The hull and machinery cost of a 35-knot Warspite

What changes would a Warspite-type battleship need to reach 35 knots?

The proposed design would need a longer hull and much more power, becoming roughly a 40,000-ton ship rather than gaining the speed through simple lightening.

A longer hull and a major increase in machinery power would be needed to reach 35 knots. Gas turbines are suggested, although the speed is also considered achievable without them. The resulting ship is estimated at around 40,000 tons. This would amount to a substantial redesign of the battleships apparently identified in the question as Warspite and her sisters.