Which signal indicates that the vessel is backing up?

The signal that indicates a vessel is backing up is represented by three short horn blasts. This sound is an important auditory signal in boating, particularly in areas with other boats or in busy waters where communication about movement is essential for safety and navigation.

When a vessel is reversing, it is crucial for nearby vessels and operators to be aware of its actions to prevent collisions. The standardized use of three short blasts effectively communicates this specific maneuver to anyone within hearing range, ensuring that all boats are informed of the vessel's intentions.

In contrast, the other signaling options serve different purposes: one prolonged blast typically indicates a vessel is operating in restricted visibility; two short horn blasts often signify that a vessel is passing another; and five rapid blasts usually denote danger or an urgent warning. Therefore, understanding these signals helps ensure safe and effective communication among vessels on the water.