Which flag lights indicate a pilot vessel at night?

The correct indication of a pilot vessel at night is represented by the lights red over white. This combination is standardized under the International Regulations for Preventing Collisions at Sea (COLREGs) and signifies a pilot vessel engaged in the service of pilotage.

The red light indicates the presence of the vessel, while the white light above it is a distinction that informs other vessels of its specific function, which is to embark or disembark pilots. This is crucial for ensuring safety and proper navigation in busy maritime areas, allowing other vessels to recognize and respond appropriately to the pilot vessel’s role.

This signaling is vital during night operations when visibility might be limited, assisting in the prevention of accidents and maintaining effective maritime traffic. The recognition of these lights plays a key role in a mariner's ability to operate safely and effectively in conjunction with pilot vessels.