What is one of the critical roles of navigation lights on a vessel at night?

Navigation lights serve a crucial function for vessels traveling at night or in low visibility conditions. Their primary role is to prevent collisions by allowing other vessels to see and identify their position, direction, and status. Different colors and positions of navigation lights provide essential information; for example, a green light indicates the starboard side and red for the port side, while a white light often indicates the stern. This visual signaling helps mariners gauge their distance and heading relative to other vessels, which is vital for maintaining safety on the water.

The other choices address various aspects of maritime operations, but they do not directly relate to the essential safety function that navigation lights fulfill. For instance, signaling fishing nets can aid in alerting other boats to potential hazards, and marking shipping lanes is vital for guiding vessels safely, but neither of these functions addresses the immediate need to prevent collisions. Indicating a vessel's name is not a role of navigation lights; identification is generally accomplished through documentation and radio communication. Thus, the primary and critical role of navigation lights is indeed to prevent collisions, making it essential for safe navigation at night.