The 2001 version of the GB/FG/1913 gunboat

My friend Cliff had conceived of an intermediate type that he called an FG (Frigate Gunboat). The ships would be laid down in 1913 and would have 5-4in QF guns and 2-21in TT. The speed would be a moderate 32 knots. They would be 1,200 tons Standard displacement. He wanted to have superfiring guns, but in 2001, I thought that the more appropriate design would just distribute the five guns on the centerline. The ship in my 2001 pencil sketch resembles a Talisman-class boat, having three funnels with a wider space between the first and second funnels. The first funnel is raised. I was able to make this work in Springsharp with lightweight machinery. This is the Springsharp report:

GB/FG/1913 2001 version, Great Britain Frigate Gunboat laid down 1913 (Engine 1937)

Displacement:
 1,154 t light; 1,199 t standard; 1,450 t normal; 1,651 t full load

Dimensions: Length overall / water x beam x draught
 316.15 ft / 315.00 ft x 30.00 ft x 10.00 ft (normal load)
 96.36 m / 96.01 m x 9.14 m  x 3.05 m

Armament:
      5 - 4.00" / 102 mm guns in single mounts, 32.00lbs / 14.51kg shells, 1913 Model
   Quick firing guns in deck mounts with hoists
   on centreline, evenly spread
 Weight of broadside 160 lbs / 73 kg
 Shells per gun, main battery: 180
 2 - 21.0" / 533.4 mm above water torpedoes

Machinery:
 Oil fired boilers, steam turbines, 
 Direct drive, 2 shafts, 35,291 shp / 26,327 Kw = 32.00 kts
 Range 6,500nm at 15.00 kts
 Bunker at max displacement = 452 tons

Complement:
 116 - 152

Cost:
 £0.177 million / $0.706 million

Distribution of weights at normal displacement:
 Armament: 20 tons, 1.4 %
 Machinery: 748 tons, 51.6 %
 Hull, fittings & equipment: 386 tons, 26.6 %
 Fuel, ammunition & stores: 296 tons, 20.4 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   425 lbs / 193 Kg = 13.3 x 4.0 " / 102 mm shells or 0.3 torpedoes
 Stability (Unstable if below 1.00): 1.51
 Metacentric height 1.7 ft / 0.5 m
 Roll period: 9.8 seconds
 Steadiness - As gun platform (Average = 50 %): 51 %
   - Recoil effect (Restricted arc if above 1.00): 0.31
 Seaboat quality  (Average = 1.00): 1.02

Hull form characteristics:
 Hull has rise forward of midbreak
 Block coefficient: 0.537
 Length to Beam Ratio: 10.50 : 1
 'Natural speed' for length: 17.75 kts
 Power going to wave formation at top speed: 71 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): 3.00 degrees
 Stern overhang: 0.00 ft / 0.00 m
 Freeboard (% = measuring location as a percentage of overall length):
    - Stem:  22.00 ft / 6.71 m
    - Forecastle (20 %): 20.00 ft / 6.10 m
    - Mid (36 %):  20.00 ft / 6.10 m (12.00 ft / 3.66 m aft of break)
    - Quarterdeck (15 %): 12.00 ft / 3.66 m
    - Stern:  12.00 ft / 3.66 m
    - Average freeboard: 15.04 ft / 4.58 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 177.3 %
  - Above water (accommodation/working, high = better): 127.7 %
 Waterplane Area: 6,516 Square feet or 605 Square metres
 Displacement factor (Displacement / loading): 69 %
 Structure weight / hull surface area: 28 lbs/sq ft or 135 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.46
  - Longitudinal: 2.31
  - Overall: 0.54
 Hull space for machinery, storage, compartmentation is cramped
 Room for accommodation and workspaces is excellent