What lights are required of vessels less than 12m?

Vessels less than 12 meters in length are required to display a specific set of navigation lights in order to ensure visibility and safety on the water. The correct answer includes a 360-degree white light, which serves as an anchor light when the vessel is at anchor, as well as sidelights, which include red and green lights that indicate the vessel's port (left) and starboard (right) sides, respectively.

When a vessel is under power or sailing, these lights help other vessels identify its direction and status, preventing collisions in crowded waterways. The combination of a 360-degree white light and sidelights adheres to the International Regulations for Preventing Collisions at Sea (COLREGS), which establish the necessary requirements for night navigation.

The other choices either do not provide adequate visibility or are incomplete in fulfilling the required regulations for vessels under 12 meters. For example, simply having a white stern light does not provide information about the direction the vessel is facing, which is vital for safe navigation. Thus, having both a 360-degree white light and sidelights is critical for vessels of this size to navigate safely in various conditions.