What should a vessel display when being towed?

When a vessel is being towed, it is required to display a specific light configuration and a day shape of a diamond to indicate its status. This is a key aspect of the Navigation Rules, which help ensure that vessels are properly identified, especially in conditions of reduced visibility or during the day.

The special light configuration typically includes a stern light and sidelights, which signal to other vessels that the towing operation is occurring. The day shape, specifically the diamond shape, serves a similar purpose during daylight hours, allowing other vessels to recognize the situation at a distance. This allows for safer navigation in shared waters by alerting other mariners to the fact that an object is being towed, which may affect their navigation and require them to take precautions.

In contrast, the other options do not fulfill the requirements set by the Navigation Rules for the indication of a vessel that is being towed. Thus, the correct response emphasizes the importance of proper signaling to maintain maritime safety.