Baseline armor, machinery, and 15-inch broadside

The Queen Elizabeth class had a 13-inch belt, 24 water-tube boilers, 75,000 shaft horsepower, a nominal 24-knot speed, and eight 15-inch guns. By a contemporary rule of thumb, that battery delivered roughly the broadside weight of twelve 13.5-inch guns, so the apparent drop from ten guns did not mean less striking power. The older Iron Duke provides the machinery baseline, with 18 boilers and about 29,000 horsepower for roughly 21.25 knots. Queen Elizabeth used far more machinery and about 5,000 additional tons for a speed gain of only a few knots. The comparison shows the class's power alongside the high cost of its incomplete fast-battleship leap.