SS Rochambeau was a French transatlantic ocean liner of the Compagnie Générale Transatlantique (CGT). She was launched in 1911 and scrapped in 1934. She was the first French ship to be powered by a combination of reciprocating steam engines and steam turbines. She was named after the Comte de Rochambeau, a French aristocrat and marshal who led an army in the American Revolutionary War. Combining reciprocating and turbine engines A turbine is smaller, simpler, lighter, faster, smoother and more reliable than an equivalent triple- or quadruple-expansion piston engine. UK shipyards had built the first turbine-powered commercial ship, , launched in 1901, and the first turbine-powered transatlantic liners, Allan Line's and Virginian, both launched in 1904. But a turbine consumes more fuel than an equivalent triple- or quadruple-expansion piston engine. It cannot run in reverse, and does not run well at low speed. Another limitation was that early turbines drove their propeller shafts directly, as satisfactory reduction gearing had yet to be developed. The speed at which a turbine runs efficiently is several times faster than that at which a marine propeller runs efficiently. UK shipyards responded by developing steamships that combined reciprocating and turbine engines. The first was the refrigerated cargo liner , closely followed by the transatlantic liner , both launched in 1908. Otaki and Laurentic each had three screws. The port and starboard screws were each powered by a triple-expansion engine. Exhaust steam from their low-pressure cylinders fed a single low-pressure turbine amidships that drove the middle screw. Otaki and Laurentic could go astern, slowly forward or manoeuvre using only their piston engines. For higher speeds they could use the turbine as well, increasing both power and fuel efficiency. Laurentic proved both more economic and more powerful than her sister , which had twin quadruple-expansion engines and no low-pressure turbine. The comparison influenced Harland and Wolff to apply the same three-screw, reciprocating and turbine combination in the White Star liners launched in 1910 and Titanic and launched in 1911. Building and early service Chantiers de l'Atlantique built Rochambeau at Saint-Nazaire, launching her on 2 March 1911. Her design was an enlargement of the , which Chantiers de l'Atlantique had launched in 1907 and completed in 1908. Rochambeau was launched on 2 March 1911 and completed later that year. Unlike Otaki, Laurentic and the s, Rochambeau had four screws: two driven by four-cylinder triple-expansion engines and two by low-pressure