PORT ROYAL, S.C. — As a military bastion of the then-powerful British Empire, Fort Frederick on the South Carolina coast was a failure.
The fort built of a concrete comprised of oyster shells and sand was falling apart six years after it was completed in 1734, its gunners never fired a shot in anger and the cannon they did fire to signal nearby Beaufort that ships were approaching apparently hastened its demise.
The remains of the 280-year-old fort, the oldest tabby fort on the Southeast coast, overlook the Beaufort River in Port Royal. It was constructed to fend off attacks by the Spanish and American Indians that never came.
Archeologists working with the South Carolina Department of Natural Resources are conducting a dig during the next month to uncover a story stretching from the prehistoric past through the Civil War.
The work, which began last week as everything from a prehistoric spearhead to pieces of British crockery and a clay marble were unearthed, is in advance of eventually opening the little-known site to the public.
The fort also was the headquarters for a unit of black South Carolinians who fought for the Union during the Civil War. It’s also on the grounds of a former plantation where hundreds of freed blacks gathered to hear the Emancipation Proclamation read on New Year’s Day 1863.
Tabby is a building material in which oyster shells are burned to create lime which is then mixed with water, sand and broken pieces of oyster shell.
Colin Brooker, an expert in tabby building, said a half-dozen such forts were built from the Carolinas to Florida and Fort Frederick is the oldest. With no stone, the only other material for coastal fortifications was sand, which doesn’t hold up well.
“It’s really a material of necessity. If you have nothing else, building with tabby is better than with sand,” he said.
But within six years of completion, the tabby walls of Fort Frederick were crumbling, the barracks had deteriorated and the powder magazine, where gun powder was stored, was unusable. The fort was abandoned in 1757 for another like it nearby that was destroyed during the Revolutionary War.
Half of Fort Frederick is under water, likely because of a combination of the tabby deteriorating and the tidal Beaufort River eroding its foundations. Brooker said vibrations from firing the signal cannon also likely caused the tabby to break up.
He is adding a layer of tabby to the top of the remaining fort walls to keep them from further falling apart. About 12 tons of oyster shell will be used for the work.
The walls, originally 5 feet high, have lost about 18 inches over the years.
“The British colonial government said pretty much it was a horrendous fort,” said Meg Gaillard, an archaeologist with the Department of Natural Resources. “The fact that it is still standing today is amazing.”
After the Civil War, the plantation passed into the hands of the U.S. government and the tract was part of the parcel where the Beaufort Naval Hospital was built in 1949, Gaillard said.
The Department of Natural Resources acquired the site in 1997. With the only way in through hospital property, access was limited when new security restrictions took effect at many government installations after the 2001 terror attacks.
But the recent removal of a house on a nearby street now provides access to the site without having to go through the hospital property.