Super ship: J/BB/1941

The J/BB/1941 is really a super ship. It has 8-21in guns and has a speed of 30 knots with a 12,000nm range at 15 knots. The armour basis is only 18in, but that is probably adequate. I had thought that I would just move to 8-20in guns, but it was possible to move to the 21in caliber, so I did. This is the Springsharp report:

J/BB/1941, Japan Battleship laid down 1941

Displacement:
 84,147 t light; 88,067 t standard; 93,800 t normal; 98,386 t full load

Dimensions: Length overall / water x beam x draught
 934.68 ft / 928.00 ft x 129.00 ft x 35.00 ft (normal load)
 284.89 m / 282.85 m x 39.32 m  x 10.67 m

Armament:
      8 - 21.00" / 533 mm guns (4x2 guns), 4,630.50lbs / 2,100.36kg shells, 1941 Model
   Breech loading guns in turrets (on barbettes)
   on centreline ends, evenly spread, 2 raised mounts - superfiring
      12 - 6.00" / 152 mm guns (4x3 guns), 108.00lbs / 48.99kg shells, 1941 Model
   Quick firing guns in turrets (on barbettes)
   on side, all amidships
      24 - 5.00" / 127 mm guns (12x2 guns), 62.50lbs / 28.35kg shells, 1941 Model
   Dual purpose guns in deck mounts with hoists
   on side, evenly spread, 6 raised mounts
      64 - 2.24" / 57.0 mm guns (32x2 guns), 5.65lbs / 2.56kg shells, 1941 Model
   Anti-aircraft guns in deck mounts 
   on side, evenly spread, 18 raised mounts
 Weight of broadside 40,202 lbs / 18,235 kg
 Shells per gun, main battery: 90

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 18.0" / 457 mm 650.00 ft / 198.12 m 9.00 ft / 2.74 m
 Ends: Unarmoured
 Upper: 12.0" / 305 mm 650.00 ft / 198.12 m 8.00 ft / 2.44 m
   Main Belt covers 108 % of normal length

   - Torpedo Bulkhead:
  8.00" / 203 mm 650.00 ft / 198.12 m 34.00 ft / 10.36 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 18.0" / 457 mm 13.0" / 330 mm  18.0" / 457 mm
 2nd: 6.00" / 152 mm 6.00" / 152 mm  6.00" / 152 mm

   - Armour deck: 8.00" / 203 mm, Conning tower: 18.00" / 457 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Geared drive, 4 shafts, 258,205 shp / 192,621 Kw = 30.00 kts
 Range 12,000nm at 15.00 kts
 Bunker at max displacement = 10,319 tons

Complement:
 2,679 - 3,483

Cost:
 £50.206 million / $200.826 million

Distribution of weights at normal displacement:
 Armament: 5,025 tons, 5.4 %
 Armour: 38,353 tons, 40.9 %
    - Belts: 7,198 tons, 7.7 %
    - Torpedo bulkhead: 6,542 tons, 7.0 %
    - Armament: 8,542 tons, 9.1 %
    - Armour Deck: 15,271 tons, 16.3 %
    - Conning Tower: 801 tons, 0.9 %
 Machinery: 6,824 tons, 7.3 %
 Hull, fittings & equipment: 33,946 tons, 36.2 %
 Fuel, ammunition & stores: 9,653 tons, 10.3 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   144,681 lbs / 65,626 Kg = 31.2 x 21.0 " / 533 mm shells or 30.9 torpedoes
 Stability (Unstable if below 1.00): 1.11
 Metacentric height 9.0 ft / 2.7 m
 Roll period: 18.1 seconds
 Steadiness - As gun platform (Average = 50 %): 56 %
   - Recoil effect (Restricted arc if above 1.00): 0.77
 Seaboat quality  (Average = 1.00): 1.11

Hull form characteristics:
 Hull has a flush deck
 Block coefficient: 0.784
 Length to Beam Ratio: 7.19 : 1
 'Natural speed' for length: 30.46 kts
 Power going to wave formation at top speed: 53 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): 6.00 degrees
 Stern overhang: 3.00 ft / 0.91 m
 Freeboard (% = measuring location as a percentage of overall length):
    - Stem:  35.00 ft / 10.67 m
    - Forecastle (20 %): 28.00 ft / 8.53 m
    - Mid (67 %):  28.00 ft / 8.53 m
    - Quarterdeck (15 %): 28.00 ft / 8.53 m
    - Stern:  28.00 ft / 8.53 m
    - Average freeboard: 28.56 ft / 8.71 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 75.9 %
  - Above water (accommodation/working, high = better): 205.4 %
 Waterplane Area: 103,180 Square feet or 9,586 Square metres
 Displacement factor (Displacement / loading): 102 %
 Structure weight / hull surface area: 249 lbs/sq ft or 1,216 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.99
  - Longitudinal: 1.13
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is excellent
 Room for accommodation and workspaces is excellent