A vessel is towing a partly submerged object less than 25m in breadth. How should it be lit?

When a vessel is towing a partly submerged object that is less than 25 meters in breadth, it is required to display specific lights to ensure safe navigation and visibility to other vessels. In this scenario, the correct lighting arrangement includes one all-round white light and a stern light.

The all-round white light is essential as it serves to indicate the presence of the tow to other vessels, marking it as an object in the water that is being towed. The purpose of this light is to communicate to other mariners that there is a towed object that might not be readily visible, especially under conditions of low visibility.

The stern light complements the all-round white light by indicating the vessel's position from the rear. This combination of lights helps to provide a complete picture of the vessel’s position and direction of travel, ensuring that other navigators can safely gauge the distance and angle of approach to the towing vessel and its tow.

While other lighting arrangements might pertain to different towing circumstances or other types of vessels, this specific combination of an all-round white light and a stern light is what is mandated under the COLREGs for a vessel towing a partly submerged object of this size.