What is the purpose of Channel 70 in marine communication?

Channel 70 serves a very specific and crucial role in marine communication as the designated Digital Selective Calling (DSC) "alert channel." This channel is used primarily for sending distress alerts and other important communication, which can include safety broadcasts and other urgent notifications. When a vessel is in distress, it can send a distress signal on Channel 70, which is picked up by nearby vessels and coast stations that are monitoring.

This channel allows for automated communication, enhancing the efficiency and effectiveness of emergency responses. It ensures that the distress calls reach not just one vessel, but all those in the vicinity that are equipped with DSC technology. The use of Channel 70 therefore plays a vital role in maritime safety, facilitating timely communication about emergencies on the water.

Other options, like public telephone calls, are not applicable to marine communication and are typically handled on land-based systems. While distress signals are indeed sent on Channel 70, it's not exclusively for that purpose; instead, it is primarily focused on the digital calling aspect to alert recipients efficiently. Communication between vessels typically occurs on other designated channels, making Channel 70’s role quite specialized.