Which lights should show aft on your vessel if your tug is pushing a barge ahead at night and it is not a composite unit?

• A. Sidelights and a stern light
• B. Two towing lights
• C. A single white light forward
• D. All-around light at stern

Answer: (B)

When a tug is pushing a barge ahead and they are not a composite unit, you signal towing status with two white towing lights shown in a vertical line to the rear. These two lights make it clear to other mariners that you are and a tow behind you, so they know to keep clear and pass safely. The standard navigation lights (sidelights and stern light) don’t indicate the towing arrangement, a single white forward light wouldn’t convey that you’re towing, and an all-around light at the stern isn’t the required signal for this situation. If the tug and barge were a composite unit, the signaling would follow the unit’s combined light configuration instead.