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Wednesday, October 25, 2006

The GB/CB/1907 Design B

I had no difficulty in making Design B for the GB/CB/1907 ship work in Springsharp. This is so much better than the Indefatigable, that you have to wonder why they built that ship, when they could have done better. Design B has a 9in armour basis, although only a 24.5-knot speed. The ship, of course, has 8-12in BLR and 16-4in QF guns. The boilers are coal-fired and the ship is propelled by turbines. This is the Springsharp report:
GB/CB/1907  Design B, Great Britain Battlecruiser laid down 1907

Displacement:
 17,800 t light; 18,622 t standard; 21,500 t normal; 23,802 t full load

Dimensions: Length overall / water x beam x draught
 575.00 ft / 575.00 ft x 79.00 ft x 26.50 ft (normal load)
 175.26 m / 175.26 m x 24.08 m  x 8.08 m

Armament:
      4 - 12.00" / 305 mm guns (2x2 guns), 864.00lbs / 391.90kg shells, 1907 Model
   Breech loading guns in turrets (on barbettes)
   on centreline ends, evenly spread
      4 - 12.00" / 305 mm guns (2x2 guns), 864.00lbs / 391.90kg shells, 1907 Model
   Breech loading guns in turrets (on barbettes)
   on side, all amidships
      16 - 4.00" / 102 mm guns in single mounts, 32.00lbs / 14.51kg shells, 1907 Model
   Quick firing guns in casemate mounts 
   on side, evenly spread, 8 raised mounts
 Weight of broadside 7,424 lbs / 3,367 kg
 Shells per gun, main battery: 90
 3 - 18.0" / 457.2 mm submerged torpedo tubes

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 9.00" / 229 mm 400.00 ft / 121.92 m 8.00 ft / 2.44 m
 Ends: 4.00" / 102 mm 100.00 ft / 30.48 m 8.00 ft / 2.44 m
   75.00 ft / 22.86 m Unarmoured ends
 Upper: 6.00" / 152 mm 400.00 ft / 121.92 m 8.00 ft / 2.44 m
   Main Belt covers 107 % of normal length
   Main belt does not fully cover magazines and engineering spaces

   - Torpedo Bulkhead:
  1.50" / 38 mm 400.00 ft / 121.92 m 26.50 ft / 8.08 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 9.00" / 229 mm 6.00" / 152 mm  9.00" / 229 mm
 2nd: 9.00" / 229 mm 6.00" / 152 mm  9.00" / 229 mm
 3rd: 4.00" / 102 mm 4.00" / 102 mm  4.00" / 102 mm

   - Armour deck: 2.00" / 51 mm, Conning tower: 9.00" / 229 mm

Machinery:
 Coal fired boilers, steam turbines, 
 Direct drive, 4 shafts, 51,677 shp / 38,551 Kw = 24.50 kts
 Range 5,200nm at 15.00 kts
 Bunker at max displacement = 5,181 tons (100% coal)

Complement:
 887 - 1,154

Cost:
 £1.855 million / $7.419 million

Distribution of weights at normal displacement:
 Armament: 928 tons, 4.3 %
 Armour: 5,823 tons, 27.1 %
    - Belts: 2,163 tons, 10.1 %
    - Torpedo bulkhead: 588 tons, 2.7 %
    - Armament: 1,663 tons, 7.7 %
    - Armour Deck: 1,258 tons, 5.9 %
    - Conning Tower: 150 tons, 0.7 %
 Machinery: 3,230 tons, 15.0 %
 Hull, fittings & equipment: 7,819 tons, 36.4 %
 Fuel, ammunition & stores: 3,700 tons, 17.2 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   28,150 lbs / 12,769 Kg = 32.6 x 12.0 " / 305 mm shells or 3.9 torpedoes
 Stability (Unstable if below 1.00): 1.14
 Metacentric height 4.5 ft / 1.4 m
 Roll period: 15.7 seconds
 Steadiness - As gun platform (Average = 50 %): 73 %
   - Recoil effect (Restricted arc if above 1.00): 0.79
 Seaboat quality  (Average = 1.00): 1.45

Hull form characteristics:
 Hull has rise forward of midbreak
 Block coefficient: 0.625
 Length to Beam Ratio: 7.28 : 1
 'Natural speed' for length: 23.98 kts
 Power going to wave formation at top speed: 51 %
 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:  28.00 ft / 8.53 m
    - Forecastle (20 %): 25.00 ft / 7.62 m
    - Mid (70 %):  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): 111.6 %
  - Above water (accommodation/working, high = better): 169.1 %
 Waterplane Area: 34,009 Square feet or 3,160 Square metres
 Displacement factor (Displacement / loading): 109 %
 Structure weight / hull surface area: 153 lbs/sq ft or 746 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.94
  - Longitudinal: 1.80
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is cramped
 Room for accommodation and workspaces is excellent
 Ship has slow, easy roll, a good, steady gun platform
 Good seaboat, rides out heavy weather easily

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