2007 Monitor Conservation Work
By David Krop Conservation Project Manager The Mariners Museum
at The Mariners' Museum
Summer 2007: Into the Turret
National Oceanic and Atmospheric Administration (NOAA) archaeologists, The Mariners’ Museum conservators, and graduate interns from East Carolina University completed archaeological excavations within USS Monitor’s revolving gun turret during the summer of 2007. Goals included final deconcretion of Monitor’s complex ceiling and roof structure, careful excavation of remaining fragile artifacts, and documentation of unique turret features. The completion of these tasks is the culmination of years of hard work and collaboration and signifies a major milestone in the preservation of America’s greatest Civil War icon.
|Conservation staff and interns work in Monitor's turret (Photo: Krista Trono/NOAA)
Archaeologists, conservators, and interns made numerous discoveries that reveal construction methods, information about turret operation, and details about life aboard the ironclad. The most interesting discovery occurred while interns were removing concreted sediment from the turret’s armor plates: they noticed Roman numerals along the top edges of the plates. Conservators and archaeologists have been unable to determine the purpose of the numerals, but speculate that they are reassembly marks. The turret was originally constructed on land, then disassembled and reassembled aboard Monitor. To simplify the process, builders may have marked the individual pieces during initial construction to aid workers who assembled it aboard Monitor. Other finds included brass gun sight covers for the Dahlgren guns, silverware, tools, a brush made from hog’s hair, an unfired cartridge, and 3 sight holes that pass through the turret wall. The sight holes have brass fixtures attached to them on the interior of the turret and the function of the fixtures is unknown. Monitor’s crew likely used the sight holes to determine the location of enemy vessels when the gun port shutters were closed during battle.
Monitor's Guns Rolled Revealing Inscriptions
In August, The Mariners’ Museum and NOAA staff successfully rolled both 16,500 pound Dahlgren shell guns recovered from Monitor’s turret to their original upright position. The turn was accomplished with the aid of specially designed steel rolling rigs fabricated by Northrop Grumman Newport News. Now that the guns are upright, conservators have easier access to the original brass hardware attached to the cast iron guns. The brass hammers and breech sight bars will eventually be removed for treatment. The gun rolling also revealed historic inscriptions on the breech of both guns. In the fall of 1862 while the Monitor was undergoing repairs at the Washington Navy Yard, workmen engraved her guns. One gun was inscribed with "Worden," in honor of the ironclad's commanding officer during her battle with the CSS Virginia; the other was engraved with "Ericsson" as a tribute to the vessel's designer. Both guns had the words "Monitor & Merrimac" engraved on them as well. The inscriptions were described by Monitor’s sailors in letters sent home to family, but this was the first time since 1862 that the engravings were visible.
|Conservation staff roll one of Monitor's guns. (Photo: Courtesy of The Mariners' Museum) |
Turret Nut Guards Molded
In October, conservators from The Mariners’ Museum completed the ambitious task of documenting, molding, and casting six nut guards from the interior of the turret. Nutguards were sheets of metal installed on the interior of the turret that kept the nuts and bolts that held it together from becoming shrapnel when the turret was hit by enemy fire. These thin wrought iron sheets contain diagnostic features such as dents from enemy shot and even dents caused by Monitor’s own Dahlgren guns. In order to preserve these archaeological features, conservators molded the fragile nutguards with a dental molding material derived from algae. They then removed the mold and applied plaster and fiberglass to the surface. Upon drying, conservators removed the durable and highly detailed casts of the nutguards, forever preserving the features for future research.
|Roman numeral discovered on the turret armor plates.(Photo: Courtesy of The Mariners' Museum) |
Conservation of Worthington Pumps
Monitor was equipped with two Worthington pumps, which served as bilge or feed pumps. Both have been recovered from the wreck. This summer conservators documented and disassembled one of the pumps. Documentation included photography and the use of x-radiography to determine what was contained beneath the heavily concreted surface of the pump. Using the detailed x-rays as a guide, conservators removed the concretion and successfully disassembled the pump into separate components by materials type. The pump is composed of wrought iron, cast iron, brass, copper, rubber gaskets, and steel. These material types require different treatment techniques and cannot be treated with a single method. Conservators are now in the process of fabricating and installing an electrolytic reduction setup to aid in the removal of chlorides and preservation of the metal surfaces. Though slightly smaller than 4 feet in length, these pumps are very complex mechanical pieces and provide the perfect opportunity for conservators to gauge the scope and methods of treatment required to treat Monitor’s other complex pieces of machinery, including the gun carriages, condenser, and steam engine.
|X-ray images mosaic (top) and pretreatment (bottom) images of the Worthington Pump.(Photos: Courtesy of The Mariners' Museum) |
NOAA and The Mariners’ Museum accomplished significant goals during the summer and fall of 2007. Archaeologists and interns completed the excavation of sediment and artifacts from within Monitor’s gun turret. Conservators successfully rotated both Dahlgren guns to their original upright positions, molded and cast fragile nutguards, and completed the disassembly and began treatment of a complex steam pump recovered the ironclad.
|East Carolina University intern shows spoon found in Monitor's turret. (Photo: Courtesy of The Mariners' Museum)
The USS Monitor Center wet lab at the museum is also undergoing changes. Conservators recently acquired a lead-lined x-ray room to be used in conjunction with a portable x-ray source designed to examine heavily concreted artifacts and metals. The conservation facility is also being outfitted with a covered outdoor artifact work area that will house additional artifact storage tanks. The new covered work area will allow conservators to actively treat and monitor additional artifacts on a large scale and will be an asset to the future success of the conservation of the USS Monitor.
For more information on the ongoing conservation of Monitor artifacts visit http://www.monitorcenter.org/