Nicholas Roosevelt (inventor) 74-gun ships. In 1797, with Robert R. Livingston and John Stevens, he agreed to build a boat on joint account, for which the engines were to be constructed by Roosevelt, and the propelling agency was to be that planned by Livingston. The experiment failed, the speed attained being only equivalent to about in still water. On September 6, 1798, Roosevelt described and earnestly recommended to Livingston a vertical wheel, which is the first practical suggestion of the combination that made steam navigation a commercial success, although four years later Robert Fulton believed that chains and floats were alone to be
Steam turbine turbine cycle efficiencies have yet to break 50%, yet diesel engines routinely exceed 50%, especially in marine applications. Diesel power plants also have lower operating costs since fewer operators are required. Thus, conventional steam power is used in very few new ships. An exception is LNG carriers which often find it more economical to use boil-off gas with a steam turbine than to re-liquify it. Nuclear-powered ships and submarines use a nuclear reactor to create steam for turbines. Nuclear power is often chosen where diesel power would be impractical (as in submarine applications) or the logistics of refuelling pose significant