Question 18 ONC02 - Second Mate/Third Mate Unlimited Tonnage

The Correct Answer is A. **Explanation for A ("A vessel constrained by her draft"):** According to the International Regulations for Preventing Collisions at Sea (COLREGs), Rule 28 (Vessels constrained by their draft), a vessel constrained by her draft is required to exhibit, in addition to the lights prescribed for a power-driven vessel underway (masthead lights, sidelights, and stern light), **three all-round red lights in a vertical line**. These lights signify that the vessel is restricted in its ability to maneuver because of its deep draft relative to the available depth and width of navigable water. **Why other options are incorrect:** * **B) A vessel moored over a wreck:** A vessel engaged in diving or underwater operations may display specific signals (e.g., rigid replica of the International Code flag 'A' or three all-round lights: red, white, red in a vertical line, depending on the circumstances), but a vessel simply moored over a wreck without ongoing operations would likely display anchor lights or be considered a vessel at anchor/moored, which does not require three all-round red lights. * **C) A vessel aground:** A vessel aground (COLREGs Rule 30) displays the lights for a vessel at anchor (forward all-round white light, and stern all-round white light if over 50 meters), and additionally displays **two all-round red lights in a vertical line** where they can best be seen. It displays two, not three, red lights. * **D) A vessel dredging:** A vessel engaged in dredging or underwater operations (COLREGs Rule 27(d)) displays lights indicating restricted maneuverability (red, white, red all-round lights in a vertical line), and also displays specific lights to indicate the obstructed side and the side on which another vessel may pass. It does not display three all-round red lights in a vertical line to indicate its primary operation status.