What signal should you sound if you do not understand the course or intention of an approaching vessel?

• A. Not less than five short blasts
• B. Two long blasts
• C. One prolonged blast
• D. No signal

Answer: (A)

When another vessel’s actions aren’t clear, you use sound signals to elicit a response and clarify intentions. The signaling rule shows that not less than five short blasts on your whistle is the correct way to indicate confusion or lack of understanding about the approaching vessel’s course or intentions. This strong, unambiguous signal prompts the other vessel to communicate its plans or alter course, helping to prevent a collision. Other signals (like long or single blasts) are used for different communications, and not signaling at all provides no clarification. So, five short blasts is the standardized way to request clarification.