A vessel not under command shall display...

A vessel not under command shall display...

• A. One red light
• B. Two red lights at night and two black balls during daylight
• C. Two white lights
• D. Red and green lights

Answer: (B)

Not under command means a vessel cannot maneuver as required by the collision regulations, so it must signal its inability to keep out of the way. To convey this clearly, the rules require two signals: at night, two all-round red lights in a vertical line; during the day, two black balls in a vertical line. This combination lets other vessels recognize that the vessel cannot take action to avoid a collision and respond accordingly. So the correct description is two red lights at night and two black balls during daylight. The other options don’t fit this signaling scheme: a single red light isn’t enough to indicate the status, two white lights aren’t the required signals for not under command, and red and green lights describe normal navigational lighting, not a vessel unable to maneuver.

Not under command means a vessel cannot maneuver as required by the collision regulations, so it must signal its inability to keep out of the way. To convey this clearly, the rules require two signals: at night, two all-round red lights in a vertical line; during the day, two black balls in a vertical line. This combination lets other vessels recognize that the vessel cannot take action to avoid a collision and respond accordingly.

So the correct description is two red lights at night and two black balls during daylight. The other options don’t fit this signaling scheme: a single red light isn’t enough to indicate the status, two white lights aren’t the required signals for not under command, and red and green lights describe normal navigational lighting, not a vessel unable to maneuver.