Boat Navigation Lights: Complete Guide to Reading Lights at Night Navigation lights — or "nav lights" — are the lighting system that keeps boaters safe after dark or in fog and reduced visibility. They work as a two-way signal: nav lights let you spot nearby vessels, and they let other boaters spot you, reducing the risk of collisions on the water. Whether you're studying for your ASA certification or just want to sail Lake St. Clair safely after sunset, understanding each light type and where it's positioned on a vessel is essential. Types of Navigation Lights Masthead LightA white light mounted along the boat's centerline (fore and aft), visible across a 225° arc.…