Question 42 RVR04 - Master or Mate of LT 200 GRT

The Correct Answer is A **Explanation for Option A (Correct Answer):** A vessel "not under command" (NUC), whether operating under International or Inland rules, is required to signal its restricted ability to maneuver. According to Rule 27(a)(i) of the COLREGs (and adopted in Inland Rules), a vessel not under command must exhibit: **two all-round red lights in a vertical line** where they can best be seen. This signal clearly communicates to other vessels that it is unable to keep out of the way. **Explanation of Why Other Options are Incorrect:** * **B) a stern light:** While a vessel not under command that is underway will eventually exhibit a stern light, a stern light *alone* is insufficient and is not the defining light signal for an NUC vessel. Furthermore, the question asks what lights the vessel is *required* to exhibit to indicate its NUC status. * **C) sidelights:** A vessel not under command that is underway (even if "not making way," meaning stationary relative to the water) is still required to show its sidelights (Rule 27(a)(iii)). However, the specific light signal for being NUC is the two all-round red lights (Option A). The combination of sidelights and stern light (running lights) is required *in addition* to the NUC lights, but the NUC status itself is defined by Option A. * **D) All of the above:** This is incorrect because although the vessel must exhibit sidelights and a stern light (Rules 27(a)(iii) and 23), the unique and mandatory signal identifying the vessel's status as "not under command" is the pair of all-round red lights (Option A). The question is testing the recognition of the primary NUC signal. If the vessel were *making way* through the water, it would exhibit all three types (A, B, and C), but Option A is the foundational requirement for indicating the NUC status itself. Since the options list the components separately, and Option A is the mandatory signal defining the status, it is the best fit.