Why dimensions alone cannot determine cruiser displacement

What would a longer, wider Hawkins-class derivative displace?

Probably more than 10,000 tons, but dimensions alone cannot settle it without knowing draft condition, machinery, fuel, armor, and how the added volume is used.

The proposed Hawkins derivative is 24 feet longer and 3 feet wider, with a stated 17-foot draft. Hawkins's comparison figure is 19 feet 3 inches at deep load, so the two drafts may describe different loading conditions. Extra hull volume could hold machinery, fuel, ammunition, or protection, each changing displacement differently. The tentative estimate is over 10,000 tons standard and possibly over 11,000, but the dimensions alone cannot settle it. A 20,000-shaft-horsepower increase also appears inconsistent with a gain of only two knots. A reliable calculation needs the loading condition and the weights assigned to machinery and other equipment.