It/CL/1939 fast design study, Italy Light Cruiser laid down 1939 (Engine 1950)
Displacement:
6,796 t light; 7,014 t standard; 7,447 t normal; 7,793 t full load
Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(625.97 ft / 614.00 ft) x 56.00 ft x (20.00 / 20.56 ft)
(190.79 m / 187.15 m) x 17.07 m x (6.10 / 6.27 m)
Armament:
9 - 5.30" / 135 mm 45.0 cal guns - 75.00lbs / 34.02kg shells, 150 per gun
Dual purpose guns in turret on barbette mounts, 1939 Model
3 x Triple mounts on centreline ends, majority forward
1 raised mount - superfiring
8 - 1.46" / 37.0 mm 55.0 cal guns - 1.67lbs / 0.76kg shells, 150 per gun
Anti-air guns in deck mounts, 1939 Model
8 x Single mounts on sides, evenly spread
8 raised mounts
Weight of broadside 688 lbs / 312 kg
8 - 21.0" / 533 mm, 21.00 ft / 6.40 m torpedoes - 1.438 t each, 11.504 t total
In 2 sets of deck mounted side rotating tubes
Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1.00" / 25 mm 1.00" / 25 mm 1.00" / 25 mm
- Armoured deck - multiple decks: 0.70" / 18 mm For and Aft decks
- Conning towers: Forward 1.00" / 25 mm, Aft 0.00" / 0 mm
Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 122,654 shp / 91,500 Kw = 39.00 kts
Range 4,200nm at 15.00 kts
Bunker at max displacement = 779 tons
Complement:
400 - 521
Cost:
£4.154 million / $16.615 million
Distribution of weights at normal displacement:
Armament: 181 tons, 2.4 %
- Guns: 170 tons, 2.3 %
- Torpedoes: 12 tons, 0.2 %
Armour: 291 tons, 3.9 %
- Armament: 64 tons, 0.9 %
- Armour Deck: 219 tons, 2.9 %
- Conning Tower: 8 tons, 0.1 %
Machinery: 2,934 tons, 39.4 %
Hull, fittings & equipment: 3,389 tons, 45.5 %
Fuel, ammunition & stores: 651 tons, 8.7 %
Miscellaneous weights: 0 tons, 0.0 %
Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
5,758 lbs / 2,612 Kg = 77.4 x 5.3 " / 135 mm shells or 0.9 torpedoes
Stability (Unstable if below 1.00): 1.21
Metacentric height 3.0 ft / 0.9 m
Roll period: 13.6 seconds
Steadiness - As gun platform (Average = 50 %): 51 %
- Recoil effect (Restricted arc if above 1.00): 0.23
Seaboat quality (Average = 1.00): 1.02
Hull form characteristics:
Hull has a flush deck,
an extended bulbous bow and large transom stern
Block coefficient (normal/deep): 0.379 / 0.386
Length to Beam Ratio: 10.96 : 1
'Natural speed' for length: 28.54 kts
Power going to wave formation at top speed: 59 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): 15.00 degrees
Stern overhang: 5.00 ft / 1.52 m
Freeboard (% = length of deck as a percentage of waterline length):
Fore end, Aft end
- Forecastle: 25.00 %, 26.00 ft / 7.92 m, 21.00 ft / 6.40 m
- Forward deck: 30.00 %, 21.00 ft / 6.40 m, 19.00 ft / 5.79 m
- Aft deck: 30.00 %, 19.00 ft / 5.79 m, 18.00 ft / 5.49 m
- Quarter deck: 15.00 %, 18.00 ft / 5.49 m, 18.00 ft / 5.49 m
- Average freeboard: 20.00 ft / 6.10 m
Ship tends to be wet forward
Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 135.8 %
- Above water (accommodation/working, high = better): 194.1 %
Waterplane Area: 21,671 Square feet or 2,013 Square metres
Displacement factor (Displacement / loading): 110 %
Structure weight / hull surface area: 95 lbs/sq ft or 465 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.94
- Longitudinal: 1.70
- 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, August 08, 2007
An "Unlimited" Italian light cruiser
I decided to see what could be done with a fast Italian light cruiser, using the Springsharp we have now. I increased the size and length to see how fast the ship could be. Without too much trouble, I was able to achieve 39 knots, with an armament of 9-5.3in/45 DP, 8-37mm AA guns, and 8-21in TT in two mounts. The size necessarily ballooned. I did a second version with a wide transom stern, and that made a big difference. This is the Springsharp report:
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