ABSTRACT Artifacts from The USS Monitor, a U.S. Civil War era warship, have been recovered from the site where the Monitor sank and are presently undergoing archeological study and preservation at The Mariners' Museum. Of concern is the continued degradation of the artifacts due to corrosion. The present condition, corrosion rate, and other characteristics of the artifacts were assessed. Based on these assessments, the corrosion rate of the artifacts is generally higher in the museum than was likely experienced when the artifacts were still submerged in the ocean, due primarily to the increased availability of oxygen and concentration of any salts present during dry-out periods. In order to help mitigate further corrosion, cathodic protection and corrosion inhibitors have been evaluated for possible use.
INTRODUCTION The USS Monitor (Figure 1) was the first successful iron-clad battleship that was equipped with a revolving gun turret and was constructed under the supervision of John Ericsson in 1861. The turret, which was located amidships was 21 feet 8 inches (~ 6.6 m) in diameter and 9 feet (~2.7m) high and was constructed from 8 layers of 1-inch (2.54 cm) iron plates. The turret contained two 11 inch (~28 cm) Dahlgren smooth-bore shell guns that were capable of firing shot weighing up to 180 lbs (~81.6 kg). The main advantage that the Monitor had over its contemporary warships was that despite having only two guns it could sail under steam power and fire the cannons in any direction rather than the traditional broadside arrangement that was in use at the time. Another advantage that the Monitor had over its contemporaries was an extremely low hull profile of 18" (~45.7 cm) above the waterline. This then presented opponent vessels with an extremely small silhouette to hit.
Following its official launch in January 1862 from Greenpoint, New York the Monitor engaged in several naval battles only to sink in a storm in December 1862 off the coast of Cape Hatteras, North Carolina. Discovered in 1973, the Monitor wreck site is now a National Marine Sanctuary under the auspices of the National Oceanographic and Atmospheric Administration (NOAA). In 1998, salvage work began and artifacts from the Monitor have been brought up to the surface for further study and preservation. NOAA has designated The Mariners' Museum in Newport News, Virginia as the caretakers of the artifacts and has charged them with the preservation work. These artifacts include the original gun turret, two gun carriages, two Dahlgren shell guns, the engine, and condenser as well as numerous other smaller artifacts.
The main mission of The Mariners' Museum with respect to the Monitor is to excavate and preserve the artifacts as they exist presently. In contrast to restoration where new components are installed to replace damaged areas, the focus of preservation is to study and eventually display the artifacts in their present condition. Thus, preservation efforts are cannot result in any permanent damage or for that matter permanent repairs.