Béarn's mixed propulsion compromise

Béarn was initially attractive for conversion because her machinery was turbine-powered. The final arrangement instead used turbines on two shafts and triple-expansion engines on the other two. Reciprocating machinery offered a modest efficiency advantage at long-range cruising speeds. By the 1920s, turbine reliability had improved enough that this small gain was difficult to justify against the loss of power density. The compromise contributed to a carrier too slow for the fast raider-hunting force that French doctrine increasingly required.