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Description
In the late 1930s, like the rest of the kantai navy battleships, the Atago-class began entering the dockyards for major reconstructions. Atago was the first to commence the refit, entering Toumachi Navy Yard on 28 November 1937. Takao followed at Toumachi Navy Yard on 4 December Atago and emerged from her refit on 28 May 1939

Displacement:
39,532 t light; 41,703 t standard; 50,847 t normal; 58,162 t full load

Dimensions: Length overall / water x beam x draught
930.30 ft / 921.00 ft x 111.00 ft x 32.00 ft (normal load)
283.55 m / 280.72 m x 33.83 m x 9.75 m

Armament:
4 - 18.00" / 457 mm guns (2x2 guns), 2,916.00lbs / 1,322.68kg shells, 1925 Model
Breech loading guns in deck mounts
on centreline ends, evenly spread
16 - 5.50" / 140 mm guns (1x16 guns), 83.19lbs / 37.73kg shells, 1919 Model
Breech loading guns in casemate mount
on side amidships
14 - 0.98" / 25.0 mm guns (2x7 guns), 0.48lbs / 0.22kg shells, 1936 Model
Anti-aircraft guns in open barbettes
on side, all amidships
8 - 5.00" / 127 mm guns (2x4 guns), 62.50lbs / 28.35kg shells, 1930 Model
Breech loading guns in deck mounts
on side, evenly spread
Weight of broadside 13,502 lbs / 6,124 kg
Shells per gun, main battery: 150

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 12.0" / 305 mm 610.63 ft / 186.12 m 18.00 ft / 5.49 m
Ends: 18.0" / 457 mm 18.00 ft / 5.49 m 18.00 ft / 5.49 m
292.37 ft / 89.11 m Unarmoured ends
Upper: 18.0" / 457 mm 18.00 ft / 5.49 m 18.00 ft / 5.49 m
Main Belt covers 102 % of normal length

- Torpedo Bulkhead:
5.00" / 127 mm 610.63 ft / 186.12 m 24.35 ft / 7.42 m

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 17.0" / 432 mm 6.20" / 157 mm 15.8" / 401 mm
2nd: 2.00" / 51 mm 2.00" / 51 mm 2.00" / 51 mm
3rd: 1.00" / 25 mm - -

- Armour deck: 4.35" / 110 mm, Conning tower: 19.00" / 483 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 159,139 shp / 118,718 Kw = 30.00 kts
Range 12,000nm at 23.00 kts
Bunker at max displacement = 16,458 tons

Complement:
1,692 - 2,200

Cost:
£26.068 million / $104.273 million

Distribution of weights at normal displacement:
Armament: 1,688 tons, 3.3 %
Armour: 17,006 tons, 33.4 %
- Belts: 7,334 tons, 14.4 %
- Torpedo bulkhead: 2,751 tons, 5.4 %
- Armament: 650 tons, 1.3 %
- Armour Deck: 5,709 tons, 11.2 %
- Conning Tower: 562 tons, 1.1 %
Machinery: 3,807 tons, 7.5 %
Hull, fittings & equipment: 17,032 tons, 33.5 %
Fuel, ammunition & stores: 11,315 tons, 22.3 %
Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
58,856 lbs / 26,696 Kg = 20.2 x 18.0 " / 457 mm shells or 15.1 torpedoes
Stability (Unstable if below 1.00): 1.89
Metacentric height 16.2 ft / 5.0 m
Roll period: 11.6 seconds
Steadiness - As gun platform (Average = 50 %): 27 %
- Recoil effect (Restricted arc if above 1.00): 0.02
Seaboat quality (Average = 1.00): 0.29

Hull form characteristics:
Hull has a flush deck
Block coefficient: 0.544
Length to Beam Ratio: 8.30 : 1
'Natural speed' for length: 30.35 kts
Power going to wave formation at top speed: 45 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): 19.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 27.00 ft / 8.23 m
- Forecastle (20 %): 6.45 ft / 1.97 m
- Mid (50 %): 5.67 ft / 1.73 m
- Quarterdeck (20 %): 6.45 ft / 1.97 m
- Stern: 6.80 ft / 2.07 m
- Average freeboard: 7.90 ft / 2.41 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 62.3 %
- Above water (accommodation/working, high = better): 48.4 %
Waterplane Area: 70,946 Square feet or 6,591 Square metres
Displacement factor (Displacement / loading): 133 %
Structure weight / hull surface area: 200 lbs/sq ft or 974 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 1.57
- Longitudinal: 0.53
- Overall: 0.69
Caution: Hull subject to strain in open-sea
Hull space for machinery, storage, compartmentation is excellent
Room for accommodation and workspaces is extremely poor

Description
In the late 1930s, like the rest of the kantai navy battleships, the Atago-class began entering the dockyards for major reconstructions. Atago was the first to commence the refit, entering Toumachi Navy Yard on 28 November 1937. Takao followed at Toumachi Navy Yard on 4 December Atago and emerged from her refit on 28 May 1939

Displacement:
39,532 t light; 41,703 t standard; 50,847 t normal; 58,162 t full load

Dimensions: Length overall / water x beam x draught
930.30 ft / 921.00 ft x 111.00 ft x 32.00 ft (normal load)
283.55 m / 280.72 m x 33.83 m x 9.75 m

Armament:
4 - 18.00" / 457 mm guns (2x2 guns), 2,916.00lbs / 1,322.68kg shells, 1925 Model
Breech loading guns in deck mounts
on centreline ends, evenly spread
16 - 5.50" / 140 mm guns (1x16 guns), 83.19lbs / 37.73kg shells, 1919 Model
Breech loading guns in casemate mount
on side amidships
14 - 0.98" / 25.0 mm guns (2x7 guns), 0.48lbs / 0.22kg shells, 1936 Model
Anti-aircraft guns in open barbettes
on side, all amidships
8 - 5.00" / 127 mm guns (2x4 guns), 62.50lbs / 28.35kg shells, 1930 Model
Breech loading guns in deck mounts
on side, evenly spread
Weight of broadside 13,502 lbs / 6,124 kg
Shells per gun, main battery: 150

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 12.0" / 305 mm 610.63 ft / 186.12 m 18.00 ft / 5.49 m
Ends: 18.0" / 457 mm 18.00 ft / 5.49 m 18.00 ft / 5.49 m
292.37 ft / 89.11 m Unarmoured ends
Upper: 18.0" / 457 mm 18.00 ft / 5.49 m 18.00 ft / 5.49 m
Main Belt covers 102 % of normal length

- Torpedo Bulkhead:
5.00" / 127 mm 610.63 ft / 186.12 m 24.35 ft / 7.42 m

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 17.0" / 432 mm 6.20" / 157 mm 15.8" / 401 mm
2nd: 2.00" / 51 mm 2.00" / 51 mm 2.00" / 51 mm
3rd: 1.00" / 25 mm - -

- Armour deck: 4.35" / 110 mm, Conning tower: 19.00" / 483 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 159,139 shp / 118,718 Kw = 30.00 kts
Range 12,000nm at 23.00 kts
Bunker at max displacement = 16,458 tons

Complement:
1,692 - 2,200

Cost:
£26.068 million / $104.273 million

Distribution of weights at normal displacement:
Armament: 1,688 tons, 3.3 %
Armour: 17,006 tons, 33.4 %
- Belts: 7,334 tons, 14.4 %
- Torpedo bulkhead: 2,751 tons, 5.4 %
- Armament: 650 tons, 1.3 %
- Armour Deck: 5,709 tons, 11.2 %
- Conning Tower: 562 tons, 1.1 %
Machinery: 3,807 tons, 7.5 %
Hull, fittings & equipment: 17,032 tons, 33.5 %
Fuel, ammunition & stores: 11,315 tons, 22.3 %
Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
58,856 lbs / 26,696 Kg = 20.2 x 18.0 " / 457 mm shells or 15.1 torpedoes
Stability (Unstable if below 1.00): 1.89
Metacentric height 16.2 ft / 5.0 m
Roll period: 11.6 seconds
Steadiness - As gun platform (Average = 50 %): 27 %
- Recoil effect (Restricted arc if above 1.00): 0.02
Seaboat quality (Average = 1.00): 0.29

Hull form characteristics:
Hull has a flush deck
Block coefficient: 0.544
Length to Beam Ratio: 8.30 : 1
'Natural speed' for length: 30.35 kts
Power going to wave formation at top speed: 45 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): 19.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 27.00 ft / 8.23 m
- Forecastle (20 %): 6.45 ft / 1.97 m
- Mid (50 %): 5.67 ft / 1.73 m
- Quarterdeck (20 %): 6.45 ft / 1.97 m
- Stern: 6.80 ft / 2.07 m
- Average freeboard: 7.90 ft / 2.41 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 62.3 %
- Above water (accommodation/working, high = better): 48.4 %
Waterplane Area: 70,946 Square feet or 6,591 Square metres
Displacement factor (Displacement / loading): 133 %
Structure weight / hull surface area: 200 lbs/sq ft or 974 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 1.57
- Longitudinal: 0.53
- Overall: 0.69
Caution: Hull subject to strain in open-sea
Hull space for machinery, storage, compartmentation is excellent
Room for accommodation and workspaces is extremely poor