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Friday, April 28, 2006

From the Red Book, the Ger/CB/1915 design

There are many Ger/CB/1915 designs in the Red Book, but this is the first one, and is rather unique. There is a scale drawing and pretty complete specifications, although only a weight, for protection. This was intended to be a 37,500 ton ship with 6-16in BLR and 12-6in QF guns. The over-optimistic speed was 36 knots. I was able to keep the ship in line with the dimensions and displacement, while achieving a decent protection and speed. The actual speed is 33 knots, with a 5,600nm range at 15 knots. This is a ship focused on North Sea fighting, so a great range is unnecessary. The armour basis is 11in, so the ship is well-protected. The original concept had 40 SHP/ton machinery. This only has 31.68 SHP/ton machinery. The drawing shows a ship with a long forecastle and three twin turrets, with two forward. There are three rather small stacks. The bridge and foremast are closely integrated and are substantial. The mainmast has a derrick, and has tripod legs. This is the Springsharp report:
Ger/CB/1915, Germany Battlecruiser laid down 1915 (Engine 1927)

Displacement:
 35,456 t light; 36,920 t standard; 38,700 t normal; 40,124 t full load

Dimensions: Length overall / water x beam x draught
 787.50 ft / 787.50 ft x 98.00 ft x 31.00 ft (normal load)
 240.03 m / 240.03 m x 29.87 m  x 9.45 m

Armament:
     6 - 16.00" / 406 mm guns (3x2 guns), 2,048.00lbs / 928.96kg shells, 1915 Model
   Breech loading guns in turrets (on barbettes)
   on centreline ends, majority forward, 1 raised mount - superfiring
     12 - 6.00" / 152 mm guns in single mounts, 108.00lbs / 48.99kg shells, 1915 Model
   Quick firing guns in deck mounts with hoists
   on centreline, all amidships, 2 raised mounts - superfiring
 Weight of broadside 13,584 lbs / 6,162 kg
 Shells per gun, main battery: 90

Armour:
  - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 11.0" / 279 mm 455.00 ft / 138.68 m 9.00 ft / 2.74 m
 Ends: 5.00" / 127 mm 260.00 ft / 79.25 m 17.00 ft / 5.18 m
   72.50 ft / 22.10 m Unarmoured ends
 Upper: 8.00" / 203 mm 455.00 ft / 138.68 m 8.00 ft / 2.44 m
   Main Belt covers 89 % of normal length
   Main belt does not fully cover magazines and engineering spaces

  - Torpedo Bulkhead:
  3.00" / 76 mm 455.00 ft / 138.68 m 30.00 ft / 9.14 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: 3.00" / 76 mm 3.00" / 76 mm  3.00" / 76 mm

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

Machinery:
 Oil fired boilers, steam turbines,
 Geared drive, 4 shafts, 208,649 shp / 155,652 Kw = 33.00 kts
 Range 5,600nm at 15.00 kts
 Bunker at max displacement = 3,204 tons

Complement:
 1,379 - 1,793

Cost:
 £5.221 million / $20.883 million

Distribution of weights at normal displacement:
 Armament: 1,698 tons, 4.4 %
 Armour: 11,473 tons, 29.6 %
    - Belts: 4,051 tons, 10.5 %
    - Torpedo bulkhead: 1,515 tons, 3.9 %
    - Armament: 2,601 tons, 6.7 %
    - Armour Deck: 3,035 tons, 7.8 %
    - Conning Tower: 271 tons, 0.7 %
 Machinery: 6,586 tons, 17.0 %
 Hull, fittings & equipment: 15,699 tons, 40.6 %
 Fuel, ammunition & stores: 3,244 tons, 8.4 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   47,584 lbs / 21,584 Kg = 23.2 x 16.0 " / 406 mm shells or 6.3 torpedoes
 Stability (Unstable if below 1.00): 1.09
 Metacentric height 5.7 ft / 1.7 m
 Roll period: 17.3 seconds
 Steadiness - As gun platform (Average = 50 %): 53 %
   - Recoil effect (Restricted arc if above 1.00): 0.74
 Seaboat quality  (Average = 1.00): 1.02

Hull form characteristics:
 Hull has rise forward of midbreak
 Block coefficient: 0.566
 Length to Beam Ratio: 8.04 : 1
 'Natural speed' for length: 28.06 kts
 Power going to wave formation at top speed: 56 %
 Trim (Max stability = 0, Max steadiness = 100): 52
 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:  33.00 ft / 10.06 m
    - Forecastle (20 %): 29.00 ft / 8.84 m
    - Mid (67 %):  29.00 ft / 8.84 m (21.00 ft / 6.40 m aft of break)
    - Quarterdeck (15 %): 21.00 ft / 6.40 m
    - Stern:  21.00 ft / 6.40 m
    - Average freeboard: 26.68 ft / 8.13 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 110.8 %
  - Above water (accommodation/working, high = better): 202.3 %
 Waterplane Area: 54,683 Square feet or 5,080 Square metres
 Displacement factor (Displacement / loading): 101 %
 Structure weight / hull surface area: 193 lbs/sq ft or 944 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

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