The Ger/DD/1915 design pushes Springsharp

The Ger/DD/1915 design should work easily in Springsharp, but does not. The main issue seems to be the empirical formula used to compute the power required to power the ship to a certain speed. For small ships, the formula seems not to work well. All my 1971 designs were based on knowledge about real ship designs from 1905 to 1921, so that there is nothing that should not be reasonable. Instead, I had to manipulate the design to work in Springsharp, as it presently is. This is the original specification:

Ger/DD/1915  800 tons Standard  20,000 SHP @ 45 SHP/ton
 Armament=   20 tons       240ft x 26ft Depth=20ft
 Machinery= 444 tons       Cp=0.58  Cm=0.80
 Hull=      272 tons       2-4in QF guns (1.7 ton)  4-21in TT
 Misc.=      64 tons       20 mines
 Oil Fuel=  200 tons
 Feedwater=  50 tons   Full load displacement= 1,050 tons

This is the Springsharp report for what I was able to implement:

Ger/DD/1915, Germany Destroyer laid down 1915 (Engine 1950)

Displacement:
 782 t light; 806 t standard; 910 t normal; 993 t full load

Dimensions: Length overall / water x beam x draught
 244.80 ft / 240.00 ft x 26.00 ft x 11.00 ft (normal load)
 74.62 m / 73.15 m x 7.92 m  x 3.35 m

Armament:
      2 - 4.00" / 102 mm guns in single mounts, 32.00lbs / 14.51kg shells, 1915 Model
   Quick firing guns in deck mounts with hoists
   on centreline ends, evenly spread
 Weight of broadside 64 lbs / 29 kg
 Shells per gun, main battery: 180
 4 - 21.0" / 533.4 mm above water torpedoes

Machinery:
 Oil fired boilers, steam turbines, 
 Geared drive, 2 shafts, 30,622 shp / 22,844 Kw = 32.00 kts
 Range 3,800nm at 15.00 kts
 Bunker at max displacement = 187 tons

Complement:
 82 - 107

Cost:
 £0.146 million / $0.584 million

Distribution of weights at normal displacement:
 Armament: 8 tons, 0.9 %
 Machinery: 474 tons, 52.1 %
 Hull, fittings & equipment: 280 tons, 30.7 %
 Fuel, ammunition & stores: 128 tons, 14.1 %
 Miscellaneous weights: 20 tons, 2.2 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   238 lbs / 108 Kg = 7.4 x 4.0 " / 102 mm shells or 0.2 torpedoes
 Stability (Unstable if below 1.00): 1.21
 Metacentric height 0.9 ft / 0.3 m
 Roll period: 11.3 seconds
 Steadiness - As gun platform (Average = 50 %): 53 %
   - Recoil effect (Restricted arc if above 1.00): 0.29
 Seaboat quality  (Average = 1.00): 1.06

Hull form characteristics:
 Hull has rise forward of midbreak
 Block coefficient: 0.464
 Length to Beam Ratio: 9.23 : 1
 'Natural speed' for length: 15.49 kts
 Power going to wave formation at top speed: 76 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): 2.00 degrees
 Stern overhang: 4.00 ft / 1.22 m
 Freeboard (% = measuring location as a percentage of overall length):
    - Stem:  23.00 ft / 7.01 m
    - Forecastle (20 %): 22.50 ft / 6.86 m
    - Mid (20 %):  22.50 ft / 6.86 m (14.50 ft / 4.42 m aft of break)
    - Quarterdeck (15 %): 14.50 ft / 4.42 m
    - Stern:  14.50 ft / 4.42 m
    - Average freeboard: 16.14 ft / 4.92 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 177.5 %
  - Above water (accommodation/working, high = better): 75.7 %
 Waterplane Area: 4,027 Square feet or 374 Square metres
 Displacement factor (Displacement / loading): 59 %
 Structure weight / hull surface area: 24 lbs/sq ft or 118 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.39
  - Longitudinal: 7.41
  - Overall: 0.53
 Hull space for machinery, storage, compartmentation is cramped
 Room for accommodation and workspaces is cramped