Question 25 OSV02 - Mate - Offshore Supply Vessels

The Correct Answer is B **Explanation for Option B (Correct Answer):** The placement rules for navigation lights, including the masthead light (or all-round white light, which serves as the masthead light for smaller vessels), are primarily governed by the COLREGs (International Regulations for Preventing Collisions at Sea) or equivalent Inland Rules. The general rule for the masthead light is that it must be placed in the fore and aft centerline. However, Rule 21(a)(ii) (often adapted into Inland Rules) provides an exception for smaller vessels: For a power-driven vessel **less than 12 meters in length**, if it is impracticable to place the masthead light (or the all-round white light) on the fore and aft centerline, it may be placed off-center, provided the sidelights are combined in one lantern and carried on the fore and aft centerline of the vessel, or virtually so. Since the premise of the question is "INLAND ONLY," the specific wording of the Inland Rules (often matching COLREG Rule 23(a)(ii) regarding the 12m threshold) allows for this deviation due to design or space constraints on very small boats. Therefore, vessels less than 12 meters in length have the specific regulatory exemption allowing the masthead light to be located off the fore and aft centerline under certain conditions. **Explanation of Incorrect Options:** * **A) which has separate sidelights carried on the outboard extremes of the vessel's breadth:** Having separate sidelights carried outboard does not, by itself, grant permission to move the masthead light off the centerline. The centerline placement of the masthead light is mandatory unless a specific length-based exemption (like the 12m rule) applies. * **C) engaged in fishing:** A vessel engaged in fishing displays specific lights (green over white all-round lights), but the required masthead light (if carried, usually when making way) must still adhere to the standard centerline placement rules based on the vessel's length, not its activity. The activity of fishing does not grant an exemption for masthead light placement. * **D) less than 20 meters in length:** While vessels less than 20 meters have several lighting simplifications (e.g., carrying a single masthead light instead of two), this length category (12m to 20m) still requires the masthead light to be located on the fore and aft centerline, unlike the exception provided only to vessels less than 12 meters.