 After 1872 , steel started to be introduced as a material for construction . Compared to iron , steel allows for greater structural strength for a lower weight . The French Navy led the way with the use of steel in its fleet , starting with the Redoutable , laid down in 1873 and launched in 1876 . Redoutable nonetheless had wrought iron armor plate , and part of her exterior hull was iron rather than steel . 
 After 1872 , steel started to be introduced as a material for construction . Compared to iron , steel <a href='uninflect' title='1'><mark>allows</mark></a> for greater structural strength for a lower weight . The French Navy led the way with the use of steel in its fleet , starting with the Redoutable , laid down in 1873 and launched in 1876 . Redoutable nonetheless had wrought iron armor plate , and part of her exterior hull was iron rather than steel . 
After 1872 , steel started to be introduced as a material for construction . Compared to iron , steel allow for greater structural strength for a lower weight . da French Navy led tdaway wid the use of steel in its fleet , starting with the Redoutable , laid down in 1873 and launched in 1876 . Redoutable nonetheless had wrought iron armor plate , and part of her exterior hull was iron rather den steel .