This just goes to show how critical SHP/ton is: GB/PG/1915

The GB/PG/1915 fast gunboat really works well with a high SHP/ton. High is a relative term, as in this case, it means 61.74 SHP/ton. The Swift from 1905-1907 could be pressed to 64 SHP/ton. This design was intended to be 800 tons, 260ft x 27ft x 9.5ft, 4-4in QF guns, and 32 knots. This is the resulting Springsharp report:

GB/PG/1915, Great Britain Fast Gunboat laid down 1915 (Engine 1945)

Displacement:
 790 t light; 819 t standard; 909 t normal; 981 t full load

Dimensions: Length overall / water x beam x draught
 261.70 ft / 260.00 ft x 27.00 ft x 10.00 ft (normal load)
 79.77 m / 79.25 m x 8.23 m  x 3.05 m

Armament:
      4 - 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, evenly spread, all raised mounts
   Aft Main mounts separated by engine room
 Weight of broadside 128 lbs / 58 kg
 Shells per gun, main battery: 150

Machinery:
 Oil fired boilers, steam turbines, 
 Geared drive, 2 shafts, 28,464 shp / 21,234 Kw = 32.00 kts
 Range 3,200nm at 15.00 kts
 Bunker at max displacement = 162 tons

Complement:
 82 - 107

Cost:
 £0.154 million / $0.614 million

Distribution of weights at normal displacement:
 Armament: 16 tons, 1.8 %
 Machinery: 461 tons, 50.7 %
 Hull, fittings & equipment: 313 tons, 34.5 %
 Fuel, ammunition & stores: 119 tons, 13.1 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   265 lbs / 120 Kg = 8.3 x 4.0 " / 102 mm shells or 0.2 torpedoes
 Stability (Unstable if below 1.00): 1.21
 Metacentric height 1.0 ft / 0.3 m
 Roll period: 11.3 seconds
 Steadiness - As gun platform (Average = 50 %): 53 %
   - Recoil effect (Restricted arc if above 1.00): 0.70
 Seaboat quality  (Average = 1.00): 1.07

Hull form characteristics:
 Hull has a flush deck
 Block coefficient: 0.453
 Length to Beam Ratio: 9.63 : 1
 'Natural speed' for length: 16.12 kts
 Power going to wave formation at top speed: 74 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): 2.00 degrees
 Stern overhang: 1.00 ft / 0.30 m
 Freeboard (% = measuring location as a percentage of overall length):
    - Stem:  20.00 ft / 6.10 m
    - Forecastle (20 %): 17.00 ft / 5.18 m
    - Mid (50 %):  15.00 ft / 4.57 m
    - Quarterdeck (15 %): 14.00 ft / 4.27 m
    - Stern:  13.00 ft / 3.96 m
    - Average freeboard: 15.54 ft / 4.74 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 177.1 %
  - Above water (accommodation/working, high = better): 158.4 %
 Waterplane Area: 4,489 Square feet or 417 Square metres
 Displacement factor (Displacement / loading): 58 %
 Structure weight / hull surface area: 27 lbs/sq ft or 132 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.41
  - Longitudinal: 5.44
  - Overall: 0.53
 Hull space for machinery, storage, compartmentation is cramped
 Room for accommodation and workspaces is excellent