What is the primary function of channel 13 in maritime communication?

Channel 13 is primarily designated for communication related to bridges and locks. This channel is used for facilitating safe passage for vessels through narrow or restricted areas, where it is necessary to notify bridge operators when a vessel is approaching. Additionally, it can be used to coordinate actions with lock operators to ensure the safety and efficiency of vessel transit through these infrastructure points.

Using Channel 13 for this specific purpose helps to streamline communication, allowing vessels to inform operators of their intentions and receive instructions or status updates regarding bridge openings and lock operations. This minimizes confusion and enhances navigational safety in congested waterways.