My Vanguard-like design didn't work, as specified

I have this drawing and partial specification for a Vanguard-like battleship. It is undated but was clearly in the series that began in 1905 and continued into the 1920's. I had understandably expected that since the Vanguard would work, that a similar ship would, as well. The dimensions were 800ft x 108ft x 30.2ft. The standard displacement was to be 41,500 tons. The armament was 8-15in/50 guns and 20-5in QF guns, as was our preference in the early 1970's. The armoring scheme simply can't be reproduced in Springsharp. There was a short, heavy belt, amidships, that was the full, two-deck height. There were decreasing thickness towards the bow and stern. To achieve an acceptable compromise, in Springsharp, the displacement had to increase, as well as the freeboard. This is the resulting report:

GB/BB/1921 Design Study, Great Britain Battleship laid down 1921 (Engine 1941)

Displacement:
 43,147 t light; 44,814 t standard; 46,600 t normal; 48,029 t full load

Dimensions: Length overall / water x beam x draught
 801.68 ft / 800.00 ft x 108.00 ft x 32.00 ft (normal load)
 244.35 m / 243.84 m x 32.92 m  x 9.75 m

Armament:
      8 - 15.00" / 381 mm guns (4x2 guns), 1,687.50lbs / 765.44kg shells, 1921 Model
   Breech loading guns in turrets (on barbettes)
   on centreline ends, evenly spread, 2 raised mounts - superfiring
      16 - 5.00" / 127 mm guns (10 mounts), 62.50lbs / 28.35kg shells, 1921 Model
   Quick firing guns in turrets (on barbettes)
   on side, evenly spread, 8 raised mounts
 Weight of broadside 14,500 lbs / 6,577 kg
 Shells per gun, main battery: 90

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 14.0" / 356 mm 450.00 ft / 137.16 m 17.00 ft / 5.18 m
 Ends: 7.00" / 178 mm 200.00 ft / 60.96 m 17.00 ft / 5.18 m
   150.00 ft / 45.72 m Unarmoured ends
   Main Belt covers 87 % of normal length

   - Torpedo Bulkhead:
  2.00" / 51 mm 450.00 ft / 137.16 m 28.00 ft / 8.53 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 14.0" / 356 mm 8.00" / 203 mm  14.0" / 356 mm
 2nd: 5.00" / 127 mm 5.00" / 127 mm  5.00" / 127 mm

   - Armour deck: 5.50" / 140 mm, Conning tower: 14.00" / 356 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Geared drive, 4 shafts, 210,397 shp / 156,956 Kw = 32.00 kts
 Range 5,600nm at 15.00 kts
 Bunker at max displacement = 3,215 tons

Complement:
 1,585 - 2,061

Cost:
 £9.701 million / $38.803 million

Distribution of weights at normal displacement:
 Armament: 1,813 tons, 3.9 %
 Armour: 17,955 tons, 38.5 %
    - Belts: 5,630 tons, 12.1 %
    - Torpedo bulkhead: 932 tons, 2.0 %
    - Armament: 4,632 tons, 9.9 %
    - Armour Deck: 6,369 tons, 13.7 %
    - Conning Tower: 391 tons, 0.8 %
 Machinery: 5,560 tons, 11.9 %
 Hull, fittings & equipment: 17,819 tons, 38.2 %
 Fuel, ammunition & stores: 3,453 tons, 7.4 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   70,053 lbs / 31,776 Kg = 41.5 x 15.0 " / 381 mm shells or 10.2 torpedoes
 Stability (Unstable if below 1.00): 1.06
 Metacentric height 6.3 ft / 1.9 m
 Roll period: 18.0 seconds
 Steadiness - As gun platform (Average = 50 %): 50 %
   - Recoil effect (Restricted arc if above 1.00): 0.57
 Seaboat quality  (Average = 1.00): 1.01

Hull form characteristics:
 Hull has low forecastle
 Block coefficient: 0.590
 Length to Beam Ratio: 7.41 : 1
 'Natural speed' for length: 28.28 kts
 Power going to wave formation at top speed: 56 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): 3.00 degrees
 Stern overhang: 0.00 ft / 0.00 m
 Freeboard (% = measuring location as a percentage of overall length):
    - Stem:  32.00 ft / 9.75 m
    - Forecastle (20 %): 25.00 ft / 7.62 m (26.00 ft / 7.92 m aft of break)
    - Mid (50 %):  26.00 ft / 7.92 m
    - Quarterdeck (15 %): 26.00 ft / 7.92 m
    - Stern:  26.00 ft / 7.92 m
    - Average freeboard: 26.36 ft / 8.03 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 83.9 %
  - Above water (accommodation/working, high = better): 195.6 %
 Waterplane Area: 62,598 Square feet or 5,816 Square metres
 Displacement factor (Displacement / loading): 107 %
 Structure weight / hull surface area: 200 lbs/sq ft or 978 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.97
  - Longitudinal: 1.27
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is adequate
 Room for accommodation and workspaces is excellent