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Thursday, January 06, 2005

I had to scale back my expections for the Ger/CB/1905

I designed a light battlecruiser for the Germans in 1905 (the Ger/CB/1905). I had to settle for increasing the displacement above the planned 19,000 tons and reduced the speed from the planned 31 knots. This is what we are left with. It actually didn't turn out so badly, although I really wanted a higher speed, considering the sacrifice of guns and armor.
Ger/CB/1905, Germany Battlecruiser laid down 1905

Displacement:
	17,405 t light; 18,068 t standard; 20,028 t normal; 21,596 t full load

Dimensions: Length overall / water x beam x draught
	700.00 ft / 700.00 ft x 80.00 ft x 24.40 ft (normal load)
	213.36 m / 213.36 m x 24.38 m  x 7.44 m

Armament:
      4 - 12.00" / 305 mm guns in single mounts, 864.00lbs / 391.90kg shells, 1905 Model
	  Breech loading guns in turrets (on barbettes)
	  on centreline ends, evenly spread, all raised mounts - superfiring
      12 - 4.00" / 102 mm guns in single mounts, 32.00lbs / 14.51kg shells, 1905 Model
	  Quick firing guns in casemate mounts 
	  on side ends, evenly spread, all raised mounts - superfiring
	Weight of broadside 3,840 lbs / 1,742 kg
	Shells per gun, main battery: 120

Armour:
   - Belts:		Width (max)	Length (avg)		Height (avg)
	Main:	4.00" / 102 mm	375.00 ft / 114.30 m	8.00 ft / 2.44 m
	Ends:	Unarmoured
	Upper:	3.00" / 76 mm	375.00 ft / 114.30 m	0.00 ft / 0.00 m
	  Main Belt covers 82 % of normal length
	  Main belt does not fully cover magazines and engineering spaces

   - Gun armour:	Face (max)	Other gunhouse (avg)	Barbette/hoist (max)
	Main:	9.00" / 229 mm	4.00" / 102 mm		4.00" / 102 mm
	2nd:	2.00" / 51 mm	1.00" / 25 mm		      -

   - Armour deck: 3.00" / 76 mm, Conning tower: 9.00" / 229 mm

Machinery:
	Oil fired boilers, steam turbines, 
	Direct drive, 4 shafts, 73,568 shp / 54,882 Kw = 28.00 kts
	Range 4,500nm at 15.00 kts
	Bunker at max displacement = 3,528 tons

Complement:
	841 - 1,094

Cost:
	£1.793 million / $7.171 million

Distribution of weights at normal displacement:
	Armament: 480 tons, 2.4 %
	Armour: 3,404 tons, 17.0 %
	   - Belts: 524 tons, 2.6 %
	   - Torpedo bulkhead: 0 tons, 0.0 %
	   - Armament: 641 tons, 3.2 %
	   - Armour Deck: 2,096 tons, 10.5 %
	   - Conning Tower: 143 tons, 0.7 %
	Machinery: 5,573 tons, 27.8 %
	Hull, fittings & equipment: 7,947 tons, 39.7 %
	Fuel, ammunition & stores: 2,623 tons, 13.1 %
	Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
	Survivability (Non-critical penetrating hits needed to sink ship):
	  21,711 lbs / 9,848 Kg = 25.1 x 12.0 " / 305 mm shells or 2.0 torpedoes
	Stability (Unstable if below 1.00): 1.19
	Metacentric height 5.0 ft / 1.5 m
	Roll period: 15.1 seconds
	Steadiness	- As gun platform (Average = 50 %): 92 %
			- Recoil effect (Restricted arc if above 1.00): 0.62
	Seaboat quality  (Average = 1.00): 1.73

Hull form characteristics:
	Hull has raised forecastle, rise forward of midbreak
	Block coefficient: 0.513
	Length to Beam Ratio: 8.75 : 1
	'Natural speed' for length: 26.46 kts
	Power going to wave formation at top speed: 47 %
	Trim (Max stability = 0, Max steadiness = 100): 53
	Bow angle (Positive = bow angles forward): -1.00 degrees
	Stern overhang: -2.00 ft / -0.61 m
	Freeboard (% = measuring location as a percentage of overall length):
	   - Stem:		32.00 ft / 9.75 m
	   - Forecastle (20 %):	28.00 ft / 8.53 m (27.00 ft / 8.23 m aft of break)
	   - Mid (70 %):		27.00 ft / 8.23 m (18.00 ft / 5.49 m aft of break)
	   - Quarterdeck (15 %):	18.00 ft / 5.49 m
	   - Stern:		18.00 ft / 5.49 m
	   - Average freeboard:	24.82 ft / 7.57 m

Ship space, strength and comments:
	Space	- Hull below water (magazines/engines, low = better): 108.7 %
		- Above water (accommodation/working, high = better): 213.1 %
	Waterplane Area: 37,758 Square feet or 3,508 Square metres
	Displacement factor (Displacement / loading): 109 %
	Structure weight / hull surface area: 137 lbs/sq ft or 667 Kg/sq metre
	Hull strength (Relative):
		- Cross-sectional: 0.97
		- Longitudinal: 1.41
		- Overall: 1.00
	Hull space for machinery, storage, compartmentation is adequate
	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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