Kanonierka "flat-iron" i torpedowiec - 03.10.2011

Bardzo popularnym w latach 70-tych XIX w. w różnych flotach świata typem okrętu były małe kanonierki, tzw. „flat-iron gunboat” (kanonierka-żelazko? ;-)) Charakteryzowały się niedużymi rozmiarami, zazwyczaj brakiem ożaglowania, małym zanurzeniem i niską wolną burtą, oraz uzbrojeniem składającym się z jednego, monstrualnego jak na ich rozmiary działa, umieszczonego na dziobie w ten sposób, że mogło się poruszać w pionie, a celowanie w poziomie odbywało się całym okrętem. Zaprojektowane jako okręty ofensywne (do ostrzeliwania wybrzeża) często były postrzegane jako tanie jednostki do obrony własnych brzegów. Miały je na stanie liczne floty na świecie, poczynając od Rogal Navy, na flocie chińskiej kończąc. Wobec tego ostatniego, nie mogło więc ich zabraknąć we flocie japońskiej.

Druga jednostka to torpedowiec. Wreszcie udało się skonstruować w miarę przyzwoity okręt tej klasy (choć dzielnością morską to on nadal nie grzeszy;-)) Okazuje się, że do osiągnięcia jako takiej prędkości potrzeba było ok. 150 ton wyporności. Mniejsze jednostki nie bardzo mają rację bytu..

Ataka, japanese gunboat laid down 1877

Displacement:
    210 t light; 235 t standard; 250 t normal; 262 t full load

Dimensions: Length overall / water x beam x draught
    99,77 ft / 97,28 ft x 26,31 ft x 6,00 ft (normal load)
    30,41 m / 29,65 m x 8,02 m  x 1,83 m

Armament:
      1 - 10,00" / 254 mm guns in single mounts, 402,50lbs / 182,57kg shells, 1877 Model
      Breech loading gun in deck mount
      on bow with limited arc
      Main guns limited to end-on fire
    Weight of broadside 403 lbs / 183 kg
    Shells per gun, main battery: 90

Machinery:
    Coal fired boilers, simple reciprocating steam engines,
    Direct drive, 1 shaft, 148 ihp / 110 Kw = 9,00 kts
    Range 1 600nm at 6,00 kts
    Bunker at max displacement = 26 tons (100% coal)

Complement:
    30 - 40

Cost:
    £0,052 million / $0,209 million

Distribution of weights at normal displacement:
    Armament: 50 tons, 20,1%
    Machinery: 18 tons, 7,4%
    Hull, fittings & equipment: 141 tons, 56,6%
    Fuel, ammunition & stores: 40 tons, 15,9%
    Miscellaneous weights: 0 tons, 0,0%

Overall survivability and seakeeping ability:
    Survivability (Non-critical penetrating hits needed to sink ship):
      97 lbs / 44 Kg = 0,2 x 10,0 " / 254 mm shells or 0,1 torpedoes
    Stability (Unstable if below 1.00): 1,56
    Metacentric height 1,4 ft / 0,4 m
    Roll period: 9,2 seconds
    Steadiness    - As gun platform (Average = 50 %): 94 %
            - Recoil effect (Restricted arc if above 1.00): 0,63
    Seaboat quality  (Average = 1.00): 1,88

Hull form characteristics:
    Hull has a flush deck
    Block coefficient: 0,569
    Length to Beam Ratio: 3,70 : 1
    'Natural speed' for length: 9,86 kts
    Power going to wave formation at top speed: 49 %
    Trim (Max stability = 0, Max steadiness = 100): 50
    Bow angle (Positive = bow angles forward): -7,00 degrees
    Stern overhang: 2,49 ft / 0,76 m
    Freeboard (% = measuring location as a percentage of overall length):
       - Stem:        6,66 ft / 2,03 m
       - Forecastle (20%):    6,27 ft / 1,91 m
       - Mid (50%):        6,27 ft / 1,91 m
       - Quarterdeck (15%):    6,27 ft / 1,91 m
       - Stern:        6,27 ft / 1,91 m
       - Average freeboard:    6,30 ft / 1,92 m
    Ship tends to be wet forward

Ship space, strength and comments:
    Space    - Hull below water (magazines/engines, low = better): 171,4%
        - Above water (accommodation/working, high = better): 70,4%
    Waterplane Area: 1 769 Square feet or 164 Square metres
    Displacement factor (Displacement / loading): 54%
    Structure weight / hull surface area: 58 lbs/sq ft or 284 Kg/sq metre
    Hull strength (Relative):
        - Cross-sectional: 0,82
        - Longitudinal: 5,92
        - Overall: 1,00
    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
    Excellent seaboat, comfortable, can fire her guns in the heaviest weather

Okręty w typie:
Ataka (1877)
Katada (1877)
Okitsu (1877)
Hira (1878)
Yaeyama (1878)
Sumida (1878)

Oite, japanese torpedo boat laid down 1878

Displacement:
    129 t light; 133 t standard; 148 t normal; 161 t full load

Dimensions: Length overall / water x beam x draught
    126,48 ft / 125,75 ft x 12,07 ft x 6,43 ft (normal load)
    38,55 m / 38,33 m x 3,68 m  x 1,96 m

Armament:
      1 - 1,85" / 47,0 mm guns in single mounts, 2,60lbs / 1,18kg shells, 1878 Model
      Breech loading gun in deck mount
      on centreline forward
    Weight of broadside 3 lbs / 1 kg
    Shells per gun, main battery: 150
    2 - 14,0" / 356 mm above water torpedoes

Machinery:
    Coal fired boilers, simple reciprocating steam engines,
    Direct drive, 1 shaft, 2 646 ihp / 1 974 Kw = 21,10 kts
    Range 750nm at 10,00 kts
    Bunker at max displacement = 28 tons (100% coal)
      Caution: Delicate, lightweight machinery

Complement:
    20 - 27

Cost:
    £0,018 million / $0,072 million

Distribution of weights at normal displacement:
    Armament: 0 tons, 0,2%
    Machinery: 94 tons, 63,6%
    Hull, fittings & equipment: 35 tons, 23,5%
    Fuel, ammunition & stores: 19 tons, 12,7%
    Miscellaneous weights: 0 tons, 0,0%

Overall survivability and seakeeping ability:
    Survivability (Non-critical penetrating hits needed to sink ship):
      18 lbs / 8 Kg = 6,9 x 1,9 " / 47 mm shells or 0,1 torpedoes
    Stability (Unstable if below 1.00): 1,24
    Metacentric height 0,3 ft / 0,1 m
    Roll period: 9,1 seconds
    Steadiness    - As gun platform (Average = 50 %): 45 %
            - Recoil effect (Restricted arc if above 1.00): 0,04
    Seaboat quality  (Average = 1.00): 0,80

Hull form characteristics:
    Hull has a flush deck
    Block coefficient: 0,531
    Length to Beam Ratio: 10,42 : 1
    'Natural speed' for length: 11,21 kts
    Power going to wave formation at top speed: 72 %
    Trim (Max stability = 0, Max steadiness = 100): 50
    Bow angle (Positive = bow angles forward): -9,00 degrees
    Stern overhang: 0,72 ft / 0,22 m
    Freeboard (% = measuring location as a percentage of overall length):
       - Stem:        7,97 ft / 2,43 m
       - Forecastle (20%):    6,50 ft / 1,98 m
       - Mid (50%):        6,50 ft / 1,98 m
       - Quarterdeck (15%):    6,50 ft / 1,98 m
       - Stern:        6,50 ft / 1,98 m
       - Average freeboard:    6,61 ft / 2,02 m
    Ship tends to be wet forward

Ship space, strength and comments:
    Space    - Hull below water (magazines/engines, low = better): 206,9%
        - Above water (accommodation/working, high = better): 37,1%
    Waterplane Area: 1 006 Square feet or 93 Square metres
    Displacement factor (Displacement / loading): 13%
    Structure weight / hull surface area: 13 lbs/sq ft or 64 Kg/sq metre
    Hull strength (Relative):
        - Cross-sectional: 0,42
        - Longitudinal: 2,95
        - Overall: 0,50
    Caution: Hull subject to strain in open-sea
    Hull space for machinery, storage, compartmentation is extremely poor
    Room for accommodation and workspaces is extremely poor
    Poor seaboat, wet and uncomfortable, reduced performance in heavy weather

Okręty w typie:
Oite (1878)
Asanagi (1878)
Mutsuki (1878)
Yayoi (1879)
Yuzuki (1879)
Akebono (1879)
Miyuki (1880)
Usugumo (1880)