GB/CA/1921, Great Britain Heavy Cruiser laid down 1921 (Engine 1927)
Displacement:
21,612 t light; 22,474 t standard; 25,832 t normal; 28,518 t full load
Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(721.59 ft / 715.00 ft) x 90.00 ft x (25.00 / 27.02 ft)
(219.94 m / 217.93 m) x 27.43 m x (7.62 / 8.24 m)
Armament:
9 - 9.20" / 234 mm 55.0 cal guns - 420.00lbs / 190.51kg shells, 150 per gun
Breech loading guns in turret on barbette mounts, 1921 Model
3 x Single mounts on centreline ends, majority forward
1 raised mount - superfiring
6 - 4.70" / 119 mm 50.0 cal guns - 54.96lbs / 24.93kg shells, 150 per gun
Anti-air guns in deck and hoist mounts, 1921 Model
6 x Single mounts on sides, forward deck aft
6 raised mounts
16 - 1.57" / 40.0 mm 50.0 cal guns - 2.00lbs / 0.91kg shells, 150 per gun
Anti-air guns in deck mounts, 1921 Model
4 x 2 row quad mounts on sides, aft deck forward
Weight of broadside 4,142 lbs / 1,879 kg
Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 8.00" / 203 mm 470.00 ft / 143.26 m 8.00 ft / 2.44 m
Ends: Unarmoured
Upper: 5.00" / 127 mm 470.00 ft / 143.26 m 8.00 ft / 2.44 m
Main Belt covers 101 % of normal length
Main belt does not fully cover magazines and engineering spaces
- Torpedo Bulkhead:
1.50" / 38 mm 470.00 ft / 143.26 m 25.00 ft / 7.62 m
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 8.00" / 203 mm 6.00" / 152 mm 8.00" / 203 mm
- Armoured deck - multiple decks: 3.00" / 76 mm For and Aft decks
Forecastle: 3.00" / 76 mm Quarter deck: 3.00" / 76 mm
- Conning towers: Forward 8.00" / 203 mm, Aft 0.00" / 0 mm
Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 156,007 shp / 116,381 Kw = 33.00 kts
Range 12,000nm at 16.00 kts
Bunker at max displacement = 6,045 tons
Complement:
1,018 - 1,324
Cost:
£4.877 million / $19.506 million
Distribution of weights at normal displacement:
Armament: 1,396 tons, 5.4 %
Armour: 6,657 tons, 25.8 %
- Belts: 2,068 tons, 8.0 %
- Torpedo bulkhead: 652 tons, 2.5 %
- Armament: 1,184 tons, 4.6 %
- Armour Deck: 2,602 tons, 10.1 %
- Conning Tower: 151 tons, 0.6 %
Machinery: 4,924 tons, 19.1 %
Hull, fittings & equipment: 8,634 tons, 33.4 %
Fuel, ammunition & stores: 4,220 tons, 16.3 %
Miscellaneous weights: 0 tons, 0.0 %
Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
41,886 lbs / 18,999 Kg = 107.6 x 9.2 " / 234 mm shells or 5.6 torpedoes
Stability (Unstable if below 1.00): 1.29
Metacentric height 6.7 ft / 2.0 m
Roll period: 14.6 seconds
Steadiness - As gun platform (Average = 50 %): 55 %
- Recoil effect (Restricted arc if above 1.00): 0.25
Seaboat quality (Average = 1.00): 1.09
Hull form characteristics:
Hull has a flush deck,
an extended bulbous bow and small transom stern
Block coefficient (normal/deep): 0.562 / 0.574
Length to Beam Ratio: 7.94 : 1
'Natural speed' for length: 28.88 kts
Power going to wave formation at top speed: 58 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): 12.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = length of deck as a percentage of waterline length):
Fore end, Aft end
- Forecastle: 30.00 %, 31.00 ft / 9.45 m, 26.00 ft / 7.92 m
- Forward deck: 30.00 %, 26.00 ft / 7.92 m, 24.00 ft / 7.32 m
- Aft deck: 25.00 %, 24.00 ft / 7.32 m, 24.00 ft / 7.32 m
- Quarter deck: 15.00 %, 24.00 ft / 7.32 m, 24.00 ft / 7.32 m
- Average freeboard: 25.50 ft / 7.77 m
Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 101.7 %
- Above water (accommodation/working, high = better): 213.8 %
Waterplane Area: 46,545 Square feet or 4,324 Square metres
Displacement factor (Displacement / loading): 123 %
Structure weight / hull surface area: 142 lbs/sq ft or 693 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.97
- Longitudinal: 1.35
- Overall: 1.00
Hull space for machinery, storage, compartmentation is adequate
Room for accommodation and workspaces is excellent
This is a forum for discussion of topics relating to the Dreadnought era, prior to the ascendency of naval aviation. We will be discussing history, ship design, and naval wargaming.
Monday, July 16, 2007
A GB/CA/1921 design
This is my first attempt at a GB/CA/1921 design in Springsharp 3.0b2 Beta. I want a fast ship that is well-protected and which can fill the armoured cruiser role for the 1921 building program. For the size, the 9-9.2in/55 guns seem rather meager, but 10in guns seem to heavy and slow-firing. Still, the ship is large, with a 22,474 tons Standard displacement. The belt is 8in at the waterline and the deck is 3in. I want speed, so I made the sacrifices necessary to obtain a 33 knot speed and a range of 12,000nm at 16 knots. All that costs size. This is the Springsharp report:
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