Screwpile lighthouses: Early road signs for mariners
By Jon Hawley
Sunday, September 9, 2018
The highways were blue and the GPS ran on lamp oil, almost two centuries ago in the Albemarle and Tidewater.
Authors Larry Saint and Karla Smith shared those insights at the Museum of the Albemarle on Wednesday, when they gave a lunch presentation on their book, “Screwpiles: The Forgotten Lighthouses.”
Screwpile lighthouses, such as the Roanoke River Lighthouse preserved in Edenton, once dotted coastal waters from Maryland to Texas. The structures' name owe to their foundations, which are iron piles screwed into place in riverbeds and ocean floors. They were simple, cheap, and often dangerous, but were vital for the throngs of ships that kept commerce alive before railroads and highways were in place, the authors explained.
The iconic, conical-style lighthouse far predates the screwpile lighthouse, Saint explained, noting the first conical lighthouse built in North America was the Boston Light, a lighthouse erected in 1716 and is still standing.
As maritime travel and commerce grew, however, so too did the need for light to navigate dark and narrow waters, he continued. Some coastlines didn't offer stable ground for lighthouses' foundations, however. Saint explained sailors instead tried relying on lightships, but those ships were unreliable and struggled to maintain a fixed position, he said.
Irish engineer Alexander Mitchell devised a better approach. Saint explained that Mitchell designed piles with flanges that workers twisted into place from floating platforms. The first such screwpile lighthouse was constructed in 1838 at the mouth of the Thames River in England.
The lighthouses soon spread to the United States, where they dotted coastal waters and helped navigate the Chesapeake Bay, Albemarle Sound and many other coastal waters.
Screwpile lighthouses also benefited from another innovation: Fresnel lenses. French engineer Augustin-Jean Fresnel invented the lenses to replace a lamp-and-reflector system that didn't project light far enough for sailors. The lenses are made up of numerous smaller lenses that must be precisely manufactured and assembled onto frames, he said. That meant they were costly – equal to almost a third of the cost of the lighthouse structure – but made navigation much safer, he said.
The lighthouses had to be manned to keep their lamps burning and the buildings maintained, and so lighthouse keepers, their assistants, and sometimes even families, would live in them, Saint continued. It was harsh and dangerous work, he said, based in part on reviewing keepers' logs.
During the winters, the lighthouses were vulnerable to ice, including passing floes that could topple them, or that simply built up around the foundations. Keepers often died, he noted.
Saint also explained there were few comforts keepers had in the simple buildings. One winter, a keeper wrote it was 14 degrees in his room, even as he sat next to a burning stove. The harsh conditions and close quarters also could make it difficult for keepers and their assistants to get along, particularly if keepers also had family there, he said.
Screwpile lighthouses eventually faded away as the United States developed highways and railroads, Saint and Smith said, but they once factored into an intricate network of maritime transportation. Captains relied on detailed charts of where lighthouses were and what type of light they used; time-keeping was also essential for orientation, they noted.
Screwpile lighthouses remind people today of that maritime history – as does another device, Saint noted. Captains would look into port cities to see “time balls” which would rise and fall along a vertical shaft to mark the time of day. Time balls are the origin of tradition of the New Year's Eve ball drop in Times Square, he noted.
Saint and Smith are part of Suffolk River Heritage, a foundation dedicated to advancing “historical knowledge and interest in the local communities of Crittenden, Hobson, Eclipse, Bennett's Creek and Suffolk,” according to the group's website. For more information on the group, including on Saint and Smith's book, go to suffolk-river-heritage.org.