When should a vessel's sound signal be used?

A vessel's sound signal is an important communication tool used to ensure safety and alert other vessels to its presence or intentions. The correct context for using sound signals is during periods of reduced visibility, which can include fog, heavy rain, or any other conditions where the visibility of vessels is compromised. This allows vessels to signal their intentions or navigate safely without visual contact.

Additionally, sound signals are also employed to communicate with other vessels when navigating in close quarters to prevent collisions. By signaling intentions, such as overtaking or changing course, vessels can better coordinate their movements in situations where they might not be able to see each other clearly.

Using sound signals strictly in fair weather or only at night would not cover the critical situations in which these signals are most needed to prevent accidents. Additionally, using them when anchored or moored is generally not necessary, as there is typically no risk of collision in those scenarios. Thus, the use of sound signals is primarily focused on enhancing communication and safety in conditions where visual cues are limited.