 The first ironclads were built on wooden or iron hulls , and protected by wrought iron armor backed by thick wooden planking . Ironclads were still being built with wooden hulls into the 1870s . 
 The first ironclads <a href='uninflect' title='1'><mark>were</mark></a> built on wooden or iron hulls , and protected by wrought iron armor backed by thick wooden planking . Ironclads <a href='uninflect' title='2'><mark>were</mark></a> still being built with wooden hulls into the 1870s . 
The first ironclads was built on wooden or iron hulls , and protected by wrought iron armor backed by thick wooden planking . Ironclads was still being built with wooden hulls into da 1870s .