Japanese Ship Designs 1912+

[Desertfox]

An improvement on the Agano class, these ships drop a bit of range and the marine accommodations for the ability to self-deploy indefinitely...

Improved Agano class, Japan Cruiser laid down 1912

Displacement:
   3,999 t light; 4,225 t standard; 4,872 t normal; 5,390 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (400.00 ft / 400.00 ft) x 49.00 ft x (17.40 / 18.79 ft)
   (121.92 m / 121.92 m) x 14.94 m  x (5.30 / 5.73 m)

Armament:
      4 - 8.00" / 203 mm 45.0 cal guns - 258.18lbs / 117.11kg shells, 150 per gun
     Breech loading guns in turret on barbette mounts, 1912 Model
     2 x Twin mounts on centreline, evenly spread
      8 - 5.00" / 127 mm 45.0 cal guns - 63.03lbs / 28.59kg shells, 150 per gun
     Breech loading guns in deck mounts, 1912 Model
     8 x Single mounts on centreline ends, evenly spread
      Weight of broadside 1,537 lbs / 697 kg

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   2.00" / 51 mm   240.00 ft / 73.15 m   14.00 ft / 4.27 m
   Ends:   Unarmoured
     Main Belt covers 92 % of normal length

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   5.00" / 127 mm   1.00" / 25 mm      5.00" / 127 mm
   2nd:   1.00" / 25 mm         -               -

   - Armoured deck - single deck:
   For and Aft decks: 2.00" / 51 mm

Machinery:
   Coal and oil fired boilers, steam turbines,
   Direct drive, 2 shafts, 20,456 shp / 15,260 Kw = 24.00 kts
   Range 4,490nm at 14.00 kts
   Bunker at max displacement = 1,165 tons (90% coal)

Complement:
   291 - 379

Cost:
   £0.385 million / $1.541 million

Distribution of weights at normal displacement:
   Armament: 308 tons, 6.3 %
      - Guns: 308 tons, 6.3 %
   Armour: 808 tons, 16.6 %
      - Belts: 286 tons, 5.9 %
      - Armament: 164 tons, 3.4 %
      - Armour Deck: 358 tons, 7.3 %
   Machinery: 888 tons, 18.2 %
   Hull, fittings & equipment: 1,475 tons, 30.3 %
   Fuel, ammunition & stores: 873 tons, 17.9 %
   Miscellaneous weights: 520 tons, 10.7 %
      - Hull below water: 400 tons
      - On freeboard deck: 50 tons
      - Above deck: 70 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     5,699 lbs / 2,585 Kg = 22.3 x 8.0 " / 203 mm shells or 1.2 torpedoes
   Stability (Unstable if below 1.00): 1.24
   Metacentric height 2.5 ft / 0.8 m
   Roll period: 12.9 seconds
   Steadiness   - As gun platform (Average = 50 %): 70 %
         - Recoil effect (Restricted arc if above 1.00): 0.61
   Seaboat quality  (Average = 1.00): 1.32

Hull form characteristics:
   Hull has a flush deck,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.500 / 0.512
   Length to Beam Ratio: 8.16 : 1
   'Natural speed' for length: 20.00 kts
   Power going to wave formation at top speed: 54 %
   Trim (Max stability = 0, Max steadiness = 100): 53
   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:   30.00 %,  17.00 ft / 5.18 m,  15.00 ft / 4.57 m
      - Forward deck:   30.00 %,  15.00 ft / 4.57 m,  15.00 ft / 4.57 m
      - Aft deck:   25.00 %,  15.00 ft / 4.57 m,  15.00 ft / 4.57 m
      - Quarter deck:   15.00 %,  15.00 ft / 4.57 m,  15.00 ft / 4.57 m
      - Average freeboard:      15.24 ft / 4.65 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 92.0 %
      - Above water (accommodation/working, high = better): 128.1 %
   Waterplane Area: 13,059 Square feet or 1,213 Square metres
   Displacement factor (Displacement / loading): 114 %
   Structure weight / hull surface area: 78 lbs/sq ft or 382 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.83
      - Longitudinal: 1.74
      - Overall: 0.90
   Caution: Hull subject to strain in open-sea
   Adequate machinery, storage, compartmentation space
   Excellent accommodation and workspace room
   Ship has slow, easy roll, a good, steady gun platform
   Good seaboat, rides out heavy weather easily

70t - FC +  Long-range wireless
10t - 4 x 18" torpedo tubes
40t - 2 x extra boats
400t - Out-of-Port Resupply

[Desertfox]

Improvement on the Umikaze class, adding 1000nm range, and a much heavier armament.

Sakura, Japan Destroyer laid down 1912

Displacement:
   710 t light; 742 t standard; 791 t normal; 830 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (303.00 ft / 300.00 ft) x 30.00 ft x (7.50 / 7.75 ft)
   (92.35 m / 91.44 m) x 9.14 m  x (2.29 / 2.36 m)

Armament:
      3 - 5.00" / 127 mm 45.0 cal guns - 63.03lbs / 28.59kg shells, 150 per gun
     Quick firing guns in deck mounts, 1912 Model
     3 x Single mounts on centreline, evenly spread
      1 raised mount
      Weight of broadside 189 lbs / 86 kg

Armour:
   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   1.00" / 25 mm         -               -

   - Conning towers: Forward 1.00" / 25 mm, Aft 0.00" / 0 mm

Machinery:
   Oil fired boilers, steam turbines,
   Direct drive, 2 shafts, 17,446 shp / 13,015 Kw = 30.00 kts
   Range 2,700nm at 10.00 kts
   Bunker at max displacement = 88 tons

Complement:
   73 - 96

Cost:
   £0.091 million / $0.362 million

Distribution of weights at normal displacement:
   Armament: 33 tons, 4.2 %
      - Guns: 33 tons, 4.2 %
   Armour: 10 tons, 1.2 %
      - Armament: 8 tons, 1.0 %
      - Conning Tower: 2 tons, 0.2 %
   Machinery: 405 tons, 51.2 %
   Hull, fittings & equipment: 247 tons, 31.2 %
   Fuel, ammunition & stores: 80 tons, 10.2 %
   Miscellaneous weights: 16 tons, 2.0 %
      - On freeboard deck: 16 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     247 lbs / 112 Kg = 4.0 x 5.0 " / 127 mm shells or 0.2 torpedoes
   Stability (Unstable if below 1.00): 1.18
   Metacentric height 1.1 ft / 0.3 m
   Roll period: 11.9 seconds
   Steadiness   - As gun platform (Average = 50 %): 70 %
         - Recoil effect (Restricted arc if above 1.00): 0.31
   Seaboat quality  (Average = 1.00): 1.01

Hull form characteristics:
   Hull has raised forecastle,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.410 / 0.417
   Length to Beam Ratio: 10.00 : 1
   'Natural speed' for length: 17.32 kts
   Power going to wave formation at top speed: 65 %
   Trim (Max stability = 0, Max steadiness = 100): 69
   Bow angle (Positive = bow angles forward): 10.00 degrees
   Stern overhang: 0.00 ft / 0.00 m
   Freeboard (% = length of deck as a percentage of waterline length):
            Fore end,    Aft end
      - Forecastle:   27.00 %,  17.00 ft / 5.18 m,  17.00 ft / 5.18 m
      - Forward deck:   30.00 %,  11.00 ft / 3.35 m,  11.00 ft / 3.35 m
      - Aft deck:   28.00 %,  11.00 ft / 3.35 m,  11.00 ft / 3.35 m
      - Quarter deck:   15.00 %,  11.00 ft / 3.35 m,  11.00 ft / 3.35 m
      - Average freeboard:      12.62 ft / 3.85 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 177.0 %
      - Above water (accommodation/working, high = better): 159.6 %
   Waterplane Area: 5,574 Square feet or 518 Square metres
   Displacement factor (Displacement / loading): 53 %
   Structure weight / hull surface area: 27 lbs/sq ft or 130 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.50
      - Longitudinal: 1.68
      - Overall: 0.56
   Cramped machinery, storage, compartmentation space
   Excellent accommodation and workspace room
   Ship has slow, easy roll, a good, steady gun platform

16t - 8 x 18" Torpedoes

[Desertfox]

Destroyer Leader version of the Mogamis, much lower range, but more speed and torpedoes.

Yahagi class, Japan Destroyer Leader laid down 1912

Displacement:
   2,001 t light; 2,083 t standard; 2,177 t normal; 2,252 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (390.00 ft / 390.00 ft) x 40.00 ft x (11.10 / 11.37 ft)
   (118.87 m / 118.87 m) x 12.19 m  x (3.38 / 3.46 m)

Armament:
      5 - 5.00" / 127 mm 45.0 cal guns - 63.03lbs / 28.59kg shells, 220 per gun
     Quick firing guns in deck mounts, 1912 Model
     3 x Single mounts on centreline ends, majority aft
      1 raised mount aft - superfiring
     2 x Single mounts on sides amidships
      Weight of broadside 315 lbs / 143 kg

Armour:
   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   1.00" / 25 mm         -               -

Machinery:
   Oil fired boilers, steam turbines,
   Direct drive, 2 shafts, 29,481 shp / 21,993 Kw = 30.00 kts
   Range 2,700nm at 10.00 kts
   Bunker at max displacement = 169 tons

Complement:
   159 - 207

Cost:
   £0.235 million / $0.939 million

Distribution of weights at normal displacement:
   Armament: 55 tons, 2.5 %
      - Guns: 55 tons, 2.5 %
   Armour: 13 tons, 0.6 %
      - Armament: 13 tons, 0.6 %
   Machinery: 1,070 tons, 49.1 %
   Hull, fittings & equipment: 799 tons, 36.7 %
   Fuel, ammunition & stores: 176 tons, 8.1 %
   Miscellaneous weights: 65 tons, 3.0 %
      - On freeboard deck: 40 tons
      - Above deck: 25 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     990 lbs / 449 Kg = 15.8 x 5.0 " / 127 mm shells or 0.4 torpedoes
   Stability (Unstable if below 1.00): 1.21
   Metacentric height 1.8 ft / 0.5 m
   Roll period: 12.6 seconds
   Steadiness   - As gun platform (Average = 50 %): 71 %
         - Recoil effect (Restricted arc if above 1.00): 0.16
   Seaboat quality  (Average = 1.00): 1.01

Hull form characteristics:
   Hull has raised forecastle,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.440 / 0.445
   Length to Beam Ratio: 9.75 : 1
   'Natural speed' for length: 19.75 kts
   Power going to wave formation at top speed: 60 %
   Trim (Max stability = 0, Max steadiness = 100): 71
   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:   33.00 %,  20.00 ft / 6.10 m,  17.00 ft / 5.18 m
      - Forward deck:   30.00 %,  12.00 ft / 3.66 m,  12.00 ft / 3.66 m
      - Aft deck:   22.00 %,  12.00 ft / 3.66 m,  12.00 ft / 3.66 m
      - Quarter deck:   15.00 %,  12.00 ft / 3.66 m,  12.00 ft / 3.66 m
      - Average freeboard:      14.05 ft / 4.28 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 166.5 %
      - Above water (accommodation/working, high = better): 141.9 %
   Waterplane Area: 9,871 Square feet or 917 Square metres
   Displacement factor (Displacement / loading): 85 %
   Structure weight / hull surface area: 53 lbs/sq ft or 256 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.85
      - Longitudinal: 1.43
      - Overall: 0.90
   Cramped machinery, storage, compartmentation space
   Excellent accommodation and workspace room
   Ship has slow, easy roll, a good, steady gun platform

25t - Long-range wireless
24t - Flag-facilities
16t - 8 x 18"  Torpedoes

[snip]

Sakura is cute. Those 5" guns pack a punch and center line is a nice layout. Cant say Im a fan of how small she is compared to the F-class, but thats a 2 year old design at this point. Maybe I should look at a 140mm armed version...

[Kaiser Kirk]

Sakura is cute. Those 5" guns pack a punch and center line is a nice layout. Cant say Im a fan of how small she is compared to the F-class, but thats a 2 year old design at this point. Maybe I should look at a 140mm armed version...

The IJN fields alot of 5" guns I've noted :)

The Parthians are just now finishing a new 120mm gun, but I'm planning a 135mm (close to 140) being more the 'standard'....if I get there..120 might have to do.

Improvement on the Umikaze class, adding 1000nm range, and a much heavier armament.

Sakura, Japan Destroyer laid down 1912

my first thought was, wow, why don't mine go 30kts, then I realized mine are a 1910 class. Plus I don't seem to have the knack of destroyer design.

[Desertfox]

Well I am restricted to 750t destroyers so can't really make them much bigger. Japan does not have a 4" or equivalent gun, so its either 3" like the previous class or 5". I do have quite a bit of experience with destroyers, New Switzerland back in the day had lots and lots and lots of them...

[Kaiser Kirk]

Well I am restricted to 750t destroyers so can't really make them much bigger. Japan does not have a 4" or equivalent gun, so its either 3" like the previous class or 5". I do have quite a bit of experience with destroyers, New Switzerland back in the day had lots and lots and lots of them...

Parthia is 750tonners as well, actually eyeing a set of new 500tonners.  But my last was 1910- 29.50 knots...smaller guns (90mm), but 50% more fuel tonnage, and 40t is a lot for ships these size.

Have the Japanese decided that FC on DDs/DDLs just doesn't add enough to the equation? Or is that an oversight?

[Desertfox]

FC or no FC you're not hitting anything from a destroyer... its not really worth the 4 tons of misc weight. The range isn't where I want it yet, but its 1,000nm that the previous class.

[Desertfox]

A concept at this point. A dedicated raider, not very fast but can cruise at high speeds for a long time. Can support itself indefinitely away from ports. Very cheap so can be built in numbers.

Mogami class, Japan Raider laid down 1912

Displacement:
   1,700 t light; 1,781 t standard; 2,464 t normal; 3,010 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (390.00 ft / 390.00 ft) x 42.00 ft x (11.70 / 13.53 ft)
   (118.87 m / 118.87 m) x 12.80 m  x (3.57 / 4.12 m)

Armament:
      5 - 5.00" / 127 mm 45.0 cal guns - 63.03lbs / 28.59kg shells, 185 per gun
     Quick firing guns in deck and hoist mounts, 1912 Model
     3 x Single mounts on centreline ends, majority aft
      1 raised mount aft - superfiring
     2 x Single mounts on sides amidships
      Weight of broadside 315 lbs / 143 kg

Armour:
   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   1.00" / 25 mm         -         1.00" / 25 mm

Machinery:
   Coal and oil fired boilers, steam turbines,
   Direct drive, 2 shafts, 13,122 shp / 9,789 Kw = 24.00 kts
   Range 7,200nm at 14.00 kts
   Bunker at max displacement = 1,229 tons (90% coal)

Complement:
   174 - 227

Cost:
   £0.169 million / $0.677 million

Distribution of weights at normal displacement:
   Armament: 85 tons, 3.4 %
      - Guns: 85 tons, 3.4 %
   Armour: 13 tons, 0.5 %
      - Armament: 13 tons, 0.5 %
   Machinery: 570 tons, 23.1 %
   Hull, fittings & equipment: 802 tons, 32.5 %
   Fuel, ammunition & stores: 764 tons, 31.0 %
   Miscellaneous weights: 230 tons, 9.3 %
      - Hull below water: 170 tons
      - On freeboard deck: 10 tons
      - Above deck: 50 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     3,321 lbs / 1,506 Kg = 53.1 x 5.0 " / 127 mm shells or 1.0 torpedoes
   Stability (Unstable if below 1.00): 1.49
   Metacentric height 2.7 ft / 0.8 m
   Roll period: 10.8 seconds
   Steadiness   - As gun platform (Average = 50 %): 71 %
         - Recoil effect (Restricted arc if above 1.00): 0.19
   Seaboat quality  (Average = 1.00): 1.26

Hull form characteristics:
   Hull has a flush deck,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.450 / 0.475
   Length to Beam Ratio: 9.29 : 1
   'Natural speed' for length: 19.75 kts
   Power going to wave formation at top speed: 50 %
   Trim (Max stability = 0, Max steadiness = 100): 56
   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:   30.00 %,  14.00 ft / 4.27 m,  11.00 ft / 3.35 m
      - Forward deck:   30.00 %,  11.00 ft / 3.35 m,  11.00 ft / 3.35 m
      - Aft deck:   25.00 %,  11.00 ft / 3.35 m,  11.00 ft / 3.35 m
      - Quarter deck:   15.00 %,  11.00 ft / 3.35 m,  11.00 ft / 3.35 m
      - Average freeboard:      11.36 ft / 3.46 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 94.5 %
      - Above water (accommodation/working, high = better): 125.8 %
   Waterplane Area: 10,448 Square feet or 971 Square metres
   Displacement factor (Displacement / loading): 148 %
   Structure weight / hull surface area: 55 lbs/sq ft or 270 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.89
      - Longitudinal: 0.98
      - Overall: 0.90
   Adequate machinery, storage, compartmentation space
   Excellent accommodation and workspace room
   Ship has slow, easy roll, a good, steady gun platform
   Good seaboat, rides out heavy weather easily

10t - 1905 Fire Control
25t - Long-range wireless
15t - Improved spotting/reconnaissance equipment
10t - 4 x 18" Torpedo Tubes
170t - Out-of-Port Resupply

[Desertfox]

Nothing to see here, just your average fishing boat.

Fishing Vessel #42, Japan Junk (Reconnaissance ship) laid down 1910

Displacement:
   100 t light; 102 t standard; 110 t normal; 116 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (80.00 ft / 80.00 ft) x 32.00 ft x (3.00 / 3.13 ft)
   (24.38 m / 24.38 m) x 9.75 m  x (0.91 / 0.95 m)

Armament:
      1 - 0.50" / 12.7 mm 45.0 cal gun - 0.06lbs / 0.03kg shells, 300 per gun
     Machine gun in deck mount, 1912 Model
     1 x Single mount on centreline amidships (forward deck)
      4 - 0.30" / 7.6 mm 45.0 cal guns - 0.01lbs / 0.01kg shells, 150 per gun
     Breech loading guns in deck mounts, 1912 Model
     4 x Single mounts on sides, evenly spread
      Weight of broadside 0 lbs / 0 kg

Machinery:
   Petrol Internal combustion motors,
   Direct drive, 1 shaft, 144 ihp / 107 Kw = 10.00 kts
   Range 900nm at 10.00 kts
   Bunker at max displacement = 14 tons

Complement:
   16 - 22

Cost:
   £0.005 million / $0.019 million

Distribution of weights at normal displacement:
   Armament: 0 tons, 0.1 %
      - Guns: 0 tons, 0.1 %
   Machinery: 9 tons, 8.2 %
   Hull, fittings & equipment: 44 tons, 39.8 %
   Fuel, ammunition & stores: 10 tons, 9.0 %
   Miscellaneous weights: 47 tons, 42.8 %
      - Hull below water: 15 tons
      - Hull above water: 2 tons
      - On freeboard deck: 25 tons
      - Above deck: 5 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     539 lbs / 244 Kg = 8,616.5 x 0.5 " / 13 mm shells or 0.9 torpedoes
   Stability (Unstable if below 1.00): 2.01
   Metacentric height 2.7 ft / 0.8 m
   Roll period: 8.1 seconds
   Steadiness   - As gun platform (Average = 50 %): 70 %
         - Recoil effect (Restricted arc if above 1.00): 0.00
   Seaboat quality  (Average = 1.00): 1.05

Hull form characteristics:
   Hull has low forecastle,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.500 / 0.506
   Length to Beam Ratio: 2.50 : 1
   'Natural speed' for length: 8.94 kts
   Power going to wave formation at top speed: 57 %
   Trim (Max stability = 0, Max steadiness = 100): 67
   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 %,  7.00 ft / 2.13 m,  4.00 ft / 1.22 m
      - Forward deck:   30.00 %,  5.00 ft / 1.52 m,  5.00 ft / 1.52 m
      - Aft deck:   30.00 %,  5.00 ft / 1.52 m,  5.00 ft / 1.52 m
      - Quarter deck:   20.00 %,  5.00 ft / 1.52 m,  7.00 ft / 2.13 m
      - Average freeboard:      5.24 ft / 1.60 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 45.2 %
      - Above water (accommodation/working, high = better): 97.6 %
   Waterplane Area: 1,640 Square feet or 152 Square metres
   Displacement factor (Displacement / loading): 167 %
   Structure weight / hull surface area: 24 lbs/sq ft or 115 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.87
      - Longitudinal: 3.60
      - Overall: 1.00
   Excellent machinery, storage, compartmentation space
   Adequate accommodation and workspace room
   Ship has slow, easy roll, a good, steady gun platform

15t- Junk sail rig
25t - Long-range wireless
6t - Espionage equipment

[Desertfox]

Updated the intelligence junk, conversion from a stock civilian junk, cost 28t, $0.028

"Fishing Boat 42", Japan Junk (espionage ship) laid down 1900 (Engine 1912)

Displacement:
   95 t light; 97 t standard; 99 t normal; 100 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (80.00 ft / 80.00 ft) x 32.00 ft x (2.70 / 2.73 ft)
   (24.38 m / 24.38 m) x 9.75 m  x (0.82 / 0.83 m)

Armament:
      1 - 0.50" / 12.7 mm 45.0 cal gun - 0.06lbs / 0.03kg shells, 300 per gun
     Machine gun in deck mount, 1900 Model
     1 x Single mount on centreline amidships (forward deck)
      4 - 0.30" / 7.6 mm 45.0 cal guns - 0.01lbs / 0.01kg shells, 150 per gun
     Breech loading guns in deck mounts, 1900 Model
     4 x Single mounts on sides, evenly spread
      Weight of broadside 0 lbs / 0 kg

Machinery:
   Petrol Internal combustion motors,
   Direct drive, 2 shafts, 54 ihp / 41 Kw = 7.90 kts
   Range 420nm at 7.90 kts
   Bunker at max displacement = 3 tons

Complement:
   15 - 20

Cost:
   £0.004 million / $0.015 million

Distribution of weights at normal displacement:
   Armament: 0 tons, 0.1 %
      - Guns: 0 tons, 0.1 %
   Machinery: 3 tons, 3.5 %
   Hull, fittings & equipment: 42 tons, 43.0 %
   Fuel, ammunition & stores: 4 tons, 3.8 %
   Miscellaneous weights: 49 tons, 49.6 %
      - Hull below water: 15 tons
      - Hull above water: 4 tons
      - On freeboard deck: 25 tons
      - Above deck: 5 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     755 lbs / 342 Kg = 12,075.9 x 0.5 " / 13 mm shells or 1.3 torpedoes
   Stability (Unstable if below 1.00): 2.29
   Metacentric height 3.2 ft / 1.0 m
   Roll period: 7.5 seconds
   Steadiness   - As gun platform (Average = 50 %): 71 %
         - Recoil effect (Restricted arc if above 1.00): 0.00
   Seaboat quality  (Average = 1.00): 1.61

Hull form characteristics:
   Hull has low forecastle,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.500 / 0.502
   Length to Beam Ratio: 2.50 : 1
   'Natural speed' for length: 8.94 kts
   Power going to wave formation at top speed: 43 %
   Trim (Max stability = 0, Max steadiness = 100): 44
   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 %,  7.00 ft / 2.13 m,  4.00 ft / 1.22 m
      - Forward deck:   30.00 %,  5.00 ft / 1.52 m,  5.00 ft / 1.52 m
      - Aft deck:   30.00 %,  5.00 ft / 1.52 m,  5.00 ft / 1.52 m
      - Quarter deck:   20.00 %,  5.00 ft / 1.52 m,  7.00 ft / 2.13 m
      - Average freeboard:      5.24 ft / 1.60 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 34.1 %
      - Above water (accommodation/working, high = better): 108.3 %
   Waterplane Area: 1,706 Square feet or 158 Square metres
   Displacement factor (Displacement / loading): 175 %
   Structure weight / hull surface area: 23 lbs/sq ft or 111 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.86
      - Longitudinal: 3.61
      - Overall: 1.00
   Excellent machinery, storage, compartmentation space
   Adequate accommodation and workspace room
   Ship has slow, easy roll, a good, steady gun platform
   Excellent seaboat, comfortable, can fire her guns in the heaviest weather

21t- Junk sail rig
25t - Long-range wireless
3t - Espionage equipment

2 separate petrol motors
1 x 50 hp powers boat, max speed 7.7kts
1 x 4 hp powers wireless

[Desertfox]

I really liked the coast defense cruiser I designed for the Inca, so made a colonial gunboat version for the Japanese. Guns are big enough to dissuade most PCs and keep the locals in check and it can self-deploy, while being very cheap.

Thonburi, Japan Colonial Gunboat laid down 1913

Displacement:
   2,499 t light; 2,670 t standard; 2,934 t normal; 3,145 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (340.00 ft / 340.00 ft) x 47.00 ft x (11.90 / 12.57 ft)
   (103.63 m / 103.63 m) x 14.33 m  x (3.63 / 3.83 m)

Armament:
      4 - 8.00" / 203 mm 45.0 cal guns - 258.18lbs / 117.11kg shells, 140 per gun
     Breech loading guns in turret on barbette mounts, 1913 Model
     2 x Twin mounts on centreline, evenly spread
      4 - 5.00" / 127 mm 45.0 cal guns - 63.03lbs / 28.59kg shells, 150 per gun
     Breech loading guns in deck mounts, 1913 Model
     4 x Single mounts on centreline ends, evenly spread
      20 - 2.00" / 50.8 mm 45.0 cal guns - 4.03lbs / 1.83kg shells, 250 per gun
     Breech loading guns in deck mounts, 1913 Model
     4 x Quintuple mounts on sides, evenly spread
      4 raised mounts
      Weight of broadside 1,366 lbs / 619 kg

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   2.00" / 51 mm   190.00 ft / 57.91 m   10.00 ft / 3.05 m
   Ends:   Unarmoured
     Main Belt covers 86 % of normal length

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   4.00" / 102 mm   1.00" / 25 mm      4.00" / 102 mm
   2nd:   1.00" / 25 mm         -               -

   - Armoured deck - multiple decks:
   For and Aft decks: 2.00" / 51 mm

   - Conning towers: Forward 4.00" / 102 mm, Aft 0.00" / 0 mm

Machinery:
   Coal and oil fired boilers, steam turbines,
   Direct drive, 2 shafts, 8,059 shp / 6,012 Kw = 20.00 kts
   Range 5,400nm at 10.00 kts
   Bunker at max displacement = 474 tons (90% coal)

Complement:
   199 - 259

Cost:
   £0.272 million / $1.087 million

Distribution of weights at normal displacement:
   Armament: 283 tons, 9.6 %
      - Guns: 283 tons, 9.6 %
   Armour: 550 tons, 18.7 %
      - Belts: 168 tons, 5.7 %
      - Armament: 98 tons, 3.3 %
      - Armour Deck: 266 tons, 9.1 %
      - Conning Tower: 18 tons, 0.6 %
   Machinery: 344 tons, 11.7 %
   Hull, fittings & equipment: 966 tons, 32.9 %
   Fuel, ammunition & stores: 435 tons, 14.8 %
   Miscellaneous weights: 357 tons, 12.2 %
      - Hull below water: 250 tons
      - On freeboard deck: 77 tons
      - Above deck: 30 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     3,668 lbs / 1,664 Kg = 14.3 x 8.0 " / 203 mm shells or 1.2 torpedoes
   Stability (Unstable if below 1.00): 1.27
   Metacentric height 2.5 ft / 0.8 m
   Roll period: 12.5 seconds
   Steadiness   - As gun platform (Average = 50 %): 71 %
         - Recoil effect (Restricted arc if above 1.00): 0.49
   Seaboat quality  (Average = 1.00): 1.16

Hull form characteristics:
   Hull has a flush deck,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.540 / 0.548
   Length to Beam Ratio: 7.23 : 1
   'Natural speed' for length: 18.44 kts
   Power going to wave formation at top speed: 50 %
   Trim (Max stability = 0, Max steadiness = 100): 61
   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:   40.00 %,  14.00 ft / 4.27 m,  10.00 ft / 3.05 m
      - Forward deck:   30.00 %,  10.00 ft / 3.05 m,  10.00 ft / 3.05 m
      - Aft deck:   15.00 %,  10.00 ft / 3.05 m,  10.00 ft / 3.05 m
      - Quarter deck:   15.00 %,  10.00 ft / 3.05 m,  10.00 ft / 3.05 m
      - Average freeboard:      10.64 ft / 3.24 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 84.0 %
      - Above water (accommodation/working, high = better): 105.7 %
   Waterplane Area: 11,048 Square feet or 1,026 Square metres
   Displacement factor (Displacement / loading): 110 %
   Structure weight / hull surface area: 74 lbs/sq ft or 360 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.86
      - Longitudinal: 1.27
      - Overall: 0.90
   Caution: Hull subject to strain in open-sea
   Adequate machinery, storage, compartmentation space
   Adequate accommodation and workspace room
   Ship has slow, easy roll, a good, steady gun platform

30t - FC
25t - LR Wireless
8t - 4 x 18" TT
44t - 2 x Extra boats
250t - Out-of-port Resupply

[Desertfox]

For the Thonburi design, I personally find the limited protected volume (86% of normal length armored) to be a major flaw and would ether improve the protected volume or provide additional total protection for the waterline. While I don't expect the ship would survive a prolonged engagement because of this, its a mean little ship that I'm ok with having a practically nonexistent need to plan for.

When you are trying to stuff 20kts, 8in guns, and self-deployment capability into 2,500t, somethings gotta give.

[snip]

I would like to hear Kirk's thoughts on the included Out-Of-Port resupply tonnage being usable by the ship its based on. That is admittedly a scenario I did not envision when writing that provision of the rules.

[eltf177]

When you are trying to stuff 20kts, 8in guns, and self-deployment capability into 2,500t, somethings gotta give.

I hope a "Tomozuru"-type incident isn't going to happen...