Ironclad
From Conservapedia
An Ironclad is the name given to the first armor plated fighting ships. The introduction of the ironclads would soon make earlier wooden fighting vessels obselete.
The first battle between ironclad ships took place during the American Civil War between the USS Merrimack and the USS Monitor. Neither ship was able to seriously damage the other.
Sources
Encyclopedia of Military History, Dupuy & Dupuy, 1979
