🔍 Key Concepts

• Rule 23 – Power-driven vessels underway (what white lights are required in addition to sidelights) • Rule 25 – Sailing vessels underway (when only sidelights and sternlight are shown, and what you might see from directly ahead) • Rule 27 – Vessels not under command (characteristic all-round red lights)

💭 Think About

• From directly ahead, which vessel types must always show at least one white light in addition to red/green sidelights? • Look at the drawing: you see only red and green at about the same height. Which vessel type is allowed to be underway at night without showing any masthead white light? • For a vessel not under command or engaged in fishing, what is the typical vertical light pattern (colors and arrangement), and does that match this horizontal pair of sidelights?

✅ Before You Answer

• Verify in the Navigation Rules that power-driven vessels must display a masthead light when underway (even if under 12 meters, check what white light is still required). • Check under sailing vessel lights what you would see when looking right at the bow at night. • Confirm that a vessel not under command shows two all-round red lights in a vertical line, not horizontal sidelights.