Question 32 GLI02 - Mate of Unlimited Tonnage

The Correct Answer is A. ### Explanation for Option A (Correct Answer) The illustration D084RR (referencing standard navigation light diagrams) shows a vessel exhibiting two vertical masthead lights, where the **upper light is red** and the **lower light is red**. According to the International Regulations for Preventing Collisions at Sea (COLREGs), Rule 27 (a) describes the lights exhibited by a **vessel not under command (NUC)**: > "A vessel not under command shall exhibit two all-round red lights in a vertical line where they can best be seen." The configuration of two all-round red lights displayed vertically clearly indicates the vessel is **not under command**. These lights are distinct from the white masthead lights used for power-driven vessels and the red-over-white-over-red lights used for restricted in ability to maneuver (RIAM) vessels. --- ### Explanation for Incorrect Options **B) showing improper lights:** This is incorrect because the specific combination of two vertical all-round red lights is a standard and proper signal defined by COLREGs (Rule 27(a)) to indicate a vessel is Not Under Command (NUC). **C) dredging:** This is incorrect. A vessel engaged in dredging or underwater operations (a specific type of Restricted in Ability to Maneuver - RIAM) exhibits **three** vertical all-round lights: Red-White-Red (R-W-R). If there is an obstruction, they may also show two vertical all-round green lights on the side of safety and two vertical all-round red lights on the side of the obstruction. The depicted R-R configuration is solely for NUC, not dredging operations. **D) towing:** This is incorrect. A vessel engaged in towing shows **two** or **three** vertical masthead lights (white) depending on the length of the tow (less than 200m or 200m or more, respectively), in addition to the standard sidelights and stern light, and potentially a yellow towing light above the stern light. The displayed lights (R-R) are not associated with towing operations.