Question 4 RVR03 - Mate of LT 500-1600 GRT

The Correct Answer is C **Explanation for Option C (Correct Answer):** The vessel described is exhibiting: 1. **Red and Green Sidelights:** Indicating the vessel is underway. 2. **Three White Lights in a Vertical Line (above the sidelights):** According to the COLREGs (Rule 24, Annex I), when a vessel is towing and the length of the tow (measured from the stern of the towing vessel to the after end of the tow) exceeds 200 meters, it must exhibit three white masthead lights in a vertical line instead of the usual two (or one) for a shorter tow. These lights replace the forward masthead light(s) and are stacked vertically. The visibility of the sidelights confirms it is the towing vessel itself that is being observed. Therefore, the lights indicate **a vessel towing a tow more than 200 meters astern**. **Explanation for Incorrect Options:** **A) a vessel not under command (NUC):** A vessel not under command (Rule 27(a)) is required to show two all-round red lights in a vertical line where they can best be seen, in addition to sidelights and sternlight if underway. It would not show three white masthead lights in a vertical line. **B) a vessel trawling:** A vessel engaged in trawling (Rule 26(b)) is required to show two lights in a vertical line: an upper green all-round light and a lower white all-round light. It would not show three white lights in a vertical line. **D) a vessel underway and dredging:** A vessel engaged in dredging or underwater operations (Rule 27(d)) is required to show three all-round lights in a vertical line: the upper and lower lights must be red (to indicate the obstructed side), and the middle light must be white (to indicate the side where it is safe to pass). It would not show three white lights in a vertical line, nor would it likely be showing only sidelights plus the three vertical lights (it must display the required day shapes/lights for the operation).