A Ger/BB/1916 design study

This design study, that I am calling the Ger/BB/1916, is for a 28.5 knot ship with 12-16.5in and 16-6in QF guns. The original specification hoped for a 60,000 ton ship, but that is too small. Looking the weights, I gave my Springsharp design better protection than I had originally planned and that accounts for the larger size. I had envisioned that the weights would be like this:

21,020 tons  hull
 6,700 tons  machinery
 3,810 tons  armament
23,670 tons  protection
 4,800 tons  miscellaneous

This is the Springsharp report:

Ger/BB/1916 design study, Germany Battleship laid down 1916 (Engine 1937)

Displacement:
 64,844 t light; 67,774 t standard; 71,905 t normal; 75,210 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
 (932.65 ft / 920.00 ft) x 120.00 ft x (32.80 / 34.11 ft)
 (284.27 m / 280.42 m) x 36.58 m  x (10.00 / 10.40 m)

Armament:
      12 - 16.50" / 419 mm 45.0 cal guns - 2,265.00lbs / 1,027.39kg shells, 90 per gun
   Breech loading guns in turret on barbette mounts, 1916 Model
   4 x Triple mounts on centreline forward
  2 raised mounts - superfiring
      16 - 6.00" / 152 mm 50.0 cal guns - 100.00lbs / 45.36kg shells, 150 per gun
   Quick firing guns in turret on barbette mounts, 1916 Model
   8 x Twin mounts on sides, forward deck aft
  4 raised mounts - superfiring
      Weight of broadside 28,780 lbs / 13,054 kg

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 15.0" / 381 mm 640.00 ft / 195.07 m 17.00 ft / 5.18 m
 Ends: Unarmoured
   Main Belt covers 107 % of normal length

   - Torpedo Bulkhead:
  6.00" / 152 mm 640.00 ft / 195.07 m 32.80 ft / 10.00 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 15.0" / 381 mm 11.0" / 279 mm  15.0" / 381 mm
 2nd: 6.00" / 152 mm 4.00" / 102 mm  6.00" / 152 mm

   - Armoured deck - multiple decks: 6.00" / 152 mm For and Aft decks
 Forecastle: 6.00" / 152 mm  Quarter deck: 6.00" / 152 mm

   - Conning towers: Forward 15.00" / 381 mm,  Aft 0.00" / 0 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Geared drive, 4 shafts, 172,832 shp / 128,932 Kw = 28.50 kts
 Range 8,500nm at 16.00 kts
 Bunker at max displacement = 7,436 tons

Complement:
 2,195 - 2,854

Cost:
 £9.271 million / $37.083 million

Distribution of weights at normal displacement:
 Armament: 4,820 tons, 6.7 %
 Armour: 29,083 tons, 40.4 %
    - Belts: 6,929 tons, 9.6 %
    - Torpedo bulkhead: 4,660 tons, 6.5 %
    - Armament: 7,078 tons, 9.8 %
    - Armour Deck: 9,857 tons, 13.7 %
    - Conning Tower: 559 tons, 0.8 %
 Machinery: 4,790 tons, 6.7 %
 Hull, fittings & equipment: 26,151 tons, 36.4 %
 Fuel, ammunition & stores: 7,061 tons, 9.8 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   131,549 lbs / 59,670 Kg = 58.6 x 16.5 " / 419 mm shells or 28.6 torpedoes
 Stability (Unstable if below 1.00): 1.12
 Metacentric height 8.1 ft / 2.5 m
 Roll period: 17.7 seconds
 Steadiness - As gun platform (Average = 50 %): 70 %
   - Recoil effect (Restricted arc if above 1.00): 0.83
 Seaboat quality  (Average = 1.00): 1.39

Hull form characteristics:
 Hull has a flush deck,
   an extended bulbous bow and a cruiser stern
 Block coefficient (normal/deep): 0.695 / 0.699
 Length to Beam Ratio: 7.67 : 1
 'Natural speed' for length: 30.33 kts
 Power going to wave formation at top speed: 47 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): 15.00 degrees
 Stern overhang: 3.00 ft / 0.91 m
 Freeboard (% = length of deck as a percentage of waterline length):
    Fore end,  Aft end
    - Forecastle: 20.00 %,  36.00 ft / 10.97 m,  30.00 ft / 9.14 m
    - Forward deck: 30.00 %,  30.00 ft / 9.14 m,  26.00 ft / 7.92 m
    - Aft deck: 35.00 %,  26.00 ft / 7.92 m,  27.00 ft / 8.23 m
    - Quarter deck: 15.00 %,  27.00 ft / 8.23 m,  28.00 ft / 8.53 m
    - Average freeboard:  28.28 ft / 8.62 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 67.6 %
  - Above water (accommodation/working, high = better): 207.9 %
 Waterplane Area: 88,093 Square feet or 8,184 Square metres
 Displacement factor (Displacement / loading): 111 %
 Structure weight / hull surface area: 232 lbs/sq ft or 1,131 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.98
  - Longitudinal: 1.15
  - 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
 Good seaboat, rides out heavy weather easily