Which signal indicates you do not understand the other vessel's intentions/Warning-Doubt?

• A. I intend to overtake you on your starboard side
• B. I do not understand your intentions/Warning-Doubt
• C. Blind bend for both; used inland when leaving berth
• D. I am operating astern propulsion

Answer: (B)

The main idea is using a dedicated signal when you’re unsure what the other vessel intends to do to avoid a collision. Saying “I do not understand your intentions/Warning-Doubt” communicates your doubt explicitly and tells the other vessel that you need clarification or a change in course before proceeding. This makes it the best choice because it directly conveys the reason for your actions—your uncertainty about their intended maneuver.

The other options don’t fit because they describe a specific maneuver you plan (overtaking on starboard), a signaling practice not used in this context (an inland blind bend signal), or a propulsion status (operating astern). None of those express doubt about the other vessel’s intentions.