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Sunday, January 23, 2005

Springsharp is using too low a SHP/ton: US/CL/1936b1 (AA cruiser)

I have my US/CL/1936b1 design, but it is warped because Springsharp is only using a 35.64 SHP/ton machinery basis. That means the machinery is too heavy and takes up too much space. Given that, I was able to achieve a 36-knot AA cruiser with 8-21 TT and 16-5in DP guns (along with 32-40mm AA). The armor basis is 3in, with a 2in deck. The range is 8,000 nm, as that seemed like a reasonable compromise:
US/CL/1936b1, United States Light Cruiser laid down 1936

Displacement:
	11,190 t light; 11,617 t standard; 12,751 t normal; 13,658 t full load

Dimensions: Length overall / water x beam x draught
	611.08 ft / 610.00 ft x 62.00 ft x 25.00 ft (normal load)
	186.26 m / 185.93 m x 18.90 m  x 7.62 m

Armament:
      16 - 5.00" / 127 mm guns (8x2 guns), 62.50lbs / 28.35kg shells, 1936 Model
	  Dual purpose guns in turrets (on barbettes)
	  on centreline ends, evenly spread, all raised mounts - superfiring
      32 - 1.57" / 40.0 mm guns (8x4 guns), 1.95lbs / 0.89kg shells, 1936 Model
	  Anti-aircraft guns in deck mounts 
	  on side ends, evenly spread, all raised mounts - superfiring
	Weight of broadside 1,062 lbs / 482 kg
	Shells per gun, main battery: 280
	8 - 21.0" / 533.4 mm above water torpedoes

Armour:
   - Belts:		Width (max)	Length (avg)		Height (avg)
	Main:	3.00" / 76 mm	395.00 ft / 120.40 m	16.00 ft / 4.88 m
	Ends:	Unarmoured
	  Main Belt covers 100 % of normal length
	  Main belt does not fully cover magazines and engineering spaces

   - Gun armour:	Face (max)	Other gunhouse (avg)	Barbette/hoist (max)
	Main:	2.00" / 51 mm	2.00" / 51 mm		2.00" / 51 mm

   - Armour deck: 2.00" / 51 mm, Conning tower: 3.00" / 76 mm

Machinery:
	Oil fired boilers, steam turbines, 
	Geared drive, 4 shafts, 155,242 shp / 115,810 Kw = 36.00 kts
	Range 8,000nm at 15.00 kts
	Bunker at max displacement = 2,042 tons

Complement:
	599 - 779

Cost:
	£5.869 million / $23.475 million

Distribution of weights at normal displacement:
	Armament: 133 tons, 1.0 %
	Armour: 2,042 tons, 16.0 %
	   - Belts: 789 tons, 6.2 %
	   - Torpedo bulkhead: 0 tons, 0.0 %
	   - Armament: 308 tons, 2.4 %
	   - Armour Deck: 909 tons, 7.1 %
	   - Conning Tower: 35 tons, 0.3 %
	Machinery: 4,356 tons, 34.2 %
	Hull, fittings & equipment: 4,660 tons, 36.5 %
	Fuel, ammunition & stores: 1,561 tons, 12.2 %
	Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
	Survivability (Non-critical penetrating hits needed to sink ship):
	  10,778 lbs / 4,889 Kg = 172.4 x 5.0 " / 127 mm shells or 1.3 torpedoes
	Stability (Unstable if below 1.00): 1.20
	Metacentric height 3.4 ft / 1.0 m
	Roll period: 14.1 seconds
	Steadiness	- As gun platform (Average = 50 %): 52 %
			- Recoil effect (Restricted arc if above 1.00): 0.29
	Seaboat quality  (Average = 1.00): 1.04

Hull form characteristics:
	Hull has a flush deck
	Block coefficient: 0.472
	Length to Beam Ratio: 9.84 : 1
	'Natural speed' for length: 24.70 kts
	Power going to wave formation at top speed: 61 %
	Trim (Max stability = 0, Max steadiness = 100): 50
	Bow angle (Positive = bow angles forward): 2.00 degrees
	Stern overhang: 0.00 ft / 0.00 m
	Freeboard (% = measuring location as a percentage of overall length):
	   - Stem:		31.00 ft / 9.45 m
	   - Forecastle (20 %):	22.00 ft / 6.71 m
	   - Mid (50 %):		22.00 ft / 6.71 m
	   - Quarterdeck (15 %):	22.00 ft / 6.71 m
	   - Stern:		22.00 ft / 6.71 m
	   - Average freeboard:	22.72 ft / 6.93 m

Ship space, strength and comments:
	Space	- Hull below water (magazines/engines, low = better): 119.7 %
		- Above water (accommodation/working, high = better): 146.9 %
	Waterplane Area: 24,577 Square feet or 2,283 Square metres
	Displacement factor (Displacement / loading): 108 %
	Structure weight / hull surface area: 106 lbs/sq ft or 516 Kg/sq metre
	Hull strength (Relative):
		- Cross-sectional: 0.94
		- Longitudinal: 1.84
		- Overall: 1.00
	Hull space for machinery, storage, compartmentation is cramped
	Room for accommodation and workspaces is excellent

1 comment:

Roberto Iza Valdés said...
This comment has been removed by a blog administrator.

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