What does three short horn blasts indicate?

Three short horn blasts is a standardized signal in maritime communication. This signal specifically indicates that a vessel is backing up. It is crucial for maintaining safety and awareness on the water, as other vessels must recognize this signal to understand the maneuvers being performed.

When a boat is uncertain of its surroundings or needs to reverse, using three short blasts helps alert nearby boaters of the potential for changed movement. This can prevent accidents or collisions since it effectively communicates the intention of the vessel operator to other boaters nearby.

The other options represent different signals with distinct meanings, highlighting the importance of understanding these communications on the water for safe navigation and operation.