I'm surprised (but maybe shouldn't be) that the shorter ship could be faster

A variant of my "super-fast battlecruiser" can reach 39 knots, and since the maximum waterline length is just 814ft, as opposed to the so-called "29,000 ton battlecruiser", which a variant was 865ft, I would have thought it might be slower. I suppose the issue is that the "super-fast battlecruiser" variant is lighter, being only 32,832.1 tons, while the longer ship is much heavier, being 39,025.2 tons. The heavier ship can reach 38 knots, which I suppose is an achievement for such a large ship. Both ships are odd types. They are like nothing ever contemplated. The closes thing to them were the British light battlecruisers such as the Glorious and Courageous and the German design studies from 1917 and 1918. The GK 3022 was designed for 34 knots and had four large guns in two turrets.