The Bellerophons used Parsons direct-drive turbines with boilers selected partly to broaden the supplier base. Boiler pressure alone did not determine performance because turbine blade design had to match the steam conditions. The later ships could equal Dreadnought's rated power and speed despite being larger, revealing improved efficiency and the constraint of keeping a uniform battle line. The discussion of blade shape, angle, position, and cruising turbines explains why steam pressure cannot be treated as a stand-alone performance figure.
Chapter · 21:02-25:58
Bellerophon's machinery corrected Dreadnought-era compromises
The discussion follows boiler pressure, turbine matching, and why nominally lower-pressure machinery could still produce an efficient 23,000-shaft-horsepower installation.