A fast battleship design study: what I am calling the Ger/BB/1917

I did a fast battleship design study that for lack of another designation, I am calling the Ger/BB/1917 design study. The ship is 850ft x 850ft x 30.4ft. The speed is 30 knots. The armament is 9-18in/45 BLR with 20-5in QF guns. I used all the original specifications, except that the displacement ballooned from what I had overoptimistically hoped (50,000 tons) to 63,375 tons. This is the Springsharp report:

Ger/BB/1917 Design Study, Germany Enter ship type laid down 1917 (Engine 1937)

Displacement:
 57,751 t light; 60,366 t standard; 63,375 t normal; 65,783 t full load

Dimensions: Length overall / water x beam x draught
 851.78 ft / 850.00 ft x 120.00 ft x 30.40 ft (normal load)
 259.62 m / 259.08 m x 36.58 m  x 9.27 m

Armament:
      9 - 18.00" / 457 mm guns (3x3 guns), 3,200.00lbs / 1,451.50kg shells, 1917 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, 1917 Model
   Quick firing guns in deck mounts with hoists
   on side, all amidships, 4 raised mounts - superfiring
 Weight of broadside 30,050 lbs / 13,630 kg
 Shells per gun, main battery: 80

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 18.0" / 457 mm 555.00 ft / 169.16 m 8.00 ft / 2.44 m
 Ends: Unarmoured
 Upper: 16.0" / 406 mm 555.00 ft / 169.16 m 8.00 ft / 2.44 m
   Main Belt covers 100 % of normal length

   - Torpedo Bulkhead:
  2.00" / 51 mm 555.00 ft / 169.16 m 28.00 ft / 8.53 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 12.0" / 305 mm 8.00" / 203 mm  16.0" / 406 mm

   - Armour deck: 7.00" / 178 mm, Conning tower: 16.00" / 406 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Geared drive, 4 shafts, 205,655 shp / 153,419 Kw = 30.00 kts
 Range 7,500nm at 15.00 kts
 Bunker at max displacement = 5,417 tons

Complement:
 1,996 - 2,596

Cost:
 £10.375 million / $41.499 million

Distribution of weights at normal displacement:
 Armament: 3,437 tons, 5.4 %
 Armour: 23,414 tons, 36.9 %
    - Belts: 6,568 tons, 10.4 %
    - Torpedo bulkhead: 1,150 tons, 1.8 %
    - Armament: 4,416 tons, 7.0 %
    - Armour Deck: 10,733 tons, 16.9 %
    - Conning Tower: 548 tons, 0.9 %
 Machinery: 5,700 tons, 9.0 %
 Hull, fittings & equipment: 25,201 tons, 39.8 %
 Fuel, ammunition & stores: 5,624 tons, 8.9 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   94,081 lbs / 42,675 Kg = 32.3 x 18.0 " / 457 mm shells or 13.7 torpedoes
 Stability (Unstable if below 1.00): 1.16
 Metacentric height 8.7 ft / 2.6 m
 Roll period: 17.1 seconds
 Steadiness - As gun platform (Average = 50 %): 52 %
   - Recoil effect (Restricted arc if above 1.00): 0.66
 Seaboat quality  (Average = 1.00): 1.03

Hull form characteristics:
 Hull has a flush deck
 Block coefficient: 0.715
 Length to Beam Ratio: 7.08 : 1
 'Natural speed' for length: 29.15 kts
 Power going to wave formation at top speed: 53 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): 3.00 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 %): 25.00 ft / 7.62 m
    - Mid (50 %):  25.00 ft / 7.62 m
    - Quarterdeck (15 %): 25.00 ft / 7.62 m
    - Stern:  25.00 ft / 7.62 m
    - Average freeboard: 25.72 ft / 7.84 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 84.0 %
  - Above water (accommodation/working, high = better): 197.7 %
 Waterplane Area: 82,877 Square feet or 7,699 Square metres
 Displacement factor (Displacement / loading): 102 %
 Structure weight / hull surface area: 232 lbs/sq ft or 1,132 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.98
  - Longitudinal: 1.18
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is adequate
 Room for accommodation and workspaces is excellent