Titanic was equipped with three main engines—two reciprocating four-cylinder, triple-expansion steam engines and one centrally placed low-pressure Parsons turbine—each driving a propeller. The two reciprocating engines had a combined output of 30,000 hp and a further 16,000 hp was contributed by the turbine.[15] The White Star Line had used the same combination of engines on an earlier liner, the SS Laurentic, where it had been a great success.[26] It provided a good combination of performance and speed; reciprocating engines by themselves were not powerful enough to propel an Olympic-class liner at the desired speeds, while turbines were sufficiently powerful but caused uncomfortable vibrations, a problem that affected the all-turbine Cunard liners Lusitania and Mauretania.[27] By combining reciprocating engines with a turbine, fuel usage could be reduced and motive power increased, while using the same amount of steam