What do 3 short blasts of the horn indicate?

Three short blasts of a horn typically indicate a vessel's intention to maneuver, particularly in situations where it may not be clear to others what the vessel is doing. In maritime contexts, this signal often means that the vessel is operating in a restricted manner or is about to make a specific maneuver, such as reversing. It is a part of the International Regulations for Preventing Collisions at Sea (COLREGS) to ensure safe navigation.