When Navy divers and NOAA archaeologists recovered the USS MONITOR steam engine from the bottom of the Atlantic in 2001, the pioneering propulsion unit was covered in a thick layer of marine concretion. sand, mud and corrosion, combined with ocean minerals of the deep Cape Hatteras, N.C. waters, covered every surface of the Swedish-American, John Ericsson’s ingenious propulsion machine.
After nine years of desalination treatment, conservators at the Mariners’ Museum and the USS MONITOR Center, drainer the 35,000 gallon container in which the engine was submerged and began removing the 2 to 3 inch thick layer of concretion with hammers, chisels and hand tools. Working slowly to avoid harming the original surface of the historic engine, more than two tons of encrustation was removed during the first week, to reveal a naval milestone not seen since the Union warship sank in a December 1862 storm off Cape Hatteras. Even though the engine spent 139 years underwater, it was in reasonable good shape. Some of the wrought iron plates had eroded , while the copper alloy parts looked brand new.
Smaller and more compact, the MONITOR’s vibrating side-lever engine was the ideal match for the revolutionary warship. The long low horizontal cylinders enabled it to be placed below the waterline and the center of gravity behind a thick belt of armor to elimate the vulnerability associated with bigger engines on the decks of contemporary warships. This design astonished both Union and Confederate observers when the MONITOR engaged the Confederate VIRGINIA, ex-MERRIMAC, during the historic battle of Hampton Roads on March 8, 1862. Some naval designers suggested John Ericsson add masts and sails, which he vehemently refused, convinced his unusual propulsion system would work without auxilary sails. The turret and guns were the MONITOR’s muscle, its steam engine its beating heart.
Once all the concretion is removed, the complete engine will be resubmirged in a solution of distilled water and sodium hydroxide, while a low level electrical current is applied to release damaging chlorides. Later, conservators will dessasemble parts to be individually treated and cataloged . The most severely corroded parts will be replaced by exact replicas . It is expected to take between 10 to 15 years before the engine is reassembled and placed on exhibit in the museum.
Edited from an article by Mark St John Erikson for the Newport News Daily Press. Both pictures transfered from Flickr. Courtesy of Crackers’ Nautical News.
Montani semper liberi ! Happy modeling to all and every one of you.
Crackers [8-|]
