 The first British , French and Russian ironclads , in a logical development of warship design from the long preceding era of wooden ships of the line , carried their weapons in a single line along their sides and so were called " broadside ironclads . " Both Gloire and HMS Warrior were examples of this type . Because their armor was so heavy , they could only carry a single row of guns along the main deck on each side rather than a row on each deck . 
