Small-tube boilers and Queen Elizabeth-class speed

How fast might the Queen Elizabeth class have been with small-tube boilers but the same hull form?

Approximately twenty-eight knots, within the normal margin of engineering estimates.

Small-tube boilers could bring the Queen Elizabeth-class battleships very close to twenty-eight knots without changing their existing hull form. The estimate carries a margin, so the exact result could fall slightly above or below that figure. Such machinery modernisation could move an older battleship toward fast-battleship performance without redesigning the whole ship.