What is the primary purpose of sound signals in navigation?

The primary purpose of sound signals in navigation is to facilitate communication between vessels in limited visibility. This is crucial because reduced visibility conditions, such as fog or heavy rain, can obscure visual signals and make it difficult for vessels to determine each other's positions and intentions. Sound signals serve as an alternative means of communication, allowing vessels to announce their presence, their actions, and their intentions to others nearby. This helps to prevent collisions and ensures the safe navigation of all vessels involved.

While announcing an arrival at a harbor may be important, it is not the primary function of sound signals, as vessels often have other ways to communicate that they are entering or leaving a harbor. Indicating vessel size and denoting vessel speed are also not the purposes of sound signals. Vessel size generally does not change, and speed is typically managed for operational reasons rather than communicated through sound signals. Therefore, the use of sound signals to communicate intentions and positions during conditions of limited visibility remains the critical primary purpose in navigation.