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Thursday, January 12, 2006

The US/CL/1921 design

The US/CL/1921 design has an increased speed to 35 knots, increased range to 6,500nm at 15 knots, and 9-6in QF, 8-5in AA, 36-0.5in MG for AA, and 12-21in TT. The result is rather like a French light cruiser. This seems to be a better bargain than an Omaha, which had the odd casemate guns (odd for the period), and too small a size, so that they proved pretty much useless in WWII. This is the Springsharp report:
US/CL/1921, United States Light Cruiser laid down 1921 (Engine 1945)

Displacement:
 8,971 t light; 9,304 t standard; 10,050 t normal; 10,647 t full load

Dimensions: Length overall / water x beam x draught
 578.96 ft / 575.00 ft x 55.00 ft x 21.00 ft (normal load)
 176.47 m / 175.26 m x 16.76 m  x 6.40 m

Armament:
      9 - 6.00" / 152 mm guns (3x3 guns), 108.00lbs / 48.99kg shells, 1921 Model
   Quick firing guns in turrets (on barbettes)
   on centreline ends, majority forward, 1 raised mount - superfiring
      8 - 5.00" / 127 mm guns in single mounts, 62.50lbs / 28.35kg shells, 1921 Model
   Anti-aircraft guns in deck mounts with hoists
   on side, all amidships
      36 - 0.50" / 12.7 mm guns in single mounts, 0.06lbs / 0.03kg shells, 1921 Model
   Anti-aircraft guns in deck mounts 
   on side, evenly spread, 24 raised mounts
 Weight of broadside 1,474 lbs / 669 kg
 Shells per gun, main battery: 150
 12 - 21.0" / 533.4 mm above water torpedoes

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 3.00" / 76 mm 440.00 ft / 134.11 m 12.00 ft / 3.66 m
 Ends: Unarmoured
   Main Belt covers 118 % of normal length

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 3.00" / 76 mm 2.00" / 51 mm  3.00" / 76 mm

   - Armour deck: 2.00" / 51 mm, Conning tower: 3.00" / 76 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Geared drive, 4 shafts, 124,907 shp / 93,181 Kw = 35.00 kts
 Range 6,500nm at 15.00 kts
 Bunker at max displacement = 1,343 tons

Complement:
 501 - 652

Cost:
 £2.317 million / $9.269 million

Distribution of weights at normal displacement:
 Armament: 184 tons, 1.8 %
 Armour: 1,690 tons, 16.8 %
    - Belts: 642 tons, 6.4 %
    - Torpedo bulkhead: 0 tons, 0.0 %
    - Armament: 216 tons, 2.1 %
    - Armour Deck: 801 tons, 8.0 %
    - Conning Tower: 30 tons, 0.3 %
 Machinery: 3,154 tons, 31.4 %
 Hull, fittings & equipment: 3,943 tons, 39.2 %
 Fuel, ammunition & stores: 1,079 tons, 10.7 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   9,440 lbs / 4,282 Kg = 87.4 x 6.0 " / 152 mm shells or 1.2 torpedoes
 Stability (Unstable if below 1.00): 1.17
 Metacentric height 2.7 ft / 0.8 m
 Roll period: 13.9 seconds
 Steadiness - As gun platform (Average = 50 %): 53 %
   - Recoil effect (Restricted arc if above 1.00): 0.53
 Seaboat quality  (Average = 1.00): 1.06

Hull form characteristics:
 Hull has rise forward of midbreak
 Block coefficient: 0.530
 Length to Beam Ratio: 10.45 : 1
 'Natural speed' for length: 23.98 kts
 Power going to wave formation at top speed: 62 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): 4.00 degrees
 Stern overhang: 2.00 ft / 0.61 m
 Freeboard (% = measuring location as a percentage of overall length):
    - Stem:  28.00 ft / 8.53 m
    - Forecastle (20 %): 24.00 ft / 7.32 m
    - Mid (67 %):  24.00 ft / 7.32 m (16.00 ft / 4.88 m aft of break)
    - Quarterdeck (15 %): 16.00 ft / 4.88 m
    - Stern:  16.00 ft / 4.88 m
    - Average freeboard: 21.68 ft / 6.61 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 116.2 %
  - Above water (accommodation/working, high = better): 132.5 %
 Waterplane Area: 21,655 Square feet or 2,012 Square metres
 Displacement factor (Displacement / loading): 106 %
 Structure weight / hull surface area: 100 lbs/sq ft or 488 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.93
  - Longitudinal: 1.98
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is cramped
 Room for accommodation and workspaces is excellent

1 comment:

Alicia Bennett said...

Greetings, I was reading some blogs and came across your blog. I really enjoy how it makes such good reading.

I'll come by again.

Regards,

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