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Monday, September 24, 2007

I have had this concept for a long time: Ger/CA/1918 fast

I have had this concept, since the early 1970's, for a fast armoured cruiser, often cast as a German ship. The look, though, is more like the Dunkerque or the Richelieu ships. In this case, the freeboard is high, with a lower quarterdeck. I gave the ship a secondary armament that is heavier than I usually use (8-5.1in guns). The main armament, as usual, is in two turrets forward. In this case, there are 6-9.4in guns. The guns would all be high-velocity, and have long barrels. They really are more like 1880's belted cruisers than the armoured cruisers of the early 20th Century. This is the Springsharp report:
Ger/CA/1918 Fast, Germany Armoured Cruiser laid down 1918 (Engine 1950)

Displacement:
 19,760 t light; 20,465 t standard; 21,592 t normal; 22,494 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
 (743.91 ft / 734.00 ft) x 78.00 ft x (24.00 / 24.79 ft)
 (226.75 m / 223.72 m) x 23.77 m  x (7.32 / 7.56 m)

Armament:
      6 - 9.40" / 239 mm 55.0 cal guns - 448.26lbs / 203.33kg shells, 150 per gun
   Breech loading guns in turret on barbette mounts, 1918 Model
   2 x Triple mounts on centreline, forward deck forward
  1 raised mount - superfiring
      8 - 5.10" / 130 mm 65.0 cal guns - 73.54lbs / 33.36kg shells, 150 per gun
   Quick firing guns in deck and hoist mounts, 1918 Model
   4 x Twin mounts on sides, aft deck forward
  4 raised mounts
      Weight of broadside 3,278 lbs / 1,487 kg

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 5.00" / 127 mm 480.00 ft / 146.30 m 12.00 ft / 3.66 m
 Ends: Unarmoured
   Main Belt covers 101 % of normal length
   Main belt does not fully cover magazines and engineering spaces

   - Torpedo Bulkhead:
  1.00" / 25 mm 480.00 ft / 146.30 m 24.00 ft / 7.32 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 5.00" / 127 mm 3.00" / 76 mm  5.00" / 127 mm
 2nd: 4.00" / 102 mm 2.00" / 51 mm  4.00" / 102 mm

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

   - Conning towers: Forward 5.00" / 127 mm,  Aft 0.00" / 0 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Geared drive, 4 shafts, 232,297 shp / 173,293 Kw = 37.00 kts
 Range 5,400nm at 16.00 kts
 Bunker at max displacement = 2,030 tons

Complement:
 889 - 1,157

Cost:
 £3.716 million / $14.864 million

Distribution of weights at normal displacement:
 Armament: 915 tons, 4.2 %
 Armour: 4,508 tons, 20.9 %
    - Belts: 1,188 tons, 5.5 %
    - Torpedo bulkhead: 426 tons, 2.0 %
    - Armament: 577 tons, 2.7 %
    - Armour Deck: 2,233 tons, 10.3 %
    - Conning Tower: 84 tons, 0.4 %
 Machinery: 5,557 tons, 25.7 %
 Hull, fittings & equipment: 8,779 tons, 40.7 %
 Fuel, ammunition & stores: 1,833 tons, 8.5 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   28,662 lbs / 13,001 Kg = 69.0 x 9.4 " / 239 mm shells or 3.2 torpedoes
 Stability (Unstable if below 1.00): 1.11
 Metacentric height 4.2 ft / 1.3 m
 Roll period: 16.0 seconds
 Steadiness - As gun platform (Average = 50 %): 63 %
   - Recoil effect (Restricted arc if above 1.00): 0.52
 Seaboat quality  (Average = 1.00): 1.27

Hull form characteristics:
 Hull has rise forward of midbreak,
   an extended bulbous bow and a cruiser stern
 Block coefficient (normal/deep): 0.550 / 0.555
 Length to Beam Ratio: 9.41 : 1
 'Natural speed' for length: 27.09 kts
 Power going to wave formation at top speed: 61 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): 15.00 degrees
 Stern overhang: -2.00 ft / -0.61 m
 Freeboard (% = length of deck as a percentage of waterline length):
    Fore end,  Aft end
    - Forecastle: 35.00 %,  37.00 ft / 11.28 m,  32.00 ft / 9.75 m
    - Forward deck: 32.00 %,  32.00 ft / 9.75 m,  32.00 ft / 9.75 m
    - Aft deck: 18.00 %,  24.00 ft / 7.32 m,  24.00 ft / 7.32 m
    - Quarter deck: 15.00 %,  24.00 ft / 7.32 m,  24.00 ft / 7.32 m
    - Average freeboard:  30.06 ft / 9.16 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 134.7 %
  - Above water (accommodation/working, high = better): 249.3 %
 Waterplane Area: 39,956 Square feet or 3,712 Square metres
 Displacement factor (Displacement / loading): 112 %
 Structure weight / hull surface area: 136 lbs/sq ft or 662 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.92
  - Longitudinal: 2.08
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is cramped
 Room for accommodation and workspaces is excellent
 Good seaboat, rides out heavy weather easily

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