 Steam @-@ powered screw frigates were built in the mid @-@ 1840s , and at the end of the decade the French Navy introduced steam power to its line of battle . The desire for change came from the ambition of Napoleon III to gain greater influence in Europe , which required a challenge to the British at sea . The first purpose @-@ built steam battleship was the 90 @-@ gun Napoléon in 1850 . Napoléon was armed as a conventional ship @-@ of @-@ the @-@ line , but her steam engines could give her a speed of 12 knots ( 22 km / h ) , regardless of the wind conditions : a potentially decisive advantage in a naval engagement . 
 Steam @-@ powered screw frigates <a href='uninflect' title='1'><mark>were</mark></a> built in the mid @-@ 1840s , and at the end of the decade the French Navy introduced steam power to its line of battle . The desire for change came from the ambition of Napoleon III to gain greater influence in Europe , which required a challenge to the British at sea . The first purpose @-@ built steam battleship was the 90 @-@ gun Napoléon in 1850 . Napoléon was armed as a conventional ship @-@ of @-@ the @-@ line , but her steam engines could give her a speed of 12 knots ( 22 km / h ) , regardless of the wind conditions : a potentially decisive advantage in a naval engagement . 
Steam @-@ powered screw frigates was built in the mid @-@ 1840s , and at da end of the decade tdaFrench Navy introduced steam power to its line of battle . The desire fa change came from the ambition of Napoleon III to gain greater influence in Europe , which required a challenge to the British at sea . The first purpose @-@ built steam battleship was the 90 @-@ gun Napoléon in 1850 . Napoléon was armed as a conventional ship @-@ of @-@ thda-@ line , but her steam engines could give her a speed of 12 knots ( 22 km / h ) , regardless of thedand conditions : a potentially decisive advantage in a naval engagement .