United States floating battery Demologos Demologos was the first warship to be propelled by a steam engine . She was a wooden floating battery built to defend New York Harbor from the Royal Navy during the War of 1812 . The vessel was designed to a unique pattern by Robert Fulton , and was renamed Fulton after his death . Because of the prompt end of the war , " Demologos " never saw action , and no other ship like her was built . History . On 9 March 1814 , Congress authorized the construction of a steam warship to be designed by Robert Fulton , a pioneer of commercial steamers in North America . The construction of the ship began on 20 June 1814 , at the civilian yard of Adam and Noah Brown , and the ship was launched on 29 October . After sea trials she was delivered to the United States Navy in June 1816 . The ship was never formally named ; Fulton christened it " Demologos " or " Demologus " , though following his death in February 1815 , the ship was named " Fulton " . By the time she was completed , the war for which " Demologos " had been built had ended . She saw only one day of active service , when she carried President James Monroe on a tour of New York Harbor . A two - masted lateen rig was added by the orders of her first commander , Captain David Porter . In 1821 her armament and machinery were removed . The remainder of her career was spent laid up in reserve ; after 1825 she served as the floating barracks for Brooklyn Navy Yard . She came to an end on 4 June 1829 in a gunpowder explosion . Design and impact . " Demologos " had an entirely unique and innovative design . A catamaran , her paddlewheel was sandwiched between two hulls . Each hull was constructed thick for protection against gunfire . The steam engine , mounted below the waterline in one of the hulls , was capable of giving speed in favorable conditions . Although designed to carry 30 32 - pounder guns , 24 port and starboard , 6 fore and aft , the Navy had trouble acquiring sufficient guns , and a varying number were mounted while in actual service . " Demologos " was also fitted for two 100 - pounder Columbiads , one mounted fore and another aft , these weapons were never actually furnished to the vessel . Fulton ' s design solved several of the problems inherent in warships powered by paddlewheels which led to the adoption of the paddle - steamer as an effective warship in following decades . By placing the paddlewheel centrally , sandwiched between two hulls , Fulton protected it from gunfire ; this design also allowed the ship to mount a full broadside of guns . The steam engine offered the prospect of tactical advantage against sail - powered warships . In a calm , sailing ships depended on the manpower of their crews to tow the ship from the boats , or to kedge with anchors . " Demologos " , with steam , might have found it easy to outmaneuver a ship - of - the - line in calm weather . The innovative construction and steam power also fundamentally limited the role " Demologos " could fill . With an unreliable engine and a hull unsuited to seaways , " Demologos " was unable to travel on the high seas . The United States Navy planned to build a number of similar steam batteries , but none of these plans got off the drawing board until the of 1837 . A number of European navies also considered acquiring the " Demologos " , but these inquiries came to nought . The " Demologos " was ultimately a dead end in the introduction of steam power to the warship . Armed paddle steamers proliferated in the 1830s and 40s as armed tugs and transports . During the Civil War , the United States Navy operated a number of iron clad steam - powered paddle - wheel gunboats as a part of the Mississippi River Squadron . Known as City class ironclad gunboats as they were named after cities on the Mississippi River or its tributaries , these ships utilized a double - hulled configuration similar to Fulton ' s design , with the paddle wheel in the center . The wheel was protected by armored plate , allowing full broad - sides , as well as bow and stern shots . An example , the USS Cairo , is on display at the Vicksburg National Military Park . Paddle - wheel propulsion , more usually side - paddle configurations , in military use continued until World War II with the USS Wolverine and USS Sable training aircraft carriers . These designs were typically limited to use in the Brown - water navy or on large lakes . Steam - powered paddle wheel propulsion would ultimately be eclipsed by the introduction of the screw propeller in the 1840s , enabling steam - powered version of the ship of the line and the frigate before steam power was properly adapted for use in a Blue water navy .