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Saturday, May 28, 2005

Another cut at the GB/BB/1906 design

Given what I learned yesterday, I updated my design for the GB/BB/1905 (Britannia class). My friend Cliff assumed that he would need to sacrifice gunpower in exchange for thicker armor and higher speed. This is in the series that has all oil fuel early, and has greater machinery power output. The only reason that the displacement is higher is due to the thick deck armor. The dimensions are 680ft x 87.7ft x 28ft. The armament is 6-12in/45 and 8-6in/50 QF. The armor basis is 13.75in, although it is on an "all-or-nothing" basis. The designed speed is 24 knots. Needless to say, it turned out quite nicely. This is the Springsharp report:
GB/BB/1906, Great Britain Battlecruiser laid down 1905 (Engine 1912)

Displacement:
 23,604 t light; 24,448 t standard; 27,099 t normal; 29,219 t full load

Dimensions: Length overall / water x beam x draught
 680.00 ft / 680.00 ft x 87.70 ft x 28.00 ft (normal load)
 207.26 m / 207.26 m x 26.73 m  x 8.53 m

Armament:
      6 - 12.00" / 305 mm guns (3x2 guns), 850.00lbs / 385.55kg shells, 1905 Model
   Breech loading guns in turrets (on barbettes)
   on centreline ends, majority forward, 1 raised mount - superfiring
      8 - 6.00" / 152 mm guns (4x2 guns), 100.00lbs / 45.36kg shells, 1905 Model
   Quick firing guns in turrets (on barbettes)
   on side, evenly spread
 Weight of broadside 5,900 lbs / 2,676 kg
 Shells per gun, main battery: 90

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 13.8" / 349 mm 450.00 ft / 137.16 m 18.00 ft / 5.49 m
 Ends: Unarmoured
   Main Belt covers 102 % of normal length

   - Torpedo Bulkhead:
  1.50" / 38 mm 450.00 ft / 137.16 m 26.00 ft / 7.92 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 13.8" / 349 mm 7.00" / 178 mm  13.8" / 349 mm
 2nd: 3.38" / 86 mm 3.00" / 76 mm  3.38" / 86 mm

   - Armour deck: 4.50" / 114 mm, Conning tower: 6.75" / 171 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Direct drive, 4 shafts, 50,984 shp / 38,034 Kw = 24.00 kts
 Range 7,500nm at 15.00 kts
 Bunker at max displacement = 4,771 tons

Complement:
 1,055 - 1,372

Cost:
 £1.746 million / $6.983 million

Distribution of weights at normal displacement:
 Armament: 756 tons, 2.8 %
 Armour: 11,235 tons, 41.5 %
    - Belts: 4,749 tons, 17.5 %
    - Torpedo bulkhead: 649 tons, 2.4 %
    - Armament: 2,182 tons, 8.1 %
    - Armour Deck: 3,524 tons, 13.0 %
    - Conning Tower: 131 tons, 0.5 %
 Machinery: 2,033 tons, 7.5 %
 Hull, fittings & equipment: 9,581 tons, 35.4 %
 Fuel, ammunition & stores: 3,494 tons, 12.9 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   64,484 lbs / 29,249 Kg = 74.6 x 12.0 " / 305 mm shells or 11.7 torpedoes
 Stability (Unstable if below 1.00): 1.10
 Metacentric height 4.9 ft / 1.5 m
 Roll period: 16.7 seconds
 Steadiness - As gun platform (Average = 50 %): 93 %
   - Recoil effect (Restricted arc if above 1.00): 0.63
 Seaboat quality  (Average = 1.00): 1.86

Hull form characteristics:
 Hull has rise forward of midbreak
 Block coefficient: 0.568
 Length to Beam Ratio: 7.75 : 1
 'Natural speed' for length: 26.08 kts
 Power going to wave formation at top speed: 43 %
 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 %): 27.00 ft / 8.23 m
    - Mid (67 %):  27.00 ft / 8.23 m (19.00 ft / 5.79 m aft of break)
    - Quarterdeck (15 %): 19.00 ft / 5.79 m
    - Stern:  19.00 ft / 5.79 m
    - Average freeboard: 24.68 ft / 7.52 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 59.9 %
  - Above water (accommodation/working, high = better): 189.4 %
 Waterplane Area: 42,328 Square feet or 3,932 Square metres
 Displacement factor (Displacement / loading): 127 %
 Structure weight / hull surface area: 151 lbs/sq ft or 737 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.95
  - Longitudinal: 1.57
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is excellent
 Room for accommodation and workspaces is excellent
 Ship has slow, easy roll, a good, steady gun platform
 Excellent seaboat, comfortable, can fire her guns in the heaviest weather

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