Another attempt at the GB/BB/1914 battleship design

My friend Cliff wanted to escalate the battleship race with an 18in design. Immediately on entering the design into Springsharp, I found that there was inadequate hull strength. The other weights are reasonable, but the overall displacement of 48,500 tons standard is too low. To obtain the speed, armor, and gunpower, on the order of 60,000 tons is required. The dimensions specificied are 800ft x 120ft with a hull depth of 55ft. that is quite inadequate for strength. The armament is 9-18in/45 and 20-5in QF guns. The armor basis is 18in. This is the Springsharp report:

GB/BB/1914, Enter country Enter ship type laid down 1914 (Engine 1917)

Displacement:
 55,945 t light; 58,421 t standard; 62,150 t normal; 65,133 t full load

Dimensions: Length overall / water x beam x draught
 801.57 ft / 800.00 ft x 120.00 ft x 34.00 ft (normal load)
 244.32 m / 243.84 m x 36.58 m  x 10.36 m

Armament:
      9 - 18.00" / 457 mm guns (3x3 guns), 2,916.00lbs / 1,322.68kg shells, 1914 Model
   Breech loading guns in turrets (on barbettes)
   on centreline ends, majority forward, 1 raised mount - superfiring
      20 - 5.00" / 127 mm guns (10x2 guns), 62.50lbs / 28.35kg shells, 1914 Model
   Quick firing guns in turrets (on barbettes)
   on side, all amidships, 4 raised mounts - superfiring
 Weight of broadside 27,494 lbs / 12,471 kg
 Shells per gun, main battery: 80

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 18.0" / 457 mm 450.00 ft / 137.16 m 17.00 ft / 5.18 m
 Ends: Unarmoured
   Main Belt covers 87 % of normal length

   - Torpedo Bulkhead:
  4.00" / 102 mm 450.00 ft / 137.16 m 32.00 ft / 9.75 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 18.0" / 457 mm 11.0" / 279 mm  18.0" / 457 mm
 2nd: 5.00" / 127 mm 5.00" / 127 mm  5.00" / 127 mm

   - Armour deck: 7.00" / 178 mm, Conning tower: 18.00" / 457 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Direct drive, 4 shafts, 99,570 shp / 74,280 Kw = 25.00 kts
 Range 7,500nm at 15.00 kts
 Bunker at max displacement = 6,713 tons

Complement:
 1,967 - 2,558

Cost:
 £6.817 million / $27.267 million

Distribution of weights at normal displacement:
 Armament: 3,437 tons, 5.5 %
 Armour: 25,051 tons, 40.3 %
    - Belts: 6,223 tons, 10.0 %
    - Torpedo bulkhead: 2,131 tons, 3.4 %
    - Armament: 6,420 tons, 10.3 %
    - Armour Deck: 9,668 tons, 15.6 %
    - Conning Tower: 608 tons, 1.0 %
 Machinery: 3,650 tons, 5.9 %
 Hull, fittings & equipment: 23,807 tons, 38.3 %
 Fuel, ammunition & stores: 6,205 tons, 10.0 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   100,780 lbs / 45,713 Kg = 34.6 x 18.0 " / 457 mm shells or 18.4 torpedoes
 Stability (Unstable if below 1.00): 1.08
 Metacentric height 7.6 ft / 2.3 m
 Roll period: 18.3 seconds
 Steadiness - As gun platform (Average = 50 %): 77 %
   - Recoil effect (Restricted arc if above 1.00): 0.82
 Seaboat quality  (Average = 1.00): 1.55

Hull form characteristics:
 Hull has a flush deck
 Block coefficient: 0.666
 Length to Beam Ratio: 6.67 : 1
 'Natural speed' for length: 28.28 kts
 Power going to wave formation at top speed: 46 %
 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:  30.00 ft / 9.14 m
    - Forecastle (20 %): 26.00 ft / 7.92 m
    - 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: 26.32 ft / 8.02 m
 Ship tends to be wet forward

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 72.8 %
  - Above water (accommodation/working, high = better): 188.0 %
 Waterplane Area: 74,654 Square feet or 6,936 Square metres
 Displacement factor (Displacement / loading): 104 %
 Structure weight / hull surface area: 235 lbs/sq ft or 1,147 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.96
  - Longitudinal: 1.45
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is excellent
 Room for accommodation and workspaces is excellent
 Ship has slow, easy roll, a good, steady gun platform
 Excellent seaboat, comfortable, can fire her guns in the heaviest weather