What determines the navigation lights you are required to display on a vessel?

The navigation lights required on a vessel are determined by its size, type, and the conditions under which it operates, as outlined in the International Regulations for Preventing Collisions at Sea (COLREGs). Vessels are classified into categories such as power-driven, sailing, and fishing vessels, each with specific light configurations. Additionally, the operational context, such as whether the vessel is at anchor or underway, also influences the required lighting. Compliance with these regulations ensures safety and visibility on the water.