How does a lighthouse helps ships navigating?
In: Engineering
Prior to GPS, you had to use a map, compass, sextant, and the stars to determine where you were and get from place to place. These are only accurate to a degree, as maps were often somewhat incorrect, your compass can sometimes be slightly off due to interference from metal around you etc. If you were able to get within a few miles of land, you often couldn’t see it at night- back then cities didn’t light up the coastline like they do today. A lighthouse is built tall, the taller (and brighter) the better, as a higher vantage gives you a better beyond-the-horizon capability. A 100 foot tall lighthouse can be seen from 16 nautical miles away. So if your maps and sextant got you into the general area, the lighthouse could guide you home. Also, to avoid reefs that could damage your ship, the other function of a lighthouse was to give you a point of reference on your map to give you an approach to shore without rubbing aground. If you are approaching a lighthouse from due west, and your map says the reef is 500 yards due east of the light house, you know to change course to go around it, or drop anchor.
They are painted in high contrast colors to stand out as much as possible during the day and serve the same general purpose.
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