The two main purposes of a lighthouse are to serve as a navigational aid and to warn boats of dangerous areas. It is like a traffic sign on the sea. Here are five other facts about lighthouses you should know.
- Lighthouses are painted differently to help mariners identify them during the day. For example, a lighthouse may be painted all white if its surroundings/background is dark. The red and white stripes help the mariner identify the lighthouse if it’s up against a white background, such as cliffs or rocks.
- The height of a lighthouse takes into account the curvature of the earth, so the higher light above MHW (mean high water), the further away it can be seen at sea. But the light should not be so high up that local sailors will not see it. This is why you will frequently get shorter lighthouses on the top of cliffs and taller lighthouses built nearer the water surface.
- Lighthouses in fairly close proximity to each other have different flash patterns to allow the mariner to identify their location. Some lighthouses in different geographical areas share the same flash patterns.
- Originally lighthouses were lit with open fires, only later progressing through candles, lanterns and electric lights.
- These days, lighthouses are run by machines and remote monitoring. The automatic sensors decide if there is extra moisture in the air, and if so turn on the fog signals. Radio signals are used to communicate with the ships. But when the technology was not so advanced the lighthouses were run by lighthouse keepers.
*Sources
https://www.trinityhouse.co.uk/about-us/trinity-house-faq/why-are-lighthouses-different-colours-and-heights
