What lights indicate a power-driven vessel underway at night?

• A. White stern light, red port sidelight, green starboard sidelight, and a white masthead light forward.
• B. Two red lights, a white stern light, and a blue stern light.
• C. Green stern light, red starboard light, white bow light.
• D. White masthead light aft, red starboard, green port, white stern.

Answer: (A)

Power-driven vessel underway at night uses a white forward masthead light, a red port sidelight on the left, a green starboard sidelight on the right, and a white stern light at the rear. The red and green sidelights identify the vessel’s sides and are visible from the front and sides, while the forward white masthead light signals that the vessel is underway and moving ahead, and the white stern light shows the rear of the vessel. This combination is what others rely on to judge your direction and status at night.

The other lighting in the options is not correct for a vessel underway: a blue light isn’t part of standard navigation lights for this scenario, a green light at the stern is wrong, and a masthead light placed aft or a white bow light doesn’t meet the required arrangement for a power-driven vessel moving.