GB/CB/1921, Great Britain Battlecruiser laid down 1921
Displacement:
49,896 t light; 51,920 t standard; 55,700 t normal; 58,724 t full load
Dimensions: Length overall / water x beam x draught
867.38 ft / 865.00 ft x 106.00 ft x 32.00 ft (normal load)
264.38 m / 263.65 m x 32.31 m x 9.75 m
Armament:
8 - 16.50" / 419 mm guns (4x2 guns), 2,246.06lbs / 1,018.80kg shells, 1921 Model
Breech loading guns in turrets (on barbettes)
on centreline ends, evenly spread, 2 raised mounts - superfiring
16 - 6.00" / 152 mm guns (8x2 guns), 108.00lbs / 48.99kg shells, 1921 Model
Quick firing guns in turrets (on barbettes)
on side, evenly spread, 4 raised mounts
6 - 4.70" / 119 mm guns in single mounts, 51.91lbs / 23.55kg shells, 1921 Model
Anti-aircraft guns in deck mounts
on side, evenly spread, 2 raised mounts
32 - 1.57" / 40.0 mm guns (8x4 guns), 1.95lbs / 0.89kg shells, 1921 Model
Anti-aircraft guns in deck mounts
on side, evenly spread
Weight of broadside 20,070 lbs / 9,104 kg
Shells per gun, main battery: 80
4 - 21.0" / 533.4 mm submerged torpedo tubes
Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 14.0" / 356 mm 570.00 ft / 173.74 m 8.00 ft / 2.44 m
Ends: Unarmoured
Upper: 10.0" / 254 mm 570.00 ft / 173.74 m 8.00 ft / 2.44 m
Main Belt covers 101 % of normal length
- Torpedo Bulkhead:
4.00" / 102 mm 570.00 ft / 173.74 m 31.00 ft / 9.45 m
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 14.0" / 356 mm 10.0" / 254 mm 14.0" / 356 mm
2nd: 4.00" / 102 mm 4.00" / 102 mm 4.00" / 102 mm
- Armour deck: 5.00" / 127 mm, Conning tower: 14.00" / 356 mm
Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 203,003 shp / 151,440 Kw = 32.00 kts
Range 6,400nm at 18.00 kts
Bunker at max displacement = 6,804 tons
Complement:
1,812 - 2,356
Cost:
£12.301 million / $49.203 million
Distribution of weights at normal displacement:
Armament: 2,509 tons, 4.5 %
Armour: 19,462 tons, 34.9 %
- Belts: 4,666 tons, 8.4 %
- Torpedo bulkhead: 2,615 tons, 4.7 %
- Armament: 4,871 tons, 8.7 %
- Armour Deck: 6,870 tons, 12.3 %
- Conning Tower: 440 tons, 0.8 %
Machinery: 6,990 tons, 12.6 %
Hull, fittings & equipment: 20,935 tons, 37.6 %
Fuel, ammunition & stores: 5,804 tons, 10.4 %
Miscellaneous weights: 0 tons, 0.0 %
Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
75,345 lbs / 34,176 Kg = 33.5 x 16.5 " / 419 mm shells or 11.3 torpedoes
Stability (Unstable if below 1.00): 1.08
Metacentric height 6.3 ft / 1.9 m
Roll period: 17.7 seconds
Steadiness - As gun platform (Average = 50 %): 51 %
- Recoil effect (Restricted arc if above 1.00): 0.77
Seaboat quality (Average = 1.00): 1.03
Hull form characteristics:
Hull has rise forward of midbreak
and transom stern
Block coefficient: 0.664
Length to Beam Ratio: 8.16 : 1
'Natural speed' for length: 33.54 kts
Power going to wave formation at top speed: 54 %
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 (67 %): 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: 25.84 ft / 7.88 m
Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 93.6 %
- Above water (accommodation/working, high = better): 201.3 %
Waterplane Area: 74,274 Square feet or 6,900 Square metres
Displacement factor (Displacement / loading): 104 %
Structure weight / hull surface area: 207 lbs/sq ft or 1,009 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.99
- Longitudinal: 1.08
- 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.
Thursday, December 01, 2005
Another 1921 battlecruiser
I thought that I would extend my battlecruiser series to 1921 with a ship with 8-16.5in BLR, 16-6in QF, 6-4.7in AA, and 32-2pdr AA guns. The armour basis is a substantial 14in with a 5in deck. The speed of 32 knots has ballooned the displacement, but I felt that the ship should do better than the 31 knots of the preceding design. The combination of strength and seakeeping through a greater freeboard, along with the 32 knot speed is behind the great displacement for the rather small dimensions, although it is primarily the speed. I thought that for a 1921 design, a transom stern was appropriate, and it reduces the power requirement, and helps to keep the displacement as low as it is. This is the Springsharp report:
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