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Friday, January 26, 2007

2nd Class Cruiser Amphion, anachronistic version

The next design I tried was an anachronistic version of a Leander class 2nd Class Cruiser. I chose the Amphion. The ship has four turrets, two twin and two triple, with 6in QF guns. There is also a thin armoured deck. The speed is still 24 knots, with coal-fired boilers and complex reciprocrating engines. The range is greater: 6,700nm at 12 knots. This is the Springsharp report:
Amphion, anachronistic version, Great Britain 2nd Class Cruiser laid down 1908 (Engine 1910)

Displacement:
 3,431 t light; 3,589 t standard; 4,300 t normal; 4,868 t full load

Dimensions: Length overall / water x beam x draught
 318.05 ft / 315.00 ft x 46.00 ft x 20.50 ft (normal load)
 96.94 m / 96.01 m x 14.02 m  x 6.25 m

Armament:
      10 - 6.00" / 152 mm guns (4 mounts), 108.00lbs / 48.99kg shells, 1908 Model
   Quick firing guns in turrets (on barbettes)
   on centreline ends, evenly spread, 2 raised mounts - superfiring
 Weight of broadside 1,080 lbs / 490 kg
 Shells per gun, main battery: 120
 4 - 18.0" / 457.2 mm above water torpedoes

Armour:
   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 1.50" / 38 mm 1.50" / 38 mm  1.50" / 38 mm

   - Armour deck: 1.50" / 38 mm

Machinery:
 Coal fired boilers, complex reciprocating steam engines, 
 Direct drive, 2 shafts, 21,724 ihp / 16,206 Kw = 24.00 kts
 Range 6,700nm at 12.00 kts
 Bunker at max displacement = 1,279 tons (100% coal)

Complement:
 265 - 345

Cost:
 £0.436 million / $1.743 million

Distribution of weights at normal displacement:
 Armament: 135 tons, 3.1 %
 Armour: 406 tons, 9.4 %
    - Belts: 0 tons, 0.0 %
    - Torpedo bulkhead: 0 tons, 0.0 %
    - Armament: 137 tons, 3.2 %
    - Armour Deck: 270 tons, 6.3 %
    - Conning Tower: 0 tons, 0.0 %
 Machinery: 1,444 tons, 33.6 %
 Hull, fittings & equipment: 1,446 tons, 33.6 %
 Fuel, ammunition & stores: 869 tons, 20.2 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   2,498 lbs / 1,133 Kg = 23.1 x 6.0 " / 152 mm shells or 0.7 torpedoes
 Stability (Unstable if below 1.00): 1.02
 Metacentric height 1.6 ft / 0.5 m
 Roll period: 15.2 seconds
 Steadiness - As gun platform (Average = 50 %): 78 %
   - Recoil effect (Restricted arc if above 1.00): 0.93
 Seaboat quality  (Average = 1.00): 1.07

Hull form characteristics:
 Hull has a flush deck
 Block coefficient: 0.507
 Length to Beam Ratio: 6.85 : 1
 'Natural speed' for length: 17.75 kts
 Power going to wave formation at top speed: 63 %
 Trim (Max stability = 0, Max steadiness = 100): 73
 Bow angle (Positive = bow angles forward): 3.00 degrees
 Stern overhang: 2.00 ft / 0.61 m
 Freeboard (% = measuring location as a percentage of overall length):
    - Stem:  20.00 ft / 6.10 m
    - Forecastle (20 %): 16.00 ft / 4.88 m
    - Mid (50 %):  16.00 ft / 4.88 m
    - Quarterdeck (15 %): 16.00 ft / 4.88 m
    - Stern:  16.00 ft / 4.88 m
    - Average freeboard: 16.32 ft / 4.97 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 132.5 %
  - Above water (accommodation/working, high = better): 96.1 %
 Waterplane Area: 9,713 Square feet or 902 Square metres
 Displacement factor (Displacement / loading): 98 %
 Structure weight / hull surface area: 83 lbs/sq ft or 406 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.87
  - Longitudinal: 3.42
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is cramped
 Room for accommodation and workspaces is adequate
 Ship has slow, easy roll, a good, steady gun platform

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