A fast GB/CB/1915 design study

There is a page with sketch specifications for a fast battlecruiser design. The page is titled "Jeun Ecole". Below that, there are the words "high speed". The 4in-6in must refer to the side armor. To the left is 6-12in, which I assume is the main armament. then, there are the indications Cp=0.54 and Cm=0.90. The dimensions are those for the GB/CB/1905 design, with a heavier armament and armor. I tried the design in Springsharp for a 1915 very fast battlecruiser with lightweight machinery. This is the result:

GB/CB/1915 Design Study, Great Britain Battlecruiser laid down 1915 (Engine 1937)

Displacement:
 22,819 t light; 23,578 t standard; 25,000 t normal; 26,138 t full load

Dimensions: Length overall / water x beam x draught
 770.00 ft / 770.00 ft x 85.00 ft x 26.00 ft (normal load)
 234.70 m / 234.70 m x 25.91 m  x 7.92 m

Armament:
      6 - 12.00" / 305 mm guns (3x2 guns), 864.00lbs / 391.90kg shells, 1915 Model
   Breech loading guns in turrets (on barbettes)
   on centreline ends, majority forward, 1 raised mount - superfiring
      16 - 4.00" / 102 mm guns in single mounts, 32.00lbs / 14.51kg shells, 1915 Model
   Quick firing guns in deck mounts with hoists
   on side, all amidships
 Weight of broadside 5,696 lbs / 2,584 kg
 Shells per gun, main battery: 80

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 6.00" / 152 mm 540.00 ft / 164.59 m 8.00 ft / 2.44 m
 Ends: Unarmoured
 Upper: 4.00" / 102 mm 540.00 ft / 164.59 m 8.00 ft / 2.44 m
   Main Belt covers 108 % of normal length
   Main belt does not fully cover magazines and engineering spaces

   - Torpedo Bulkhead:
  2.00" / 51 mm 540.00 ft / 164.59 m 25.00 ft / 7.62 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 9.00" / 229 mm 6.00" / 152 mm  8.00" / 203 mm
 2nd: 2.00" / 51 mm 2.00" / 51 mm  2.00" / 51 mm

   - Armour deck: 3.00" / 76 mm, Conning tower: 9.00" / 229 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Geared drive, 4 shafts, 174,301 shp / 130,028 Kw = 34.00 kts
 Range 6,500nm at 15.00 kts
 Bunker at max displacement = 2,559 tons

Complement:
 993 - 1,292

Cost:
 £3.015 million / $12.062 million

Distribution of weights at normal displacement:
 Armament: 712 tons, 2.8 %
 Armour: 6,780 tons, 27.1 %
    - Belts: 1,793 tons, 7.2 %
    - Torpedo bulkhead: 999 tons, 4.0 %
    - Armament: 1,370 tons, 5.5 %
    - Armour Deck: 2,452 tons, 9.8 %
    - Conning Tower: 166 tons, 0.7 %
 Machinery: 4,831 tons, 19.3 %
 Hull, fittings & equipment: 10,497 tons, 42.0 %
 Fuel, ammunition & stores: 2,181 tons, 8.7 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   37,056 lbs / 16,808 Kg = 42.9 x 12.0 " / 305 mm shells or 5.0 torpedoes
 Stability (Unstable if below 1.00): 1.13
 Metacentric height 5.0 ft / 1.5 m
 Roll period: 16.0 seconds
 Steadiness - As gun platform (Average = 50 %): 61 %
   - Recoil effect (Restricted arc if above 1.00): 0.55
 Seaboat quality  (Average = 1.00): 1.21

Hull form characteristics:
 Hull has rise forward of midbreak
 Block coefficient: 0.514
 Length to Beam Ratio: 9.06 : 1
 'Natural speed' for length: 27.75 kts
 Power going to wave formation at top speed: 54 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): -1.00 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 %): 29.00 ft / 8.84 m
    - Mid (67 %):  29.00 ft / 8.84 m (21.00 ft / 6.40 m aft of break)
    - Quarterdeck (15 %): 21.00 ft / 6.40 m
    - Stern:  21.00 ft / 6.40 m
    - Average freeboard: 26.60 ft / 8.11 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 110.2 %
  - Above water (accommodation/working, high = better): 227.0 %
 Waterplane Area: 44,179 Square feet or 4,104 Square metres
 Displacement factor (Displacement / loading): 113 %
 Structure weight / hull surface area: 154 lbs/sq ft or 751 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.96
  - Longitudinal: 1.37
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is adequate
 Room for accommodation and workspaces is excellent
 Good seaboat, rides out heavy weather easily