Patrolboats

[Desertfox]

The former Cairo torpedo boats, reffited and reclassified as Patrol boats.


PT-1
PT-2
PT-3

PT-1 class, New Zion (ex-Cairo) Patrol-Torpedo boat laid down 1891 (Engine 1905)

Displacement:
   90 t light; 92 t standard; 98 t normal; 103 t full load

Dimensions: Length overall / water x beam x draught
   120.00 ft / 120.00 ft x 12.00 ft x 5.90 ft (normal load)
   36.58 m / 36.58 m x 3.66 m  x 1.80 m

Armament:
      1 - 3.00" / 76.2 mm guns in single mounts, 13.50lbs / 6.12kg shells, 1905 Model
     Quick firing gun in deck mount
     on centreline forward
      4 - 0.50" / 12.7 mm guns in single mounts, 0.06lbs / 0.03kg shells, 1905 Model
     Machine guns in deck mounts
     on side, all amidships
   Weight of broadside 14 lbs / 6 kg
   Shells per gun, main battery: 50
   2 - 14.0" / 355.6 mm above water torpedoes

Machinery:
   Coal and oil fired boilers, complex reciprocating steam engines,
   Direct drive, 2 shafts, 1,385 ihp / 1,033 Kw = 20.00 kts
   Range 700nm at 10.00 kts
   Bunker at max displacement = 11 tons (90% coal)
     Caution: Delicate, lightweight machinery

Complement:
   15 - 20

Cost:
   £0.012 million / $0.050 million

Distribution of weights at normal displacement:
   Armament: 2 tons, 1.7 %
   Machinery: 56 tons, 57.3 %
   Hull, fittings & equipment: 31 tons, 31.6 %
   Fuel, ammunition & stores: 8 tons, 8.4 %
   Miscellaneous weights: 1 tons, 1.0 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     21 lbs / 10 Kg = 1.6 x 3.0 " / 76 mm shells or 0.1 torpedoes
   Stability (Unstable if below 1.00): 1.19
   Metacentric height 0.3 ft / 0.1 m
   Roll period: 9.4 seconds
   Steadiness   - As gun platform (Average = 50 %): 69 %
         - Recoil effect (Restricted arc if above 1.00): 0.37
   Seaboat quality  (Average = 1.00): 1.62

Hull form characteristics:
   Hull has a flush deck
   Block coefficient: 0.405
   Length to Beam Ratio: 10.00 : 1
   'Natural speed' for length: 10.95 kts
   Power going to wave formation at top speed: 66 %
   Trim (Max stability = 0, Max steadiness = 100): 43
   Bow angle (Positive = bow angles forward): 0.00 degrees
   Stern overhang: 0.00 ft / 0.00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      11.00 ft / 3.35 m
      - Forecastle (20 %):   7.00 ft / 2.13 m
      - Mid (50 %):      7.00 ft / 2.13 m
      - Quarterdeck (15 %):   7.00 ft / 2.13 m
      - Stern:      7.00 ft / 2.13 m
      - Average freeboard:   7.32 ft / 2.23 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 198.3 %
      - Above water (accommodation/working, high = better): 45.4 %
   Waterplane Area: 889 Square feet or 83 Square metres
   Displacement factor (Displacement / loading): 24 %
   Structure weight / hull surface area: 12 lbs/sq ft or 58 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.43
      - Longitudinal: 6.14
      - Overall: 0.56
   Caution: Hull subject to strain in open-sea
   Hull space for machinery, storage, compartmentation is cramped
   Room for accommodation and workspaces is extremely poor
   Excellent seaboat, comfortable, can fire her guns in the heaviest weather