In inland navigation, what does the signal of two short blasts indicate when you are overtaking another vessel?

• A. I intend to overtake you on your starboard side.
• B. I am overtaking you from astern.
• C. I intend to overtake you on your port side.
• D. I intend to pass you on the bow.

Answer: (C)

In inland navigation, vessels use sound signals to communicate overtaking intentions to avoid close-quarters danger. Two short blasts specifically tell the other vessel: I intend to overtake you on your port side. This lets the vessel being overtaken know which side you’ll pass on, so they can adjust if needed or simply maintain their current course and speed to allow a safe pass. The signal is all about the passing side, not about other maneuvers. If you were to pass on the starboard side, a different signal would be used, but two short blasts clearly communicates port-side passing.