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Wednesday, June 14, 2006

The Ger/CB/1915 design

The Ger/CB/1915 design dates from work I did in about 1973, judging by the drawing. This was intended to be a Hood sort of ship, except with 9-16.5in guns in triple turrets. The secondary armament is a rather light 10-6in QF guns. The armour basis is 12in. I tried to obtain the power, machinery weight, and protection weight in the original specification. For 200,000 SHP, I was only able to reach 31.5 knots, not 33 knots. Partly, this is due to the greater displacement and draft, over what was originally specified. The original concept had a 45,000 ton Standard displacement, while this design is 48,358 tons Standard. I also had to increase the draft from 30.3ft to 32ft to obtain adequate strength. This is the Sprinsharp report:
Ger/CB/1915, Germany Battle Cruiser laid down 1915 (Engine 1927)

Displacement:
 46,254 t light; 48,358 t standard; 51,500 t normal; 54,014 t full load

Dimensions: Length overall / water x beam x draught
 852.45 ft / 850.00 ft x 110.00 ft x 32.00 ft (normal load)
 259.83 m / 259.08 m x 33.53 m  x 9.75 m

Armament:
      9 - 16.50" / 419 mm guns (3x3 guns), 2,246.06lbs / 1,018.80kg shells, 1915 Model
   Breech loading guns in turrets (on barbettes)
   on centreline ends, majority forward, 1 raised mount - superfiring
      10 - 6.00" / 152 mm guns in single mounts, 108.00lbs / 48.99kg shells, 1915 Model
   Quick firing guns in deck mounts with hoists
   on side, all amidships, 2 raised mounts - superfiring
 Weight of broadside 21,295 lbs / 9,659 kg
 Shells per gun, main battery: 90

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 12.0" / 305 mm 467.00 ft / 142.34 m 17.00 ft / 5.18 m
 Ends: Unarmoured
   Main Belt covers 85 % of normal length
   Main belt does not fully cover magazines and engineering spaces

   - Torpedo Bulkhead:
  4.00" / 102 mm 467.00 ft / 142.34 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: 6.00" / 152 mm 6.00" / 152 mm  6.00" / 152 mm

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

Machinery:
 Oil fired boilers, steam turbines, 
 Geared drive, 4 shafts, 205,354 shp / 153,194 Kw = 31.50 kts
 Range 8,500nm at 15.00 kts
 Bunker at max displacement = 5,656 tons

Complement:
 1,709 - 2,222

Cost:
 £6.927 million / $27.708 million

Distribution of weights at normal displacement:
 Armament: 2,662 tons, 5.2 %
 Armour: 15,706 tons, 30.5 %
    - Belts: 4,225 tons, 8.2 %
    - Torpedo bulkhead: 2,212 tons, 4.3 %
    - Armament: 3,840 tons, 7.5 %
    - Armour Deck: 5,072 tons, 9.8 %
    - Conning Tower: 358 tons, 0.7 %
 Machinery: 6,482 tons, 12.6 %
 Hull, fittings & equipment: 21,404 tons, 41.6 %
 Fuel, ammunition & stores: 5,246 tons, 10.2 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   70,313 lbs / 31,893 Kg = 31.3 x 16.5 " / 419 mm shells or 10.4 torpedoes
 Stability (Unstable if below 1.00): 1.13
 Metacentric height 7.2 ft / 2.2 m
 Roll period: 17.2 seconds
 Steadiness - As gun platform (Average = 50 %): 59 %
   - Recoil effect (Restricted arc if above 1.00): 0.78
 Seaboat quality  (Average = 1.00): 1.18

Hull form characteristics:
 Hull has rise forward of midbreak
 Block coefficient: 0.602
 Length to Beam Ratio: 7.73 : 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: -1.00 ft / -0.30 m
 Freeboard (% = measuring location as a percentage of overall length):
    - Stem:  35.00 ft / 10.67 m
    - Forecastle (20 %): 30.00 ft / 9.14 m
    - Mid (66 %):  30.00 ft / 9.14 m (22.00 ft / 6.71 m aft of break)
    - Quarterdeck (15 %): 22.00 ft / 6.71 m
    - Stern:  22.00 ft / 6.71 m
    - Average freeboard: 27.68 ft / 8.44 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 97.4 %
  - Above water (accommodation/working, high = better): 211.3 %
 Waterplane Area: 68,540 Square feet or 6,368 Square metres
 Displacement factor (Displacement / loading): 103 %
 Structure weight / hull surface area: 220 lbs/sq ft or 1,073 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.97
  - Longitudinal: 1.35
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is adequate
 Room for accommodation and workspaces is excellent

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