Which lights must a barge being towed exhibit according to international rules?

A barge being towed must exhibit side lights and a sternlight in accordance with international maritime regulations, specifically the COLREGs. The side lights are essential as they indicate the duration of the vessel's presence and act as a signal to other vessels regarding its direction. The sternlight, which is also required, provides visibility from the rear and is crucial in delineating the vessel's presence in the waters, especially when viewed from behind.

The requirement for side lights ensures that the barge can be identified as a tow while on the water, just as any other vessel would be, thus enhancing safety during navigation. A lack of these lights would make it difficult for other vessels to determine the barge's orientation and direction of travel, significantly increasing the risk of collisions.

Other options, while presenting individual light types, do not encompass the full set of lights required under the COLREGs. For example, just a sternlight would not provide adequate visibility from the side, while navigation lights alone do not specify the combination needed for a barge. Similarly, an all-round white light is insufficient to provide the proper identification that side lights and a sternlight would collectively offer. Therefore, the requirement for a barge being towed to exhibit both side