What is the minimum length of a power-driven vessel that must show forward and after masthead lights?

The requirement for power-driven vessels to display masthead lights is based on their length. According to navigation rules, vessels that are 50 meters or longer must exhibit both forward and after masthead lights when under way. This is laid out in the International Regulations for Preventing Collisions at Sea (COLREGs), which establishes standards for the visibility and arrangement of lights on vessels to ensure safe navigation and to prevent collisions.

For a vessel that is less than 50 meters, while it does need to show lights, the specific requirement for both forward and after masthead lights does not apply. Instead, smaller vessels have different lighting requirements that may include combinations of other types of lights but not the dual masthead lights specified for longer vessels.

This distinction is crucial for ensuring compliance with maritime navigation rules and for the safety of all vessels operating in crowded waters. Understanding the importance of these lighting requirements can help mariners avoid accidents and maintain safe passing protocols.