The It/DD/1931 design

Springsharp seems to have some pretty extreme limitations for small ships. To even reach 35 knots, rather than the 38 knots of the real Italian destroyers, I had to have an unrealistically high freeboard, too deep a draft, and too great a displacement. The only improvement of these ships over the It/DD/1927 design is a knot of speed. This is the Springsharp report:

It/DD/1931, Italy Destroyer laid down 1931 (Engine 1950)

Displacement:
 1,395 t light; 1,445 t standard; 1,600 t normal; 1,724 t full load

Dimensions: Length overall / water x beam x draught
 317.10 ft / 315.00 ft x 32.00 ft x 12.00 ft (normal load)
 96.65 m / 96.01 m x 9.75 m  x 3.66 m

Armament:
      4 - 4.70" / 119 mm guns in single mounts, 51.91lbs / 23.55kg shells, 1931 Model
   Quick firing guns in deck mounts with hoists
   on centreline, evenly spread, 1 raised mount
   Aft Main mounts separated by engine room
      4 - 1.46" / 37.0 mm guns (2x2 guns), 1.55lbs / 0.70kg shells, 1931 Model
   Anti-aircraft guns in deck mounts with hoists
   on side, all amidships, all raised mounts - superfiring
 Weight of broadside 214 lbs / 97 kg
 Shells per gun, main battery: 150
 6 - 21.0" / 533.4 mm above water torpedoes

Machinery:
 Oil fired boilers, steam turbines, 
 Geared drive, 2 shafts, 53,744 shp / 40,093 Kw = 35.00 kts
 Range 4,200nm at 15.00 kts
 Bunker at max displacement = 280 tons

Complement:
 126 - 164

Cost:
 £0.850 million / $3.399 million

Distribution of weights at normal displacement:
 Armament: 27 tons, 1.7 %
 Machinery: 882 tons, 55.1 %
 Hull, fittings & equipment: 486 tons, 30.4 %
 Fuel, ammunition & stores: 205 tons, 12.8 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   379 lbs / 172 Kg = 7.3 x 4.7 " / 119 mm shells or 0.2 torpedoes
 Stability (Unstable if below 1.00): 1.34
 Metacentric height 1.5 ft / 0.5 m
 Roll period: 10.9 seconds
 Steadiness - As gun platform (Average = 50 %): 50 %
   - Recoil effect (Restricted arc if above 1.00): 0.48
 Seaboat quality  (Average = 1.00): 1.01

Hull form characteristics:
 Hull has rise forward of midbreak
 Block coefficient: 0.463
 Length to Beam Ratio: 9.84 : 1
 'Natural speed' for length: 17.75 kts
 Power going to wave formation at top speed: 74 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): 5.00 degrees
 Stern overhang: 0.00 ft / 0.00 m
 Freeboard (% = measuring location as a percentage of overall length):
    - Stem:  24.00 ft / 7.32 m
    - Forecastle (20 %): 22.00 ft / 6.71 m
    - Mid (42 %):  22.00 ft / 6.71 m (14.00 ft / 4.27 m aft of break)
    - Quarterdeck (15 %): 14.00 ft / 4.27 m
    - Stern:  14.00 ft / 4.27 m
    - Average freeboard: 17.52 ft / 5.34 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 190.6 %
  - Above water (accommodation/working, high = better): 96.8 %
 Waterplane Area: 6,500 Square feet or 604 Square metres
 Displacement factor (Displacement / loading): 57 %
 Structure weight / hull surface area: 30 lbs/sq ft or 149 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.40
  - Longitudinal: 4.05
  - Overall: 0.51
 Hull space for machinery, storage, compartmentation is cramped
 Room for accommodation and workspaces is adequate