River Gunboats

[Sachmle]

With the realization that I have a city in MK territory that only has one way to get to it, which is up the Yang-tze River from Shanghai through RRC territory, I thought I might need some river gunboats. Swampy already had 8, but at 81t light, they were very slow and short legged. Figure the range allows them to run from Hankow to Shanghai and back at cruising speed.

Drachefliege, Brandenburg Fluss-Kanonbooten laid down 1916

Displacement:
   128 t light; 143 t standard; 160 t normal; 174 t full load

Dimensions: Length overall / water x beam x draught
   165.68 ft / 165.68 ft x 24.61 ft x 3.61 ft (normal load)
   50.50 m / 50.50 m x 7.50 m  x 1.10 m

Armament:
      3 - 3.46" / 88.0 mm guns in single mounts, 22.05lbs / 10.00kg shells, 1916 Model
     Quick firing guns in deck mounts
     on centreline, evenly spread
     Aft Main mounts separated by engine room
      2 - 1.97" / 50.0 mm guns in single mounts, 3.81lbs / 1.73kg shells, 1916 Model
     Quick firing guns in deck mounts
     on side, all amidships
      2 - 1.46" / 37.0 mm guns in single mounts, 1.55lbs / 0.70kg shells, 1916 Model
     Quick firing guns in deck mounts
     on side, all forward
      4 - 0.30" / 7.7 mm guns in single mounts, 0.01lbs / 0.01kg shells, 1916 Model
     Machine guns in deck mounts
     on side, evenly spread, all raised mounts
   Weight of broadside 77 lbs / 35 kg
   Shells per gun, main battery: 250

Machinery:
   Diesel Internal combustion motors,
   Direct drive, 1 shaft, 750 shp / 560 Kw = 16.35 kts
   Range 3,000nm at 10.00 kts
   Bunker at max displacement = 31 tons

Complement:
   22 - 29

Cost:
   £0.026 million / $0.105 million

Distribution of weights at normal displacement:
   Armament: 9 tons, 5.7 %
   Machinery: 28 tons, 17.5 %
   Hull, fittings & equipment: 91 tons, 56.8 %
   Fuel, ammunition & stores: 32 tons, 20.0 %
   Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     250 lbs / 113 Kg = 12.0 x 3.5 " / 88 mm shells or 0.3 torpedoes
   Stability (Unstable if below 1.00): 1.32
   Metacentric height 1.0 ft / 0.3 m
   Roll period: 10.3 seconds
   Steadiness   - As gun platform (Average = 50 %): 70 %
         - Recoil effect (Restricted arc if above 1.00): 0.12
   Seaboat quality  (Average = 1.00): 1.03

Hull form characteristics:
   Hull has raised forecastle, raised quarterdeck
   Block coefficient: 0.381
   Length to Beam Ratio: 6.73 : 1
   'Natural speed' for length: 12.87 kts
   Power going to wave formation at top speed: 50 %
   Trim (Max stability = 0, Max steadiness = 100): 68
   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:      9.45 ft / 2.88 m
      - Forecastle (20 %):   9.45 ft / 2.88 m (4.72 ft / 1.44 m aft of break)
      - Mid (50 %):      4.72 ft / 1.44 m
      - Quarterdeck (15 %):   9.45 ft / 2.88 m (4.72 ft / 1.44 m before break)
      - Stern:      9.45 ft / 2.88 m
      - Average freeboard:   6.38 ft / 1.94 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 104.5 %
      - Above water (accommodation/working, high = better): 96.0 %
   Waterplane Area: 2,346 Square feet or 218 Square metres
   Displacement factor (Displacement / loading): 124 %
   Structure weight / hull surface area: 29 lbs/sq ft or 141 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.94
      - Longitudinal: 1.65
      - Overall: 1.00
   Hull space for machinery, storage, compartmentation is adequate
   Room for accommodation and workspaces is adequate
   Ship has slow, easy roll, a good, steady gun platform

[The Rock Doctor]

I'm not sure about this.  These would be overkill for defending against pirates or criminals on the river.  However, if the RRC decides to oppose transit, shore batteries could inflict crippling damage on these unarmored hulls.  A High/Low mix, with light patrol craft and heavy river monitors (such as GC's Pescador, perhaps) might be appropriate.

I'd also suggest considering at least partial coal-firing machinery, as this is more likely to be available up-river than diesel in the event of a seige.

[maddox]

The MK has heavy river monitors.  The old 1000 tons, slow , but heavy armed and reasonably armored ones.

[Sachmle]

I'm not sure about this.  These would be overkill for defending against pirates or criminals on the river.  However, if the RRC decides to oppose transit, shore batteries could inflict crippling damage on these unarmored hulls.  A High/Low mix, with light patrol craft and heavy river monitors (such as GC's Pescador, perhaps) might be appropriate.

I'd also suggest considering at least partial coal-firing machinery, as this is more likely to be available up-river than diesel in the event of a seige.

How's this? 90t heavier, 1 less 88, but 25mm armor on the main guns, CT, deck, and belt.

Drachefliege, Brandenburg Fluss-Kanonbooten laid down 1916

Displacement:
   220 t light; 234 t standard; 266 t normal; 292 t full load

Dimensions: Length overall / water x beam x draught
   165.68 ft / 165.68 ft x 24.61 ft x 4.92 ft (normal load)
   50.50 m / 50.50 m x 7.50 m  x 1.50 m

Armament:
      2 - 3.46" / 88.0 mm guns in single mounts, 22.05lbs / 10.00kg shells, 1916 Model
     Quick firing guns in deck mounts
     on centreline ends, evenly spread, 1 raised mount
      2 - 1.97" / 50.0 mm guns in single mounts, 3.75lbs / 1.70kg shells, 1916 Model
     Quick firing guns in deck mounts
     on side, all amidships
      2 - 1.46" / 37.0 mm guns in single mounts, 1.55lbs / 0.70kg shells, 1916 Model
     Quick firing guns in deck mounts
     on side, all forward
      8 - 0.30" / 7.7 mm guns in single mounts, 0.01lbs / 0.00kg shells, 1916 Model
     Machine guns in deck mounts
     on side, evenly spread, all raised mounts
   Weight of broadside 55 lbs / 25 kg
   Shells per gun, main battery: 250

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   0.98" / 25 mm     70.54 ft / 21.50 m   8.20 ft / 2.50 m
   Ends:   Unarmoured
     Main Belt covers 65 % of normal length

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   0.98" / 25 mm         -               -

   - Armour deck: 0.98" / 25 mm, Conning tower: 0.98" / 25 mm

Machinery:
   Coal fired boilers, complex reciprocating steam engines plus diesel motors,
   Direct drive, 1 shaft, 750 ihp / 560 Kw = 14.99 kts
   Range 3,000nm at 10.00 kts
   Bunker at max displacement = 58 tons (50% coal)

Complement:
   32 - 42

Cost:
   £0.030 million / $0.119 million

Distribution of weights at normal displacement:
   Armament: 7 tons, 2.5 %
   Armour: 77 tons, 29.1 %
      - Belts: 27 tons, 10.2 %
      - Torpedo bulkhead: 0 tons, 0.0 %
      - Armament: 4 tons, 1.3 %
      - Armour Deck: 46 tons, 17.2 %
      - Conning Tower: 1 tons, 0.3 %
   Machinery: 36 tons, 13.5 %
   Hull, fittings & equipment: 100 tons, 37.6 %
   Fuel, ammunition & stores: 46 tons, 17.3 %
   Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     559 lbs / 254 Kg = 26.9 x 3.5 " / 88 mm shells or 0.7 torpedoes
   Stability (Unstable if below 1.00): 1.47
   Metacentric height 1.2 ft / 0.4 m
   Roll period: 9.5 seconds
   Steadiness   - As gun platform (Average = 50 %): 70 %
         - Recoil effect (Restricted arc if above 1.00): 0.08
   Seaboat quality  (Average = 1.00): 1.23

Hull form characteristics:
   Hull has raised forecastle, raised quarterdeck
   Block coefficient: 0.464
   Length to Beam Ratio: 6.73 : 1
   'Natural speed' for length: 12.87 kts
   Power going to wave formation at top speed: 50 %
   Trim (Max stability = 0, Max steadiness = 100): 57
   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:      9.45 ft / 2.88 m
      - Forecastle (20 %):   9.45 ft / 2.88 m (4.72 ft / 1.44 m aft of break)
      - Mid (50 %):      4.72 ft / 1.44 m
      - Quarterdeck (15 %):   9.45 ft / 2.88 m (4.72 ft / 1.44 m before break)
      - Stern:      9.45 ft / 2.88 m
      - Average freeboard:   6.38 ft / 1.94 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 65.5 %
      - Above water (accommodation/working, high = better): 70.7 %
   Waterplane Area: 2,513 Square feet or 233 Square metres
   Displacement factor (Displacement / loading): 132 %
   Structure weight / hull surface area: 28 lbs/sq ft or 138 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.96
      - Longitudinal: 1.48
      - Overall: 1.00
   Hull space for machinery, storage, compartmentation is excellent
   Room for accommodation and workspaces is cramped
   Ship has slow, easy roll, a good, steady gun platform
   Good seaboat, rides out heavy weather easily