Mapping Charleston’s Civil War naval battlefield
All that remains of a five-year siege for control of Charleston Harbour during the American Civil War now lies in watery graves amid the harbour’s channels and beneath beaches of nearby islands.
A team of archaeologists at the University of South Carolina, has mapped the Charleston Harbour naval battlefield for the first time, providing historical and archaeological detail on the drawn-out struggle that spanned 1861-1865. The survey shows where military actions took place, where underwater obstructions were created to thwart enemy forces and the locations where Union ironclads and Confederate blockade runners sank.
The National Park Service, which funded the project through an American Battlefield Protection Program grant, with matching funds from USC, will use the survey to preserve the battlefield.
Information gathered about the wrecks and obstructions will also be valuable to harbour managers, the U.S. Army Corps of Engineers and to USC archaeologists to ensure that these relics of the conflict are not damaged.
Applying the Gettysburg approach
James Spirek, a USC underwater archaeologist directed the project that began in 2008 and wrapped up this spring. He applied the same approach that was used to understand the historic landscape of Gettysburg to understand the Civil War naval operations at Charleston Harbour.
“The scheme, called KOCOA , is a modern concept based on ages-old military tenets that gets archaeologists and historians to think about how the participants saw the battlefield,” Spirek said. “Today, all we see is the aftermath. But how did the battle come to be? And why are things where they are in Charleston Harbour?”
To answer those questions, Spirek had to define the boundaries of the harbour battlefield from the perspective of Union and Confederate forces. He conducted research on Confederate and Union ships and naval actions using official records of the armed forces, the National Archives, Library of Congress and USC’s South Caroliniana Library and Digital Collections.
His archaeological work centred on locating the various shipwrecks and obstructions. Two key elements were locating the famous ‘First Stone Fleet‘, a series of New England whaling and merchant vessels filled with stone and intentionally sunk by Union forces to prevent Confederate blockade runners from entering the harbour, and also finding exactly where many of the blockade runners sank in Maffitt’s Channel along Sullivan’s Island.
Spirek said Union forces, wanting to prevent Confederate supplies from entering and leaving the harbour, created a blockade of naval ships placed in an arc that stretched from Dewee’s Inlet by the north end of Isle of Palms, then called Long Island, down to Stono Inlet, south of Folly Beach, which was considered the back door to Charleston by travelling up the Stono River.
Between the two inlets and within the arc were five channels that led into the harbour. From north to south were Maffitt’s Channel, North Channel, Swash Channel, the Main Ship Channel and Lawford Channel.
Besides the city being fortified there were key points within the harbour itself. Closest to the city was Castle Pinckney and a sand island that was turned into Fort Ripley. In the mouth of the harbour were Fort Sumter and Fort Moultrie on Sullivan’s Island and further out was Battery Marshall to the north on Isle of Palms and Battery Wagner on Morris Island to the south, which today is underwater.
Securing the inner harbour was critical to the Confederacy, Spirek said.
“They set up a variety of obstructions including framed torpedoes so that Union ships coming in would hit them and blow up. Chains and rock weights held the torpedoes at an incline and slightly below the water to cause the torpedoes to strike the bottom of a vessel. They essentially created a mine field for Union forces,”said Spirek.
First stone fleet
Charleston Harbour was a lifeline for the Confederacy to bring in war materials and supplies and as one measure to stop ships from running the Union blockade, the U.S. Navy bought 45 ex-whaling and merchant vessels, which they stripped, filled with rock to be sunk in the channels, thus preventing Confederate ships from passing through.
While some sank en route or were diverted for other uses, 16 of the vessels were sunk on Dec. 17 – 21, 1861, by the U.S. Navy in the Main Ship Channel. Another 13 were sunk a month later, Jan. 20 – 26, in Maffitt’s Channel.
Recognising a stone fleet vessel
The team knew there would be a lot more rock given the nature of the vessels. Large mounds of rock would be key in recognising it was a stone fleet vessel.
Overlaying old maps with new maps, they began their search. Using a magnetometer and a side-scan sonar, a device that uses acoustic waves to picture the ocean floor, Spirek and his team found the mounds that comprised the Stone Fleet.
Historical accounts indicated that the U.S. Navy sunk the ships in an organized checkerboard fashion so that ships couldn’t travel straight through. That isn’t what Spirek found.
Everyone thought it was going to be very orderly,what they found though was 15 ballast mounds, 14 of which were tightly packed together with the wrecks oriented along various points of the compass. In fact, the archaeological record shows a more haphazard distribution. Not quite how the historical records suggest, though still an obstruction to a blockade runner.
The Second Stone Fleet remains somewhat elusive to Spirek’s team. While they found four wrecks with large stones at the entrance of Maffitt’s channel, Spirek said they appear to be boulder-laden flat-bottom boats used to construct the Charleston Harbor jetties that were built in 1878 – 1896 rather than stone fleet hulks.
Confederate blockade runners
Despite the blockade of Union ships and sunken obstruction of the stone fleets, the majority of Confederate blockade runners were successful in getting in and out of Charleston Harbour.
The Confederate blockade runners were low and painted grey to blend with the background. They would steam quietly in, close to the beach during high tides on moonless nights, letting the lights of the Confederate armies on Sullivan’s Island and the sound of the surf indicate whether they were too close to shore and needed to bear left.
Spirek said while positions of the Union ironclads were well-documented, the locations of Confederate blockade runners were hazy and incomplete and of the 16 wrecks they investigated, 13 were blockade runners.
The team found remains of the blockade runners in two clusters with two outliers, all wrecked along Maffitt’s Channel in attempts to elude the Union blockaders.
Close to the beach of the Isle of Palms is the wreck of the Georgiana, which led to the sinking of the Mary Bowers, found at the same site, followed by the Constance close by.
A second cluster of seven wrecks were located at Fort Moultrie and Bowman’s Jetty on Sullivan’s Island, all victims of the blockade and composing the monitors and small launches.
Four wrecks were found buried under the beach on Sullivan’s Island, covered by the build up of a century’s worth of sand and sediment. With the help of USC archaeologist Jonathan Leader, the team tentatively identified two out of three blockade runners, most likely the Beatrice and the Flora on the beach, with the Celt remaining undetected. The Presto is under an area covered with trees and will be revisited in the winter.
A fluid battlefield
While the major findings of the survey were the First Stone Fleet and Confederate blockade runners, Spirek was able to locate several Union ironclad monitors by using previous survey reports and sonar technology and magnetometers.
These included the Patapsco, sunk by a torpedo obstruction near Fort Sumter; the Weehawken, south of Battery Wagner in the Main Ship Channel; and the Keokuk, an ironclad of experimental design that met its fate at the entrance of the Main Ship Channel after a severe pounding by Confederate artillery on April 7, 1863. Specific GPS coordinates were assigned to each wreck for future investigation.
The USC survey took nearly as long as the battle did more than a century ago, but the results are worth it, said Spirek.
“I’ve developed a passion for the Civil War through my work with the Hunley submarine and the Charleston Harbour project. We now know more about the history and the archaeology of this naval battlefield, what it means to people today and what it meant to the participants 150 years ago,” he said.
Source: University of South Carolina
- American Battlefield Protection Program
- Charleston Harbour Navel Battlefield Website
-  KOCOA is a modern acronym which stands for:
· Key terrain · Observation and fields of fire · Cover and concealment · Obstacles (both natural and man-made) · Avenues of Approach
Using this technique of terrain analysis, the entire battlefield can be examined for each of these characteristics.
- First Battle of Charleston Harbour
- Second Battle of Charleston Harbour
- The Hunley Submarine website
- Charleston During the Civil War