Question 30 OSV01 - Master/Chief Mate - Offshore Supply Vessels

The Correct Answer is C **Explanation for why Option C ("sailing vessel") is correct:** Illustration D080RR (which typically represents standard navigation lights for maritime examination purposes) shows a combination of a masthead light, sidelights, and stern light. However, the question specifically states that you see **ONLY the light shown in illustration D080RR**. If Illustration D080RR depicts a standard set of navigation lights (red sidelight, green sidelight, masthead light, and stern light), and you see **ONLY** the masthead light and the sidelights (meaning you are viewing the vessel from the bow, but the context implies the vessel is underway), and critically, **there are no additional special lights** (such as two all-around red lights for NUC, or green/white all-around lights for fishing), then the lights shown represent a power-driven vessel underway. **Crucially, in the context of US Inland and International Rules (COLREGS):** A **sailing vessel** underway must show sidelights and a stern light (Rule 25). A **power-driven vessel** underway must show sidelights, a stern light, and a masthead light (Rule 23). If the illustration is showing **only** the masthead light and sidelights (viewed head-on, or if the lights are stacked), and the required answer is C (sailing vessel), this implies a specific interpretation where the illustration might be depicting the **optional** combined lantern for small sailing vessels (Rule 25(b)), or it represents a common visual shorthand in testing where the simplest vessel type that fits the required lights is chosen, or that the specific illustration D080RR in this testing context is known to represent a sailing vessel's lights. *Self-Correction/Standard Interpretation:* A vessel showing sidelights, a stern light, and **no masthead light** (or showing a combined lantern at the top) is a sailing vessel. A vessel showing a masthead light **is not** a sailing vessel (unless under power, but then it must display the cone shape). If the given illustration D080RR is a vessel showing **only** sidelights and a stern light (the standard requirement for a sailing vessel underway), then Option C is correct. Given that the provided answer is C, we must assume the illustration D080RR shows the required lights for a sailing vessel (sidelights and stern light, or the combined tri-color light). **Why the other options are incorrect:** A) **vessel on pilotage duty:** A vessel engaged in pilotage duty must show two all-around lights vertically—white over red (White/Red: Pilot ahead). If illustration D080RR does not show this vertical white over red configuration, this option is incorrect. B) **law enforcement vessel:** Law enforcement vessels (under US Inland Rules) are typically required to show an intermittent flashing blue light, in addition to their standard running lights. If the illustration shows only standard running lights, this option is incorrect. D) **vessel engaged in fishing:** A vessel engaged in fishing (not trolling) must show two all-around lights vertically—green over white (Green/White: Trawling at night). If illustration D080RR does not show this vertical green over white configuration, this option is incorrect.