Where Springsharp is known to be weak: an example is the GB/PG/1915

Springsharp inherited some of the issues from Springstyle, in that Springsharp has a problem with very fast destroyer-type ships. From the real world, the Thornycroft "Special" S-class ship Speedy made 37.511 knots at a displacement of 1,034 tons with power of 33,020 SHP. The waterline length was nominally 272ft-9in. Compare that with my friend Cliff's design for the GB/PG/1915 destroyer-like fast gunboat. The nominal waterline length there is 275ft with an intended displacement of 900 tons. The armament was intended to be 3-5in/50 QF guns with no torpedo tubes. The speed was intended to be 36 knots. that should be possible, even if the displacement needed to rise some. Now look at the Springsharp report. The power is too great for the length and displacement:

GB/PG/1915, Great Britain Fast Gunboat laid down 1915 (Engine 1941)

Displacement:
 1,016 t light; 1,049 t standard; 1,085 t normal; 1,114 t full load

Dimensions: Length overall / water x beam x draught
 275.70 ft / 275.00 ft x 27.00 ft x 15.00 ft (normal load)
 84.03 m / 83.82 m x 8.23 m  x 4.57 m

Armament:
      3 - 5.00" / 127 mm guns in single mounts, 62.50lbs / 28.35kg shells, 1915 Model
   Quick firing guns in deck mounts with hoists
   on centreline ends, majority forward, all raised mounts - superfiring
 Weight of broadside 188 lbs / 85 kg
 Shells per gun, main battery: 100

Machinery:
 Oil fired boilers, steam turbines, 
 Geared drive, 2 shafts, 47,382 shp / 35,347 Kw = 36.00 kts
 Range 2,500nm at 10.00 kts
 Bunker at max displacement = 66 tons

Complement:
 93 - 122

Cost:
 £0.206 million / $0.822 million

Distribution of weights at normal displacement:
 Armament: 23 tons, 2.2 %
 Machinery: 615 tons, 56.7 %
 Hull, fittings & equipment: 378 tons, 34.9 %
 Fuel, ammunition & stores: 69 tons, 6.3 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   186 lbs / 84 Kg = 3.0 x 5.0 " / 127 mm shells or 0.2 torpedoes
 Stability (Unstable if below 1.00): 1.13
 Metacentric height 0.9 ft / 0.3 m
 Roll period: 12.1 seconds
 Steadiness - As gun platform (Average = 50 %): 56 %
   - Recoil effect (Restricted arc if above 1.00): 0.92
 Seaboat quality  (Average = 1.00): 1.05

Hull form characteristics:
 Hull has rise forward of midbreak
 Block coefficient: 0.341
 Length to Beam Ratio: 10.19 : 1
 'Natural speed' for length: 16.58 kts
 Power going to wave formation at top speed: 72 %
 Trim (Max stability = 0, Max steadiness = 100): 54
 Bow angle (Positive = bow angles forward): 2.00 degrees
 Stern overhang: 0.00 ft / 0.00 m
 Freeboard (% = measuring location as a percentage of overall length):
    - Stem:  20.00 ft / 6.10 m
    - Forecastle (36 %): 19.00 ft / 5.79 m
    - Mid (36 %):  19.00 ft / 5.79 m (13.00 ft / 3.96 m aft of break)
    - Quarterdeck (15 %): 13.00 ft / 3.96 m
    - Stern:  13.00 ft / 3.96 m
    - Average freeboard: 15.30 ft / 4.66 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 198.7 %
  - Above water (accommodation/working, high = better): 120.3 %
 Waterplane Area: 4,518 Square feet or 420 Square metres
 Displacement factor (Displacement / loading): 40 %
 Structure weight / hull surface area: 30 lbs/sq ft or 146 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.38
  - Longitudinal: 5.80
  - Overall: 0.50
 Hull space for machinery, storage, compartmentation is cramped
 Room for accommodation and workspaces is excellent