Question 31 OSV02 - Mate - Offshore Supply Vessels

The Correct Answer is C **Explanation for Option C (Correct Answer):** The illustration D010RR shows a vessel displaying three shapes arranged vertically: a diamond shape, followed by a circle (or ball) shape, and then another diamond shape. According to the International Regulations for Preventing Collisions at Sea (COLREGs), Rule 24 (Towing and Pushing), a vessel engaged in towing where the length of the tow (measured from the stern of the towing vessel to the after end of the tow) exceeds 200 meters, must display specific day signals. These signals are a **diamond shape**, where it can best be seen, and two masthead lights in a vertical line (at night). However, if the vessel is restricted in its ability to maneuver due to the tow (which is common for long tows), it must also display the signals for a vessel restricted in its ability to maneuver (Rule 27(b)): three shapes in a vertical line—ball, diamond, ball. Therefore, the combination of shapes shown (Diamond-Ball-Diamond) signifies: 1. **The top Diamond:** Indicates a tow exceeding 200 meters. 2. **The Ball-Diamond-Ball (overlapping with the top Diamond):** Indicates a vessel restricted in its ability to maneuver (RIM). Since the combination includes the diamond required by Rule 24, the primary reason for displaying these specific shapes is that the vessel **has a tow that exceeds 200 meters in length** and is simultaneously restricted in its maneuverability by that tow. **Explanation for Incorrect Options:** **A) Is at anchor:** A vessel at anchor displays a single ball shape where it can best be seen (Rule 30). The illustration shows three distinct shapes (Diamond-Ball-Diamond), not just a single ball. **B) Is not under command:** A vessel not under command (NUC) displays two balls in a vertical line where they can best be seen (Rule 27(a)). The illustration displays three shapes including diamonds, which is incorrect for a NUC vessel. **D) Has a tow that is carrying hazardous cargo:** COLREGs do not prescribe specific day shapes for a vessel solely based on the hazardous nature of its cargo. Vessels carrying hazardous or dangerous cargo typically rely on other signage (such as placards, IMO numbers, or required lighting/shapes under different regulations, e.g., NUC or RIM, if applicable) but not this specific day shape combination. The shape combination relates directly to the length of the tow and restricted maneuverability, not the cargo itself.