Question 18 ONC06 - Master LT 100 GRT

The Correct Answer is A. **Explanation for Option 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 may, in addition to the lights prescribed for a power-driven vessel under way, exhibit **three all-round red lights in a vertical line**. These lights signify the vessel's restricted maneuverability due to the relationship between the available depth of water and her draft. **Explanation for why other options are incorrect:** * **B) A vessel moored over a wreck:** While a vessel might be involved in salvage operations or marking a wreck, the primary lights displayed by a vessel engaged in diving or underwater operations are **three all-round lights in a vertical line: red, white, red** (COLREGs Rule 27(d)). Three all-round red lights specifically denote a vessel constrained by her draft (or a vessel aground, but only when displayed in addition to the anchor lights – see C). * **C) A vessel aground:** A vessel aground must exhibit the lights for a vessel at anchor (forward anchor light, and an after anchor light if over 50 meters in length) and, in addition, **two all-round red lights in a vertical line** where they can best be seen (COLREGs Rule 30(e)). A vessel aground displays two red lights, not three. * **D) A vessel dredging:** A vessel engaged in dredging or underwater operations (a type of vessel restricted in her ability to maneuver) must exhibit the masthead lights, sidelights, and sternlight. Additionally, she must display **three all-round lights in a vertical line: red, white, red**, to indicate the side on which the obstruction exists and the side on which it is safe to pass (COLREGs Rule 27(d)). Three all-round red lights are not the standard signal for a vessel dredging.