Divers in Savannah are checking out "cribs" -- underwater obstructions placed by Confederates defending the city from sea attack

Sonar image of four Confederate cribs in Savannah River (USACE, Savannah)

Archaeologists using sonar to scan the bottom of the Savannah River have located the remnants of four underwater obstructions placed by Confederate defenders during the Civil War.

The U.S. Army Corp of Engineer’s Savannah office last week released a video and press release on the discovery of the so-called cribs, which were intended to prevent a Federal attack on the Georgia city.

“A crib is actually the wooden structure that would have held rubble, in this case mostly bricks,” Will Wilson, an archaeologist with Commonwealth Heritage Group said in the video. 

“This is a fairly simple frame system that is (put) in place really to hold the rubble and provide an obstruction to ships that might want to pass up the river.”

Wilson and others recorded 3D images ahead of dives on two of the crib sites. The dives are underway, Corps officials said this week.

While tourists coming to the popular coastal destination gaze upon the supertankers coming from or to the Atlantic Ocean, they likely have no idea what lies beneath the river's surface: Remnants of vessels, pieces of Native American pottery that washed down stream, and other items deposited over the centuries.

The Corps began new fact finding and artifacts recovery in the past couple weeks. (The recent photo above shows diver James Duff holding a bar shot, a form of artillery used against ships during the Revolutionary War.)

The project follows the discovery earlier this year of three historic artillery pieces in the river. (Photo below, USACE Savannah)

The cannons appear to have been made in the mid-1700s, and some theorize they may have been carried by the HMS Rose, a British warship that took part in the siege of Savannah during the Revolutionary War.

The Rose was scuttled to block the channel from French ships that might come to the aid of colonists trying to retake the city.

“A definitive conclusion on their origins is still pending and may require future conservation efforts to study any identifying marks that may tie the artifacts to a specific vessel or wreck,” the Corps said.

It’s possible the artillery pieces were on a Confederate warship, such as the CSS Georgia, which was used in conjunction with cribs to defend the city.

The cannons were found this past February in the general vicinity of where the Rebel ironclad was scuttled in December 1864 during the Civil War. Most of the ironclad’s wreckage was removed a few years back as part of the Corps’ deepening of the Savannah harbor.

The ironclad itself was an obstruction: Too slow to travel downstream and engage the enemy, the CSS Georgia was a floating battery stationed near Fort Jackson, another defensive bastion a few miles east of downtown. 

Smaller batteries dotted the river banks toward Fort Pulaski, near Tybee Island. The fort fell to Union forces in 1862 and the city was effectively bottled up for the remainder of the conflict.

In its press release, the Corps said investigators this spring “found additional artifacts related to the cannons on the river bottom. The exact number and types of artifacts remaining in the Savannah River will be determined through the current and upcoming investigations, and these materials will be recovered for further study.”

Corps spokesman Billy Birdwell told the Picket on Tuesday that the crib dives and artifact recovery are part of necessary clearing for ongoing deepening of the harbor.

He said divers are working in an area filled with all kinds of debris, from before and after the Civil War. A photo shows what appears to be a Revolutionary War-era artifact.

Dozens of cribs were placed in the river during the Civil War.

Click map to see Fort Jackson, area of placed cribs (Library of Congress)

The Confederacy used a wide array of weapons and obstructions to defend against advances on Savannah from the sea. Besides forts and warships, wooden cribs, pile dams, torpedoes (mines), snags, logs and dozens of shipwrecks were employed.

A 2007 report by New South Associates on the CSS Georgia said the ironclad was situated to protect obstructions from Federal wrecking parties.

“The obstructions themselves were double-lines of sunken structures, comprised of cribs put together with 18 to 20-inch timbers, and loaded with bricks. Except for a small opening to allow Confederate patrol boats to go in and out, these obstructions stretched across the navigable width of the river. In the south channel, these cribs were reported to have a height of 30 to 35 feet,” the report says.

Shore batteries supported Fort Jackson.

Confederate torpedoes in Charleston at war's end (Library of Congress)

“There were two lines of obstructions in the vicinity of Fort Jackson. The line furthest downstream, on either side of the head of Elba Island, appears to have been Georgia’s first home,” New South Associates said. “A more irregular line of obstructions was also laid in the immediate vicinity of Fort Jackson, upstream from the first line. This line too appears to have had moorings for Georgia.”

Wilson, the archaeologist speaking in the Corps video, said the cribs being investigated now are north of the river channel, a bit outside of freighter traffic.

An 1865 map in the collection of the Library of Congress (above) shows a narrow waterway labeled “obstructed by cribs” not far from CSS Georgia and Fort Jackson. The river’s flow has changed since then and some land that appeared in the map is now underwater. It is unclear exactly where these cribs being studied by the Corps were discovered.

Will Wilson and Jeffrey Pardee during a recent dive trip (USACE, Savannah)

A map by Robert Knox Sneden, a renowned Union mapmaker, shows Southern batteries and obstructions all the way to Fort Pulaski. (below, click to enlarge)

An 1874 account of the fortifications in and around Savannah includes this description:

“The guns in these positions were supplied with an average of rather more than one hundred rounds of ammunition to the piece. As additional obstructions to an ascent of the Savannah river by the enemy, cribs, filled with brick and stone, had been sunk in the channel below the forts and under cover of their guns. Below the Thunderbolt battery the river was impeded by quantities of live oak logs.”

All of these defensive weapons did the trick: Savannah did not succumb to the Federal navy. Instead, it fell to the Union army during Sherman’s March to the Sea.

After the war, contractors were hired to raise obstructions, including cribs, sunken vessels, piles, snags and torpedoes, so that commercial traffic could safely resume. They even got part of the CSS Georgia. (Interestingly, there were complaints during the Civil War of obstructions left over from the Revolutionary War).

W. Todd Groce, president and CEO of the Georgia Historical Society, told the Picket a friend in 1996 discovered a Confederate torpedo buried in the mud along the river and downstream from the city.

“It was one of the old wooden barrel types. He excavated it and kept it in a big tub of water so it would not dry out and disintegrate.” The man wanted to donate it to the society, but it did not have proper facilities to care for and display it, Groce said.

Stay tuned to the Picket for an update on this project.

“These submerged crib obstructions are believed to be some of the last remaining examples of this type of obstruction placed in the Savannah River during the Civil War,” the Corps said.

Related: Divers find more cannons in Savannah River. Click here