How would small-tube boilers, geared turbines, and triple turrets have changed the Queen Elizabeth class and later battlecruiser construction?
Short answerA 28-knot Queen Elizabeth would have been a true fast battleship, making 30-knot battlecruisers difficult to justify and pressuring other navies to raise battle-fleet speed.
NotesA more radical Queen Elizabeth might have combined small-tube boilers, geared turbines, and four triple turrets. The preference for four mountings reflects concern about losing a third of the battery when one of three turrets failed. A 28-knot battleship would make Renown and Repulse harder to justify unless battlecruisers reached roughly 35 knots, imposing severe design constraints. Against a slower battle line, the faster battleships could choose when and where to engage. In this counterfactual, American designers might accept 24 or 25 knots to reduce that disadvantage while retaining their preference for guns and armour. The comparison depends on how other navies responded to the faster British ships.