A faster, heavier-gunned HMS Dreadnought

Which moment would Dr. Clarke revisit to change naval history most dramatically?

He would join the 1905 Dreadnought design work, replace wing turrets with superfiring positions, seek 24 knots, and push for the Elswick 14-inch gun.

The proposed redesign would lengthen and narrow Dreadnought, eliminate the wing-turret layout, use superfiring guns at both ends, and seek a 24-knot speed with Elswick's available 14-inch work. Such a leap would make early American and German responses visibly obsolete, potentially pausing foreign construction while their gun and propulsion industries caught up and forcing later British battlecruisers toward still higher speeds.