The USS Monitor’s turret was armed with two XI-inch Dahlgren guns resting on specially designed gun carriages. These carriages are composite artifacts consisting of about 300 individual parts made of a variety of materials including: wood, copper alloy, wrought and cast iron. The carriages are each: 43-1/2” wide x 76” deep x 30” high. Two iron brackets with wooden cores create the sides. The forward and aft ends consist of an iron plate secured to the sides with angled iron, screws and rivets. The carriages were designed to roll back and forth on iron rails attached to the floor of the turret. A large brass wheel tightened or loosened the braking assembly.
These gun carriages made it possible for the USS Monitor’s revolving turret, the first in the world placed on a ship, to fire nearly 360 degrees around the ship except where the shot was obstructed by the pilot house. Additionally, Ericsson introduced the use of a friction braking mechanism to control the recoil of the Dahlgren guns because of the confined space inside the turret. The guns are 13 feet long and the turret has an interior diameter of 20 feet, making recoil an interesting exercise in physics. Without a braking mechanism the guns would have hit the back of the turret after every shot. On sailor wrote that during the initial test firing, the brake assemblies were accidentally loosened rather than tightened. When the guns fired each slammed into the rear wall of the turret leaving clear dents. Finding these dents on the shipwreck added archaeological evidence to support this account. Stories like this provide a more complete picture of the Monitor’s history.
Both carriages are very fragile because of their over 140 years of degradation on the ocean floor. They were found resting on top of the guns as the turret had flipped upside down during the sinking. This made them very difficult and dangerous to remove from the turret for treatment. The composite nature of the carriages adds to their fragility and complicates their conservation to this day. No treatment exists to preserve copper alloy, iron and wood simultaneously; therefore the carriages must be disassembled as much as possible for treatment. When disassembling is not possible without harming the integrity of the artifacts, conservators must research methods to attempt the conservation of several materials at once.
To date, one carriage has been completely dissembled and the individual pieces are undergoing their own conservation treatments. The second carriage has only been partially disassembled and is visible to visitors in its treatment tank from our special viewing platform.
Photos of the Conservation Process
Monitor’s rotating gun turret was an important technological advance in naval architecture and warfare. Its cylindrical frame was constructed of eight layers of 1″ thick wrought iron plates strong enough to withstand enemy fire. The turret rotated to aim the two XI” Dahlgren shell guns and then rotated away after firing to protect the sailors inside from return fire. When the Monitor sank, the vessel flipped over and the turret fell upside down onto the seabed. A number of important artifacts were excavated from this part of the ship, including the remains of two sailors. Visitors can see the turret in the Batten Conservation Laboratory Complex as it undergoes treatment in a large tank of water to prevent further corrosion.
Monitor’s coal-fired steam engine was another of engineer John Ericsson’s improved designs. He oriented the engine so that the piston oscillated horizontally instead of vertically, greatly reducing the height of the engine compartment, allowing it to stay below the waterline. The components of the engine are constructed of various material types: iron, brass, nickel alloys, glass, rubber, grease, and coatings. Conservators will disassemble the engine so that each component can be conserved without negative effects on other components. Upon conclusion of the treatment, the engine will be reassembled and placed on display in the Large Artifact Gallery of Ironclad Revolution.
The condenser is part of the Monitor’s steam engine propulsion assembly. After steam moved the engine piston that turned the propeller, it passed through the condenser where it expanded into cooler, lower pressure gas that was discharged from the engine room. The condenser is another example of a large, complex artifact with many composite parts.
The Monitor was armed with two XI-Inch Dahlgren shell guns that were located inside the revolving gun turret. The cast iron guns are over thirteen feet long with a bore diameter of eleven inches. Each gun weighs approximately eight tons. Rear Admiral John A. Dahlgren designed the guns, numbers 27 and 28, which were manufactured at Robert P. Parrott’s West Point Foundry in Cold Springs, NY in 1859. After the battle with the C.S.S. Virginia, one was engraved “Monitor & Merrimac– Worden” to commemorate the battle and captain of the Monitor. The other gun was engraved “Monitor & Merrimac– Ericsson” to honor the man who designed the revolutionary warship. Visitors can see these massive guns undergoing electrolytic reduction and desalination in the Batten Conservation Laboratory Complex.
The Worthington simplex pumps, or “donkey pumps”, were hardworking general purpose pumps. They were used to pump feed water in and out of the boiler, as bilge pumps, and as essential firefighting pumps. Conservators at The Mariner’s Museum have already disassembled one of the pumps to facilitate easier treatment of the pump’s different component materials such as rubber, iron, brass, textiles and lead. The pump will be reassembled and placed on display when treatment is complete. The main iron cradle of each pump contains a casting that says “H. R. Worthington New York, Patented April 3, 1849.“
The packing seal, or “stuffing box”, is an assembly of cast iron, wrought iron, and organic packing material that prevented water from entering the ship where the propeller shaft passed through the hull. The packing seal kept out leaks and still allowed the shaft to turn unimpeded. Sailors tightened two cast iron sleeves to compress a layer of plant fibers made waterproof with resins. At some point before excavation, the outer cast iron gland fractured, revealing an informative cross section the materials used in this part. The damage likely occurred during the wrecking process when a large section of the propeller shaft, near the packing seal, bent under the force of the sinking vessel.
Monitor’s four-blade, cast iron screw propeller is currently on display in the Large Artifact Gallery of the USS Monitor Center. The nine-foot diameter propeller was protected from enemy shot because it was located safely forward of the aft-most portion of the hull. The screw propeller was better protected than exposed paddlewheels on other ships at the time. This made it extremely difficult to crippleMonitor’s propulsion system.
Though it may not look like it, Monitor’s anchor is made of wrought iron. When wrought iron artifacts suchas this one corrode, the surfaces often look like decayed wood. The core of the anchor is still composed of solid, shiny iron despite its outward appearance. The anchor was recovered from the wreck site in the 1980’s and was the first large artifact treated.
During the excavation of Monitor’s revolving gun turret in 2002, archaeologists and conservators discovered twenty-four pieces of silverware. Some pieces of silverware were engraved with the names or initials of crewmembers or officers who served aboard the Monitor. A few pieces silverware carry the names of sailors who perished the night of the sinking, and these artifact offer a personal and emotional connection to the past.
On the night of December 31, 1862, while en route to the Carolinas, the Monitor sank in heavy seas off the coast of Cape Hatteras, North Carolina. Eye witnesses reported that at approximately 1:30 A.M., the red distress signal lantern burning atop the turret and the ship itself were no longer visible. Recovered in 1977, this lantern was discovered lying in the sand near USS Monitor’s turret. This lantern was the last visible sign of the Monitor before she sank and the very first artifact recovered from the wreck, signaling a rebirth of this mighty Civil War icon.
The engine’s reversing wheel is a large brass wheel with a single handle and six curved spokes. The engineer changed the orientation of the valves in the engine by turning the wheel, thus altering the direction of the steam hitting the pistons and changing the ship’s direction from forward to reverse. The recovery of the reversing wheel revealed a modification to Ericsson’s engine design; he had originally specified a hand crank.
The engine register is a brass gauge and was mounted to the ship’s engine. The engine register consists of a round metal container which houses six numbered brass wheels that would rotate as the propeller shaft turned. The numbered wheels reflected the number of revolutions made by the engine, (74,9088), during the vessel’s service. The function of this artifact was similar to an odometer in modern automobiles. The engine register faceplate reads “Monitor, Engine Register, 1862″ and was the first artifact recovered from the wreck with the vessel’s name on it. There is a small hole torn in the face of the register. This damage was likely caused by impact during the sinking.
Monitor’s engine room clock is built primarily of brass components. The clock also had a silvered face and glass plate, though the glass no longer remains intact. During treatment, a conservator discovered a maker’s mark on the surface of an interior component of the clock’s gear box. The mark, “V. GIROUD”, stands for Victor Giroud, a well-known clock maker in New York at the time of Monitor’s construction.
Personal effects related to the men that served aboard Monitor offer a glimpse of life on an ironclad during the Civil War. Archaeologists excavated a rubber comb from sediment inside Monitor’s gun turret. The comb is a standard issue Navy comb and is made of black hard rubber with longer, wider teeth on one end and shorter thinner teeth on the other. The comb is inscribed with, “U.S. NAVY, IR. COMB Co. GOODYEARS PATENT MAY 6 1851” and is in near perfect condition. It looks quite similar to plastic combs available in modern pharmacies.
Several naval jacket buttons have also been found during excavation. The large, round black buttons are made of India rubber. Each button has four small holes for attachment. The front has a circular edging around it with printing and three five-point stars above an anchor. The buttons are inscribed, “U.S.N. NOVELTY RUBBER Co / GOODYEAR’S PATENT / 1851 / NEW YORK”.