Bringing history to life: Reproducing a Worthington steam pump from the USS Monitor

William Hoffmann

Abstract

On December 31st, 1862, the USS Monitor sank off the coast of Cape Hatteras, North Carolina, taking to the ocean floor a complex mechanical steam system, which included two directacting steam pumps designed and built by the H.R.Worthington Company in Brooklyn, New York.

In 1973, the Monitor’s wreck site was discovered in 240 feet of seawater, and in 1975, the site fell under the jurisdiction of the National Oceanic and Atmospheric Administration (NOAA), which currently oversees, protects, and studies the wreck. Over the past three decades, NOAA, with the assistance of the US Navy, has recovered over 200 tons of material from the site, including the two Worthington pumps in 2001.

Since 1987, when it was designated as the repository of all Monitor artifacts, The Mariners’ Museum in Newport News, Virginia, has been conducting conservation on recovered objects to stabilize and preserve them for eventual display and curation. As deconcretion and conservation treatment began on the Worthington pumps, much of the artifacts’ original surfaces were exposed, which not only enabled the advancement of the treatment process but also revealed machining, file, and casting marks left on the objects from the manufacturing process. Also, through the use of x-radiography, loss due to years of corrosion as well as structural weakness to some of the surviving components soon became apparent.

As the conservation treatment of the pumps progressed, discussion on final display also began, which led to further dialogue on how to visually convey to the public the pumps’ movement. By conservation ethical standards and from structural loss and weakness, operation of either original pump is not possible, so the use of a 3-D model was suggested. However, it was felt that a computer-generated model could never fully represent the impact of a live-running steam pump. Therefore, in 2010, Mariners’ Museum conservators began a project to create an operational replica of the pumps using multiple molding methods, laser scanning, computer-aided drafting (CAD), fused deposition modeling (FDM), and several casting and machining techniques.

This paper will provide an overview of the methods and challenges of reproducing a variety of pump components using both modern and traditional casting methods aided by the interpretation of foundry marks that remained on original components. Furthermore, it will describe the outreach potential of a project of this scale and how it has been used to attract new audiences, gain donor support, and spread awareness about the need for conservation.

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