Final answer:
An anchored vessel that is servicing an aid to navigation would show specific lights: three all-round lights in a vertical line with the top and bottom being red and the middle one white, accompanied by two additional red lights to indicate its restricted ability to maneuver.
Step-by-step explanation:
An anchored vessel that is servicing an aid to navigation and is restricted in its ability to maneuver traditionally displays specific lights by international regulations for preventing collisions at sea. These lights are designed to notify other vessels of the restricted vessel's presence and movement limitations to ensure maritime safety.
By day, the vessel would show three shapes in a vertical line where the highest and lowest are balls and the middle is a diamond. By night, a vessel restricted in her ability to maneuver would show three all-round lights in a vertical line where the highest and lowest are red and the middle is white. This is accompanied by two additional all-round red lights, one above and one below the vertical line, visible all around the horizon. These would be lit to indicate that the vessel is restricted and to alert other vessels to steer clear of her path while operations are underway.