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Saturday, January 06, 2007

My GB/CB/1921 design from about 1988

I was finally able to find a date on the papers that I found in the last few days. They apparently date from about 1988. In that package of papers is a scale outboard profile of a British battlecruiser that I am calling the GB/CB/1921. The ship has 9-16in BLR and 16-5.5in QF guns. The speed is 32 knots. The specifications work well in Springsharp, at least if I accept rather light armour. This is the Springsharp report:
GB/CB/1921, Great Britain Battlecruiser laid down 1921

Displacement:
 44,119 t light; 46,091 t standard; 48,600 t normal; 50,607 t full load

Dimensions: Length overall / water x beam x draught
 852.24 ft / 850.00 ft x 107.00 ft x 32.00 ft (normal load)
 259.76 m / 259.08 m x 32.61 m  x 9.75 m

Armament:
      9 - 16.00" / 406 mm guns (3x3 guns), 2,048.00lbs / 928.96kg shells, 1921 Model
   Breech loading guns in turrets (on barbettes)
   on centreline ends, majority forward, 1 raised mount - superfiring
      16 - 5.50" / 140 mm guns in single mounts, 83.19lbs / 37.73kg shells, 1921 Model
   Quick firing guns in deck mounts with hoists
   on side, evenly spread, 6 raised mounts
 Weight of broadside 19,763 lbs / 8,964 kg
 Shells per gun, main battery: 90

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 10.0" / 254 mm 500.00 ft / 152.40 m 8.00 ft / 2.44 m
 Ends: Unarmoured
 Upper: 8.00" / 203 mm 500.00 ft / 152.40 m 8.00 ft / 2.44 m
   Main Belt covers 90 % of normal length
   Main belt does not fully cover magazines and engineering spaces

   - Torpedo Bulkhead:
  5.00" / 127 mm 500.00 ft / 152.40 m 32.00 ft / 9.75 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 12.0" / 305 mm 9.00" / 229 mm  12.0" / 305 mm
 2nd: 5.00" / 127 mm 3.00" / 76 mm  5.00" / 127 mm

   - Armour deck: 4.00" / 102 mm, Conning tower: 12.00" / 305 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Geared drive, 4 shafts, 208,357 shp / 155,435 Kw = 32.00 kts
 Range 6,500nm at 15.00 kts
 Bunker at max displacement = 4,516 tons

Complement:
 1,636 - 2,127

Cost:
 £11.770 million / $47.078 million

Distribution of weights at normal displacement:
 Armament: 2,470 tons, 5.1 %
 Armour: 14,767 tons, 30.4 %
    - Belts: 3,138 tons, 6.5 %
    - Torpedo bulkhead: 2,960 tons, 6.1 %
    - Armament: 3,474 tons, 7.1 %
    - Armour Deck: 4,851 tons, 10.0 %
    - Conning Tower: 344 tons, 0.7 %
 Machinery: 7,175 tons, 14.8 %
 Hull, fittings & equipment: 19,706 tons, 40.5 %
 Fuel, ammunition & stores: 4,481 tons, 9.2 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   58,995 lbs / 26,760 Kg = 28.8 x 16.0 " / 406 mm shells or 8.9 torpedoes
 Stability (Unstable if below 1.00): 1.13
 Metacentric height 7.0 ft / 2.1 m
 Roll period: 17.0 seconds
 Steadiness - As gun platform (Average = 50 %): 55 %
   - Recoil effect (Restricted arc if above 1.00): 0.70
 Seaboat quality  (Average = 1.00): 1.10

Hull form characteristics:
 Hull has a flush deck
 Block coefficient: 0.584
 Length to Beam Ratio: 7.94 : 1
 'Natural speed' for length: 29.15 kts
 Power going to wave formation at top speed: 53 %
 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:  32.00 ft / 9.75 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: 25.56 ft / 7.79 m
 Ship tends to be wet forward

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 105.8 %
  - Above water (accommodation/working, high = better): 190.8 %
 Waterplane Area: 65,559 Square feet or 6,091 Square metres
 Displacement factor (Displacement / loading): 99 %
 Structure weight / hull surface area: 212 lbs/sq ft or 1,034 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.98
  - Longitudinal: 1.21
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is adequate
 Room for accommodation and workspaces is excellent

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