What are the two types of sound signals used in the Navigation Rules?

The correct answer identifies the two types of sound signals as prolonged blasts and short blasts. In the context of the Navigation Rules, prolonged blasts are defined as signals lasting at least four to six seconds, while short blasts last about one second. These sound signals are essential for communication between vessels, particularly in situations where visibility is poor, such as fog or heavy rain.

Prolonged blasts typically indicate a vessel's presence or an intention to navigate in a certain manner, whereas short blasts can signal a variety of meanings, including warnings or intentions to maneuver. This distinction is crucial for maintaining safety on the water, as it helps avoid collisions and ensures that vessels can respond appropriately to one another’s actions. Understanding these sound signals and their meanings is key to effective navigation and adherence to the Navigation Rules.