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Friday, April 20, 2007

A Super Fast Battlecruiser variant

I had this design, but I had forgotten to use a transom stern. Having the small transom, in typical British 1921 style, allowed me to improve the overall qualities and decrease displacement. The GB/CB/1921 Super Fast carried 4-17in/45 BLR and 12-5.5in QF guns. The lower belt is 8in and the deck is 3in. The top speed is 40 knots and the ship has a range of 6,500nm at 16 knots. This is a photo that I struggled to produce using a chisle and hammer, which is all I have to work with in a locked down environment, and it shows (you should be able to click on it to get a larger photo):

This is the Springsharp report:
GB/CB/1921 Super Fast, Great Britain Light Battlecruiser laid down 1921 (Engine 1941)

Displacement:
 34,937 t light; 36,283 t standard; 38,265 t normal; 39,851 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
 (899.34 ft / 894.00 ft) x 97.00 ft x (33.00 / 33.95 ft)
 (274.12 m / 272.49 m) x 29.57 m  x (10.06 / 10.35 m)

Armament:
      4 - 17.00" / 432 mm 45.0 cal guns - 2,480.00lbs / 1,124.91kg shells, 90 per gun
   Breech loading guns in turret on barbette mounts , 1921 Model
   1 x Twin mount on centreline, forward deck forward
   1 x Twin mount on centreline, forward deck aft
      12 - 5.50" / 140 mm 50.0 cal guns - 85.00lbs / 38.56kg shells, 150 per gun
   Quick firing guns in deck and hoist mounts , 1921 Model
   12 x Single mounts on sides, forward deck aft
 Weight of broadside 10,940 lbs / 10,940 kg

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 7.00" / 178 mm 490.00 ft / 149.35 m 8.00 ft / 2.44 m
 Ends: Unarmoured
 Upper: 5.00" / 127 mm 490.00 ft / 149.35 m 8.00 ft / 2.44 m
   Main Belt covers 84 % of normal length
   Main belt does not fully cover magazines and engineering spaces

   - Torpedo Bulkhead:
  1.50" / 38 mm 490.00 ft / 149.35 m 33.00 ft / 10.06 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 8.00" / 203 mm 5.00" / 127 mm  8.00" / 203 mm
 2nd: 4.00" / 102 mm 2.00" / 51 mm  4.00" / 102 mm

   - Armour deck: 3.00" / 76 mm, Conning tower: 8.00" / 203 mm

Machinery:
 Oil fired boilers, steam turbines,
 Geared drive, 6 shafts, 343,077 shp / 255,935 Kw = 40.00 kts
 Range 6,500nm at 16.00 kts
 Bunker at max displacement = 3,568 tons

Complement:
 1,367 - 1,778

Cost:
 £8.977 million / $35.910 million

Distribution of weights at normal displacement:
 Armament: 1,883 tons, 4.9 %
 Armour: 7,843 tons, 20.5 %
    - Belts: 2,029 tons, 5.3 %
    - Torpedo bulkhead: 897 tons, 2.3 %
    - Armament: 1,482 tons, 3.9 %
    - Armour Deck: 3,239 tons, 8.5 %
    - Conning Tower: 196 tons, 0.5 %
 Machinery: 9,067 tons, 23.7 %
 Hull, fittings & equipment: 16,796 tons, 43.9 %
 Fuel, ammunition & stores: 3,328 tons, 8.7 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   45,577 lbs / 20,673 Kg = 18.6 x 17.0 " / 432 mm shells or 4.9 torpedoes
 Stability (Unstable if below 1.00): 1.15
 Metacentric height 6.2 ft / 1.9 m
 Roll period: 16.4 seconds
 Steadiness - As gun platform (Average = 50 %): 53 %
   - Recoil effect (Restricted arc if above 1.00): 0.59
 Seaboat quality  (Average = 1.00): 1.06

Hull form characteristics:
 Hull has rise forward of midbreak,
   a normal bow and small transom stern
 Block coefficient (normal/deep): 0.468 / 0.474
 Length to Beam Ratio: 9.22 : 1
 'Natural speed' for length: 34.48 kts
 Power going to wave formation at top speed: 58 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): 8.00 degrees
 Stern overhang: -3.00 ft / -0.91 m
 Freeboard (% = length of deck as a percentage of waterline length):
    Fore end,  Aft end
    - Forecastle: 25.00 %,  38.00 ft / 11.58 m,  33.00 ft / 10.06 m
    - Forward deck: 35.00 %,  33.00 ft / 10.06 m,  32.00 ft / 9.75 m
    - Aft deck: 20.00 %,  24.00 ft / 7.32 m,  24.00 ft / 7.32 m
    - Quarter deck: 20.00 %,  24.00 ft / 7.32 m,  26.00 ft / 7.92 m
    - Average freeboard:  29.93 ft / 9.12 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 127.6 %
  - Above water (accommodation/working, high = better): 239.1 %
 Waterplane Area: 58,358 Square feet or 5,422 Square metres
 Displacement factor (Displacement / loading): 107 %
 Structure weight / hull surface area: 186 lbs/sq ft or 907 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.95
  - Longitudinal: 1.61
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is cramped
 Room for accommodation and workspaces is excellent

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