Krążownik pancerny Alagoas - 01.06.2011

Dziś prezentuję projekt ekonomicznego, bo stosunkowo niedużego, krążownika pancernego dla MW Brazylii, pomyślanego jako odpowiedź i przeciwwaga dla czterech argentyńskich okrętów typu Garibaldi, zbudowanych we Włoszech w latach 90-tych XIX w. Niestety, nad projektem zaciążył mocno ograniczona wyporność i  w efekcie okręty nie prezentują się zbyt okazale na tle wyjątkowo udanych jednostek typu Garibaldi. Wydaje się, że aby uzyskać wyraźnie lepszy okręt, potrzebna będzie jednak wyporność rzędu 10.000 ton..  

Okręty w typie:

Alagoas (1896)

Roraima (1897)

Maranhao (1898)

Amazonas (1898)

  
Alagoas, brazilian armoured cruiser laid down 1895 (Engine 1896)

Displacement:
    7 115 t light; 7 389 t standard; 7 920 t normal; 8 345 t full load

Dimensions: Length overall / water x beam x draught
    428,64 ft / 428,64 ft x 55,31 ft x 20,37 ft (normal load)
    130,65 m / 130,65 m x 16,86 m  x 6,21 m

Armament:
      2 - 8,27" / 210 mm guns in single mounts, 282,57lbs / 128,17kg shells, 1895 Model
      Breech loading guns in turrets (on barbettes)
      on centreline ends, evenly spread
      8 - 5,91" / 150 mm guns in single mounts, 102,98lbs / 46,71kg shells, 1895 Model
      Quick firing guns in casemate mounts
      on side, all amidships
      12 - 2,95" / 75,0 mm guns in single mounts, 12,87lbs / 5,84kg shells, 1895 Model
      Quick firing guns in casemate mounts
      on side, evenly spread, 8 raised mounts
      4 guns in hull casemates - Limited use in heavy seas
    Weight of broadside 1 543 lbs / 700 kg
    Shells per gun, main battery: 120
    2 - 18,0" / 457 mm submerged torpedo tubes

Armour:
   - Belts:        Width (max)    Length (avg)        Height (avg)
    Main:    6,30" / 160 mm    148,16 ft / 45,16 m    6,66 ft / 2,03 m
    Ends:    4,72" / 120 mm    206,36 ft / 62,90 m    6,66 ft / 2,03 m
      74,11 ft / 22,59 m Unarmoured ends
    Upper:    3,54" / 90 mm    322,18 ft / 98,20 m    7,74 ft / 2,36 m
      Main Belt covers 53% of normal length
      Main belt does not fully cover magazines and engineering spaces

   - Gun armour:    Face (max)    Other gunhouse (avg)    Barbette/hoist (max)
    Main:    7,09" / 180 mm    4,13" / 105 mm        3,94" / 100 mm
    2nd:    3,94" / 100 mm          -                  -
    3rd:    1,97" / 50 mm          -                  -

   - Armour deck: 1,57" / 40 mm, Conning tower: 4,72" / 120 mm

Machinery:
    Coal fired boilers, complex reciprocating steam engines,
    Direct drive, 2 shafts, 13 642 ihp / 10 177 Kw = 20,00 kts
    Range 4 000nm at 10,00 kts
    Bunker at max displacement = 956 tons (100% coal)

Complement:
    419 - 545

Cost:
    £0,729 million / $2,918 million

Distribution of weights at normal displacement:
    Armament: 193 tons, 2,4%
    Armour: 1 746 tons, 22,0%
       - Belts: 916 tons, 11,6%
       - Torpedo bulkhead: 0 tons, 0,0%
       - Armament: 297 tons, 3,7%
       - Armour Deck: 493 tons, 6,2%
       - Conning Tower: 40 tons, 0,5%
    Machinery: 2 274 tons, 28,7%
    Hull, fittings & equipment: 2 902 tons, 36,6%
    Fuel, ammunition & stores: 805 tons, 10,2%
    Miscellaneous weights: 0 tons, 0,0%

Overall survivability and seakeeping ability:
    Survivability (Non-critical penetrating hits needed to sink ship):
      7 930 lbs / 3 597 Kg = 28,1 x 8,3 " / 210 mm shells or 1,1 torpedoes
    Stability (Unstable if below 1.00): 1,17
    Metacentric height 2,7 ft / 0,8 m
    Roll period: 14,0 seconds
    Steadiness    - As gun platform (Average = 50 %): 100 %
            - Recoil effect (Restricted arc if above 1.00): 0,66
    Seaboat quality  (Average = 1.00): 2,00

Hull form characteristics:
    Hull has rise forward of midbreak
    Block coefficient: 0,574
    Length to Beam Ratio: 7,75 : 1
    'Natural speed' for length: 20,70 kts
    Power going to wave formation at top speed: 46 %
    Trim (Max stability = 0, Max steadiness = 100): 50
    Bow angle (Positive = bow angles forward): -15,00 degrees
    Stern overhang: 0,00 ft / 0,00 m
    Freeboard (% = measuring location as a percentage of overall length):
       - Stem:        28,12 ft / 8,57 m
       - Forecastle (14%):    25,36 ft / 7,73 m
       - Mid (72%):        25,36 ft / 7,73 m (18,24 ft / 5,56 m aft of break)
       - Quarterdeck (16%):    18,24 ft / 5,56 m
       - Stern:        18,24 ft / 5,56 m
       - Average freeboard:    23,52 ft / 7,17 m

Ship space, strength and comments:
    Space    - Hull below water (magazines/engines, low = better): 115,4%
        - Above water (accommodation/working, high = better): 185,8%
    Waterplane Area: 16 921 Square feet or 1 572 Square metres
    Displacement factor (Displacement / loading): 101%
    Structure weight / hull surface area: 91 lbs/sq ft or 446 Kg/sq metre
    Hull strength (Relative):
        - Cross-sectional: 0,87
        - Longitudinal: 3,53
        - Overall: 1,00
    Hull space for machinery, storage, compartmentation is cramped
    Room for accommodation and workspaces is excellent
    Ship has slow, easy roll, a good, steady gun platform
    Excellent seaboat, comfortable, can fire her guns in the heaviest weather