The BBX-Mod.A design

I had been dissatisfied with the low speed that Cliff had intended for the BBX design. I thought that a ship of that size should have a higher speed, more like a WWII fast battleship. I somewhat reduced the weight given to protection and increased the power, as well as wanted 40SHP/ton machinery. I adjusted the weights to match what I had specified (although the hull weight is much greater, because of the needs of Springsharp to achieve adequate strength). I did not try for a specific speed, but rather, wanted a power output figure of about 179,000 SHP. I was able to come close to what I had specified, and the result seems quite adequate:

GB/BB/BBX Mod.A Red Book, Great Britain Battleship laid down 1915 (Engine 1941)

Displacement:
 72,616 t light; 76,102 t standard; 79,800 t normal; 82,758 t full load

Dimensions: Length overall / water x beam x draught
 802.89 ft / 800.00 ft x 135.00 ft x 37.00 ft (normal load)
 244.72 m / 243.84 m x 41.15 m  x 11.28 m

Armament:
      9 - 20.00" / 508 mm guns (3x3 guns), 4,000.00lbs / 1,814.37kg shells, 1915 Model
   Breech loading guns in turrets (on barbettes)
   on centreline ends, majority forward, 1 raised mount - superfiring
      24 - 5.00" / 127 mm guns (12x2 guns), 62.50lbs / 28.35kg shells, 1915 Model
   Quick firing guns in turrets (on barbettes)
   on side, all amidships, 4 raised mounts - superfiring
 Weight of broadside 37,500 lbs / 17,010 kg
 Shells per gun, main battery: 90

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 18.0" / 457 mm 450.00 ft / 137.16 m 21.00 ft / 6.40 m
 Ends: Unarmoured
   Main Belt covers 87 % of normal length

   - Torpedo Bulkhead:
  8.00" / 203 mm 450.00 ft / 137.16 m 36.00 ft / 10.97 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 18.0" / 457 mm 15.0" / 381 mm  18.0" / 457 mm
 2nd: 5.00" / 127 mm 5.00" / 127 mm  5.00" / 127 mm

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

Machinery:
 Oil fired boilers, steam turbines, 
 Geared drive, 4 shafts, 173,012 shp / 129,067 Kw = 27.50 kts
 Range 8,500nm at 15.00 kts
 Bunker at max displacement = 6,656 tons

Complement:
 2,373 - 3,086

Cost:
 £10.355 million / $41.421 million

Distribution of weights at normal displacement:
 Armament: 4,688 tons, 5.9 %
 Armour: 33,872 tons, 42.4 %
    - Belts: 7,840 tons, 9.8 %
    - Torpedo bulkhead: 4,795 tons, 6.0 %
    - Armament: 7,718 tons, 9.7 %
    - Armour Deck: 12,799 tons, 16.0 %
    - Conning Tower: 719 tons, 0.9 %
 Machinery: 4,572 tons, 5.7 %
 Hull, fittings & equipment: 29,485 tons, 36.9 %
 Fuel, ammunition & stores: 7,184 tons, 9.0 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   121,265 lbs / 55,005 Kg = 30.3 x 20.0 " / 508 mm shells or 26.6 torpedoes
 Stability (Unstable if below 1.00): 1.12
 Metacentric height 9.8 ft / 3.0 m
 Roll period: 18.1 seconds
 Steadiness - As gun platform (Average = 50 %): 57 %
   - Recoil effect (Restricted arc if above 1.00): 0.60
 Seaboat quality  (Average = 1.00): 1.15

Hull form characteristics:
 Hull has a flush deck
 Block coefficient: 0.699
 Length to Beam Ratio: 5.93 : 1
 'Natural speed' for length: 28.28 kts
 Power going to wave formation at top speed: 53 %
 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:  33.00 ft / 10.06 m
    - Forecastle (20 %): 26.00 ft / 7.92 m
    - Mid (50 %):  26.00 ft / 7.92 m
    - Quarterdeck (15 %): 26.00 ft / 7.92 m
    - Stern:  26.00 ft / 7.92 m
    - Average freeboard: 26.56 ft / 8.10 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 73.9 %
  - Above water (accommodation/working, high = better): 180.5 %
 Waterplane Area: 86,483 Square feet or 8,035 Square metres
 Displacement factor (Displacement / loading): 99 %
 Structure weight / hull surface area: 259 lbs/sq ft or 1,266 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.96
  - Longitudinal: 1.55
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is excellent
 Room for accommodation and workspaces is excellent