The Nelson class's official machinery output was 45,000 shaft horsepower from eight boilers. Warspite's 1937 refit produced an official 72,000 shaft horsepower from six boilers. The comparison illustrates improvements in boiler efficiency over that period and why boiler count alone cannot establish power output. Warspite also drove four shafts, while the Nelson class drove two. A machinery comparison therefore needs to consider both boiler performance and the arrangement of the propulsion system.
Notable Point · 36:16-37:27
Warspite's refit produced more power from fewer boilers
Nelson's eight boilers and Warspite's six produced very different power outputs and drove different numbers of shafts.