🔍 Key Concepts

• Look carefully at the colors and positions of the lights: one white higher, one red on one side, one green on the other side. • Review Navigation Rules Rule 23 – Power‑driven vessels underway and Rule 30 – Anchored and aground vessels to see which combinations are required. • Think about the difference between sidelights and all‑round lights, and which situations require sidelights.

💭 Think About

• If you can see both the red and green sidelights at the same time, what does that usually tell you about your relative position to the vessel and whether it is making way or not? • Which of the answer choices would normally show only white lights (or white plus additional vertical reds), and which would show the standard red/green sidelights? • Does a vessel that is dredging or aground show normal sidelights alone, or do they have extra vertical red/green/all‑round lights to indicate a special condition?

✅ Before You Answer

• Verify in Rule 23 whether a power‑driven vessel underway shows a masthead white light and both sidelights when seen from ahead. • Verify in Rule 30 what lights a vessel at anchor or aground must show at night and whether they include sidelights. • Check whether a dredging vessel would have additional red/green all‑round obstruction lights beyond the basic sidelights and masthead.