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Monday, December 25, 2006

The sort of ship that the British worried about: the Ger/CB/1918

Admiral Jellicoe worried about German ships armed with 17in guns. Even the Hood class ships seemed inadequate compared to such battlecruisers (particularly). I thought that I would try a battlecruiser design with 8-17in (43cm) and with a 32 knot speed. My dimensions are 820ft x 111.5ft x 32.8ft. The lower belt is 12.6in and the deck is 4.1in. The Germans had to use coal-fired boilers, due to their strategic situation. This is the Springsharp report:
Ger/CB/1918, Germany Battlecruiser laid down 1918 (Engine 1927)

Displacement:
 48,686 t light; 50,841 t standard; 54,700 t normal; 57,788 t full load

Dimensions: Length overall / water x beam x draught
 821.58 ft / 820.21 ft x 111.55 ft x 32.81 ft (normal load)
 250.42 m / 250.00 m x 34.00 m  x 10.00 m

Armament:
      8 - 16.93" / 430 mm guns (4x2 guns), 2,425.91lbs / 1,100.37kg shells, 1918 Model
   Breech loading guns in turrets (on barbettes)
   on centreline ends, evenly spread, 2 raised mounts - superfiring
      12 - 5.91" / 150 mm guns in single mounts, 102.98lbs / 46.71kg shells, 1918 Model
   Quick firing guns in casemate mounts 
   on side, all amidships
   12 guns in hull casemates - Limited use in heavy seas
      8 - 4.13" / 105 mm guns in single mounts, 35.32lbs / 16.02kg shells, 1918 Model
   Anti-aircraft guns in deck mounts 
   on side, evenly spread, all raised mounts
 Weight of broadside 20,926 lbs / 9,492 kg
 Shells per gun, main battery: 90
 5 - 23.6" / 600 mm submerged torpedo tubes

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 12.6" / 320 mm 590.55 ft / 180.00 m 9.84 ft / 3.00 m
 Ends: 3.94" / 100 mm 131.23 ft / 40.00 m 9.84 ft / 3.00 m
   98.43 ft / 30.00 m Unarmoured ends
 Upper: 9.45" / 240 mm 590.55 ft / 180.00 m 9.84 ft / 3.00 m
   Main Belt covers 111 % of normal length

   - Torpedo Bulkhead:
  2.36" / 60 mm 590.55 ft / 180.00 m 32.81 ft / 10.00 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 12.6" / 320 mm 7.87" / 200 mm  11.8" / 300 mm
 2nd: 5.91" / 150 mm 5.91" / 150 mm  1.97" / 50 mm

   - Armour deck: 4.13" / 105 mm, Conning tower: 13.78" / 350 mm

Machinery:
 Coal fired boilers, steam turbines, 
 Geared drive, 4 shafts, 235,264 shp / 175,507 Kw = 32.00 kts
 Range 10,000nm at 13.00 kts
 Bunker at max displacement = 6,947 tons (100% coal)

Complement:
 1,787 - 2,324

Cost:
 £10.090 million / $40.359 million

Distribution of weights at normal displacement:
 Armament: 2,616 tons, 4.8 %
 Armour: 17,047 tons, 31.2 %
    - Belts: 5,612 tons, 10.3 %
    - Torpedo bulkhead: 1,693 tons, 3.1 %
    - Armament: 4,014 tons, 7.3 %
    - Armour Deck: 5,300 tons, 9.7 %
    - Conning Tower: 428 tons, 0.8 %
 Machinery: 8,169 tons, 14.9 %
 Hull, fittings & equipment: 20,855 tons, 38.1 %
 Fuel, ammunition & stores: 6,014 tons, 11.0 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   67,262 lbs / 30,509 Kg = 27.7 x 16.9 " / 430 mm shells or 8.9 torpedoes
 Stability (Unstable if below 1.00): 1.12
 Metacentric height 7.3 ft / 2.2 m
 Roll period: 17.3 seconds
 Steadiness - As gun platform (Average = 50 %): 53 %
   - Recoil effect (Restricted arc if above 1.00): 0.70
 Seaboat quality  (Average = 1.00): 1.06

Hull form characteristics:
 Hull has rise forward of midbreak
 Block coefficient: 0.638
 Length to Beam Ratio: 7.35 : 1
 'Natural speed' for length: 28.64 kts
 Power going to wave formation at top speed: 56 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): 2.00 degrees
 Stern overhang: -9.84 ft / -3.00 m
 Freeboard (% = measuring location as a percentage of overall length):
    - Stem:  39.37 ft / 12.00 m
    - Forecastle (20 %): 31.17 ft / 9.50 m
    - Mid (64 %):  31.17 ft / 9.50 m (21.33 ft / 6.50 m aft of break)
    - Quarterdeck (15 %): 21.33 ft / 6.50 m
    - Stern:  21.33 ft / 6.50 m
    - Average freeboard: 28.28 ft / 8.62 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 105.6 %
  - Above water (accommodation/working, high = better): 206.8 %
 Waterplane Area: 69,307 Square feet or 6,439 Square metres
 Displacement factor (Displacement / loading): 101 %
 Structure weight / hull surface area: 213 lbs/sq ft or 1,038 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.97
  - Longitudinal: 1.37
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is adequate
 Room for accommodation and workspaces is excellent

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