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Monday, November 28, 2005

A GB/CB/1909 battlecruiser with 11in armour

Perhaps using oil-fired boilers on a British capital ship in 1909 is "cheating", but having them allows for a very potent ship. This is a small-dimension battlecruiser with 8-13.5 guns with the superfiring guns aft. The lower belt, barbettes, and turret faces are 11in thick. The deck is 3in with a 2in torpedo bulkhead. This design is much more capable than the Lion class, but probably only is due to the oil-fired boilers. I also omit armour at the ends, as the unarmoured length is relatively small. This is the Springsharp report:
GB/CB/1909, Great Britain Battlecruiser laid down 1909

Displacement:
 24,493 t light; 25,541 t standard; 29,100 t normal; 31,947 t full load

Dimensions: Length overall / water x beam x draught
 670.00 ft / 670.00 ft x 87.00 ft x 28.00 ft (normal load)
 204.22 m / 204.22 m x 26.52 m  x 8.53 m

Armament:
      8 - 13.50" / 343 mm guns (4x2 guns), 1,230.19lbs / 558.00kg shells, 1909 Model
   Breech loading guns in turrets (on barbettes)
   on centreline ends, evenly spread, 1 raised mount aft - superfiring
      16 - 4.00" / 102 mm guns in single mounts, 32.00lbs / 14.51kg shells, 1909 Model
   Quick firing guns in casemate mounts 
   on side, evenly spread, 6 raised mounts
 Weight of broadside 10,354 lbs / 4,696 kg
 Shells per gun, main battery: 80
 4 - 21.0" / 533.4 mm submerged torpedo tubes

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 11.0" / 279 mm 450.00 ft / 137.16 m 8.00 ft / 2.44 m
 Ends: Unarmoured
 Upper: 8.00" / 203 mm 450.00 ft / 137.16 m 8.00 ft / 2.44 m
   Main Belt covers 103 % of normal length

   - Torpedo Bulkhead:
  2.00" / 51 mm 450.00 ft / 137.16 m 27.00 ft / 8.23 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 11.0" / 279 mm 8.00" / 203 mm  11.0" / 279 mm
 2nd: 4.00" / 102 mm 4.00" / 102 mm  4.00" / 102 mm

   - Armour deck: 3.00" / 76 mm, Conning tower: 11.00" / 279 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Direct drive, 4 shafts, 86,024 shp / 64,174 Kw = 27.00 kts
 Range 5,400nm at 18.00 kts
 Bunker at max displacement = 6,406 tons

Complement:
 1,113 - 1,448

Cost:
 £2.492 million / $9.967 million

Distribution of weights at normal displacement:
 Armament: 1,294 tons, 4.4 %
 Armour: 8,832 tons, 30.3 %
    - Belts: 2,919 tons, 10.0 %
    - Torpedo bulkhead: 899 tons, 3.1 %
    - Armament: 2,370 tons, 8.1 %
    - Armour Deck: 2,420 tons, 8.3 %
    - Conning Tower: 224 tons, 0.8 %
 Machinery: 3,910 tons, 13.4 %
 Hull, fittings & equipment: 10,457 tons, 35.9 %
 Fuel, ammunition & stores: 4,607 tons, 15.8 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   38,281 lbs / 17,364 Kg = 31.1 x 13.5 " / 343 mm shells or 5.4 torpedoes
 Stability (Unstable if below 1.00): 1.12
 Metacentric height 5.0 ft / 1.5 m
 Roll period: 16.4 seconds
 Steadiness - As gun platform (Average = 50 %): 63 %
   - Recoil effect (Restricted arc if above 1.00): 0.75
 Seaboat quality  (Average = 1.00): 1.26

Hull form characteristics:
 Hull has rise forward of midbreak
 Block coefficient: 0.624
 Length to Beam Ratio: 7.70 : 1
 'Natural speed' for length: 25.88 kts
 Power going to wave formation at top speed: 52 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): -2.00 degrees
 Stern overhang: -2.00 ft / -0.61 m
 Freeboard (% = measuring location as a percentage of overall length):
    - Stem:  29.00 ft / 8.84 m
    - Forecastle (20 %): 25.00 ft / 7.62 m
    - Mid (67 %):  25.00 ft / 7.62 m (17.00 ft / 5.18 m aft of break)
    - Quarterdeck (15 %): 17.00 ft / 5.18 m
    - Stern:  17.00 ft / 5.18 m
    - Average freeboard: 22.68 ft / 6.91 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 102.9 %
  - Above water (accommodation/working, high = better): 170.0 %
 Waterplane Area: 43,597 Square feet or 4,050 Square metres
 Displacement factor (Displacement / loading): 108 %
 Structure weight / hull surface area: 165 lbs/sq ft or 804 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.97
  - Longitudinal: 1.36
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is adequate
 Room for accommodation and workspaces is excellent
 Good seaboat, rides out heavy weather easily

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