Which light configuration indicates passing intentions internationally?

• A. Two all-round white lights in a vertical line
• B. Green over white
• C. One white light
• D. All-round white light only

Answer: (D)

Light signals are used at sea to convey a vessel’s status and intentions, with each arrangement mapping to a specific meaning that other mariners can quickly interpret. The choice that uses only an all-round white light communicates a neutral, unambiguous signal to nearby vessels that overtaking or passing is intended, without implying any particular vessel type, maneuvering restriction, or other status. This simplicity makes it the clearest way to indicate passing intentions under international rules.

Other light configurations convey different meanings—such as a combination of lights that indicates anchorage, towing, sailing status, or specific vessel types—so they are not appropriate for signaling passing intentions.