United States Coast Guard Captains License Practice Exam

A pilot vessel on pilotage duty at night is required to show sidelights and a sternlight at any time when it is underway. This is in accordance with the International Regulations for Preventing Collisions at Sea (COLREGs), which stipulates that all vessels underway, regardless of their specific function, must display appropriate navigation lights.

By displaying these lights, the pilot vessel ensures that it is clearly visible to other vessels, which enhances safety in maritime navigation. Sidelights (red and green lights) indicate the sides of the vessel, allowing other vessels to determine its heading and position, while the sternlight (white light) indicates the vessel's rear.

The requirement for these lights when underway distinguishes the pilot vessel's status and function, contributing to the overall safety of navigation. In contrast, specific conditions such as anchoring would entail different lighting requirements, which do not apply in this scenario.