Sailing vessels during periods of reduced visibility typically sound which of the following signals?

Sailing vessels during periods of reduced visibility are required to signal their presence and intentions using sound signals that are appropriate for their type and operation. A series of irregular blasts is the correct signal as it effectively communicates the vessel’s status to nearby boats in conditions where visual cues are limited.

This method of signaling is designed to alert other vessels of the sailing boat’s presence, especially since normal means of sight are compromised. The irregular pattern serves to convey an active engagement, indicating that the vessel is navigating or making its way through the area. This option is consistent with the standards laid out in the International Regulations for Preventing Collisions at Sea (COLREGs), which seeks to ensure safety and prevent collisions in low visibility conditions.

While other sound signals such as a continuous horn or a gong serve specific purposes, they do not align with the requirements for sailing vessels in reduced visibility scenarios, where communicating the vessel's movements is critical.