At the Core of the Problem: A new method used to clean the bores of USS Monitor’s XI-Inch Dahlgren Shell Guns

Erik Farrell

Abstract

When the turret from USS Monitor (1862) was archaeologically recovered in 2002, it contained the ship’s primary armament: two XI-Inch Dahlgren Shell Guns. These guns are the largest caliber smoothbore, cast iron artillery ever recovered from a marine archaeological site, and as a result they represented a particular engineering challenge to clean. After comparing apparatuses used by other conservation laboratories to clean artillery bores, it was found that no extant boring method ideally fitted the requirements for the guns from USS Monitor. As such it was necessary to create a new method, incorporating some features of other designs into a largely unique system, tailored to the specific goals of the Monitor project. This involved the modification of a prior gun mount design, creation of a new drill mount design, and refinement of the methods used to establish alignment of the cleaning tool and gun bore. Additionally, a new set of tools and methods was created to remove concretion from the hemispheroidal, Gomer-type powder chamber. This paper describes the reasoning behind the decision to create a new methodology, details the equipment designs and construction, and provides a case study for its operation.

2020 | Online | Volume 27