In what situation is a sounding board or whistle required aboard a vessel?

The requirement for a sounding board or whistle aboard a vessel is especially pertinent in situations of reduced visibility, such as fog, heavy rain, or darkness. These conditions can significantly impair a boater's ability to see other vessels, navigation aids, and hazards in the water. Consequently, using sound signals becomes essential for safety, as they help communicate a vessel's presence to others nearby and avoid collisions.

Under regulations, vessels are mandated to use sound signals to indicate their position or intentions when visibility is compromised. This practice is a critical part of maritime safety and adheres to the rules set forth by the International Regulations for Preventing Collisions at Sea. While other options might have specific situations where signaling may be advisable, the necessity of a sounding device directly correlates with conditions of reduced visibility, emphasizing its importance in maintaining safe navigation.