Gavin sounded rather disappointed when I started to build the Taiyo and Unryu classes, because they were smaller than the previous carriers I started. Originally I wasn't planning to build this Hiyo class, but decided to make Gavin happy and included them again in the building program.
An enlarged Shokaku class carrier, capable of carrying 130 planes.
Hiyo, Japan Carrier laid down 1940
Displacement:
47,000 t light; 48,475 t standard; 53,681 t normal; 57,845 t full load
Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(936.08 ft / 900.00 ft) x 108.00 ft x (35.00 / 37.06 ft)
(285.32 m / 274.32 m) x 32.92 m x (10.67 / 11.30 m)
Armament:
8 - 5.00" / 127 mm 38.0 cal guns - 55.12lbs / 25.00kg shells, 450 per gun
Dual purpose guns in deck and hoist mounts, 1940 Model
4 x Twin mounts on sides, forward evenly spread
2 raised mounts
16 - 4.13" / 105 mm 50.0 cal guns - 34.00lbs / 15.42kg shells, 750 per gun
Dual purpose guns in deck and hoist mounts, 1940 Model
4 x 2-gun mounts on sides, forward deck forward
4 x Twin mounts on sides, aft deck aft
32 - 1.57" / 40.0 mm 39.0 cal guns - 2.01lbs / 0.91kg shells, 1,000 per gun
Anti-air guns in deck mounts, 1940 Model
3 x 2 row octuple mounts on sides, forward evenly spread
2 raised mounts
1 x 2 row octuple mount on sides, forward deck centre
1 double raised mount
51 - 0.98" / 25.0 mm 65.0 cal guns - 0.57lbs / 0.26kg shells, 1,500 per gun
Anti-air guns in deck mounts, 1940 Model
17 x Triple mounts on sides, evenly spread
32 - 0.52" / 13.2 mm 70.0 cal guns - 0.09lbs / 0.04kg shells, 2,500 per gun
Machine guns in deck mounts, 1940 Model
2 x 2 row octuple mounts on centreline, forward deck forward
2 x 2 row octuple mounts on centreline, aft deck aft
Weight of broadside 1,081 lbs / 490 kg
Main Torpedoes
320 - 17.7" / 450 mm, 18.04 ft / 5.50 m torpedoes - 0.960 t each, 307.067 t total
In 80 sets of deck mounted carriage/fixed tubes
Main DC/AS Mortars
80 - 1,763.70 lbs / 800.00 kg Depth Charges + 320 reloads - 314.946 t total
in Stern depth charge racks
2nd DC/AS Mortars
80 - 1,102.31 lbs / 500.00 kg Depth Charges + 640 reloads - 354.314 t total
in Stern depth charge racks
Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 6.00" / 152 mm 650.00 ft / 198.12 m 12.00 ft / 3.66 m
Ends: Unarmoured
Main Belt covers 111% of normal length
Main Belt inclined 10.00 degrees (positive = in)
- Torpedo Bulkhead - Strengthened structural bulkheads:
2.75" / 70 mm 650.00 ft / 198.12 m 32.13 ft / 9.79 m
Beam between torpedo bulkheads 108.00 ft / 32.92 m
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 3.00" / 76 mm 1.00" / 25 mm 2.00" / 51 mm
2nd: 2.00" / 51 mm 1.00" / 25 mm 2.00" / 51 mm
3rd: 1.00" / 25 mm 1.00" / 25 mm -
4th: 1.00" / 25 mm 1.00" / 25 mm -
5th: 0.50" / 13 mm 0.50" / 13 mm -
- Armoured deck - multiple decks:
For and Aft decks: 3.25" / 83 mm
Forecastle: 3.25" / 83 mm Quarter deck: 3.25" / 83 mm
- Conning towers: Forward 2.75" / 70 mm, Aft 0.00" / 0 mm
Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 186,189 shp / 138,897 Kw = 32.00 kts
Range 15,000nm at 15.00 kts
Bunker at max displacement = 9,371 tons
Complement:
1,763 - 2,292
Cost:
£14.713 million / $58.853 million
Distribution of weights at normal displacement:
Armament: 1,511 tons, 2.8%
- Guns: 291 tons, 0.5%
- Weapons: 1,220 tons, 2.3%
Armour: 8,741 tons, 16.3%
- Belts: 1,935 tons, 3.6%
- Torpedo bulkhead: 2,125 tons, 4.0%
- Armament: 305 tons, 0.6%
- Armour Deck: 4,291 tons, 8.0%
- Conning Tower: 84 tons, 0.2%
Machinery: 4,978 tons, 9.3%
Hull, fittings & equipment: 11,770 tons, 21.9%
Fuel, ammunition & stores: 6,680 tons, 12.4%
Miscellaneous weights: 20,000 tons, 37.3%
- Hull below water: 1,200 tons
- Hull above water: 8,500 tons
- On freeboard deck: 8,500 tons
- Above deck: 1,800 tons
Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
100,324 lbs / 45,506 Kg = 1,605.2 x 5.0 " / 127 mm shells or 25.5 torpedoes
Stability (Unstable if below 1.00): 1.10
Metacentric height 6.7 ft / 2.0 m
Roll period: 17.5 seconds
Steadiness - As gun platform (Average = 50 %): 70 %
- Recoil effect (Restricted arc if above 1.00): 0.03
Seaboat quality (Average = 1.00): 1.40
Hull form characteristics:
Hull has a flush deck,
an extended bulbous bow and large transom stern
Block coefficient (normal/deep): 0.552 / 0.562
Length to Beam Ratio: 8.33 : 1
'Natural speed' for length: 34.53 kts
Power going to wave formation at top speed: 50 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): 25.00 degrees
Stern overhang: 15.00 ft / 4.57 m
Freeboard (% = length of deck as a percentage of waterline length):
Fore end, Aft end
- Forecastle: 15.00%, 45.20 ft / 13.78 m, 24.20 ft / 7.38 m
- Forward deck: 40.00%, 24.20 ft / 7.38 m, 24.20 ft / 7.38 m
- Aft deck: 30.00%, 24.20 ft / 7.38 m, 24.20 ft / 7.38 m
- Quarter deck: 15.00%, 24.20 ft / 7.38 m, 24.20 ft / 7.38 m
- Average freeboard: 25.46 ft / 7.76 m
Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 53.4%
- Above water (accommodation/working, high = better): 162.8%
Waterplane Area: 70,776 Square feet or 6,575 Square metres
Displacement factor (Displacement / loading): 135%
Structure weight / hull surface area: 141 lbs/sq ft or 687 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 1.00
- Longitudinal: 1.00
- Overall: 1.00
Excellent 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