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Thursday, June 21, 2007

My modified Colony class design

As long ago as 1968 (I was making a model out of index paper, watching TV when Bobby Kennedy was assassinated by a Palestinian terrorist), I had this concept for a Colony class-like cruiser that had inclined side armour. This is an attempt at such a ship in Springsharp 3.0b2 Beta. The displacement is a bit high, but otherwise, the design seems reasonable. The SHP required for 31.5 knots is about what we would expect. My ship has 12-6in QF guns (rather than the original BLR), 8-4in AA guns, and 12-2pdr AA guns. There are also 6-21in TT in triple mounts. The armour basis is 3.5in with a 2in protective deck. This is the Springsharp report:
GB/CL/1941, Great Britain Light Cruiser laid down 1941

Displacement:
 8,402 t light; 8,737 t standard; 9,443 t normal; 10,008 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
 (557.94 ft / 555.00 ft) x 62.00 ft x (17.00 / 17.81 ft)
 (170.06 m / 169.16 m) x 18.90 m  x (5.18 / 5.43 m)

Armament:
      12 - 6.00" / 152 mm 50.0 cal guns - 114.33lbs / 51.86kg shells, 150 per gun
   Quick firing guns in turret on barbette mounts, 1941 Model
   4 x Triple mounts on centreline ends, evenly spread
      8 - 4.00" / 102 mm 45.0 cal guns - 32.27lbs / 14.64kg shells, 150 per gun
   Anti-air guns in deck and hoist mounts, 1941 Model
   4 x 2-gun mounts on sides, aft deck forward
  4 raised mounts
      12 - 1.57" / 40.0 mm 50.0 cal guns - 2.00lbs / 0.91kg shells, 150 per gun
   Anti-air guns in deck mounts, 1941 Model
   2 x 2 row quad mounts on sides amidships
  2 raised mounts
   1 x Single mount on centreline, aft deck forward
      Weight of broadside 1,654 lbs / 750 kg
      6 - 21.0" / 533 mm, 20.00 ft / 6.10 m torpedoes - 1.387 t each, 8.321 t total
 In 2 sets of deck mounted carriage/fixed tubes

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 3.50" / 89 mm 370.00 ft / 112.78 m 8.00 ft / 2.44 m
 Ends: Unarmoured
 Upper: 3.50" / 89 mm 210.00 ft / 64.01 m 8.00 ft / 2.44 m
   Main Belt covers 103 % of normal length
   Main belt does not fully cover magazines and engineering spaces

   - Torpedo Bulkhead:
  1.00" / 25 mm 370.00 ft / 112.78 m 16.50 ft / 5.03 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 4.00" / 102 mm 3.00" / 76 mm  4.00" / 102 mm
 2nd: 1.00" / 25 mm 1.00" / 25 mm  1.00" / 25 mm

   - Protected deck - single deck: 2.00" / 51 mm For and Aft decks

   - Conning towers: Forward 4.00" / 102 mm,  Aft 0.00" / 0 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Geared drive, 4 shafts, 82,961 shp / 61,889 Kw = 31.50 kts
 Range 10,000nm at 12.00 kts
 Bunker at max displacement = 1,270 tons

Complement:
 478 - 622

Cost:
 £4.771 million / $19.084 million

Distribution of weights at normal displacement:
 Armament: 434 tons, 4.6 %
    - Guns: 426 tons, 4.5 %
    - Torpedoes: 8 tons, 0.1 %
 Armour: 1,897 tons, 20.1 %
    - Belts: 703 tons, 7.4 %
    - Torpedo bulkhead: 226 tons, 2.4 %
    - Armament: 402 tons, 4.3 %
    - Armour Deck: 528 tons, 5.6 %
    - Conning Tower: 39 tons, 0.4 %
 Machinery: 2,192 tons, 23.2 %
 Hull, fittings & equipment: 3,879 tons, 41.1 %
 Fuel, ammunition & stores: 1,041 tons, 11.0 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   15,213 lbs / 6,900 Kg = 140.9 x 6.0 " / 152 mm shells or 2.2 torpedoes
 Stability (Unstable if below 1.00): 1.16
 Metacentric height 3.2 ft / 1.0 m
 Roll period: 14.5 seconds
 Steadiness - As gun platform (Average = 50 %): 54 %
   - Recoil effect (Restricted arc if above 1.00): 0.45
 Seaboat quality  (Average = 1.00): 1.07

Hull form characteristics:
 Hull has low quarterdeck ,
   a normal bow and a cruiser stern
 Block coefficient (normal/deep): 0.565 / 0.572
 Length to Beam Ratio: 8.95 : 1
 'Natural speed' for length: 23.56 kts
 Power going to wave formation at top speed: 60 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): 6.00 degrees
 Stern overhang: -3.00 ft / -0.91 m
 Freeboard (% = length of deck as a percentage of waterline length):
    Fore end,  Aft end
    - Forecastle: 28.00 %,  28.00 ft / 8.53 m,  24.00 ft / 7.32 m
    - Forward deck: 30.00 %,  24.00 ft / 7.32 m,  24.00 ft / 7.32 m
    - Aft deck: 9.00 %,  24.00 ft / 7.32 m,  24.00 ft / 7.32 m
    - Quarter deck: 33.00 %,  16.00 ft / 4.88 m,  18.00 ft / 5.49 m
    - Average freeboard:  22.14 ft / 6.75 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 136.5 %
  - Above water (accommodation/working, high = better): 230.9 %
 Waterplane Area: 24,355 Square feet or 2,263 Square metres
 Displacement factor (Displacement / loading): 119 %
 Structure weight / hull surface area: 107 lbs/sq ft or 521 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.95
  - Longitudinal: 1.67
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is cramped
 Room for accommodation and workspaces is excellent

2 comments:

Mike said...

The Colony's have always been among my favorite cruisers. Any chance of a graphic representation of this enhanced ship?

Jim said...

I have taken photographs of my model built of cardstock. The date on the bottom is "6-4-68". I am old enough that I was staying up late watching TV, working on this model, the night that Robert Kennedy was assassinated by the Palestinian terrorist in Los Angeles. The card stock of the model is discolored, but you can still see the inclined side armor. The ship model is at 1:1200 scale.

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