River Craft

[Darman]

List of Commissioned Riverrine Craft

Sumida-class river gunboats (1899)
       Sumida
       Fushimi
       Okitsu
       Karatsu
       Katada

[Darman]

Sumida, Empire of Japan Riverrine Gunboat laid down 1899

Displacement:
   143 t light; 147 t standard; 150 t normal; 152 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (145.00 ft / 145.00 ft) x 25.00 ft x (2.00 / 2.03 ft)
   (44.20 m / 44.20 m) x 7.62 m  x (0.61 / 0.62 m)

Armament:
      2 - 1.85" / 47.0 mm 40.0 cal guns - 3.04lbs / 1.38kg shells, 50 per gun
     Quick firing guns in deck mounts, 1899 Model
     2 x Single mounts on sides, aft deck centre
      1 - 4.50" / 114 mm 15.0 cal gun - 40.36lbs / 18.31kg shells, 50 per gun
     Quick firing gun in deck mount, 1899 Model
     1 x Single mount on centreline, forward deck forward
      4 - 0.50" / 12.7 mm 40.0 cal guns - 0.06lbs / 0.03kg shells, 250 per gun
     Machine guns in deck mounts, 1899 Model
     3 x Single mounts on sides, forward evenly spread
     1 x Single mount on centreline, forward deck aft
      1 raised mount
      Weight of broadside 47 lbs / 21 kg

Armour:
   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   1.00" / 25 mm   0.25" / 6 mm            -
   2nd:   1.00" / 25 mm   0.25" / 6 mm            -
   3rd:   0.25" / 6 mm         -               -

Machinery:
   Coal fired boilers, complex reciprocating steam engines,
   Direct drive, 2 shafts, 165 ihp / 123 Kw = 10.00 kts
   Range 250nm at 8.00 kts
   Bunker at max displacement = 5 tons (100% coal)

Complement:
   20 - 27

Cost:
   £0.010 million / $0.039 million

Distribution of weights at normal displacement:
   Armament: 4 tons, 2.5 %
   Armour: 8 tons, 5.4 %
      - Armament: 8 tons, 5.4 %
   Machinery: 26 tons, 17.5 %
   Hull, fittings & equipment: 105 tons, 69.8 %
   Fuel, ammunition & stores: 7 tons, 4.9 %
   Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     736 lbs / 334 Kg = 232.2 x 1.9 " / 47 mm shells or 0.7 torpedoes
   Stability (Unstable if below 1.00): 1.30
   Metacentric height 1.0 ft / 0.3 m
   Roll period: 10.5 seconds
   Steadiness   - As gun platform (Average = 50 %): 61 %
         - Recoil effect (Restricted arc if above 1.00): 0.12
   Seaboat quality  (Average = 1.00): 1.22

Hull form characteristics:
   Hull has a flush deck,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.724 / 0.725
   Length to Beam Ratio: 5.80 : 1
   'Natural speed' for length: 12.04 kts
   Power going to wave formation at top speed: 31 %
   Trim (Max stability = 0, Max steadiness = 100): 50
   Bow angle (Positive = bow angles forward): 0.00 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 %,  11.00 ft / 3.35 m,  8.00 ft / 2.44 m
      - Forward deck:   30.00 %,  8.00 ft / 2.44 m,  8.00 ft / 2.44 m
      - Aft deck:   35.00 %,  8.00 ft / 2.44 m,  8.00 ft / 2.44 m
      - Quarter deck:   15.00 %,  8.00 ft / 2.44 m,  8.00 ft / 2.44 m
      - Average freeboard:      8.24 ft / 2.51 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 64.3 %
      - Above water (accommodation/working, high = better): 226.1 %
   Waterplane Area: 2,968 Square feet or 276 Square metres
   Displacement factor (Displacement / loading): 214 %
   Structure weight / hull surface area: 28 lbs/sq ft or 138 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.90
      - Longitudinal: 2.90
      - Overall: 1.01
   Hull space for machinery, storage, compartmentation is excellent
   Room for accommodation and workspaces is excellent
   Good seaboat, rides out heavy weather easily