Amazon Ad

Monday, October 09, 2006

Another try at the GB/CA/1921d design

The GB/CA/1921d design is only viable with extremely lightweight machinery. The machinery is 39.6 SHP/ton. The ship is heavier than the original Standard displacement of 24,500 tons. The ship ended up at 27,287 tons Standard. The armament is 9-10in BLR, 12-5.5in QF, and 6-4.7in AA guns. The speed is great, at 37 knots. This is the Springsharp report:
GB/CA/1921d, Great Britain Armoured Cruiser laid down 1921 (Engine 1945)

Displacement:
 26,355 t light; 27,287 t standard; 29,800 t normal; 31,810 t full load

Dimensions: Length overall / water x beam x draught
 838.32 ft / 835.00 ft x 82.00 ft x 25.50 ft (normal load)
 255.52 m / 254.51 m x 24.99 m  x 7.77 m

Armament:
      9 - 10.00" / 254 mm guns (3x3 guns), 500.00lbs / 226.80kg shells, 1921 Model
   Breech loading guns in turrets (on barbettes)
   on centreline ends, majority forward, 1 raised mount - superfiring
      12 - 5.50" / 140 mm guns (6x2 guns), 83.19lbs / 37.73kg shells, 1921 Model
   Quick firing guns in turrets (on barbettes)
   on side, all amidships, all raised mounts - superfiring
      6 - 4.70" / 119 mm guns in single mounts, 51.91lbs / 23.55kg shells, 1921 Model
   Anti-aircraft guns in deck mounts with hoists
   on side, evenly spread, all raised mounts
 Weight of broadside 5,810 lbs / 2,635 kg
 Shells per gun, main battery: 100

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 5.00" / 127 mm 405.00 ft / 123.44 m 17.00 ft / 5.18 m
 Ends: Unarmoured
   Main Belt covers 75 % of normal length
   Main belt does not fully cover magazines and engineering spaces

   - Torpedo Bulkhead:
  2.00" / 51 mm 405.00 ft / 123.44 m 25.00 ft / 7.62 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 7.00" / 178 mm 4.00" / 102 mm  7.00" / 178 mm
 2nd: 4.00" / 102 mm 4.00" / 102 mm  4.00" / 102 mm
 3rd: 2.00" / 51 mm       -         -

   - Armour deck: 3.00" / 76 mm, Conning tower: 7.00" / 178 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Geared drive, 4 shafts, 270,562 shp / 201,839 Kw = 37.00 kts
 Range 7,500nm at 18.00 kts
 Bunker at max displacement = 4,523 tons

Complement:
 1,133 - 1,474

Cost:
 £6.336 million / $25.342 million

Distribution of weights at normal displacement:
 Armament: 726 tons, 2.4 %
 Armour: 6,841 tons, 23.0 %
    - Belts: 1,505 tons, 5.1 %
    - Torpedo bulkhead: 749 tons, 2.5 %
    - Armament: 1,670 tons, 5.6 %
    - Armour Deck: 2,772 tons, 9.3 %
    - Conning Tower: 145 tons, 0.5 %
 Machinery: 6,832 tons, 22.9 %
 Hull, fittings & equipment: 11,955 tons, 40.1 %
 Fuel, ammunition & stores: 3,445 tons, 11.6 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   38,887 lbs / 17,639 Kg = 77.8 x 10.0 " / 254 mm shells or 4.3 torpedoes
 Stability (Unstable if below 1.00): 1.13
 Metacentric height 4.7 ft / 1.4 m
 Roll period: 15.9 seconds
 Steadiness - As gun platform (Average = 50 %): 51 %
   - Recoil effect (Restricted arc if above 1.00): 0.60
 Seaboat quality  (Average = 1.00): 1.03

Hull form characteristics:
 Hull has a flush deck
 Block coefficient: 0.597
 Length to Beam Ratio: 10.18 : 1
 'Natural speed' for length: 28.90 kts
 Power going to wave formation at top speed: 58 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): 5.00 degrees
 Stern overhang: 0.00 ft / 0.00 m
 Freeboard (% = measuring location as a percentage of overall length):
    - Stem:  38.00 ft / 11.58 m
    - Forecastle (20 %): 27.00 ft / 8.23 m
    - Mid (50 %):  27.00 ft / 8.23 m
    - Quarterdeck (15 %): 27.00 ft / 8.23 m
    - Stern:  27.00 ft / 8.23 m
    - Average freeboard: 27.88 ft / 8.50 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 123.1 %
  - Above water (accommodation/working, high = better): 226.8 %
 Waterplane Area: 49,955 Square feet or 4,641 Square metres
 Displacement factor (Displacement / loading): 113 %
 Structure weight / hull surface area: 153 lbs/sq ft or 749 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.98
  - Longitudinal: 1.13
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is cramped
 Room for accommodation and workspaces is excellent

No comments:

Amazon Context Links