🔍 Key Concepts

• Navigation Rules – Lights and Shapes (Part C), especially the basic sidelights for a vessel underway • What a single green sidelight by itself tells you about the relative bearing of the observer • Which special-vessel types (towing, not under command, fishing) must show extra all-round lights in addition to normal sidelights

💭 Think About

• First, identify exactly what kind of light is shown in the illustration: its color and what it likely represents on a vessel at night. • Then, for each answer choice, ask: Would this kind of vessel ever be seen showing only that one green light from this angle, or would I also expect to see other lights (masthead, stern, or special all‑round lights)? • Think about small craft that do not have to display lots of extra lights – which option best matches a vessel that might legally show just a single green sidelight from this viewpoint?

✅ Before You Answer

• Confirm from the Rules that towing vessels, NUC vessels, and fishing vessels all carry additional all-round or towing lights besides their sidelights when underway. • Check which type of vessel in the choices is treated (for lighting purposes) like a simple small craft with ordinary sidelights only and no extra special lights. • Make sure you understand that seeing only a green light means you are looking at the vessel’s starboard side, and ask which listed vessel type could appear that way without any other lights visible from your position.