Data on the Atsusa class Coast Defense Ship, released by the Imperial Navy:
Atsusa, Japan CDS laid down 1921
Number of ships to be built: 6.
Ships and names:
Atsusa means “Heat”
Zansho means “Lingering [summer] Heat”
Asasamu means “Morning Chill” or “Morning Cold”
Yosamu means “Night Chill” or “Cold Night”
Kanya means “Cold Night” or “Midwinter Night”
Sokobie means “Deep Cold”
Displacement:
3,630 t light; 3,840 t standard; 4,149 t normal; 4,379 t full load
Loading submergence 421 tons/feet
Dimensions:
400.00 ft x 55.00 ft x 12.00 ft (normal load)
121.92 m x 16.76 m x 3.66 m
Armament:
4 - 9.06" / 230 mm guns (2 Main turrets x 2 guns)
8 - 1.97" / 50 mm AA guns
20 - 0.98" / 25 mm guns
Weight of broadside 1,525 lbs / 692 kg
Armour:
Belt 5.00" / 127 mm, ends unarmoured
Belts cover 65 % of normal area
Main turrets 8.00" / 203 mm, AA gun shields 1.00" / 25 mm, Light gun shields 1.00" / 25 mm
Armour deck 2.00" / 51 mm, Conning tower 5.00" / 127 mm
Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 9,620 shp / 7,176 Kw = 20.00 kts
Range 5,800nm at 12.00 kts
Complement:
258 - 335
Cost:
£0.849 million / $3.396 million
Distribution of weights at normal displacement:
Armament: 191 tons, 4.6 %
Armour: 1,274 tons, 30.7 %
Belts: 319 tons, 7.7 %, Armament: 381 tons, 9.2 %, Armour Deck: 545 tons, 13.1 %
Conning Tower: 28 tons, 0.7 %, Torpedo bulkhead: 0 tons, 0.0 %
Machinery: 331 tons, 8.0 %
Hull, fittings & equipment: 1,834 tons, 44.2 %
Fuel, ammunition & stores: 519 tons, 12.5 %
Miscellaneous weights: 0 tons, 0.0 %
Metacentric height 3.3
Remarks:
Hull space for machinery, storage & compartmentation is excellent
Room for accommodation & workspaces is adequate
Estimated overall survivability and seakeeping ability:
Relative margin of stability: 1.30
Shellfire needed to sink: 7,757 lbs / 3,518 Kg = 20.9 x 9.1 " / 230 mm shells
(Approx weight of penetrating shell hits needed to sink ship excluding critical hits)
Torpedoes needed to sink: 2.1
(Approx number of typical torpedo hits needed to sink ship)
Relative steadiness as gun platform: 53 %
(Average = 50 %)
Relative rocking effect from firing to beam: 0.29
Relative quality as seaboat: 1.06
Hull form characteristics:
Block coefficient: 0.550
Sharpness coefficient: 0.39
Hull speed coefficient 'M': 7.61
'Natural speed' for length: 20.00 kts
Power going to wave formation at top speed: 45 %
Trim: 50
(Maximise stabilty/flotation = 0, Maximise steadiness/seakeeping = 100)
Estimated hull characteristics & strength:
Underwater volume absorbed by magazines and engineering spaces: 62.2 %
Relative accommodation and working space: 112.1 %
(Average = 100%)
Displacement factor: 120 %
(Displacement relative to loading factors)
Relative cross-sectional hull strength: 1.00
(Structure weight / hull surface area: 95 lbs / square foot or 464 Kg / square metre)
Relative longitudinal hull strength: 1.00
(for 10.30 ft / 3.14 m average freeboard, freeboard adjustment -2.40 ft)
Relative composite hull strength: 1.00
Walter