What is NOT a requirement for additional lights on a vessel?

The option indicating that additional lights on a vessel must indicate a specific action of the vessel is not a requirement. In maritime navigation, the purpose of additional lights is primarily related to safety and visibility rather than conveying specific actions.

When a vessel displays additional lights, those lights serve to enhance visibility and ensure that other vessels can see and identify the vessel, but they do not necessarily need to represent or indicate particular maneuvers or statuses of the vessel. This means that while lights can indicate whether a vessel is anchored, sailing, or engaged in fishing, not all additional lights must fulfill this role.

The other options reflect established maritime regulations. The visibility requirement ensures that lights can be seen from a distance, the stipulation regarding not interfering with proper lookout emphasizes the importance of safety and awareness, and the allowance for lights to be either fixed or flashing provides flexibility in the design and use of navigational lights.