furthermore, the inclusion of MF Frequency 2187.5 kHz is significant as it is the standard frequency for DSC calls in the medium frequency range. This frequency works in conjunction with the VHF frequencies to ensure a comprehensive communication network, especially in areas that may be beyond VHF range but still require effective distress communication.

The presence of HF on 8414.5 kHz also aligns with GMDSS requirements as this frequency is used for high seas applications and allows for long-range communication. The requirement to monitor one additional HF DSC frequency provides redundancy and ensures that the vessel can earnestly receive distress communications from other