Dispatch Boats

[Walter]

Yaeyama, Japan Dispach boat laid down 1887


Displacement:
   1,467 t light; 1,516 t standard; 1,644 t normal; 1,747 t full load

Dimensions: Length overall / water x beam x draught
   318.24 ft / 318.24 ft x 32.81 ft x 13.12 ft (normal load)
   97.00 m / 97.00 m x 10.00 m  x 4.00 m

Armament:
      3 - 4.72" / 120 mm guns in single mounts, 50.35lbs / 22.84kg shells, 1887 Model
     Breech loading guns in deck mounts
     on centreline ends, majority forward
      8 - 1.85" / 47.0 mm guns in single mounts, 3.03lbs / 1.37kg shells, 1887 Model
     Quick firing guns in deck mounts
     on side, all amidships
   Weight of broadside 175 lbs / 80 kg
   Shells per gun, main battery: 150
   2 - 17.7" / 450 mm submerged torpedo tubes

Machinery:
   Coal fired boilers, simple reciprocating steam engines,
   Direct drive, 2 shafts, 4,941 ihp / 3,686 Kw = 19.45 kts
   Range 2,000nm at 10.00 kts
   Bunker at max displacement = 232 tons (100% coal)

Complement:
   128 - 167

Cost:
   £0.182 million / $0.729 million

Distribution of weights at normal displacement:
   Armament: 22 tons, 1.3 %
   Machinery: 803 tons, 48.8 %
   Hull, fittings & equipment: 592 tons, 36.0 %
   Fuel, ammunition & stores: 177 tons, 10.8 %
   Miscellaneous weights: 50 tons, 3.0 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     586 lbs / 266 Kg = 11.6 x 4.7 " / 120 mm shells or 0.3 torpedoes
   Stability (Unstable if below 1.00): 1.44
   Metacentric height 1.8 ft / 0.5 m
   Roll period: 10.4 seconds
   Steadiness   - As gun platform (Average = 50 %): 100 %
         - Recoil effect (Restricted arc if above 1.00): 0.14
   Seaboat quality  (Average = 1.00): 1.58

Hull form characteristics:
   Hull has a flush deck
   Block coefficient: 0.420
   Length to Beam Ratio: 9.70 : 1
   'Natural speed' for length: 17.84 kts
   Power going to wave formation at top speed: 42 %
   Trim (Max stability = 0, Max steadiness = 100): 64
   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:      9.84 ft / 3.00 m
      - Forecastle (20 %):   9.84 ft / 3.00 m
      - Mid (50 %):      9.84 ft / 3.00 m
      - Quarterdeck (15 %):   9.84 ft / 3.00 m
      - Stern:      9.84 ft / 3.00 m
      - Average freeboard:   9.84 ft / 3.00 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 183.8 %
      - Above water (accommodation/working, high = better): 95.3 %
   Waterplane Area: 6,509 Square feet or 605 Square metres
   Displacement factor (Displacement / loading): 77 %
   Structure weight / hull surface area: 55 lbs/sq ft or 267 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.96
      - Longitudinal: 1.39
      - Overall: 1.00
   Hull space for machinery, storage, compartmentation is cramped
   Room for accommodation and workspaces is adequate
   Ship has slow, easy roll, a good, steady gun platform
   Excellent seaboat, comfortable, can fire her guns in the heaviest weather

[Walter]

Tatsuta, Japan Dispach boat laid down 1893

Displacement:
   761 t light; 789 t standard; 845 t normal; 889 t full load

Dimensions: Length overall / water x beam x draught
   242.78 ft / 242.78 ft x 27.49 ft x 9.84 ft (normal load)
   74.00 m / 74.00 m x 8.38 m  x 3.00 m

Armament:
      2 - 4.72" / 120 mm guns in single mounts, 52.72lbs / 23.92kg shells, 1893 Model
     Breech loading guns in deck mounts
     on centreline ends, evenly spread
      4 - 1.85" / 47.0 mm guns in single mounts, 3.17lbs / 1.44kg shells, 1893 Model
     Quick firing guns in deck mounts
     on side, all amidships
      5 - 1.46" / 37.0 mm guns in single mounts, 1.55lbs / 0.70kg shells, 1893 Model
     Quick firing guns in deck mounts
     on side, evenly spread
   Weight of broadside 126 lbs / 57 kg
   Shells per gun, main battery: 150
   5 - 17.7" / 450 mm submerged torpedo tubes

Machinery:
   Coal fired boilers, complex reciprocating steam engines,
   Direct drive, 2 shafts, 3,937 ihp / 2,937 Kw = 20.00 kts
   Range 1,500nm at 10.00 kts
   Bunker at max displacement = 100 tons (100% coal)

Complement:
   77 - 101

Cost:
   £0.098 million / $0.392 million

Distribution of weights at normal displacement:
   Armament: 16 tons, 1.9 %
   Machinery: 415 tons, 49.2 %
   Hull, fittings & equipment: 280 tons, 33.1 %
   Fuel, ammunition & stores: 84 tons, 9.9 %
   Miscellaneous weights: 50 tons, 5.9 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     151 lbs / 68 Kg = 2.9 x 4.7 " / 120 mm shells or 0.1 torpedoes
   Stability (Unstable if below 1.00): 1.10
   Metacentric height 0.9 ft / 0.3 m
   Roll period: 12.5 seconds
   Steadiness   - As gun platform (Average = 50 %): 100 %
         - Recoil effect (Restricted arc if above 1.00): 0.20
   Seaboat quality  (Average = 1.00): 1.05

Hull form characteristics:
   Hull has a flush deck
   Block coefficient: 0.450
   Length to Beam Ratio: 8.83 : 1
   'Natural speed' for length: 15.58 kts
   Power going to wave formation at top speed: 53 %
   Trim (Max stability = 0, Max steadiness = 100): 95
   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:      7.22 ft / 2.20 m
      - Forecastle (20 %):   7.22 ft / 2.20 m
      - Mid (50 %):      7.22 ft / 2.20 m
      - Quarterdeck (15 %):   7.22 ft / 2.20 m
      - Stern:      7.22 ft / 2.20 m
      - Average freeboard:   7.22 ft / 2.20 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 244.4 %
      - Above water (accommodation/working, high = better): 76.0 %
   Waterplane Area: 4,258 Square feet or 396 Square metres
   Displacement factor (Displacement / loading): 54 %
   Structure weight / hull surface area: 42 lbs/sq ft or 206 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.97
      - Longitudinal: 1.29
      - Overall: 1.00
   Hull space for machinery, storage, compartmentation is extremely poor
   Room for accommodation and workspaces is cramped
   Ship has slow, easy roll, a good, steady gun platform

[Walter]

Miyako, Japan Dispach boat laid down 1894

Displacement:
   1,537 t light; 1,586 t standard; 1,759 t normal; 1,898 t full load

Dimensions: Length overall / water x beam x draught
   318.24 ft / 318.24 ft x 34.45 ft x 14.04 ft (normal load)
   97.00 m / 97.00 m x 10.50 m  x 4.28 m

Armament:
      2 - 4.72" / 120 mm guns in single mounts, 52.72lbs / 23.92kg shells, 1894 Model
     Breech loading guns in deck mounts
     on centreline ends, evenly spread
      8 - 2.24" / 57.0 mm guns in single mounts, 5.65lbs / 2.56kg shells, 1894 Model
     Quick firing guns in deck mounts
     on side, all amidships
   Weight of broadside 151 lbs / 68 kg
   Shells per gun, main battery: 150
   2 - 17.7" / 450 mm submerged torpedo tubes

Machinery:
   Coal fired boilers, complex reciprocating steam engines,
   Direct drive, 2 shafts, 6,130 ihp / 4,573 Kw = 20.54 kts
   Range 3,100nm at 10.00 kts
   Bunker at max displacement = 312 tons (100% coal)

Complement:
   135 - 176

Cost:
   £0.193 million / $0.774 million

Distribution of weights at normal displacement:
   Armament: 19 tons, 1.1 %
   Machinery: 885 tons, 50.3 %
   Hull, fittings & equipment: 583 tons, 33.1 %
   Fuel, ammunition & stores: 223 tons, 12.7 %
   Miscellaneous weights: 50 tons, 2.8 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     651 lbs / 295 Kg = 12.3 x 4.7 " / 120 mm shells or 0.3 torpedoes
   Stability (Unstable if below 1.00): 1.52
   Metacentric height 2.1 ft / 0.6 m
   Roll period: 10.1 seconds
   Steadiness   - As gun platform (Average = 50 %): 100 %
         - Recoil effect (Restricted arc if above 1.00): 0.09
   Seaboat quality  (Average = 1.00): 1.61

Hull form characteristics:
   Hull has a flush deck
   Block coefficient: 0.400
   Length to Beam Ratio: 9.24 : 1
   'Natural speed' for length: 17.84 kts
   Power going to wave formation at top speed: 45 %
   Trim (Max stability = 0, Max steadiness = 100): 64
   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:      9.84 ft / 3.00 m
      - Forecastle (20 %):   9.84 ft / 3.00 m
      - Mid (50 %):      9.84 ft / 3.00 m
      - Quarterdeck (15 %):   9.84 ft / 3.00 m
      - Stern:      9.84 ft / 3.00 m
      - Average freeboard:   9.84 ft / 3.00 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 185.8 %
      - Above water (accommodation/working, high = better): 93.7 %
   Waterplane Area: 6,748 Square feet or 627 Square metres
   Displacement factor (Displacement / loading): 76 %
   Structure weight / hull surface area: 52 lbs/sq ft or 255 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.95
      - Longitudinal: 1.49
      - Overall: 1.00
   Hull space for machinery, storage, compartmentation is cramped
   Room for accommodation and workspaces is adequate
   Ship has slow, easy roll, a good, steady gun platform
   Excellent seaboat, comfortable, can fire her guns in the heaviest weather

[Walter]

Chihaya, Japan Dispach boat laid down 1894

Displacement:
   1,108 t light; 1,144 t standard; 1,235 t normal; 1,308 t full load

Dimensions: Length overall / water x beam x draught
   275.59 ft / 275.59 ft x 31.50 ft x 9.06 ft (normal load)
   84.00 m / 84.00 m x 9.60 m  x 2.76 m

Armament:
      2 - 4.72" / 120 mm guns in single mounts, 52.72lbs / 23.92kg shells, 1894 Model
     Breech loading guns in deck mounts
     on centreline ends, evenly spread
      4 - 2.24" / 57.0 mm guns in single mounts, 5.65lbs / 2.56kg shells, 1894 Model
     Quick firing guns in deck mounts
     on side, all amidships
   Weight of broadside 128 lbs / 58 kg
   Shells per gun, main battery: 150
   3 - 17.7" / 450 mm submerged torpedo tubes

Machinery:
   Coal fired boilers, complex reciprocating steam engines,
   Direct drive, 2 shafts, 4,987 ihp / 3,720 Kw = 20.00 kts
   Range 2,000nm at 10.00 kts
   Bunker at max displacement = 164 tons (100% coal)

Complement:
   103 - 135

Cost:
   £0.139 million / $0.557 million

Distribution of weights at normal displacement:
   Armament: 16 tons, 1.3 %
   Machinery: 622 tons, 50.4 %
   Hull, fittings & equipment: 419 tons, 34.0 %
   Fuel, ammunition & stores: 127 tons, 10.3 %
   Miscellaneous weights: 50 tons, 4.0 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     413 lbs / 187 Kg = 7.8 x 4.7 " / 120 mm shells or 0.2 torpedoes
   Stability (Unstable if below 1.00): 1.32
   Metacentric height 1.4 ft / 0.4 m
   Roll period: 11.0 seconds
   Steadiness   - As gun platform (Average = 50 %): 100 %
         - Recoil effect (Restricted arc if above 1.00): 0.13
   Seaboat quality  (Average = 1.00): 1.29

Hull form characteristics:
   Hull has a flush deck
   Block coefficient: 0.550
   Length to Beam Ratio: 8.75 : 1
   'Natural speed' for length: 16.60 kts
   Power going to wave formation at top speed: 53 %
   Trim (Max stability = 0, Max steadiness = 100): 77
   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:      9.84 ft / 3.00 m
      - Forecastle (20 %):   9.84 ft / 3.00 m
      - Mid (50 %):      9.84 ft / 3.00 m
      - Quarterdeck (15 %):   9.84 ft / 3.00 m
      - Stern:      9.84 ft / 3.00 m
      - Average freeboard:   9.84 ft / 3.00 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 201.7 %
      - Above water (accommodation/working, high = better): 110.3 %
   Waterplane Area: 6,058 Square feet or 563 Square metres
   Displacement factor (Displacement / loading): 65 %
   Structure weight / hull surface area: 46 lbs/sq ft or 224 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.97
      - Longitudinal: 1.28
      - Overall: 1.00
   Hull space for machinery, storage, compartmentation is extremely poor
   Room for accommodation and workspaces is adequate
   Ship has slow, easy roll, a good, steady gun platform
   Good seaboat, rides out heavy weather easily