GB/CB/1921 Very Fast, Great Britain Battlecruiser laid down 1921 (Engine 1937)
Displacement:
31,143 t light; 32,294 t standard; 34,000 t normal; 35,365 t full load
Dimensions: Length overall / water x beam x draught
838.38 ft / 836.00 ft x 95.00 ft x 29.00 ft (normal load)
255.54 m / 254.81 m x 28.96 m x 8.84 m
Armament:
6 - 14.00" / 356 mm guns (2x3 guns), 1,372.00lbs / 622.33kg shells, 1921 Model
Breech loading guns in turrets (on barbettes)
on centreline, all forward, 1 raised mount - superfiring
12 - 5.50" / 140 mm guns (6x2 guns), 83.19lbs / 37.73kg shells, 1921 Model
Quick firing guns in turrets (on barbettes)
on side, all amidships, 2 raised mounts - superfiring
Weight of broadside 9,230 lbs / 4,187 kg
Shells per gun, main battery: 90
Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 8.00" / 203 mm 460.00 ft / 140.21 m 8.00 ft / 2.44 m
Ends: Unarmoured
Upper: 4.00" / 102 mm 460.00 ft / 140.21 m 8.00 ft / 2.44 m
Main Belt covers 85 % of normal length
Main belt does not fully cover magazines and engineering spaces
- Torpedo Bulkhead:
2.00" / 51 mm 460.00 ft / 140.21 m 28.00 ft / 8.53 m
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 9.00" / 229 mm 6.00" / 152 mm 9.00" / 229 mm
2nd: 4.00" / 102 mm 4.00" / 102 mm 4.00" / 102 mm
- Armour deck: 3.00" / 76 mm, Conning tower: 9.00" / 229 mm
Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 257,953 shp / 192,433 Kw = 36.00 kts
Range 6,400nm at 15.00 kts
Bunker at max displacement = 3,072 tons
Complement:
1,251 - 1,627
Cost:
£7.789 million / $31.157 million
Distribution of weights at normal displacement:
Armament: 1,154 tons, 3.4 %
Armour: 8,057 tons, 23.7 %
- Belts: 1,916 tons, 5.6 %
- Torpedo bulkhead: 953 tons, 2.8 %
- Armament: 2,003 tons, 5.9 %
- Armour Deck: 2,982 tons, 8.8 %
- Conning Tower: 203 tons, 0.6 %
Machinery: 7,149 tons, 21.0 %
Hull, fittings & equipment: 14,782 tons, 43.5 %
Fuel, ammunition & stores: 2,857 tons, 8.4 %
Miscellaneous weights: 0 tons, 0.0 %
Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
42,777 lbs / 19,403 Kg = 31.2 x 14.0 " / 356 mm shells or 5.2 torpedoes
Stability (Unstable if below 1.00): 1.14
Metacentric height 5.9 ft / 1.8 m
Roll period: 16.4 seconds
Steadiness - As gun platform (Average = 50 %): 53 %
- Recoil effect (Restricted arc if above 1.00): 0.58
Seaboat quality (Average = 1.00): 1.06
Hull form characteristics:
Hull has rise forward of midbreak
Block coefficient: 0.517
Length to Beam Ratio: 8.80 : 1
'Natural speed' for length: 28.91 kts
Power going to wave formation at top speed: 56 %
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: 34.00 ft / 10.36 m
- Forecastle (20 %): 28.00 ft / 8.53 m
- Mid (76 %): 28.00 ft / 8.53 m (20.00 ft / 6.10 m aft of break)
- Quarterdeck (15 %): 20.00 ft / 6.10 m
- Stern: 20.00 ft / 6.10 m
- Average freeboard: 26.56 ft / 8.10 m
Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 118.8 %
- Above water (accommodation/working, high = better): 220.0 %
Waterplane Area: 53,732 Square feet or 4,992 Square metres
Displacement factor (Displacement / loading): 108 %
Structure weight / hull surface area: 184 lbs/sq ft or 896 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.97
- Longitudinal: 1.36
- Overall: 1.00
Hull space for machinery, storage, compartmentation is cramped
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.
Wednesday, November 08, 2006
I am further feeding my obsession with big, fast ships
Perhaps no one but me is interested in the big, fast battlecruisers. I wanted to see if we could have a fast ship that is more reasonable, meaning that there are four propellor shafts, not six. That means reducing the displacment, which requires other compromises. My latest "GB/CB/1921 Very Fast" can make 36 knots and has to twin 14in turrets forward. The belt is 8in and the deck is 3in. What I am particularly pleased with is that seakeeping is 1.06 and the roll period is a very nice 16.4 seconds. Much of this is possible due to the short citadel of 460ft. This ship also requires lightweight machinery, having machinery that is 36 SHP/ton. This is the Springsharp report:
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