 In the 18th and early 19th centuries fleets had relied on two types of major warship , the ship of the line and the frigate . The first major change to these types was the introduction of steam power for propulsion . While paddle steamer warships had been used from the 1830s onwards , steam propulsion only became suitable for major warships after the adoption of the screw propeller in the 1840s . 
 In the 18th and early 19th centuries fleets <a href='been_done' title='1'><mark>had</mark></a> relied on two types of major warship , the ship of the line and the frigate . The first major change to these types was the introduction of steam power for propulsion . While paddle steamer warships <a href='been_done' title='2'><mark>had</mark></a> been used from the 1830s onwards , steam propulsion only became suitable for major warships after the adoption of the screw propeller in the 1840s . 
In da 18th and early 19th centuries fleets done relied on two types of major warship , the ship of the line and the frigate . The first major change to these types was tdaintroduction of steam power for propulsion . While paddle steamer warships done been used from the 1830s onwards , steam propulsion only became suitable fa major warships after the adoption of thdacrew propeller in theda40s .