OPV-33 Class

[TacCovert4]

OPV-33, Aztec Offshore Patrol Vessel laid down 1933

Displacement:
   672 t light; 722 t standard; 832 t normal; 921 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (240.64 ft / 236.22 ft) x 26.90 ft x (8.37 / 9.06 ft)
   (73.35 m / 72.00 m) x 8.20 m  x (2.55 / 2.76 m)

Armament:
      4 - 3.54" / 90.0 mm 55.0 cal guns - 24.01lbs / 10.89kg shells, 400 per gun
     Dual purpose guns in deck mounts, 1933 Model
     2 x Twin mounts on centreline, forward evenly spread
      1 raised mount
      4 - 1.57" / 40.0 mm 50.0 cal guns - 2.07lbs / 0.94kg shells, 1,000 per gun
     Anti-air guns in deck mounts, 1933 Model
     2 x Twin mounts on sides, forward deck aft
      8 - 1.18" / 30.0 mm 50.0 cal guns - 0.86lbs / 0.39kg shells, 2,000 per gun
     Anti-air guns in deck mounts, 1933 Model
     8 x Single mounts on sides, aft evenly spread
      Weight of broadside 111 lbs / 50 kg

Armour:
   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   1.06" / 27 mm   1.06" / 27 mm            -

   - Box over magazines:
   1.06" / 27 mm

   - Conning towers: Forward 1.06" / 27 mm, Aft 0.00" / 0 mm

Machinery:
   Diesel Internal combustion motors,
   Geared drive, 2 shafts, 6,131 shp / 4,573 Kw = 22.00 kts
   Range 4,300nm at 14.00 kts
   Bunker at max displacement = 199 tons

Complement:
   76 - 100

Cost:
   £0.262 million / $1.049 million

Distribution of weights at normal displacement:
   Armament: 23 tons, 2.8 %
      - Guns: 23 tons, 2.8 %
   Armour: 28 tons, 3.4 %
      - Armament: 12 tons, 1.5 %
      - Armour Deck: 14 tons, 1.7 %
      - Conning Tower: 2 tons, 0.2 %
   Machinery: 179 tons, 21.5 %
   Hull, fittings & equipment: 207 tons, 24.8 %
   Fuel, ammunition & stores: 161 tons, 19.3 %
   Miscellaneous weights: 235 tons, 28.2 %
      - Hull below water: 79 tons
      - Hull above water: 10 tons
      - On freeboard deck: 93 tons
      - Above deck: 53 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     891 lbs / 404 Kg = 40.0 x 3.5 " / 90 mm shells or 0.6 torpedoes
   Stability (Unstable if below 1.00): 1.12
   Metacentric height 0.9 ft / 0.3 m
   Roll period: 12.2 seconds
   Steadiness   - As gun platform (Average = 50 %): 60 %
         - Recoil effect (Restricted arc if above 1.00): 0.23
   Seaboat quality  (Average = 1.00): 1.08

Hull form characteristics:
   Hull has rise forward of midbreak,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.548 / 0.559
   Length to Beam Ratio: 8.78 : 1
   'Natural speed' for length: 15.37 kts
   Power going to wave formation at top speed: 62 %
   Trim (Max stability = 0, Max steadiness = 100): 56
   Bow angle (Positive = bow angles forward): 20.00 degrees
   Stern overhang: 0.00 ft / 0.00 m
   Freeboard (% = length of deck as a percentage of waterline length):
            Fore end,    Aft end
      - Forecastle:   20.00 %,  12.14 ft / 3.70 m,  12.14 ft / 3.70 m
      - Forward deck:   30.00 %,  12.14 ft / 3.70 m,  12.14 ft / 3.70 m
      - Aft deck:   35.00 %,  8.20 ft / 2.50 m,  8.20 ft / 2.50 m
      - Quarter deck:   15.00 %,  8.20 ft / 2.50 m,  8.20 ft / 2.50 m
      - Average freeboard:      10.17 ft / 3.10 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 93.0 %
      - Above water (accommodation/working, high = better): 111.2 %
   Waterplane Area: 4,427 Square feet or 411 Square metres
   Displacement factor (Displacement / loading): 121 %
   Structure weight / hull surface area: 30 lbs/sq ft or 145 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.69
      - Longitudinal: 1.57
      - Overall: 0.75
   Caution: Hull subject to strain in open-sea
   Adequate machinery, storage, compartmentation space
   Adequate accommodation and workspace room

54t - Diesel Engines
15t - Enhanced Hydrophones
10t - Sonar

10t - Crew Comfort Improvements (Air Conditioning, recreation space)

25t - Minesweeping Equipment
2t - 2 x Y Throwers
30t - Depth Charges or Mines
12t - 1x3x21in HW TT
24t - 2 x 6t Motor Launches


3t - 1930 FC
25t - LR Radio
25t - NF Devices

Range:  8653nm @ 14kts