Navigation lights are traffic indicators installed on rivers or seas. There are four types: fixed beacons, light buoys, lightships, and lighthouses. Fixed beacons, light buoys, and lightships serve as navigational and warning beacons.
Lighthouses emit recognizable signals day and night at sea, allowing ships to determine their position and providing hazard warnings. Ships emit lights of specified colors and frequencies at night or in cloudy or foggy weather, enabling other vessels to judge the depth and presence of reefs in the river, ensuring safe navigation and avoiding accidents.
Navigation lights are particularly common in rivers, especially near reefs, under bridges, or at forks in the road.
Navigation light signals include fixed signals and flashing signals. Simply put, they are fixed and flashing lights, or similar to the constant and flashing lights of aviation obstruction lights. Fixed navigation lights typically emit red or green light. The red and green lights help guide navigation and avoid collisions with reefs.
The earliest navigation lights were built in 1964, using wave-powered lighthouses. Their working principle involved using the undulations of waves to draw in and compress air, which then propelled the light through a turbine to generate electricity.
Modern navigation lights use solar panels, which are much more efficient. With no buildings obstructing the view at sea, they can generate electricity 24 hours a day using solar energy. A single full charge can last for more than half a month, making them a significant technological advancement over the past.
