What is the required range of masthead lights on a vessel of 50 meters or more?

For vessels that are 50 meters or more in length, the COLREGs (International Regulations for Preventing Collisions at Sea) stipulate specific requirements regarding navigational lights. The masthead light, which is positioned at the forepart of the vessel, must have a minimum range of visibility of 6 miles. This requirement is designed to ensure that the vessel is adequately visible to other ships, particularly in conditions of reduced visibility, and to help prevent collisions at sea.

The 6-mile range reflects the size and type of the vessel, ensuring that larger vessels can be seen from a significant distance, providing other mariners with advanced warning of its presence and heading. This is crucial for maintaining safe navigational practices on the water.

The other options—3 miles, 4 miles, and 5 miles—do not meet the regulatory standards for a vessel of this length and would be insufficient for ensuring adequate visibility. Therefore, the requirement for 6 miles ensures that larger vessels maintain proper visibility to enhance maritime safety.