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Friday, March 13, 2009

The Ger/CB/1905 design

This version of the Ger/CB/1905 design is very faithful to the original concept. Everything about it is accurate, based on my early 1971 drawings that show the size and thickness of the armour and freeboard. The ship is a 31 knot light battlecruiser with 4-12in/45 and 12-4in QF guns. The armour basis is 4in, with some components protected with up to 9in of armour. This is the Springsharp report:
Ger/CB/1905, Germany Battlecruiser laid down 1905 (Engine 1909)

Displacement:
 18,281 t light; 18,900 t standard; 20,808 t normal; 22,335 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
 (702.00 ft / 700.00 ft) x 80.00 ft x (24.40 / 25.79 ft)
 (213.97 m / 213.36 m) x 24.38 m  x (7.44 / 7.86 m)

Armament:
      4 - 12.00" / 305 mm 45.0 cal guns - 850.00lbs / 385.55kg shells, 90 per gun
   Breech loading guns in turret on barbette mounts, 1905 Model
   2 x Twin mounts on centreline ends, evenly spread
      12 - 4.00" / 102 mm 50.0 cal guns - 32.00lbs / 14.51kg shells, 150 per gun
   Quick firing guns in deck and hoist mounts, 1905 Model
   6 x Single mounts on sides, forward deck aft
   6 x Single mounts on sides, aft deck forward
      Weight of broadside 3,784 lbs / 1,716 kg

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 4.00" / 102 mm 380.00 ft / 115.82 m 8.00 ft / 2.44 m
 Ends: Unarmoured
 Upper: 3.00" / 76 mm 380.00 ft / 115.82 m 8.00 ft / 2.44 m
   Main Belt covers 84 % of normal length
   Main belt does not fully cover magazines and engineering spaces

   - Torpedo Bulkhead - Additional damage containing bulkheads:
  1.00" / 25 mm 380.00 ft / 115.82 m 24.40 ft / 7.44 m
 Beam between torpedo bulkheads 59.00 ft / 17.98 m

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

   - Armoured deck - multiple decks:
 For and Aft decks: 3.00" / 76 mm
 Forecastle: 3.00" / 76 mm  Quarter deck: 3.00" / 76 mm

   - Conning towers: Forward 9.00" / 229 mm, Aft 4.00" / 102 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Direct drive, 4 shafts, 113,127 shp / 84,392 Kw = 31.00 kts
 Range 5,400nm at 15.00 kts
 Bunker at max displacement = 3,436 tons

Complement:
 866 - 1,126

Cost:
 £1.729 million / $6.915 million

Distribution of weights at normal displacement:
 Armament: 744 tons, 3.6 %
    - Guns: 744 tons, 3.6 %
 Armour: 4,571 tons, 22.0 %
    - Belts: 917 tons, 4.4 %
    - Torpedo bulkhead: 343 tons, 1.6 %
    - Armament: 952 tons, 4.6 %
    - Armour Deck: 2,148 tons, 10.3 %
    - Conning Towers: 212 tons, 1.0 %
 Machinery: 5,142 tons, 24.7 %
 Hull, fittings & equipment: 7,823 tons, 37.6 %
 Fuel, ammunition & stores: 2,527 tons, 12.1 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   28,663 lbs / 13,001 Kg = 33.2 x 12.0 " / 305 mm shells or 3.3 torpedoes
 Stability (Unstable if below 1.00): 1.23
 Metacentric height 5.3 ft / 1.6 m
 Roll period: 14.7 seconds
 Steadiness - As gun platform (Average = 50 %): 65 %
   - Recoil effect (Restricted arc if above 1.00): 0.40
 Seaboat quality  (Average = 1.00): 1.30

Hull form characteristics:
 Hull has low quarterdeck ,
   a ram bow and a cruiser stern
 Block coefficient (normal/deep): 0.533 / 0.541
 Length to Beam Ratio: 8.75 : 1
 'Natural speed' for length: 26.46 kts
 Power going to wave formation at top speed: 53 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): -2.00 degrees
 Stern overhang: -2.00 ft / -0.61 m
 Freeboard (% = length of deck as a percentage of waterline length):
    Fore end,  Aft end
    - Forecastle: 20.00 %,  28.00 ft / 8.53 m,  27.00 ft / 8.23 m
    - Forward deck: 30.00 %,  27.00 ft / 8.23 m,  26.00 ft / 7.92 m
    - Aft deck: 15.00 %,  26.00 ft / 7.92 m,  26.00 ft / 7.92 m
    - Quarter deck: 35.00 %,  18.00 ft / 5.49 m,  19.00 ft / 5.79 m
    - Average freeboard:  23.81 ft / 7.26 m
 Ship tends to be wet forward

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 130.7 %
  - Above water (accommodation/working, high = better): 222.8 %
 Waterplane Area: 38,465 Square feet or 3,574 Square metres
 Displacement factor (Displacement / loading): 113 %
 Structure weight / hull surface area: 139 lbs/sq ft or 680 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.97
  - Longitudinal: 1.34
  - Overall: 1.00
 Cramped machinery, storage, compartmentation space
 Excellent accommodation and workspace room
 Good seaboat, rides out heavy weather easily

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