What channel must VHF-FM-equipped vessels monitor at all times when at sea?

VHF-FM-equipped vessels are required to monitor Channel 16 at all times when at sea. This channel is designated as the international distress, safety, and calling frequency. It serves a crucial role in maritime communication, allowing vessels to communicate distress signals and important safety messages. Monitoring Channel 16 ensures that vessels can receive emergency alerts and facilitate communications with other vessels or shore stations in case of an emergency.

While other channels may serve specific purposes or local communication needs, none carry the same significance for safety and urgency as Channel 16 does in maritime operations. It acts as a vital link for distress calls and is the primary channel for all ships, allowing quick response to emergencies. This importance significantly differentiates it from Channel 8, Channel 5A, and Channel 1A, which do not serve the same universal emergency communication role.