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Wednesday, November 30, 2005

A compact analog to the Hood

The next obvious step was a 15in-gun battlecruiser with 12in armour. I continued the practice of reducing dimensions to obtain greater strength. I had to increase the beam due to stability and recoil issues. I kept the soft ends and a thicker lower belt and thinner upper belt. This is sort of a more heavily armed and armoured Renown. I also settled for a lower speed to keep the size reasonable. The secondary armament is transitional, with twin 4in QF mounts. This is the Springsharp report:
GB/CB/1915, Great Britain Battlecruiser laid down 1915

Displacement:
 32,975 t light; 34,446 t standard; 37,750 t normal; 40,393 t full load

Dimensions: Length overall / water x beam x draught
 780.00 ft / 780.00 ft x 95.00 ft x 29.00 ft (normal load)
 237.74 m / 237.74 m x 28.96 m  x 8.84 m

Armament:
      8 - 15.00" / 381 mm guns (4x2 guns), 1,920.00lbs / 870.90kg shells, 1915 Model
   Breech loading guns in turrets (on barbettes)
   on centreline ends, evenly spread, 2 raised mounts - superfiring
      16 - 4.00" / 102 mm guns (8x2 guns), 32.00lbs / 14.51kg shells, 1915 Model
   Quick firing guns in deck mounts with hoists
   on side, evenly spread, 6 raised mounts
      2 - 4.00" / 102 mm guns in single mounts, 32.00lbs / 14.51kg shells, 1915 Model
   Anti-aircraft guns in deck mounts 
   on side, evenly spread, all raised mounts
      16 - 1.57" / 40.0 mm guns (4x4 guns), 2.00lbs / 0.91kg shells, 1915 Model
   Anti-aircraft guns in deck mounts 
   on side, evenly spread
 Weight of broadside 15,968 lbs / 7,243 kg
 Shells per gun, main battery: 80
 4 - 21.0" / 533.4 mm submerged torpedo tubes

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 12.0" / 305 mm 570.00 ft / 173.74 m 8.00 ft / 2.44 m
 Ends: Unarmoured
 Upper: 8.00" / 203 mm 570.00 ft / 173.74 m 8.00 ft / 2.44 m
   Main Belt covers 112 % of normal length

   - Torpedo Bulkhead:
  2.00" / 51 mm 570.00 ft / 173.74 m 28.00 ft / 8.53 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: 4.00" / 102 mm 4.00" / 102 mm  4.00" / 102 mm

   - Armour deck: 3.00" / 76 mm, Conning tower: 12.00" / 305 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Geared drive, 4 shafts, 125,717 shp / 93,785 Kw = 29.00 kts
 Range 5,600nm at 18.00 kts
 Bunker at max displacement = 5,946 tons

Complement:
 1,353 - 1,760

Cost:
 £4.803 million / $19.212 million

Distribution of weights at normal displacement:
 Armament: 1,763 tons, 4.7 %
 Armour: 11,398 tons, 30.2 %
    - Belts: 3,807 tons, 10.1 %
    - Torpedo bulkhead: 1,181 tons, 3.1 %
    - Armament: 3,070 tons, 8.1 %
    - Armour Deck: 3,050 tons, 8.1 %
    - Conning Tower: 291 tons, 0.8 %
 Machinery: 4,762 tons, 12.6 %
 Hull, fittings & equipment: 15,051 tons, 39.9 %
 Fuel, ammunition & stores: 4,775 tons, 12.7 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   49,031 lbs / 22,240 Kg = 29.1 x 15.0 " / 381 mm shells or 6.9 torpedoes
 Stability (Unstable if below 1.00): 1.08
 Metacentric height 5.4 ft / 1.6 m
 Roll period: 17.2 seconds
 Steadiness - As gun platform (Average = 50 %): 58 %
   - Recoil effect (Restricted arc if above 1.00): 0.90
 Seaboat quality  (Average = 1.00): 1.16

Hull form characteristics:
 Hull has rise forward of midbreak
 Block coefficient: 0.615
 Length to Beam Ratio: 8.21 : 1
 'Natural speed' for length: 27.93 kts
 Power going to wave formation at top speed: 50 %
 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 (% = measuring location as a percentage of overall length):
    - Stem:  31.00 ft / 9.45 m
    - Forecastle (20 %): 25.00 ft / 7.62 m
    - Mid (67 %):  25.00 ft / 7.62 m (17.00 ft / 5.18 m aft of break)
    - Quarterdeck (15 %): 17.00 ft / 5.18 m
    - Stern:  17.00 ft / 5.18 m
    - Average freeboard: 22.84 ft / 6.96 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 98.8 %
  - Above water (accommodation/working, high = better): 176.3 %
 Waterplane Area: 54,951 Square feet or 5,105 Square metres
 Displacement factor (Displacement / loading): 108 %
 Structure weight / hull surface area: 193 lbs/sq ft or 943 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.99
  - Longitudinal: 1.13
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is adequate
 Room for accommodation and workspaces is excellent

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