Question 44 RVR01 - Master of Unlimited Tonnage

The Correct Answer is A **Explanation for Option A (less than 12 meters in length) being correct:** The navigation rules (specifically Rule 23, regarding power-driven vessels underway, and the associated Annex I, Positioning and Technical Details) acknowledge that vessels under 12 meters in length have physical constraints that may make strict adherence to the positioning requirements impossible. The general rule (Rule 21(a)) defines the masthead light as being placed over the fore and aft centerline. However, Annex I, Section 5(a) allows vessels less than 12 meters in length to deviate from the required horizontal and vertical positioning for lights, provided their placement is as nearly as possible in compliance with the Rules. This deviation often includes placing the masthead light (or the all-round white light that substitutes for the masthead light and stern light) slightly off the centerline if the vessel's structure (e.g., a small center console, engine housing, or railing placement) demands it. **Why the other options are incorrect:** * **B) which has separate sidelights carried on the outboard extremes of the vessel's breadth:** The positioning of the sidelights (at the outboard extremes) relates to visibility angles and preventing cross-visibility, which is mandatory for most vessels, but it does not grant permission to move the masthead light off the centerline. The requirement that the masthead light must be on the fore and aft centerline applies regardless of where the sidelights are placed, unless the vessel falls under the less-than-12-meter exemption. * **C) engaged in fishing:** Vessels engaged in fishing (Rule 26) have specific lighting requirements (two all-round lights, red over white, plus navigation lights), but the positioning requirement that the masthead light (if carried) must be on the fore and aft centerline remains standard for such vessels, unless they also happen to fall under the size exemption (less than 12m). * **D) less than 20 meters in length:** While vessels under 20 meters have slightly relaxed requirements for light separation compared to larger vessels, the fundamental requirement that the masthead light must be located over the fore and aft centerline (Rule 21(a)) still applies strictly to all vessels 12 meters and greater in length. The exemption for positioning applies only to vessels less than 12 meters in length.