MateDow > RE: Modelling an ASW Light Cruiser (9/24/2012 9:07:17 PM)

quote:
ORIGINAL: Shark7 There are also some AKs in there that are DC armed and will attacked if they spot a sub in range. Have to agree with Gridley380, all that stuff on a 7,500 ton hull is badly overloaded, it would likely be top heavy and unstable. Here is what I came up with based on a Cleveland class hull, done in Springsharp: ...This would be a stable boat, though wet up front an suffers from reduced performance in heavy weather. Basically this is a Cleveland class CL that trades in 1 of its aft 6in turrets and its aft 5 in turret to gain the ASW equipment. I used Springsharp when I came up with the design and here is what I came up with... quote:
Boise, United States ASW Light Cruiser laid down 1937 Displacement: 7,093 t light; 7,406 t standard; 9,012 t normal; 10,296 t full load Dimensions: Length (overall / waterline) x beam x draught (normal/deep) (540.97 ft / 530.00 ft) x 55.00 ft x (20.00 / 22.14 ft) (164.89 m / 161.54 m) x 16.76 m x (6.10 / 6.75 m) Armament: 8  5.00" / 127 mm 38.0 cal guns  55.18lbs / 25.03kg shells, 500 per gun Dual purpose guns in turret on barbette mounts, 1932 Model 2 x Quad mounts on centreline, forward deck forward 1 raised mount  superfiring 24  1.10" / 27.9 mm 75.0 cal guns  0.75lbs / 0.34kg shells, 1,000 per gun Antiair guns in deck mounts, 1929 Model 4 x Quad mounts on centreline ends, evenly spread 4 raised mounts 2 x Quad mounts on centreline, aft evenly spread 2 double raised mounts Weight of broadside 459 lbs / 208 kg Main Torpedoes 8  21.0" / 533 mm, 22.60 ft / 6.89 m torpedoes  1.525 t each, 12.197 t total In 2 sets of deck mounted side rotating tubes 2nd Torpedoes 16  21.0" / 533 mm, 22.60 ft / 6.89 m torpedoes  1.525 t each, 24.394 t total In 2 sets of deck mounted reloads Main DC/AS Mortars 2  745.00 lbs / 337.93 kg Depth Charges + 100 reloads  33.924 t total in Stern depth charge racks Armour:  Belts: Width (max) Length (avg) Height (avg) Main: 2.50" / 64 mm 350.00 ft / 106.68 m 12.00 ft / 3.66 m Ends: Unarmoured Main Belt covers 102 % of normal length  Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max) Main: 0.75" / 19 mm 0.75" / 19 mm 2.00" / 51 mm 2nd:  0.50" / 13 mm   Armoured deck  single deck: For and Aft decks: 1.00" / 25 mm  Conning towers: Forward 4.00" / 102 mm, Aft 0.00" / 0 mm Machinery: Oil fired boilers, steam turbines, Geared drive, 4 shafts, 82,997 shp / 61,916 Kw = 33.00 kts Range 13,200nm at 15.00 kts Bunker at max displacement = 2,890 tons Complement: 462  601 Cost: £3.333 million / $13.331 million Distribution of weights at normal displacement: Armament: 205 tons, 2.3 %  Guns: 107 tons, 1.2 %  Weapons: 97 tons, 1.1 % Armour: 885 tons, 9.8 %  Belts: 434 tons, 4.8 %  Armament: 95 tons, 1.1 %  Armour Deck: 319 tons, 3.5 %  Conning Tower: 37 tons, 0.4 % Machinery: 2,300 tons, 25.5 % Hull, fittings & equipment: 3,143 tons, 34.9 % Fuel, ammunition & stores: 1,919 tons, 21.3 % Miscellaneous weights: 560 tons, 6.2 %  Hull below water: 120 tons  Hull above water: 30 tons  On freeboard deck: 280 tons  Above deck: 130 tons Overall survivability and seakeeping ability: Survivability (Noncritical penetrating hits needed to sink ship): 12,835 lbs / 5,822 Kg = 205.4 x 5.0 " / 127 mm shells or 1.4 torpedoes Stability (Unstable if below 1.00): 1.12 Metacentric height 2.5 ft / 0.8 m Roll period: 14.6 seconds Steadiness  As gun platform (Average = 50 %): 72 %  Recoil effect (Restricted arc if above 1.00): 0.21 Seaboat quality (Average = 1.00): 1.23 Hull form characteristics: Hull has a flush deck, an extended bulbous bow and large transom stern Block coefficient (normal/deep): 0.541 / 0.558 Length to Beam Ratio: 9.64 : 1 'Natural speed' for length: 26.23 kts Power going to wave formation at top speed: 62 % Trim (Max stability = 0, Max steadiness = 100): 58 Bow angle (Positive = bow angles forward): 15.00 degrees Stern overhang: 4.00 ft / 1.22 m Freeboard (% = length of deck as a percentage of waterline length): Fore end, Aft end  Forecastle: 20.00 %, 26.00 ft / 7.92 m, 23.00 ft / 7.01 m  Forward deck: 30.00 %, 23.00 ft / 7.01 m, 21.00 ft / 6.40 m  Aft deck: 35.00 %, 21.00 ft / 6.40 m, 22.00 ft / 6.71 m  Quarter deck: 15.00 %, 22.00 ft / 6.71 m, 22.00 ft / 6.71 m  Average freeboard: 22.27 ft / 6.79 m Ship space, strength and comments: Space  Hull below water (magazines/engines, low = better): 90.6 %  Above water (accommodation/working, high = better): 172.2 % Waterplane Area: 20,997 Square feet or 1,951 Square metres Displacement factor (Displacement / loading): 140 % Structure weight / hull surface area: 86 lbs/sq ft or 420 Kg/sq metre Hull strength (Relative):  Crosssectional: 0.91  Longitudinal: 2.32  Overall: 1.00 Adequate machinery, storage, compartmentation space Excellent accommodation and workspace room Ship has slow, easy roll, a good, steady gun platform Good seaboat, rides out heavy weather easily I figured 280 tons for the aircraft complement in my design. I also made some different choices regarding armor protection. I went with significantly less armor coverage (less than an Omahaclass CL). I also dreamed of a quad 5" mount similar to those used by the French on the Dunkerque. Not exactly historical, but I liked the idea and it does concentrate some of the weight on the design. The design does work though, or at least in the design realm that is Springsharp. [;)] For a 1942 refit, the weight gained reduces the freeboard and a tenth of a knot of speed for the throwers and radar.



