Swiss Patrol Torpedo Boat

[Desertfox]

A development of the Multi Purpose Ship, made with the intent of reducing cost even further. While this ship can still be turned into an ad hoc minelayer/sweeper, it no longer has the full capability. It also doesnt have the full quick change capability. Only the rear gun (40mm->4") and the two foward fixed torpedo tubes (18"TT->40mm) can be exchanged. She can also use 76mm army field guns in emergencies.

100 of these will be built and only 50 Multi Purpose (down from 120)

PT-1 , New Switzerland Patrol Torpedo Boat laid down 1907 (Engine 1909)

Displacement:
   191 t light; 201 t standard; 226 t normal; 246 t full load

Dimensions: Length overall / water x beam x draught
   194.73 ft / 190.00 ft x 19.00 ft x 5.10 ft (normal load)
   59.35 m / 57.91 m x 5.79 m  x 1.55 m

Armament:
      1 - 4.00" / 102 mm guns in single mounts, 32.00lbs / 14.51kg shells, 1907 Model
     Quick firing gun in deck mount
     on centreline forward
      2 - 1.57" / 40.0 mm guns (1x2 guns), 1.95lbs / 0.89kg shells, 1907 Model
     Quick firing guns in deck mount
     on centreline aft
      2 - 0.50" / 12.7 mm guns in single mounts, 0.06lbs / 0.03kg shells, 1907 Model
     Machine guns in deck mounts
     on side, evenly spread
   Weight of broadside 36 lbs / 16 kg
   Shells per gun, main battery: 270
   4 - 18.0" / 457.2 mm above water torpedoes

Armour:
   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   0.50" / 13 mm         -               -

Machinery:
   Coal and oil fired boilers, steam turbines,
   Direct drive, 2 shafts, 3,991 shp / 2,977 Kw = 24.00 kts
   Range 2,000nm at 10.00 kts
   Bunker at max displacement = 45 tons (90% coal)

Complement:
   28 - 37

Cost:
   £0.026 million / $0.104 million

Distribution of weights at normal displacement:
   Armament: 5 tons, 2.0 %
   Armour: 1 tons, 0.5 %
      - Belts: 0 tons, 0.0 %
      - Torpedo bulkhead: 0 tons, 0.0 %
      - Armament: 1 tons, 0.5 %
      - Armour Deck: 0 tons, 0.0 %
      - Conning Tower: 0 tons, 0.0 %
   Machinery: 111 tons, 48.9 %
   Hull, fittings & equipment: 69 tons, 30.7 %
   Fuel, ammunition & stores: 36 tons, 15.7 %
   Miscellaneous weights: 5 tons, 2.2 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     74 lbs / 33 Kg = 2.3 x 4.0 " / 102 mm shells or 0.1 torpedoes
   Stability (Unstable if below 1.00): 1.25
   Metacentric height 0.6 ft / 0.2 m
   Roll period: 10.2 seconds
   Steadiness   - As gun platform (Average = 50 %): 70 %
         - Recoil effect (Restricted arc if above 1.00): 0.20
   Seaboat quality  (Average = 1.00): 1.01

Hull form characteristics:
   Hull has a flush deck
   Block coefficient: 0.430
   Length to Beam Ratio: 10.00 : 1
   'Natural speed' for length: 13.78 kts
   Power going to wave formation at top speed: 65 %
   Trim (Max stability = 0, Max steadiness = 100): 69
   Bow angle (Positive = bow angles forward): 20.00 degrees
   Stern overhang: 0.00 ft / 0.00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      13.00 ft / 3.96 m
      - Forecastle (20 %):   9.00 ft / 2.74 m
      - Mid (40 %):      8.00 ft / 2.44 m
      - Quarterdeck (20 %):   7.00 ft / 2.13 m
      - Stern:      7.00 ft / 2.13 m
      - Average freeboard:   8.22 ft / 2.51 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 176.8 %
      - Above water (accommodation/working, high = better): 53.0 %
   Waterplane Area: 2,267 Square feet or 211 Square metres
   Displacement factor (Displacement / loading): 52 %
   Structure weight / hull surface area: 16 lbs/sq ft or 80 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.50
      - Longitudinal: 1.74
      - Overall: 0.56
   Hull space for machinery, storage, compartmentation is cramped
   Room for accommodation and workspaces is cramped
   Ship has slow, easy roll, a good, steady gun platform

[The Rock Doctor]

I'm not really keen on the whole weapon/kit swapping concept, really, but I suppose it's a decent coastal defence vessel.