The lighthouse represented the final stretch and possibly the most hazardous part of a long voyage to weary sailors of days gone by. Today, it represents a glimmering monument to the history of the maritime community. Whatever meaning we attach to it, a lighthouse is still a tower and a beacon.
Lighthouses served two primary purposes in an era before GPS and other technologically advanced navigational apparatuses.
- Illuminating treacherous waterways. As ships left the open ocean and pulled into port, the lighthouse showed them the way past treacherous rocks, reefs and other hazards. They also warned ships of hazards during low visibility by using horns, bells or cannons as fog signals.
- To serve as a reference to mariners. The color schemes and patterns on the tower – its light signature – were part of its day mark and helped distinguish an individual lighthouse i.e. one lighthouse emits two flashes every three seconds while another emits four flashes every three seconds. Crews still reference light lists to plot courses if their GPS goes on the fritz.
Lighthouses had to accommodate cumbersome systems as well as a light-keeping staff to keep shining 24 hours a day at points before their automation in the 20th century. A complete light station might include – in addition to a lighthouse, living quarters for the keeper and his family, a separate oil house to cordon off the flammable agents that powered the lamps, a boathouse, and a fog signal building.
There have never been two lighthouses built the same. Whatever materials were available locally: wood, brick, stone, concrete, reinforced steel and cast iron were used to build early lighthouses. While some are built offshore on reefs or patches of rocks, some lighthouses are placed onshore overlooking the water. Depending on the view from the water, even the height of the tower changes from one lighthouse to the next.
The earliest illuminants were wood fires. Lamps powered by coal, whale oil, kerosene and other fuels became commonplace as lighthouses proliferated. The Fresnel lens came along in 1822 and used a network of prisms to magnify a small amount of light and cast a beam over distances of 20 miles (32.18 kilometers) or more. It was one of the most novel of lighthouse inventions.
Serving as a lighthouse in New York Harbor for fifteen years, the Statue of Liberty became the first lighthouse powered by electricity in 1886. By the 1930s and after access to electrical lines expanded, most lighthouses had gone electric. Including automated time clocks, devices to replace burnt-out light bulbs and improved radio communications technology, propelling lighthouses down the path toward automation, electrical lines led to a series of inventions.
By the time The Coast Guard implemented the Lighthouse Automation and Modernization Program in the 1960’s, manned lighthouses had grown rare and by the end of the decade, there were fewer than 60 manned lighthouses. Comprised of an automated beacon atop a steel skeletal tower, the modern lighthouse is a bare-bones structure. There is only one manned lighthouse left in the United States today.