Another GB/BB/1915 design

This is another GB/BB/1915 design study. This study explored how well 9-16.5in guns would work on a relatively short 45,000 ton ship. I implemented the design so that the machinery power, weight, and protection weight were as close as possible to what was specified. This is an outline of the original specification:

Dimensions= 755ft x 110ft x 32ft          9-16.5in (130 ton)             Weights:
Cp = 0.61  Cm=0.97                               10-6in (6 ton)                       Hull=  14,200 tons
Displacement=45,000 tons                   120,000 SHP=24.8 knots  Mach=  4,000 tons
Machinery weight basis=30 SHP/ton  On overload=26.2 knots    Prot=  20,530 tons
                                                                                                                  Arm=   2,670 tons
                                                                                                                  Misc=   3,600 tons

As usual, this specification underestimated the hull weight needed to achieve adequate strength. The power specified actually would propel the ship to a higher speed. This is the Springsharp report:

GB/BB/1915 Alt, Great Britain Battleship laid down 1915 (Engine 1924)

Displacement:
    46,855 t light; 48,959 t standard; 51,500 t normal; 53,533 t full load

Dimensions: Length overall / water x beam x draught
    757.17 ft / 755.00 ft x 110.00 ft x 32.00 ft (normal load)
    230.78 m / 230.12 m x 33.53 m  x 9.75 m

Armament:
      9 - 16.50" / 419 mm guns (3x3 guns), 2,246.06lbs / 1,018.80kg shells, 1915 Model
      Breech loading guns in turrets (on barbettes)
      on centreline ends, majority forward, 1 raised mount - superfiring
      10 - 6.00" / 152 mm guns in single mounts, 108.00lbs / 48.99kg shells, 1915 Model
      Quick firing guns in deck mounts with hoists
      on side, all amidships, 2 raised mounts - superfiring
    Weight of broadside 21,295 lbs / 9,659 kg
    Shells per gun, main battery: 90

Armour:
   - Belts:        Width (max)    Length (avg)        Height (avg)
    Main:    17.0" / 432 mm    400.00 ft / 121.92 m    17.00 ft / 5.18 m
    Ends:    Unarmoured
      Main Belt covers 82 % of normal length

   - Torpedo Bulkhead:
        6.00" / 152 mm    400.00 ft / 121.92 m    32.00 ft / 9.75 m

   - Gun armour:    Face (max)    Other gunhouse (avg)    Barbette/hoist (max)
    Main:    17.0" / 432 mm    10.0" / 254 mm        17.0" / 432 mm
    2nd:    4.00" / 102 mm    4.00" / 102 mm        4.00" / 102 mm

   - Armour deck: 6.00" / 152 mm, Conning tower: 17.00" / 432 mm

Machinery:
    Oil fired boilers, steam turbines,
    Geared drive, 4 shafts, 121,839 shp / 90,892 Kw = 27.00 kts
    Range 6,500nm at 15.00 kts
    Bunker at max displacement = 4,575 tons

Complement:
    1,709 - 2,222

Cost:
    £6.455 million / $25.819 million

Distribution of weights at normal displacement:
    Armament: 2,662 tons, 5.2 %
    Armour: 20,734 tons, 40.3 %
       - Belts: 5,277 tons, 10.2 %
       - Torpedo bulkhead: 2,842 tons, 5.5 %
       - Armament: 4,862 tons, 9.4 %
       - Armour Deck: 7,246 tons, 14.1 %
       - Conning Tower: 507 tons, 1.0 %
    Machinery: 4,013 tons, 7.8 %
    Hull, fittings & equipment: 19,446 tons, 37.8 %
    Fuel, ammunition & stores: 4,645 tons, 9.0 %
    Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
    Survivability (Non-critical penetrating hits needed to sink ship):
      82,094 lbs / 37,237 Kg = 36.6 x 16.5 " / 419 mm shells or 15.1 torpedoes
    Stability (Unstable if below 1.00): 1.10
    Metacentric height 6.9 ft / 2.1 m
    Roll period: 17.6 seconds
    Steadiness    - As gun platform (Average = 50 %): 62 %
            - Recoil effect (Restricted arc if above 1.00): 0.79
    Seaboat quality  (Average = 1.00): 1.25

Hull form characteristics:
    Hull has rise forward of midbreak
    Block coefficient: 0.678
    Length to Beam Ratio: 6.86 : 1
    'Natural speed' for length: 27.48 kts
    Power going to wave formation at top speed: 51 %
    Trim (Max stability = 0, Max steadiness = 100): 50
    Bow angle (Positive = bow angles forward): 4.00 degrees
    Stern overhang: -2.00 ft / -0.61 m
    Freeboard (% = measuring location as a percentage of overall length):
       - Stem:        31.00 ft / 9.45 m
       - Forecastle (20 %):    29.00 ft / 8.84 m
       - Mid (65 %):        29.00 ft / 8.84 m (21.00 ft / 6.40 m aft of break)
       - Quarterdeck (15 %):    21.00 ft / 6.40 m
       - Stern:        0.00 ft / 0.00 m
       - Average freeboard:    24.79 ft / 7.55 m

Ship space, strength and comments:
    Space    - Hull below water (magazines/engines, low = better): 78.7 %
        - Above water (accommodation/working, high = better): 193.1 %
    Waterplane Area: 65,278 Square feet or 6,065 Square metres
    Displacement factor (Displacement / loading): 103 %
    Structure weight / hull surface area: 218 lbs/sq ft or 1,063 Kg/sq metre
    Hull strength (Relative):
        - Cross-sectional: 0.96
        - Longitudinal: 1.42
        - Overall: 1.00
    Hull space for machinery, storage, compartmentation is excellent
    Room for accommodation and workspaces is excellent
    Good seaboat, rides out heavy weather easily