What is the purpose of a sound signal on a buoy?

A sound signal on a buoy serves primarily to alert vessels in low visibility conditions. This is critical because fog, rain, or other environmental factors can significantly reduce visibility at sea, making it difficult for vessels to detect navigational aids like buoys. The sound signal acts as an auditory marker, allowing mariners to locate the buoy even when visual identification is compromised.

While it is important for navigational aids to be identifiable during the day, the primary function of sound signals is to enhance safety during conditions of limited visibility. Sound signals do not indicate malfunctions or provide weather updates; rather, they are solely intended to assist in navigation by alerting vessels to the buoy’s presence when visibility is low.