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Wednesday, January 05, 2005

I redid my Ger/CS/1905 design

Given what I learned about Springsharp, I redid my design for the Ger/CS/1905 scout cruiser. By reducing the speed way down to 30 knots, I was able to use my original dimensions and give them the 2in Belt over the machinery spaces. I had thought that I would have to accept 29 knots, but 30 knots is not so bad, given the date of the design. Admittedly, I wanted to have too light a machinery for 1905, although I don't think that what I want is out of line. This is the Springsharp report:
Ger/CS/1905, Germany CL laid down 1905 (Engine 1908)

Displacement:
	2,150 t light; 2,213 t standard; 2,475 t normal; 2,685 t full load

Dimensions: Length overall / water x beam x draught
	372.76 ft / 370.00 ft x 38.00 ft x 13.00 ft (normal load)
	113.62 m / 112.78 m x 11.58 m  x 3.96 m

Armament:
      5 - 4.00" / 102 mm guns (3 mounts), 32.00lbs / 14.51kg shells, 1905 Model
	  Quick firing guns in deck mounts 
	  on centreline ends, majority forward, all raised mounts - superfiring
	Weight of broadside 160 lbs / 73 kg
	Shells per gun, main battery: 150
	2 - 21.0" / 533.4 mm above water torpedoes

Armour:
   - Belts:		Width (max)	Length (avg)		Height (avg)
	Main:	2.00" / 51 mm	165.00 ft / 50.29 m	16.00 ft / 4.88 m
	Ends:	Unarmoured
	  Main Belt covers 69 % of normal length
	  Main belt does not fully cover magazines and engineering spaces

   - Gun armour:	Face (max)	Other gunhouse (avg)	Barbette/hoist (max)
	Main:	1.00" / 25 mm	      -			      -

Machinery:
	Oil fired boilers, steam turbines, 
	Direct drive, 2 shafts, 33,411 shp / 24,925 Kw = 30.00 kts
	Range 2,500nm at 15.00 kts
	Bunker at max displacement = 472 tons

Complement:
	175 - 228

Cost:
	£0.283 million / $1.131 million

Distribution of weights at normal displacement:
	Armament: 20 tons, 0.8 %
	Armour: 246 tons, 9.9 %
	   - Belts: 235 tons, 9.5 %
	   - Torpedo bulkhead: 0 tons, 0.0 %
	   - Armament: 11 tons, 0.4 %
	   - Armour Deck: 0 tons, 0.0 %
	   - Conning Tower: 0 tons, 0.0 %
	Machinery: 1,363 tons, 55.0 %
	Hull, fittings & equipment: 522 tons, 21.1 %
	Fuel, ammunition & stores: 325 tons, 13.1 %
	Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
	Survivability (Non-critical penetrating hits needed to sink ship):
	  614 lbs / 279 Kg = 19.2 x 4.0 " / 102 mm shells or 0.3 torpedoes
	Stability (Unstable if below 1.00): 1.58
	Metacentric height 2.5 ft / 0.8 m
	Roll period: 10.0 seconds
	Steadiness	- As gun platform (Average = 50 %): 88 %
			- Recoil effect (Restricted arc if above 1.00): 0.12
	Seaboat quality  (Average = 1.00): 1.52

Hull form characteristics:
	Hull has rise forward of midbreak
	Block coefficient: 0.474
	Length to Beam Ratio: 9.74 : 1
	'Natural speed' for length: 19.24 kts
	Power going to wave formation at top speed: 63 %
	Trim (Max stability = 0, Max steadiness = 100): 58
	Bow angle (Positive = bow angles forward): 3.00 degrees
	Stern overhang: 1.50 ft / 0.46 m
	Freeboard (% = measuring location as a percentage of overall length):
	   - Stem:		24.00 ft / 7.32 m
	   - Forecastle (20 %):	23.00 ft / 7.01 m
	   - Mid (33 %):		22.00 ft / 6.71 m (14.00 ft / 4.27 m aft of break)
	   - Quarterdeck (15 %):	14.00 ft / 4.27 m
	   - Stern:		15.00 ft / 4.57 m
	   - Average freeboard:	17.06 ft / 5.20 m

Ship space, strength and comments:
	Space	- Hull below water (magazines/engines, low = better): 183.9 %
		- Above water (accommodation/working, high = better): 141.1 %
	Waterplane Area: 9,153 Square feet or 850 Square metres
	Displacement factor (Displacement / loading): 65 %
	Structure weight / hull surface area: 29 lbs/sq ft or 139 Kg/sq metre
	Hull strength (Relative):
		- Cross-sectional: 0.44
		- Longitudinal: 1.67
		- Overall: 0.50
	Hull space for machinery, storage, compartmentation is cramped
	Room for accommodation and workspaces is excellent
	Ship has slow, easy roll, a good, steady gun platform
	Excellent seaboat, comfortable, can fire her guns in the heaviest weather

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