By Shanna Daniel, Archaeological Conservator, Underwater Archaeology Branch, Naval History and Heritage Command
Many have been waiting for an update from our last blog post about the ongoing efforts to conserve a cannon recovered from the suspected wreck site of the 14-gun U.S. naval schooner Revenge. Well, the wait is over! Archaeological conservators at the Naval History and Heritage Command (NHHC) Underwater Archaeology (UA) Branch have been carefully removing the thick concretion covering the cannon’s surface.
After several months of diligent work in the UA Archaeology & Conservation Laboratory, the cannon’s exterior has been de-concreted revealing a surface that has not been seen in over 200 years. Archaeologists were hopeful that the surface would provide clues such as maker or foundry marks to help date the cannon and provide clues as to the identity of the wreck. These marks would usually be located on the top of the cannon around the first and second reinforce area or the trunnions. Unfortunately, the surface appears to have received a lot of historical damages affecting the areas where these marks would have been visible providing no conclusive evidence.
But all is not lost! UA archaeologists have found that the cannon closely resembles the Armstrong pattern 6 pounder (not to be confused with the Civil War-era Armstrong breech loading field gun) and appears to be an American replica. The reinforcing rings around the cannon’s barrel and the design of the knob at the breech-end are consistent with the pattern created in 1725 by John Armstrong, England’s Surveyor General of Ordnance. Below is a picture of an Armstrong pattern cannon associated with the Revolutionary War on display at the National Museum of the United States Navy. UA archaeologists will now dive into archival research to determine the foundry in which this gun was produced.
Another item of interest was the discovery of rope around the cascabel neck during the initial stage of mechanical cleaning. Conservators are often tasked with deciding the best way forward when dealing with an artifact with different types of material, such as iron with organics (rope). Each material has a different method of treatment to ensure its stability, so it’s best to separate these materials. UA conservators decided to carefully remove the rope and place it in deionized water for further desalination. The rope is impregnated with iron corrosion products and is very fragile. So, conservators will have to be cautious and tread carefully when removing the iron corrosion using cleaning methods that will ensure the overall structural integrity of the rope.
The next phase in the cannon’s treatment is to focus on removing the thick concretion from inside the bore, as well as employing electrolysis to further help the desalination process. This will take some time and ingenuity on the conservators’ part, but these steps are paramount to ensure a well-preserved artifact. Stay tuned for the next blog when conservators talk about the electrolysis process on this unique Navy artifact!