By Kate Morrand, Naval History and Heritage Command Underwater Archaeology Conservator
As a conservator for NHHC’s Underwater Archaeology (UA) Branch, the majority of my work is focused on treatment of archaeological material recovered from U.S. Navy sunken military craft and primarily takes place in the UA Archaeology & Conservation Laboratory located on the Washington Navy Yard. However, I am occasionally afforded the chance to participate in archaeological field operations and a few weeks ago I was able to work on site at the CSS Georgia recovery project in the Savannah River. Conservators are often part of archaeological project teams and assist in the field with artifact recovery and documentation, data collection, artifact preparation for transport, and sometimes preliminary on-site treatment. For me, it was also particularly thrilling to experience the Georgia project in person after having participated in aspects of the planning phase related to conservation of the artifact collection.
Recovering CSS Georgia is a complex task with many moving parts led by the U.S. Army Corps of Engineers and multiple other partners. The majority of operations over the 10 days I spent on site were focused on mechanized recovery of Georgia artifacts and ship remains. The project barge is equipped with a 150-ton crane which utilizes different pieces of equipment to close around and lift material from the river bottom then place it onto the barge’s processing areas for screening and documentation by the archaeological field team. In order to ensure that the site is excavated as fully as possible, the lifting equipment is fitted with a GPS transponder which sends its precise location to the barge’s command center and allows project archaeologists to systematically direct each recovery. Sequential recoveries correspond with specific units on a gridded, geo-referenced topographical map of the Georgia site. One particular recovery was guided using an underwater 3D imaging sonar to place the lifting equipment more precisely over specific sections of the wreck to lift a particular group of material.
Once on deck, each group of recovered material is carefully rinsed and screened for artifacts by a team composed of archaeologists from around the country. Georgia was originally clad in casemate (i.e. armor) composed of railroad iron so there was predictably a large number of iron rails recovered. While some rails were brought up twisted and heavily concreted with iron compounds and marine growth, it was fascinating to observe the articulated sections which maintained their original orientation with individual rails interlocking snugly together, sometimes with pieces of the wood hull still attached! Also recovered were a number of unidentified concretions (i.e. layers of ferrous and calcareous compounds which often form around metal artifacts underwater) which will be x-rayed later to identify their contents. A number of pieces of ordnance, machinery, and smaller artifacts like buttons, intact bottles, medical equipment, and some as yet unidentified pieces were also recovered.
The majority of recovered material, currently more than 1,600 artifacts, will be transported to Texas A&M’s Conservation Research Laboratory for stabilization and treatment. Following treatment, the Georgia collection will be accessioned into the Navy’s artifact collection and managed by NHHC’s Underwater Archaeology Branch. It was particularly special to assist in the recovery of CSS Georgia artifacts in anticipation of eventually witnessing their full circle journey from river bottom to fully treated, stable and on display for the public to see, appreciate and use to learn about a particularly fascinating period in our country’s history.
June 2017 update
On June 21st, the U.S. Army Corps of Engineers crew raised the CSS Georgia’s east casemate. Watch as it’s rasied below! The section measures 20×24 feet and weighs about 47 tons (Notice how much the barge shifts when the crane sets it down.) Next up for the recovery of CSS Georgia: the even larger west casemate!