Bearn had 12 boilers, with a turbine set driving the two inner shafts and triple-expansion engines driving the outer pair. Each choice had a logic: turbines promised speed, while reciprocating engines offered efficient cruising and proven reliability. The combined plant produced an incoherent compromise. Bearn was neither a fast carrier nor a simple range specialist, and her top speed reached only 21.5 knots. Individually defensible subsystems failed to add up to a coherent warship design.
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Bearn's mixed propulsion compromise
Bearn's mixed machinery pursued cruising economy without producing the coherent high-speed plant a fleet carrier required.