As some of you may have seen on our Facebook page, Susanne, Kate, and Nicole have just finished conservation of a Civil War torpedo keg on loan from the Savannah History Museum. Underwater torpedoes were used extensively during the Civil War for coastal defense. Keg style torpedoes proved especially effective. They were constructed from wooden barrels or recycled beer kegs and fitted with conical reinforcing pieces secured over the barrel heads. Metal fuses containing combustible chemicals were mounted in the staves and the barrels were filled with powder. The torpedoes were then weighted and set adrift in waterways. Collision with a passing ship would cause the fuse to ignite the powder and explode.
This particular torpedo was converted from an oaken beer keg. The name Constance Brewery is still legible on the barrel heads. The torpedo was found in 1996 in a riverbank outside of Savannah, Georgia. Shortly thereafter it was brought to the ECU Maritime Conservation Lab for its first treatment. The wooden components were treated with sucrose but the copper alloy fuses were in good condition and left untreated. After conservation was completed the torpedo was transported to Georgia and displayed at the Savannah History Museum. Over time the fuses were exposed to sulfate reducing bacteria in the air and developed an unsightly black patina. In 2009 the torpedo was brought back to the ECU Lab for follow-up treatment.
It has been more than 12 years since the artifact’s initial conservation. In addition to the black patina on the fuses, the wooden components of the barrel showed patches of mold growth. The follow-up treatment began with a gentle mechanical cleaning using paintbrushes and a vacuum to remove loose particulate matter. The wood was then wet cleaned with acetone and cotton swabs to remove the moldy film growing on it. The copper alloy fuses were treated with citric acid to remove the black sulfide staining and a corrosion inhibitor and wax coating were then applied to help prevent future deterioration. All components received a final mechanical cleaning to remove any remaining cotton fibers. The torpedo keg is once again ready for display!