The Ger/CB/1905 design from the Red Book

I had designed the Ger/CB/1915 light battlecruiser to be a lower-cost alternative to my friend Cliff's GB/CB/1905 design. I had done a fresh drawing and specificatino on 18 July 1973. I also played around with how to stretch the design. One feature of the specification is that I underestimated the power required to reach 31 knots. The only saving grace is that the design concept had enough slop so that enough power could be added not only to reach 31 knots, but 32 knots and to have an 18 knot cruising speed for 7,800nm miles on top of that! In the wargame campaign, I unimaginatively named the ship Blücher. My original specification had the following weights:

Hull =          8,070 tons
Machinery =     3,000 tons
Protection =    5,895 tons
Armament =        515 tons
Miscellaneous = 1,520 tons
Oil fuel =      3,500 tons (1,000 tons normal)
Feed water =      150 tons

The original standard displacement was 19,000 tons, but the Springsharp design ended up lower than that simply because I had spare capacity that could be removed. This is the Springsharp report:

Ger/CB/1905, Germany Light Battlecruiser laid down 1905 (Engine 1931)

Displacement:
 17,035 t light; 17,630 t standard; 19,900 t normal; 21,716 t full load

Dimensions: Length overall / water x beam x draught
 700.00 ft / 700.00 ft x 80.00 ft x 25.00 ft (normal load)
 213.36 m / 213.36 m x 24.38 m  x 7.62 m

Armament:
      4 - 12.00" / 305 mm guns (2x2 guns), 864.00lbs / 391.90kg shells, 1905 Model
   Breech loading guns in turrets (on barbettes)
   on centreline ends, evenly spread
      12 - 4.00" / 102 mm guns in single mounts, 32.00lbs / 14.51kg shells, 1905 Model
   Quick firing guns in casemate mounts 
   on centreline ends, evenly spread
 Weight of broadside 3,840 lbs / 1,742 kg
 Shells per gun, main battery: 90

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 4.00" / 102 mm 370.00 ft / 112.78 m 16.00 ft / 4.88 m
 Ends: Unarmoured
 Upper: 4.00" / 102 mm 320.00 ft / 97.54 m 8.00 ft / 2.44 m
   Main Belt covers 81 % of normal length
   Main belt does not fully cover magazines and engineering spaces

   - Torpedo Bulkhead:
  2.00" / 51 mm 370.00 ft / 112.78 m 25.00 ft / 7.62 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 9.00" / 229 mm 7.00" / 178 mm  6.00" / 152 mm
 2nd: 4.00" / 102 mm 4.00" / 102 mm  4.00" / 102 mm

   - Armour deck: 3.00" / 76 mm, Conning tower: 4.00" / 102 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Direct drive, 4 shafts, 122,812 shp / 91,618 Kw = 32.00 kts
 Range 7,800nm at 18.00 kts
 Bunker at max displacement = 4,086 tons

Complement:
 837 - 1,089

Cost:
 £1.514 million / $6.054 million

Distribution of weights at normal displacement:
 Armament: 480 tons, 2.4 %
 Armour: 5,078 tons, 25.5 %
    - Belts: 1,497 tons, 7.5 %
    - Torpedo bulkhead: 685 tons, 3.4 %
    - Armament: 767 tons, 3.9 %
    - Armour Deck: 2,066 tons, 10.4 %
    - Conning Tower: 63 tons, 0.3 %
 Machinery: 3,673 tons, 18.5 %
 Hull, fittings & equipment: 7,804 tons, 39.2 %
 Fuel, ammunition & stores: 2,865 tons, 14.4 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   32,987 lbs / 14,963 Kg = 38.2 x 12.0 " / 305 mm shells or 4.6 torpedoes
 Stability (Unstable if below 1.00): 1.25
 Metacentric height 5.4 ft / 1.6 m
 Roll period: 14.5 seconds
 Steadiness - As gun platform (Average = 50 %): 69 %
   - Recoil effect (Restricted arc if above 1.00): 0.37
 Seaboat quality  (Average = 1.00): 1.37

Hull form characteristics:
 Hull has rise forward of midbreak
 Block coefficient: 0.498
 Length to Beam Ratio: 8.75 : 1
 'Natural speed' for length: 26.46 kts
 Power going to wave formation at top speed: 54 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): -1.00 degrees
 Stern overhang: -1.00 ft / -0.30 m
 Freeboard (% = measuring location as a percentage of overall length):
    - Stem:  31.00 ft / 9.45 m
    - Forecastle (20 %): 28.00 ft / 8.53 m
    - Mid (61 %):  28.00 ft / 8.53 m (20.00 ft / 6.10 m aft of break)
    - Quarterdeck (15 %): 20.00 ft / 6.10 m
    - Stern:  20.00 ft / 6.10 m
    - Average freeboard: 25.12 ft / 7.66 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 104.7 %
  - Above water (accommodation/working, high = better): 212.2 %
 Waterplane Area: 37,227 Square feet or 3,458 Square metres
 Displacement factor (Displacement / loading): 122 %
 Structure weight / hull surface area: 134 lbs/sq ft or 657 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.95
  - Longitudinal: 1.53
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is adequate
 Room for accommodation and workspaces is excellent
 Good seaboat, rides out heavy weather easily