WesWorld

Minesweepers of the Japanese Navy.

Data here is the data released to the public

Mu Ichi Class
M-1 to M-18

Dimensions: 220.00 ft x 25.00 ft x 7.00 ft
Standard Displacement: 500 tons
Armament: 6 - 10.5 cm / 50 cal Model 1914 guns
4 - 50 mm / 60 cal Model 1914 AA guns
12 - 25 mm / 60 cal Model 1914 light AA guns
Armour: Main gun shields 1.00", AA gun shields 1.00", Light AA gun shields 1.00"
Machinery: 3 Kanpon oil fired boilers, Brown Curtis geared,
Geared drive, 2 shafts, 2,400 shp = 18.00 kts
Range 4,500nm at 12.00 kts
Complement: 9 Officers, 68 other rank

Mu Ichi, Japan Minesweeper laid down 1916
All scrapped in 1943

Displacement:
473 t light; 505 t standard; 605 t normal; 683 t full load
Loading submergence 105 tons/feet

Dimensions:
220.00 ft x 25.00 ft x 7.00 ft (normal load)
67.06 m x 7.62 m x 2.13 m

Armament:
6 - 4.13" / 105 mm guns
4 - 1.97" / 50 mm AA guns
12 - 0.98" / 25 mm guns
Weight of broadside 233 lbs / 106 kg

Armour:
Main gun shields 1.00" / 25 mm, AA gun shields 1.00" / 25 mm, Light gun shields 1.00" / 25 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 2,569 shp / 1,916 Kw = 18.50 kts
Range 5,000nm at 12.00 kts

Complement:
60 - 79

Cost:
£0.089 million / $0.356 million

Distribution of weights at normal displacement:
Armament: 29 tons, 4.8 %
Armour: 10 tons, 1.7 %
Belts: 0 tons, 0.0 %, Armament: 10 tons, 1.7 %, Armour Deck: 0 tons, 0.0 %
Conning Tower: 0 tons, 0.0 %, Torpedo bulkhead: 0 tons, 0.0 %
Machinery: 96 tons, 15.8 %
Hull, fittings & equipment: 273 tons, 45.2 %
Fuel, ammunition & stores: 132 tons, 21.8 %
Miscellaneous weights: 65 tons, 10.7 %

Metacentric height 0.8

Remarks:
Hull space for machinery, storage & compartmentation is adequate
Room for accommodation & workspaces is adequate

Estimated overall survivability and seakeeping ability:
Relative margin of stability: 1.14
Shellfire needed to sink: 780 lbs / 354 Kg = 22.1 x 4.1 " / 105 mm shells
(Approx weight of penetrating shell hits needed to sink ship excluding critical hits)
Torpedoes needed to sink: 0.5
(Approx number of typical torpedo hits needed to sink ship)
Relative steadiness as gun platform: 52 %
(Average = 50 %)
Relative rocking effect from firing to beam: 0.42
Relative quality as seaboat: 1.04

Hull form characteristics:
Block coefficient: 0.550
Sharpness coefficient: 0.36
Hull speed coefficient 'M': 7.95
'Natural speed' for length: 14.83 kts
Power going to wave formation at top speed: 54 %
Trim: 50
(Maximise stabilty/flotation = 0, Maximise steadiness/seakeeping = 100)

Estimated hull characteristics & strength:
Underwater volume absorbed by magazines and engineering spaces: 100.2 %
Relative accommodation and working space: 95.9 %
(Average = 100%)
Displacement factor: 121 %
(Displacement relative to loading factors)
Relative cross-sectional hull strength: 1.01
(Structure weight / hull surface area: 47 lbs / square foot or 231 Kg / square metre)
Relative longitudinal hull strength: 1.62
(for 8.20 ft / 2.50 m average freeboard, freeboard adjustment -0.44 ft)
Relative composite hull strength: 1.05

W-1, Japan Minesweeper laid down 1942


Displacement:
581 t light; 622 t standard; 666 t normal; 701 t full load

Dimensions: Length overall / water x beam x draught
234.00 ft / 234.00 ft x 25.75 ft x 8.60 ft (normal load)
71.32 m / 71.32 m x 7.85 m x 2.62 m

Armament:
3 - 5.00" / 127 mm guns in single mounts, 55.12lbs / 25.00kg shells, 1942 Model
Dual purpose guns in deck mounts with hoists
on centreline ends, majority aft
3 - 0.98" / 25.0 mm guns (1x3 guns), 0.57lbs / 0.26kg shells, 1942 Model
Anti-aircraft guns in deck mount
on side amidships
Weight of broadside 167 lbs / 76 kg
Shells per gun, main battery: 300

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

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 3,436 shp / 2,563 Kw = 20.00 kts
Range 2,100nm at 14.00 kts
Bunker at max displacement = 79 tons

Complement:
65 - 85

Cost:
£0.336 million / $1.342 million

Distribution of weights at normal displacement:
Armament: 24 tons, 3.5%
Armour: 12 tons, 1.8%
- Belts: 0 tons, 0.0%
- Torpedo bulkhead: 0 tons, 0.0%
- Armament: 12 tons, 1.8%
- Armour Deck: 0 tons, 0.0%
- Conning Tower: 0 tons, 0.0%
Machinery: 90 tons, 13.5%
Hull, fittings & equipment: 320 tons, 48.1%
Fuel, ammunition & stores: 85 tons, 12.8%
Miscellaneous weights: 135 tons, 20.3%

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
963 lbs / 437 Kg = 15.4 x 5.0 " / 127 mm shells or 0.5 torpedoes
Stability (Unstable if below 1.00): 1.05
Metacentric height 0.7 ft / 0.2 m
Roll period: 12.7 seconds
Steadiness - As gun platform (Average = 50 %): 51 %
- Recoil effect (Restricted arc if above 1.00): 0.69
Seaboat quality (Average = 1.00): 1.64

Hull form characteristics:
Hull has rise forward of midbreak
Block coefficient: 0.450
Length to Beam Ratio: 9.09 : 1
'Natural speed' for length: 15.30 kts
Power going to wave formation at top speed: 53 %
Trim (Max stability = 0, Max steadiness = 100): 31
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: 16.00 ft / 4.88 m
- Forecastle (20%): 14.00 ft / 4.27 m
- Mid (50%): 14.00 ft / 4.27 m (7.00 ft / 2.13 m aft of break)
- Quarterdeck (15%): 7.00 ft / 2.13 m
- Stern: 7.00 ft / 2.13 m
- Average freeboard: 10.66 ft / 3.25 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 95.3%
- Above water (accommodation/working, high = better): 115.2%
Waterplane Area: 3,843 Square feet or 357 Square metres
Displacement factor (Displacement / loading): 129%
Structure weight / hull surface area: 44 lbs/sq ft or 217 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.88
- Longitudinal: 3.23
- Overall: 1.00
Hull space for machinery, storage, compartmentation is adequate
Room for accommodation and workspaces is adequate
Excellent seaboat, comfortable, can fire her guns in the heaviest weather

35 tons for electronics.
40 tons for depth charges and depth charge projector.
60 tons for mine sweeping equipment.

WA-1, Japan Minesweeper laid down 1942


Displacement:
138 t light; 144 t standard; 151 t normal; 157 t full load

Dimensions: Length overall / water x beam x draught
108.45 ft / 98.00 ft x 20.00 ft x 6.00 ft (normal load)
33.05 m / 29.87 m x 6.10 m x 1.83 m

Armament:
1 - 2.95" / 75.0 mm guns in single mounts, 12.00lbs / 5.44kg shells, 1942 Model
Dual purpose gun in a deck mount with hoist
on centreline forward
1 - 0.52" / 13.2 mm guns in single mounts, 0.09lbs / 0.04kg shells, 1942 Model
Machine gun in deck mount
on centreline aft, 1 raised gun
1 - 0.30" / 7.7 mm guns in single mounts, 0.01lbs / 0.01kg shells, 1942 Model
Machine gun in deck mount
on centreline amidships, 1 raised gun
Weight of broadside 12 lbs / 5 kg
Shells per gun, main battery: 300

Machinery:
Diesel Internal combustion motors,
Geared drive, 1 shaft, 108 shp / 81 Kw = 9.50 kts
Range 2,000nm at 9.50 kts
Bunker at max displacement = 14 tons

Complement:
21 - 28

Cost:
£0.042 million / $0.168 million

Distribution of weights at normal displacement:
Armament: 2 tons, 1.1%
Machinery: 3 tons, 1.9%
Hull, fittings & equipment: 69 tons, 45.6%
Fuel, ammunition & stores: 13 tons, 8.4%
Miscellaneous weights: 65 tons, 43.0%

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
286 lbs / 130 Kg = 22.2 x 3.0 " / 75 mm shells or 0.5 torpedoes
Stability (Unstable if below 1.00): 1.05
Metacentric height 0.5 ft / 0.2 m
Roll period: 11.9 seconds
Steadiness - As gun platform (Average = 50 %): 50 %
- Recoil effect (Restricted arc if above 1.00): 0.10
Seaboat quality (Average = 1.00): 2.00

Hull form characteristics:
Hull has rise forward of midbreak
Block coefficient: 0.450
Length to Beam Ratio: 4.90 : 1
'Natural speed' for length: 9.90 kts
Power going to wave formation at top speed: 45 %
Trim (Max stability = 0, Max steadiness = 100): 25
Bow angle (Positive = bow angles forward): 15.00 degrees
Stern overhang: 7.50 ft / 2.29 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 11.00 ft / 3.35 m
- Forecastle (10%): 11.00 ft / 3.35 m
- Mid (20%): 11.00 ft / 3.35 m (5.00 ft / 1.52 m aft of break)
- Quarterdeck (15%): 5.00 ft / 1.52 m
- Stern: 5.00 ft / 1.52 m
- Average freeboard: 6.20 ft / 1.89 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 62.6%
- Above water (accommodation/working, high = better): 62.7%
Waterplane Area: 1,191 Square feet or 111 Square metres
Displacement factor (Displacement / loading): 181%
Structure weight / hull surface area: 36 lbs/sq ft or 176 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 1.24
- Longitudinal: 5.95
- Overall: 1.45
Hull space for machinery, storage, compartmentation is excellent
Room for accommodation and workspaces is cramped
Excellent seaboat, comfortable, can fire her guns in the heaviest weather

20 tons for electronics.
10 tons for depth charges.
35 tons for mine sweeping equipment.