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Saving a Screwpile

One of the most beloved structures on Chesapeake Bay is in trouble
Thomas Point Shoal Lighthouse, commissioned in 1875, is one of the most recognizable structures on Chesapeake Bay. 

Thomas Point Shoal Lighthouse, commissioned in 1875, is one of the most recognizable structures on Chesapeake Bay. 

It was 144 years ago when several hundred iron, steel and wooden parts and pieces were floated down the Chesapeake Bay from Baltimore, Maryland, to where the Thomas Point Shoal Lighthouse stands today. The screwpile lighthouse, which is about 50 feet tall and around a mile and a half from the Annapolis, Maryland, shoreline, is one of the Chesapeake’s most iconic structures.

And it’s in dire straits. After decades of exposure, dozens of steel tie rods and beams that stabilize the lighthouse cottage are badly corroded, endangering the integrity of the cottage itself.

John Potvin is one of the people trying to save it. He serves as the lighthouse’s preservation foreman, and he took me out for a look one chilly November morning. Three carpenters were also on board, to work on replacing one of the lighthouse’s wooden beams.

“She looks fine from here,” I said from the boat as the lighthouse came into view. “Wait until we get closer,” Potvin replied.

He was right. As I unloaded my gear onto the wooden dock, the lighthouse’s troubles were immediately apparent. Rust and corrosion had consumed a good portion of the base, including many of the tie rods and beams that keep the cottage stable. Some of the tie rods were so severely corroded that they’d been reduced to the diameter of a pinkie on an average hand. The last preservation work to these components took place approximately 15 years ago.

“Many beams and some tie rods were replaced.” Potvin says, “but the work was a sort of Band-Aid.”

Though another lighthouse once stood farther inshore, the current Thomas Point Shoal Lighthouse was constructed in 1875 from a kit of sorts, shipped down in stages from Baltimore. Thomas Point Shoal Lighthouse is a screwpile lighthouse, built upon several beefy, cast-iron pilings that workers hand-screwed about 10 feet into the clay bottom, which, where the lighthouse stands, is 8 feet below the surface of Chesapeake Bay. These screwpiles are in remarkably good shape, even though the reinforcing steel beams and tie rods bolted and riveted to them are decaying.

“Various bits and pieces have been replaced or repaired over the years,” Potvin says, “but we’ve got a real project on our hands.”

Preservation foreman John Potvin points out a new beam that was recently fitted to the lighthouse. 

Preservation foreman John Potvin points out a new beam that was recently fitted to the lighthouse. 

Lighthouse preservation is expensive, backbreaking work. Since the structure is a National Historic Landmark, Potvin says, it should be repaired with the materials and methods of its time.

“We’ve replaced quite a few tie rods already,” he says. “They have to be done very carefully, one at a time. The new beams and rods we’re installing have better corrosion-resistant coating systems, so we’re hoping to get 40 to 60 years out of them.”

The lighthouse at one time was fully manned. Lightkeepers were required for chores such as refilling the kerosene lamp, raising counterweights that turned the fourth-order Fresnel lens, winding a bulky metal contraption that rang the fog bell in reduced visibility, and recording shipping traffic. Despite the gorgeous view, it was boring, monotonous and sometimes lonely work.

The U.S. Coast Guard took over managing Thomas Point from the U.S. Lighthouse Society, and detailed plans in 1972 to dismantle and automate the light. Public outcry over the plans saved the lighthouse, which was listed on the National Register of Historic Places in 1975. In 1986, the lighthouse became the last navigational aid of its type on Chesapeake Bay to be automated. It received National Historic Landmark status in 1999.

Today, Thomas Point Shoal Lighthouse is owned by the city of Annapolis, which purchased it in 2004. The United States Lighthouse Society and Annapolis Maritime Museum manage the renovations, upkeep and fundraising. The U.S. Coast Guard maintains an easement to maintain the light as an aid to navigation, and the National Oceanic and Atmospheric Administration maintains a weather station here.

“The goal is to continue making the inside of the lighthouse more presentable for tours and visitors,” Potvin says, “but our main priority right now is the corroded beams and tie rods.”

As of December, Potvin’s organization had raised $248,866 with the help of grants and fundraising events, leaving a $150,000 shortfall for the repair work. A GoFundMe page had raised an additional $43,000. For more information, go to

This article originally appeared in the February 2020 issue.



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