I thought that it would be interesting to try a 1921-style 48,500 ton battlecruiser

I have long been interested in desigining a viable 1921-style British battlecruiser of 48,500 tons. I just failed at producing a viable design at that normal displacement. this design has a transom stern, 9-16in guns, and 31 knots. To do that required 51,600 tons normal, and that with lightweight machinery. The problem may be that I want a This is the Springsharp report:

GB/CB/1921, Great Britain Battlecruiser laid down 1921 (Engine 1927)

Displacement:
 47,444 t light; 49,521 t standard; 51,600 t normal; 53,263 t full load

Dimensions: Length overall / water x beam x draught
 859.38 ft / 855.00 ft x 108.00 ft x 32.00 ft (normal load)
 261.94 m / 260.60 m x 32.92 m  x 9.75 m

Armament:
      9 - 16.00" / 406 mm guns (3x3 guns), 2,048.00lbs / 928.96kg shells, 1921 Model
   Breech loading guns in turrets (on barbettes)
   on centreline ends, majority forward, 1 raised mount - superfiring
      16 - 6.00" / 152 mm guns (8x2 guns), 108.00lbs / 48.99kg shells, 1921 Model
   Quick firing guns in turrets (on barbettes)
   on side, all amidships, 4 raised mounts - superfiring
      6 - 4.70" / 119 mm guns in single mounts, 51.91lbs / 23.55kg shells, 1921 Model
   Anti-aircraft guns in deck mounts with hoists
   on side, evenly spread, all raised mounts
      24 - 1.57" / 40.0 mm guns (2 mounts), 2.00lbs / 0.91kg shells, 1921 Model
   Breech loading guns in deck mounts 
   on side, evenly spread, 16 raised guns
 Weight of broadside 20,519 lbs / 9,307 kg
 Shells per gun, main battery: 90

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 13.0" / 330 mm 560.00 ft / 170.69 m 16.00 ft / 4.88 m
 Ends: Unarmoured
   Main Belt covers 101 % of normal length

   - Torpedo Bulkhead:
  3.00" / 76 mm 560.00 ft / 170.69 m 31.00 ft / 9.45 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 14.0" / 356 mm 10.0" / 254 mm  14.0" / 356 mm
 2nd: 3.00" / 76 mm 3.00" / 76 mm  3.00" / 76 mm

   - Armour deck: 5.00" / 127 mm, Conning tower: 14.00" / 356 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Geared drive, 4 shafts, 168,401 shp / 125,627 Kw = 31.00 kts
 Range 5,600nm at 15.00 kts
 Bunker at max displacement = 3,742 tons

Complement:
 1,711 - 2,225

Cost:
 £11.605 million / $46.421 million

Distribution of weights at normal displacement:
 Armament: 2,565 tons, 5.0 %
 Armour: 18,393 tons, 35.6 %
    - Belts: 4,977 tons, 9.6 %
    - Torpedo bulkhead: 1,927 tons, 3.7 %
    - Armament: 4,491 tons, 8.7 %
    - Armour Deck: 6,581 tons, 12.8 %
    - Conning Tower: 418 tons, 0.8 %
 Machinery: 5,316 tons, 10.3 %
 Hull, fittings & equipment: 21,170 tons, 41.0 %
 Fuel, ammunition & stores: 4,156 tons, 8.1 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   77,635 lbs / 35,215 Kg = 37.9 x 16.0 " / 406 mm shells or 11.9 torpedoes
 Stability (Unstable if below 1.00): 1.08
 Metacentric height 6.5 ft / 2.0 m
 Roll period: 17.8 seconds
 Steadiness - As gun platform (Average = 50 %): 61 %
   - Recoil effect (Restricted arc if above 1.00): 0.83
 Seaboat quality  (Average = 1.00): 1.23

Hull form characteristics:
 Hull has a flush deck
   and transom stern
 Block coefficient: 0.611
 Length to Beam Ratio: 7.92 : 1
 'Natural speed' for length: 33.59 kts
 Power going to wave formation at top speed: 52 %
 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:  34.00 ft / 10.36 m
    - Forecastle (20 %): 27.00 ft / 8.23 m
    - Mid (50 %):  27.00 ft / 8.23 m
    - Quarterdeck (15 %): 27.00 ft / 8.23 m
    - Stern:  27.00 ft / 8.23 m
    - Average freeboard: 27.56 ft / 8.40 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 87.1 %
  - Above water (accommodation/working, high = better): 213.8 %
 Waterplane Area: 71,143 Square feet or 6,609 Square metres
 Displacement factor (Displacement / loading): 104 %
 Structure weight / hull surface area: 214 lbs/sq ft or 1,047 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.97
  - Longitudinal: 1.31
  - 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