BOTH INTERNATIONAL & INLAND Which vessel would show 3 shapes in a vertical line, the highest and lowest being balls and the middle shape being a diamond?

Correct Answer: Option C — Vessel restricted in her ability to maneuver

Rule 27(b)(iii) explicitly lists three shapes in a vertical line—ball, diamond, ball—as the required day signal for a vessel restricted in her ability to maneuver. This signal informs other traffic that the vessel's ability to deviate from her course is limited by the nature of her current work.