Because British heavy boiler and turbine factories had spare capacity, the efficiency gain could make machinery replacement worthwhile on ships previously judged poor refit candidates. Royal Oak might replace eighteen old boilers with only two modern units; Courageous could test the carrier machinery arrangement while gaining speed and range; and Renown could achieve greater power with four boilers rather than eight. The scenario turns machinery renewal into a fleet policy, potentially modernizing all five Queen Elizabeths plus selected R-class ships and Renown before the war. Britain had more headroom in heavy turbine and boiler manufacture than in some smaller machinery categories, making this broader program industrially less implausible than its scale first suggests.
Chapter · 40:25-50:22
Re-engining Royal Oak, Courageous, and Renown
Britain's underused heavy-turbine capacity could support a wider program that makes older battleships and converted carriers faster, longer-ranged, or better protected.