Moniter Preservation Section
We first saw exhibits on the Monitor in the North Carolina Aquarium on Roanoke Island, where they had a replica in one of the ocean tanks. The Monitor was found off Cape Hatteras.
On the 145th anniversary of the historic clash between the Civil War ironclads, The Mariners' Museum and its partner NOAA will open the doors to the USS Monitor Center.
Bob is looking at one of the ironclad's two XI-inch Dahlgren cannon.
According to the sign on the side of the tank:
"Installed on the USS Monitor in early 1862, these XI-inch Dahlgren guns were inside the rotating gun turret when it was recovered on August 6, 2002. The guns were cast at the West Point Foundry in Cold Spring NY in 1859.
"After months of excavation of sand, debris and artifacts from the Monitor's turret, the guns were removed on September 9, 2004. Crews from Northruop Grumman Newport News, NOAA, The Mariner's Museum and Hampton Roads Crane and Rigging removed the guns and placed them in these conservation tanks."
- Two massive XI-inch Dahlgren smooth-bore guns, capable of firing solid shot weighing 140 pounds, were inside the turret. Weighing nearly nine tons apiece, these guns are extremely fragile in their current state and will undergo years of conservation before they are completely stabilized. Paymaster William Keeler wrote in November of 1862, “Our guns have had engraved in large letters, on one of them MONITOR & MERRIMAC WORDEN on the other MONITOR & MERRIMAC ERICSSON” Conservators and NOAA archaeologists recently uncovered these engravings on the guns.
This sign says:
"Carriage for the XI-Inch Dahlgren Gun recovered from the wreck of the USS Monitor.
"John Ericsson designed these gun carriages specifically for the USS Monitor. A handwheel on each carriage allowed the gun crews to control the amount of recoil of the guns by applying more or less friction.
"The carriages are currently upside-down in their tanks."
Bob wanted to know why they were upside down, and someone said that it was because that was the way they were found.
According to the museum website, metal artifacts are being conserved through a process known as electrolytic reduction. This procedure helps remove organic encrustations from the surface and corrosive chloride compounds from the interior. Without conservation, these objects would corrode and disintegrate.
The metal objects are submersed in an electrolytic solution of sodium carbonate or sodium hydroxide. Platinum surface electrodes are then suspended around the metal artifacts and a 3- to 3.5-volt current is passed through the objects. This removes chlorides from the artifacts and stabilizes them through the process of reduction. This process also loosens the marine encrustation consisting of seabed debris cemented by corrosion products. The chlorides are trapped in the electrolyte solution, which is changed when it becomes contaminated with chlorides. The process is complete when no more chlorides can be detected in the solution.
In order to complete the electrolytic reduction circuit in the conservation tank, there has to be a place for the electricity to go when it leaves the artifacts. Platinum coated electrodes complete the circuit. The white tubes cover and protect the electrodes.
The 4,600-pound cast-iron propeller is on display in The Mariners’ Museum. This artifact was recovered in 1998 and completed conservation in February 2004. The propeller was the first artifact from the Monitor to be received at The Mariners' Museum for conservation and future exhibition.
This is the explanation of the 2002 Monitor Expedition. The lighted side of the poster says:
"Monitor Expedition 2002 is the most complex mission to the USS Monitor wreck site to date....for the fifth straight year..recover significant components and artifacts from the Civil War ironclad. During the summer of 2002,...plan to recover the Monitor's 130 ton gun turret and its two eight-ton Dahlgren cannons..."
The photo shows Navy divers returning to the surface, and the other photo shows Northrup Grumman apprentices constructing the enormous tank to house the turret.
The dark side shows diagrams of how the turret was actually lifted.