Battlecruiser – fast battleship Haruna

As seen in the table above, the question of main armament was not entirely agreed upon and requirements concerning main artillery varied between 12 and 14 inches as they were based on solutions employed on HMS Thunderer, Neptune, Lion or Indefatigable. During the design development (B.42 – B.45), discussions concerning the ship’s dimensions and speed, pushed the matter of the main armament aside. Twelve-inch guns were to be fitted on the ship. The final design of Kongō, dated on May 13, 1910, confirmed the data. According to it, the main armament was to include eight 12-inch guns with the length of 50 calibres. They were to be mounted in two-gun turrets with an ammunition unit of 80 rounds per gun. The gun calibre was changed after a Japanese 14-inch (355.6 mm) gun construction had been approved on November 29, 1911. It was designated as 14 inch/45 calibres type 41 (45 Kōkei 41 Nendo Shiki 14 In Hō). The design was based on the British Vickers Mk J built in 19103. The Kongō prototype ship was armed with eight 14-inch guns (45 Kōkei Hi Shiki 36 cm Hō) Kai 1 mounted in the Hi Shiki type gun turret with a Hi Shiki type breech, made in the British Vickers factory. Technical data of the guns and gun turrets of that type are presented along with their modifications in Table 7. As the data shows, not all units of that class were equipped with identical and homogeneous armament. Changes introduced on Haruna are presented in Tables 8 and 9. The last ship of the class – Haruna – was armed with eight 36 cm guns (Kōkei 41 Shiki 36 cm Hō) Kai 3 mounted in the Hi Shiki type gun turrets but fitted with the 41 Shiki type breech. The guns were produced in the Kure arsenal.
During the entire period of service, the only guns mounted on all ships were the ones presented in the table. The issue of gun turrets was different. Kongō, right after her commissioning, was fitted with gun turrets manufactured by Vickers. During the ship’s modernization, they were replaced by new ones with higher elevation angle, which increased the guns’ range.

Medium artillery

Medium artillery, after commissioning, comprised sixteen 15 cm guns mounted in casemates at midship, on both sides. The prototype Kongō was armed with homogeneous guns made by Vickers designated 50 Kōkei Hi Shiki 15 cm Hō. The other ships were equipped with Japanese guns designated 50 Kōkei 41 Shiki 15 cm Hō. Detailed specifications of both gun types is presented in Table 9. The construction of Japanese 15cm/50 calibres guns was based on the British Vickers model. It was introduced in 1914, as 41 Shiki and became part of the armament installed on the battlecruisers Hiei, Haruna and Kirisima.

Haruna 3


Anti-aircraft armament

The first Japanese anti-aircraft guns were developed on the basis of low elevation guns and turrets. The base design was a 7.62 cm 40 Kōkei 41 Shiki type gun, approved in 1915. Its maximum elevation angle was 75 degrees, which, at that time, was appropriate for that type of gun. A new design was accepted on February 5, 1916, designated 40 Kōkei 3 Nen Shiki Dai Gyōkaku hō4 (with high angle of elevation). For the first time, the gun was mounted on the battleship Yamashiro and later, on the Kongō class battlecruisers, battleship Fūso and the Ise class ships. The gun, designed by engineer C. Hada, was developed in 1914 and its prototype, after successful field trials, was approved to be mounted on all Japanese heavy ships. It was produced by the Kure Arsenal with cooperation of the Hiroshima Armament Factory. The person responsible for the construction was Cpt. M. Oyamada. During the first period of service, the gun proved to be very effective when engaging slowly moving aircraft at medium distance. However, with aircraft development, it needed to be replaced by a more modern type with higher ceiling and rate of fire. The prototype Kongō, after entering service, received 8 guns of that calibre, made by Vickers. Further ships, commissioned between 1914 and 1915, were equipped with only four type 41 Shiki Japanese guns. Specifications of both guns and their modifications are presented in Table 11. The short version of the gun, designated Tan5 8 cm Hō with length of 20 calibres, was also mounted on the battlecruisers. This time, Kongō received 4 guns made by Vickers, the other ships were armed with 8 guns of the Japanese type 41. Their specifications are presented in Table 12. The gun mount was designed by engineer C. Hada and produced by the arsenal in Maizuru, under supervision of Commander Hisasue. With time, the guns became outdated and did not meet the requirements for anti-aircraft armament, which was confirmed during gunnery exercise conducted by the battleships of the 1st Squadron in 1926. The guns achieved an average accuracy of 4.57% when firing at 10-meter targets flying at 110 km/h, with the ships’ constant speed of 15 knots. The poor results were also caused by lack of appropriate aerial target acquisition system. It is worth noting that the guns remained on the decks of the Japanese heavy units for a very long time, until the beginning of the war in 1941.
Guns designated as Kōkaku hō (with high elevation) were also mounted on Japanese battlecruisers and battleships. Their specifications and numbers of mounts on individual ships are presented in Table 13.