Japanese Aoba-class Heavy Cruisers
The Aoba-class composed of two ships and directly derives from the heavy cruiser of Furutaka-class. The initial plan consisted in producing at least 4 ships of the Furutaka-class in what was called “A class” cruisers. With that purposes, the ships Aoba and Kinugasa were laid down in 1924.
However, by that time, the IJN General Staff asked new requirements such as to use the newly designed twin 20 cm (8 in) gun turrets on the Furutaka-class ships. The designer in charge, Fujimoto, agreed to modify Aoba and Kinugasa. However, it was already too late to apply the same modifications to the cruisers Furutaka and Kako since then they had been laid down in late 1922. Because of these modifications, the two ships were subsequently renamed as a separate class of Japanese heavy cruisers.
In spite of these modifications, the Aoba and Kinugasa cruisers shared many simularities with the predecessors because they were otherwise built on the same hull as Furutaka and Kako, with identical machinery and armor. The modifications applied to the Aoba, increased the weight and had negative impact in her performance. Similar issues were reported for the Furutaka-class after different additions.
The modifications were significant. The six 20 cm (8 in) semi-turrets, 1 through 6, were replaced by three twin turrets, two fore and one aft. The main superstructure was also modified to accommodate the different fire control requirements of the twin turrets.
The heavy cruiser Aoba was laid down at the Mitsubishi Nagasaki Shipyard on 4 February 1924. On 25 September 1926 was launched and on 20 September 1927 was comissioned. She was sunk 28 July 1945 during Bombing of Kure.
The heavy cruiser Kinugasa was laid down at the Kōbe-Kawasaki Ship building Yard on 23 January 1924. She was launched on 24 October 1926 and she was commissioned on 30 September 1927. she was also sunk on 14 November 1942 at Naval Battle of Guadalcanal.