The GB/BB/1915 design study

This is a design study for a British battleship to be built in 1915. The drawing style seems to date the design to what I was doing about 1973. The ship had 12-16in BLR and 12-6in QF guns. I had underestimated the necessary displacement to achieve adequate strength. I had thought that the Standard displacement could be as low as 50,000 tons, but I had to increase the displacement in Springsharp. I had underestimated the speed that could be achieved with 170,000 SHP. Instead of 27.5 knots, the design can reach 29.5 knots. This is the Springsharp report:

GB/BB/1915, Great Britain Battleship laid down 1915 (Engine 1925)

Displacement:
 50,176 t light; 52,585 t standard; 55,200 t normal; 57,292 t full load

Dimensions: Length overall / water x beam x draught
 846.32 ft / 841.00 ft x 120.00 ft x 33.00 ft (normal load)
 257.96 m / 256.34 m x 36.58 m  x 10.06 m

Armament:
      12 - 16.00" / 406 mm guns (4x3 guns), 2,048.00lbs / 928.96kg shells, 1915 Model
   Breech loading guns in turrets (on barbettes)
   on centreline ends, evenly spread, 2 raised mounts - superfiring
      12 - 6.00" / 152 mm guns in single mounts, 108.00lbs / 48.99kg shells, 1915 Model
   Breech loading guns in deck mounts with hoists
   on side, all amidships, 2 raised mounts - superfiring
 Weight of broadside 25,872 lbs / 11,735 kg
 Shells per gun, main battery: 90

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 15.0" / 381 mm 430.00 ft / 131.06 m 17.00 ft / 5.18 m
 Ends: Unarmoured
   Main Belt covers 79 % of normal length
   Main belt does not fully cover magazines and engineering spaces

   - Torpedo Bulkhead:
  4.00" / 102 mm 430.00 ft / 131.06 m 31.00 ft / 9.45 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 15.0" / 381 mm 8.00" / 203 mm  15.0" / 381 mm
 2nd: 4.00" / 102 mm 4.00" / 102 mm  4.00" / 102 mm

   - Armour deck: 4.00" / 102 mm, Conning tower: 15.00" / 381 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Geared drive, 4 shafts, 166,795 shp / 124,429 Kw = 29.50 kts
 Range 6,500nm at 15.00 kts
 Bunker at max displacement = 4,708 tons

Complement:
 1,799 - 2,340

Cost:
 £7.609 million / $30.434 million

Distribution of weights at normal displacement:
 Armament: 3,234 tons, 5.9 %
 Armour: 18,226 tons, 33.0 %
    - Belts: 5,006 tons, 9.1 %
    - Torpedo bulkhead: 1,973 tons, 3.6 %
    - Armament: 5,417 tons, 9.8 %
    - Armour Deck: 5,361 tons, 9.7 %
    - Conning Tower: 469 tons, 0.8 %
 Machinery: 5,415 tons, 9.8 %
 Hull, fittings & equipment: 23,301 tons, 42.2 %
 Fuel, ammunition & stores: 5,024 tons, 9.1 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   73,230 lbs / 33,217 Kg = 35.8 x 16.0 " / 406 mm shells or 11.8 torpedoes
 Stability (Unstable if below 1.00): 1.09
 Metacentric height 7.7 ft / 2.4 m
 Roll period: 18.1 seconds
 Steadiness - As gun platform (Average = 50 %): 59 %
   - Recoil effect (Restricted arc if above 1.00): 0.69
 Seaboat quality  (Average = 1.00): 1.18

Hull form characteristics:
 Hull has a flush deck
 Block coefficient: 0.580
 Length to Beam Ratio: 7.01 : 1
 'Natural speed' for length: 29.00 kts
 Power going to wave formation at top speed: 50 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): 5.00 degrees
 Stern overhang: 2.00 ft / 0.61 m
 Freeboard (% = measuring location as a percentage of overall length):
    - Stem:  38.00 ft / 11.58 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: 26.04 ft / 7.94 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 91.0 %
  - Above water (accommodation/working, high = better): 191.8 %
 Waterplane Area: 72,450 Square feet or 6,731 Square metres
 Displacement factor (Displacement / loading): 100 %
 Structure weight / hull surface area: 235 lbs/sq ft or 1,148 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.97
  - Longitudinal: 1.29
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is adequate
 Room for accommodation and workspaces is excellent