What is the purpose of five or more short, rapid blasts?

The purpose of five or more short, rapid blasts on a vessel's horn or whistle is to signal danger or disagreement. This particular sound is an internationally recognized indication that something is amiss or that the operator believes there may be an impending risk to safety, whether due to physical obstructions, confusion about maneuvering intentions, or other hazardous situations on the water. Such signaling is critical in ensuring that all vessels are aware of potential dangers, facilitating better communication among boaters to prevent accidents.

In navigation contexts, additional signals are designated for various maneuvers and intentions, such as signaling to pass on a specific side, but five short blasts are unequivocally recognized as a warning for danger or a call for clarification in a potentially hazardous or confusing situation. Understanding these sound signals is crucial for maintaining safety and effectiveness in boating operations.