I wanted to see if I could get more speed from the Ger/CBL/1915 design

I wondered if I could get the Ger/CBL/1915 design to reach 40 knots, but the answer is that can only be done with the lightest possible machinery. The basic dimensions are relatively unchanged, except that the freeboard is raised and the draft slightly increased. The new standard displacement is 19,102 tons. The survivability is acceptable, as the ship can absorb 22 12in hits and could take one torpedo hit without sinking. I don't like the roll period being as quick as it is: 13.9 seconds, but it is acceptable. The modified design can now carry 2-12in BLR and 12-6in QF guns at up to 40 knots or for 7,500nm at 15 knots. The design lacks a torpedo bulkhead. The effect of the weight was prohibitive. This is the Springsharp report:

Ger/CBL/1915 Mod.A High Speed  Red Book, Germany Light Battlecruiser laid down 1915 (Engine 1941)

Displacement:
 18,567 t light; 19,195 t standard; 20,600 t normal; 21,724 t full load

Dimensions: Length overall / water x beam x draught
 802.24 ft / 800.00 ft x 80.00 ft x 23.50 ft (normal load)
 244.52 m / 243.84 m x 24.38 m  x 7.16 m

Armament:
      2 - 12.00" / 305 mm guns (1x2 guns), 864.00lbs / 391.90kg shells, 1915 Model
   Breech loading guns in a turret (on a barbette)
   on centreline forward
      12 - 6.00" / 152 mm guns in single mounts, 108.00lbs / 48.99kg shells, 1915 Model
   Quick firing guns in deck mounts with hoists
   on side, evenly spread
 Weight of broadside 3,024 lbs / 1,372 kg
 Shells per gun, main battery: 120

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 4.00" / 102 mm 470.00 ft / 143.26 m 17.00 ft / 5.18 m
 Ends: Unarmoured
   Main Belt covers 90 % of normal length
   Main belt does not fully cover magazines and engineering spaces

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 5.00" / 127 mm 3.00" / 76 mm  5.00" / 127 mm
 2nd: 3.00" / 76 mm 3.00" / 76 mm  3.00" / 76 mm

   - Armour deck: 1.00" / 25 mm, Conning tower: 5.00" / 127 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Geared drive, 4 shafts, 257,302 shp / 191,947 Kw = 39.00 kts
 Range 7,500nm at 15.00 kts
 Bunker at max displacement = 2,529 tons

Complement:
 859 - 1,117

Cost:
 £2.792 million / $11.167 million

Distribution of weights at normal displacement:
 Armament: 378 tons, 1.8 %
 Armour: 2,634 tons, 12.8 %
    - Belts: 1,350 tons, 6.6 %
    - Torpedo bulkhead: 0 tons, 0.0 %
    - Armament: 429 tons, 2.1 %
    - Armour Deck: 774 tons, 3.8 %
    - Conning Tower: 81 tons, 0.4 %
 Machinery: 6,800 tons, 33.0 %
 Hull, fittings & equipment: 8,755 tons, 42.5 %
 Fuel, ammunition & stores: 2,033 tons, 9.9 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   19,865 lbs / 9,011 Kg = 23.0 x 12.0 " / 305 mm shells or 1.8 torpedoes
 Stability (Unstable if below 1.00): 1.34
 Metacentric height 6.0 ft / 1.8 m
 Roll period: 13.7 seconds
 Steadiness - As gun platform (Average = 50 %): 51 %
   - Recoil effect (Restricted arc if above 1.00): 0.26
 Seaboat quality  (Average = 1.00): 1.03

Hull form characteristics:
 Hull has rise forward of midbreak
 Block coefficient: 0.479
 Length to Beam Ratio: 10.00 : 1
 'Natural speed' for length: 28.28 kts
 Power going to wave formation at top speed: 58 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): 4.00 degrees
 Stern overhang: -2.00 ft / -0.61 m
 Freeboard (% = measuring location as a percentage of overall length):
    - Stem:  32.00 ft / 9.75 m
    - Forecastle (20 %): 27.00 ft / 8.23 m
    - Mid (68 %):  27.00 ft / 8.23 m (19.00 ft / 5.79 m aft of break)
    - Quarterdeck (15 %): 19.00 ft / 5.79 m
    - Stern:  19.00 ft / 5.79 m
    - Average freeboard: 24.84 ft / 7.57 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 121.1 %
  - Above water (accommodation/working, high = better): 231.2 %
 Waterplane Area: 41,860 Square feet or 3,889 Square metres
 Displacement factor (Displacement / loading): 107 %
 Structure weight / hull surface area: 136 lbs/sq ft or 664 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.98
  - Longitudinal: 1.23
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is cramped
 Room for accommodation and workspaces is excellent