A German light cruiser design study

I didn't supply a date or designation to a pencil sketch and specifications, but I thought it might date from 1916. It looks very much like a German WWI light cruiser, except that it has three twin 6in gun mounts. The dimensions are specified as 475ft x 48ft x 16.5ft. The armament is 6-6in QF guns and 4-23.6in TT in twin mounts. The standard displacement is 5,400 tons and the specified machinery power is 60,000 SHP. The weights specified originally are:

• Hull: 1663 tons
• Mach: 1500 tons
• Arm: 93 tons
• Prot: 1712 tons
• Misc: 432 tons

This is the Springsharp report that shows what I was able to achieve in the design. The only reason that this was possible is due to lightweight machinery:

Ger/CL/1916 Design Study, Germany Light Cruiser laid down 1916 (Engine 1950)

Displacement:
 5,322 t light; 5,503 t standard; 5,850 t normal; 6,127 t full load

Dimensions: Length overall / water x beam x draught
 477.87 ft / 475.00 ft x 48.00 ft x 16.50 ft (normal load)
 145.66 m / 144.78 m x 14.63 m  x 5.03 m

Armament:
      6 - 6.00" / 152 mm guns (3x2 guns), 108.00lbs / 48.99kg shells, 1916 Model
   Quick firing guns in deck mounts with hoists
   on centreline ends, majority aft, 1 raised mount aft - superfiring
 Weight of broadside 648 lbs / 294 kg
 Shells per gun, main battery: 180
 4 - 23.6" / 599.44 mm above water torpedoes

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 4.00" / 102 mm 340.00 ft / 103.63 m 9.00 ft / 2.74 m
 Ends: Unarmoured
 Upper: 4.00" / 102 mm 190.00 ft / 57.91 m 8.00 ft / 2.44 m
   Main Belt covers 110 % of normal length
   Main belt does not fully cover magazines and engineering spaces

   - Torpedo Bulkhead:
  1.00" / 25 mm 340.00 ft / 103.63 m 15.00 ft / 4.57 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 4.00" / 102 mm       -   4.00" / 102 mm

   - Armour deck: 2.00" / 51 mm, Conning tower: 4.00" / 102 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Geared drive, 2 shafts, 60,020 shp / 44,775 Kw = 31.00 kts
 Range 4,250nm at 15.00 kts
 Bunker at max displacement = 624 tons

Complement:
 333 - 434

Cost:
 £0.745 million / $2.980 million

Distribution of weights at normal displacement:
 Armament: 81 tons, 1.4 %
 Armour: 1,659 tons, 28.4 %
    - Belts: 780 tons, 13.3 %
    - Torpedo bulkhead: 189 tons, 3.2 %
    - Armament: 77 tons, 1.3 %
    - Armour Deck: 586 tons, 10.0 %
    - Conning Tower: 28 tons, 0.5 %
 Machinery: 1,436 tons, 24.5 %
 Hull, fittings & equipment: 2,146 tons, 36.7 %
 Fuel, ammunition & stores: 528 tons, 9.0 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   7,970 lbs / 3,615 Kg = 73.8 x 6.0 " / 152 mm shells or 1.5 torpedoes
 Stability (Unstable if below 1.00): 1.19
 Metacentric height 2.3 ft / 0.7 m
 Roll period: 13.3 seconds
 Steadiness - As gun platform (Average = 50 %): 50 %
   - Recoil effect (Restricted arc if above 1.00): 0.31
 Seaboat quality  (Average = 1.00): 1.01

Hull form characteristics:
 Hull has rise forward of midbreak
 Block coefficient: 0.544
 Length to Beam Ratio: 9.90 : 1
 'Natural speed' for length: 21.79 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: 2.00 ft / 0.61 m
 Freeboard (% = measuring location as a percentage of overall length):
    - Stem:  25.00 ft / 7.62 m
    - Forecastle (20 %): 23.00 ft / 7.01 m
    - Mid (32 %):  23.00 ft / 7.01 m (15.00 ft / 4.57 m aft of break)
    - Quarterdeck (15 %): 15.00 ft / 4.57 m
    - Stern:  15.00 ft / 4.57 m
    - Average freeboard: 17.72 ft / 5.40 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 156.1 %
  - Above water (accommodation/working, high = better): 126.4 %
 Waterplane Area: 15,827 Square feet or 1,470 Square metres
 Displacement factor (Displacement / loading): 113 %
 Structure weight / hull surface area: 80 lbs/sq ft or 390 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.95
  - Longitudinal: 1.64
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is cramped
 Room for accommodation and workspaces is excellent