IJN Aoba
Contents
Description
The Aoba (青葉, namesake: Mount Aoba) was a Japanese heavy cruiser commissioned in September 1927, designed as a modified version of the Furutaka-class with improved twin 20.3 cm gun turrets and aircraft catapults. Despite being overweight upon completion, she joined the Sixth Squadron alongside her sister ship Kinugasa and the two Furutaka-class vessels, participating in patrols along the China coast during the 1920s and 1930s. During the Second World War, Aoba took part in the invasions of Guam and Wake Island in December 1941, escorted the light carrier Shōhō during the Battle of the Coral Sea in May 1942, and was involved in the Battle of Savo Island in August 1942, where she contributed to the sinking of several Allied cruisers. In October 1942, at the Battle of Cape Esperance, Aoba was severely damaged, losing her second and third turrets and suffering heavy casualties, including the death of Rear Admiral Goto. After repairs, she returned to action but was damaged again by an air raid in April 1943, leading to her being disguised as an island, nicknamed "The Aoba Island", to avoid detection while undergoing emergency repairs. She continued to serve in escort and patrol duties despite engine damage limiting her speed but suffered further torpedo and air attack damages in late 1944, eventually being deemed irreparable and reclassified as a reserve ship. In 1945, Aoba was converted into a floating anti-aircraft battery but was sunk during air raids on Kure in July, settling at the bottom of the harbour with her stern broken off. Her wreck was scrapped between 1946 and 1947.
The Aoba-class, IJN Aoba, 1945 was introduced in Update "Direct Hit". She shares her survivability, mobility, and main armament with Furutaka, with the key difference being her vastly improved anti-aircraft capability, which also includes a simple air-search radar but lacks the hydroplane. In all other ways, the vessel performs exactly the same as its direct predecessor, possessing excellent main guns, outstanding torpedoes, and a decent capability for dealing with coastal vessels. One of the class's biggest advantages are its deeply submerged magazines, making direct explosions of the ammo racks much less likely than among the foreign equivalents. However, her poorly protected turrets are easy to knock out, even by enemy destroyers or frigates.
General info
Survivability and armour
Aoba is lightly armoured. The belt armour is only 76.2 mm of rolled homogeneous armour (RHA) and does not extend towards the front and rear turrets to offer additional protection for the magazines; most other heavy cruisers and some light cruisers have thicker armour. Fortunately, the ammunition magazines for the main guns are below the water line and the top is covered by 32 mm of RHA. The fuel tanks in the centre are protected by the belt armour, but the thin steel means these can be easily set on fire which can then spread to the engines. Additional fuel tanks in the bow and stern are completely unprotected and since they are located quite close to the ammunition, the fire can spread to the ammunition. The turrets are large and easy to hit, with only 25mm of RHA. HE from destroyer calibre guns have no issue disabling the turrets.
With only 657 crew, Aoba has the second fewest number of sailors for a heavy cruiser after IJN Kako. This leaves her vulnerable to complete crew loss in a few minutes if concentrated upon by multiple ships.
Although other cruisers can easily put Aoba out of commission, destroyers will have a hard time dealing any significant damage outside of disabling turrets and starting fires.
Mobility
With 12 boilers producing 102,000 SHP combined, Aoba will accelerate to her top speed of 72 km/h (38.9 knots) in AB and 62 km/h (33.5 knots) in RB in 40 seconds. In Arcade, the rudder takes 7 seconds to traverse completely from either side to the next and Aoba can complete a sustained turn in 102 seconds. Realistic battles drops Aoba's sustained turn time to 180 seconds. Overall, Aoba has good mobility, closely matching a number of lighter vessels such as the Omaha-class and Leipzig-class cruisers.
| Mobility Characteristics | |||
|---|---|---|---|
| Game Mode | Upgrade Status | Maximum Speed (km/h) | |
| Forward | Reverse | ||
| AB | |||
| Upgraded | 72 | 27 | |
| RB/SB | |||
| Upgraded | 62 | 23 | |
Modifications and economy
| Seakeeping | Unsinkability | Firepower | ||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
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Armament
Primary armament
Aoba has 6 x 20.3 cm/50 3rd year type No.2 guns split into 3 turrets with 2 guns each. 2 turrets are forward and a single aft of the superstructure. The forward turrets are superfiring, meaning the one behind can shoot over the one in front. She can use HE, HE-TF, and AP shells. The turrets have a slow rotation speed but great firing angles. The guns have a reload time of 12 seconds with the top crew skills, putting them on par with the German Admiral Hipper-class and British County-class heavy cruisers.
HE-TF should be avoided since the slow turret rotation speed and low rate of fire makes this shell basically useless against air targets, and it is not effective against surface targets unlike HE-VT. However, the AP has the best HE filler of all the 20.3 cm (8 inch) armed cruisers and is shared with the much larger and more powerful heavy cruisers in the Japanese fleet, Mogami and Tone. The great HE filler deals significant damage to cruisers and has an increased chance of detonating the ammunition storages of enemy ships.
| Penetration statistics | |||||||
|---|---|---|---|---|---|---|---|
| Ammunition | Type of warhead |
Penetration @ 0° Angle of Attack (mm) | |||||
| 1,000 m | 2,500 m | 5,000 m | 7,500 m | 10,000 m | 15,000 m | ||
| Type 0 HE | HE | 61 | 61 | 61 | 61 | 61 | 61 |
| Type 91 AP | APHEBC | 362 | 321 | 263 | 218 | 182 | 139 |
| Type 0 HE-TF | HE-TF | 61 | 61 | 61 | 61 | 61 | 61 |
| Shell details | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Ammunition | Type of warhead |
Velocity (m/s) |
Projectile mass (kg) |
Fuse delay (s) |
Fuse sensitivity (mm) |
Explosive mass (TNT equivalent) (kg) |
Ricochet | |||||
| 0% | 50% | 100% | ||||||||||
| Type 0 HE | HE | 835 | 125.4 | 0 | 0.1 | 8.57 | 79° | 80° | 81° | |||
| Type 91 AP | APHEBC | 835 | 125.85 | 0.05 | 9 | 3.26 | 48° | 63° | 71° | |||
| Type 0 HE-TF | HE-TF | 835 | 125.4 | 0 | 0.1 | 8.57 | 79° | 80° | 81° | |||
Secondary armament
Aoba comes equipped with 4 turrets with a single 120 mm gun each. These guns are dual purpose, able to use HE-TF against aircraft. Since there are only 4 guns however, it is unlikely these will deter any oncoming aircraft. With very thin armour, and limited numbers, these guns are not all that useful.
| Penetration statistics | |||||||
|---|---|---|---|---|---|---|---|
| Ammunition | Type of warhead |
Penetration @ 0° Angle of Attack (mm) | |||||
| 1,000 m | 2,500 m | 5,000 m | 7,500 m | 10,000 m | 15,000 m | ||
| 120 mm Type 1 HE | HE | 24 | 24 | 24 | 24 | 24 | 24 |
| 120 mm Type 0 HE | HE-TF | 24 | 24 | 24 | 24 | 24 | 24 |
| Shell details | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Ammunition | Type of warhead |
Velocity (m/s) |
Projectile mass (kg) |
Fuse delay (s) |
Fuse sensitivity (mm) |
Explosive mass (TNT equivalent) (kg) |
Ricochet | |||||
| 0% | 50% | 100% | ||||||||||
| 120 mm Type 1 HE | HE | 850 | 20.33 | 0 | 0.1 | 1.95 | 79° | 80° | 81° | |||
| 120 mm Type 0 HE | HE-TF | 850 | 20.33 | 0 | 0.1 | 1.95 | 79° | 80° | 81° | |||
Anti-aircraft armament
Aoba sees a great improvement over Furutaka in the anti-air department, going from just 4 x dual mount 25 mm auto cannons and 2 x 13.2 mm machine guns, to 15 x single mount, 10 x double mount, and 5 x triple mount 25 mm cannons (a total of 50 cannons overall). The 25 mm auto cannons can shoot down fighters and small attackers with ease, although some heavier aircraft such as bombers can shrug off enough of the fire to get close enough to drop bombs or torpedoes, although the addition of an air search radar allows the player to spot and plan for air attacks.
Additional armament
The Type 93 torpedoes can be found on Aoba. Also nicknamed the "Long Lance", these are arguably the best family of torpedoes in the game. The ones carried by Aoba are the longer range versions. With a top speed of 93 km/h (50 knots), range of 20 km, and explosive TNT equivalent of over 600 kg, these torpedoes have the power to destroy even battleships with a single salvo.
Usage in battles
The decent turret firing angles allow the Aoba to sail bow front, maximizing the protective capabilities of the relatively thin armour while keeping all 6 guns pointed at the enemy. The AP shells have decent HE filler and deal good damage against all but the most heavily armoured ships. Target light and heavy cruisers, aiming for turrets can help you get satisfying ammunition detonations.
The Type 93 torpedoes can be launched from the spawn and can hit targets from extreme ranges, although the probability of a successful torpedo hit at these ranges is low due to many factors such as the low speed making them easier to dodge. Alternatively the torpedoes can be used at closer ranges where they will be much more difficult to dodge due to their speed.
If downtiered, Aoba can be played more aggressively as she will be able to shrug off destroyer gunfire despite her thin armour. Be mindful though as other heavy cruisers such as Admiral Hipper class and HMS Kent can also be in the same situation: both of these will be able to outgun you.
Pros and cons
Pros:
- Access to search radar antenna for detecting aircraft
- The main guns have decent firing angles
- AP shells have great explosive filler
- Torpedoes have excellent range, speed and explosive filler
- Improved AA defence capability over Furutaka
Cons:
- Torpedo launchers have limited firing angles
- Thin armour compared to other heavy cruisers
- Only 3 main gun turrets
- Main gun turrets are fragile
History
Design and construction
In 1922, after revisions made to the navy following the signing of the Washington Naval Treaty, the proposed 7,500-ton scout cruisers before the treaty were now to become the Furutaka-class cruisers. The ships were designed by Constructor Captain Hiraga Yuzuru with assistance from Constructor Lieutenant Commander Fujimoto Kikuo. The Furutaka-class were designed to surpass the Omaha and Hawklins-class cruisers of the US and Royal British Navy, incorporating 6 x 20 cm guns in single turrets and giving the ships a broadside weight of fire nearly double that of the Omahas as well as a top speed of 35 kts achieved using 12 boilers with a combined 110,000 SHP, and armour that could resist 15 cm shells from 12-15 km away.
In 1922, the Furutaka-class cruisers were first laid down. In 1924, the recently promoted Rear Admiral Hiraga was sent abroad and during his absence Fujimoto was pressured into using the newly developed 2 x 20 cm gun turrets by the Naval General Staff on the new ships. However, Furutaka and Kako were too far into construction to retrofit the new equipment, therefore the remaining two ships, Aoba and Kinugasa, would be retrofitted with the new armament and placed in a separate class. Fujimoto modified the designs of Aoba and Kinugasa to incorporate the new gun turrets and also agreed to add aircraft catapults to the ships while the machinery and armour remained the same. After Kako was completed in 1926, design flaws in the funnel and bridge structure were discovered, corrections to these would also be used before completion of Aoba and her sistership.
When completed, Aoba was overweight by almost 1,000 tons, sparking fears that this would negatively affect the stability of Aoba and her sistership. Luckily, the ships were designed with a considerable degree of stability, owing to Captain Hiraga designing the ships to be more stable than necessary so that the ships can have the machine spaces on one side be flooded without the threat of capsizing. Thus the stability loss was minor and the seaworthiness of the ships proved to be good. Aoba received her gunpowder-powered aircraft catapult in 1929. In 1930, the navy won approval for the modernization of the A-class cruisers to counter the numerical advantage enjoyed by the US Navy. However, the political situation limited the modernization given. Modifications started in 1938 and included new 20.3 cm/50 main guns, 4 x dual 25 mm AA guns around the funnel, and mounting of new quad torpedo launchers with the Type 90 torpedoes (Replaced with Type 93s in 1940). The total increase in weight meant Aoba had needed bulges added to the hull to restore stability.
Service Career
Aoba was completed in 1927 and assigned to Cruiser Division (CruDiv) 5, then CruDiv6 in 1933, and then CruDiv7. In the late 1920s to 1930s, Aoba was frequently used to patrol the China coast. After her 1938-40 modifications were completed, she was returned to CruDiv6. In 1941, during the attack on Pearl Harbour, Aoba and the other cruisers of CruDiv6 engaged in the invasion of Guam, and she then participated in the second invasion of Wake Island.
In the Battle of Coral Sea, 1942, Aoba and CruDiv6 rendezvous at sea with light carrier Shoho. Dive and torpedo bombers from USS Yorktown and Lexington sunk Shoho on May 7th at 1100 hours. The next day, Aoba covered the withdrawal of the Port Moresby invasion convoy. On May 22nd, Aoba returned to Kure Naval Arsenal for repairs and was then sent to Santa Isabel Island for patrols before being assigned to the recently created Eighth Fleet on July 14th and was assigned to patrols around New Britain, New Ireland, and the Solomon Islands.
On August 7th 1942, an E13 spotter plane from Aoba found "one battleship, one auxiliary carrier, four cruisers, seven destroyers and 15 transports" off Teluga Point. In the Battle of Savo Island, Aoba accompanied CruDiv6, Takao-class cruiser Chokai, light cruisers Tenryuu and Yubari, and destroyer Yunagi, and engaged the Allied fleet at night, sinking cruisers USS Astoria, Quincy, Vincennes and HMAS Canberra and damaging the cruiser USS Chicago and destroyers Ralph Talbot and Patterson. Aoba was hit once during the battle while her sister ship Kinugasa was hit twice with Chokai being hit 3 times. Aoba then provided cover for the Japanese reinforcements heading for Guadalcanal.
In the Battle of Cape Esperance on October 11th 1942, CruDiv6 departed with destroyers Fubuki and Hatsuyuki to cover reinforcement troops by shelling Henderson Field. They were spotted by 2 American OS2U Kingfishers and at 2235 the fleet was spotted by radar from USS Helena. Both sides opened fire, however Admiral Goto who was in command of CruDiv6 believed they were under friendly fire and ordered his ships to turn, thus exposing the broadsides of the fleet. Furutaka was sunk and Aoba suffered severe damage, No.2 turret was knocked out and No.3 turret was destroyed. 4 of Aoba's boilers were inoperable. Admiral Goto was mortally wounded and 80 crewmen were killed. After temporary repairs at Shortland, Aoba sailed to Truk on October 15th where Admiral Isoroku Yamamoto inspected the damage before sending her back to Japan.
After returning to Kure, Aoba was repaired. The destroyed No.3 turret was replaced with a triple mount 25 mm AA gun and sent back to Truk on February 24th 1943. On April 3rd, Aoba was bombed by B-17 Flying Fortresses while moored at Kavieng. Two of Aoba's Type 93 torpedoes exploded and started a fire while she was strafed by machine gun fire from the B-17s. She was beached to prevent her from sinking. Aoba was then towed to Truk and then back to Kure where she was repaired and refitted. No.3 turret was returned, a Type 21 air-search radar was installed and 2 twin mount 25 mm AA guns were added. Irreparable engine damage limited Aoba's top speed to just 46 km/h (25 knots).
Aoba was then sent to Singapore as part of the First Southern Expeditionary Fleet on December 24th 1943. She was based outside of Singapore and escorted convoys to Burma and the Andaman Islands. On February 25th 1944, Aoba returned to CruDiv6 where she participated in the Indian Ocean raid in March and then resumed escort duties through the Dutch East Indies and New Guinea. In July, Aoba was refitted again in Singapore with the Type 22 air-search radar and gained an additional 4 triple mount 25 mm AA guns and 15 single mount 25 mm AA guns.
On October 11th, Aoba received minor damage after an accidental collision with cruiser Kinu. However, US submarine Bream attacked Aoba on October 23rd. 1 of 6 torpedoes struck Aoba in the No.2 engine room, she then sailed to Cavite Naval Yard near Manila for emergency repairs. While undergoing repairs, on October 29th Aoba was bombed by planes from Task Force 38. Aoba was then assigned to a convoy and sent back to Japan again despite incomplete repairs. While heading for Japan, the convoy was attacked by US submarines Guitarro, Bream, Raton and Ray off Luzon on November 6th. 23 torpedoes were launched by the submarines, 2 hit cruiser Kumano but Aoba escaped with no further damage. Upon arrival at Kure, Aoba was declared irreparable and re-rated into a reserve ship.
A US air raid on Kure on April 24th 1945 damaged Aoba further, causing her to sink and settle at the bottom of the shallow harbour. She was not repaired, instead additional 25 mm AA guns were fitted and she was turned into a floating AA battery with a total of 50 x 25 mm guns, 5 triple, 10 double and 15 single mounts. On July 14th, Kure was attacked again, this time by planes from Task Force 38. Aoba was bombed once again where she settled at the bottom at 2200 hours. 4 days later, the wreck of Aoba was bombed again by Task Force 38, 4 bomb hits set her on fire and B-24 Liberators hit her again with 4 bombs, breaking off her stern.
Aoba was formally removed from the Navy list in November 15th 1945 and her wreckage was scrapped in 1946-47.
Media
- Skins
See also
External links
- [Wikipedia] Japanese cruiser Aoba
- [大日本帝国軍 主要兵器] 青葉【青葉型重巡洋艦 一番艦】 Aoba【Aoba-class heavy cruiser First】
- [Combined Fleet] IJN AOBA
- [Naval Encyclopedia] Aoba class heavy cruisers (1926)
- [The Pacific War Online Encyclopedia] Aoba Class, Japanese Heavy Cruisers
- [WW2 Cruisers] Aoba Class Heavy Cruiser
- [World War II Database] Heavy Cruiser Aoba
- [Navypedia] AOBA heavy cruisers (1927)
- [Pacific Wrecks] Aoba 青葉
- Bibliography
| Mitsubishi Shipbuilding Company Ltd. | |
|---|---|
| Light Cruisers (CL) | |
| Kuma-class | IJN Tama |
| Sendai-class | IJN Sendai |
| Mogami-class | IJN Mikuma |
| Heavy Cruisers (CA) | |
| Furutaka-class | IJN Furutaka |
| Aoba-class | IJN Aoba |
| Myōkō-class | IJN Haguro |
| Tone-class | IJN Tone |
| Battleships (BB) | |
| Ise-class | IJN Hyuga |
| See also | Mitsubishi Heavy Industries, Ltd. (Post-War) |
| Japan heavy cruisers | |
|---|---|
| Furutaka-class | IJN Furutaka · IJN Kako |
| Aoba-class | IJN Aoba |
| Myōkō-class | IJN Myoko · IJN Haguro |
| Mogami-class | IJN Mogami |
| Tone-class | IJN Tone |
