was one of two

semi-dreadnought The dreadnought (alternatively spelled dreadnaught) was the predominant type of battleship in the early 20th century. The first of the kind, the Royal Navy's , had such an impact when launched in 1906 that similar battleships built after her ...

battleship built for the

Imperial Japanese Navy The Imperial Japanese Navy (IJN; Kyūjitai: Shinjitai: ' 'Navy of the Greater Japanese Empire', or ''Nippon Kaigun'', 'Japanese Navy') was the navy of the Empire of Japan from 1868 to 1945, when it was dissolved following Japan's surrend ...

(IJN) during the first decade of the 20th century. She was the second battleship built domestically in Japan and the first to use steam turbines for propulsion. The ship was named for

Aki Province or Geishū () was a province in the Chūgoku Region of western Honshū, comprising the western part of what is today Hiroshima Prefecture. History When Emperor Shōmu ordered two official temples for each province (one for male Buddhist p ...

, now a part of Hiroshima Prefecture. The ship saw no combat during

World War I World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fightin ...

. ''Aki'' was disarmed in 1922 and sunk as a target in 1924 in accordance with the terms of the

Washington Naval Treaty The Washington Naval Treaty, also known as the Five-Power Treaty, was a treaty signed during 1922 among the major Allies of World War I, which agreed to prevent an arms race by limiting naval construction. It was negotiated at the Washington Nav ...

of 1922.

Background

The ''Satsuma'' class was ordered in late 1904 under the 1904 War Naval Supplementary Program during the

Russo-Japanese War The Russo-Japanese War ( ja, 日露戦争, Nichiro sensō, Japanese-Russian War; russian: Ру́сско-япóнская войнá, Rússko-yapónskaya voyná) was fought between the Empire of Japan and the Russian Empire during 1904 and 1 ...

. Unlike the previous

pre-dreadnought battleship Pre-dreadnought battleships were sea-going battleships built between the mid- to late- 1880s and 1905, before the launch of in 1906. The pre-dreadnought ships replaced the ironclad battleships of the 1870s and 1880s. Built from steel, protec ...

s, they were the first battleships ordered from Japanese shipyards.Evans & Peattie, p. 159 They were originally designed with a dozen guns, but had to be redesigned because of a shortage of guns in Japan and to reduce costs.

Design and description

The ship had an

overall length The overall length (OAL) of an ammunition cartridge is a measurement from the base of the brass shell casing to the tip of the bullet, seated into the brass casing. Cartridge overall length, or "COL", is important to safe functioning of reloads i ...

of , a beam of , and a normal

draft Draft, The Draft, or Draught may refer to: Watercraft dimensions * Draft (hull), the distance from waterline to keel of a vessel * Draft (sail), degree of curvature in a sail * Air draft, distance from waterline to the highest point on a vesse ...

of . She displaced at normal load. The crew consisted of 931 officers and enlisted men.Jentschura, Jung & Mickel, p. 23 ''Aki'' was fitted with a pair of Curtiss steam turbine sets, each driving one shaft using steam from 15 Miyabara

water-tube boiler A high pressure watertube boiler (also spelled water-tube and water tube) is a type of boiler in which water circulates in tubes heated externally by the fire. Fuel is burned inside the furnace, creating hot gas which boils water in the steam-gen ...

s. The turbines were rated at a total of for a design speed of . The ship reached a top speed of during her sea trials from .Jentschura, Jung & Mickel, pp. 23–24 She carried enough coal and oil to give her a range of at a speed of . Unlike her

half-sister A sibling is a relative that shares at least one parent with the subject. A male sibling is a brother and a female sibling is a sister. A person with no siblings is an only child. While some circumstances can cause siblings to be raised sepa ...

, she had three

funnel A funnel is a tube or pipe that is wide at the top and narrow at the bottom, used for guiding liquid or powder into a small opening. Funnels are usually made of stainless steel, aluminium, glass, or plastic. The material used in its construct ...

s.Preston, p. 195 The ship's main battery consisted of four 45- caliber 12-inch (305 mm) 41st Year Type guns in two twin-

gun turret A gun turret (or simply turret) is a mounting platform from which weapons can be fired that affords protection, visibility and ability to turn and aim. A modern gun turret is generally a rotatable weapon mount that houses the crew or mechani ...

s, one each fore and aft of the superstructure. Her intermediate armament consisted of six twin-gun turrets equipped with 45-caliber Type 41 10-inch (254 mm) guns, three turrets on each side of the superstructure. Her heavy intermediate armament of guns larger than is why the ship is considered to be a semi-dreadnought. ''Aki''s secondary armament consisted of eight 45-caliber 6-inch (152 mm) 41st Year Type guns, mounted in casemates in the sides of the hull. The ship was also equipped with eight quick-firing (QF) 40-caliber 12-pounder () 12-cwt guns"Cwt" is the abbreviation for

hundredweight The hundredweight (abbreviation: cwt), formerly also known as the centum weight or quintal, is a British imperial and US customary unit of weight or mass. Its value differs between the US and British imperial systems. The two values are distingu ...

, 12 cwt referring to the weight of the gun. and four 28-caliber 12-pounder QF guns. In addition, the battleship was fitted with five submerged

torpedo tube A torpedo tube is a cylindrical device for launching torpedoes. There are two main types of torpedo tube: underwater tubes fitted to submarines and some surface ships, and deck-mounted units (also referred to as torpedo launchers) installed aboa ...

s, two on each broadside and one in the stern. The

waterline The waterline is the line where the hull of a ship meets the surface of the water. Specifically, it is also the name of a special marking, also known as an international load line, Plimsoll line and water line (positioned amidships), that indi ...

main belt The asteroid belt is a torus-shaped region in the Solar System, located roughly between the orbits of the planets Jupiter and Mars. It contains a great many solid, irregularly shaped bodies, of many sizes, but much smaller than planets, called ...

of the ''Satsuma''-class vessels consisted of

Krupp cemented armor Krupp armour was a type of steel naval armour used in the construction of capital ships starting shortly before the end of the nineteenth century. It was developed by Germany's Krupp Arms Works in 1893 and quickly replaced Harvey armour as the ...

that had a maximum thickness of nine inches

amidships This glossary of nautical terms is an alphabetical listing of terms and expressions connected with ships, shipping, seamanship and navigation on water (mostly though not necessarily on the sea). Some remain current, while many date from the 17th ...

. It tapered to a thickness of at the ends of the ship. A six-inch

strake On a vessel's hull, a strake is a longitudinal course of planking or plating which runs from the boat's stempost (at the bows) to the sternpost or transom (at the rear). The garboard strakes are the two immediately adjacent to the keel on ea ...

of armor protected the casemates. The barbettes for the main guns were thick. The armor of ''Aki''s main gun turrets had a maximum thickness of . The deck armor was thick and the conning tower was protected by six inches of armor.Gardiner & Gray, p. 238

Construction and service

''Aki'' was

laid down Laying the keel or laying down is the formal recognition of the start of a ship's construction. It is often marked with a ceremony attended by dignitaries from the shipbuilding company and the ultimate owners of the ship. Keel laying is one o ...

Kure Naval Arsenal was one of four principal naval shipyards owned and operated by the Imperial Japanese Navy. History The Kure Naval District was established at Kure, Hiroshima in 1889, as the second of the naval districts responsible for the defense of the Ja ...

on 15 March 1906. She was launched on 15 April 1907, but construction was suspended for about five months after the decision was made on 26 November to install steam turbines on ''Aki'' and the

armored cruiser The armored cruiser was a type of warship of the late 19th and early 20th centuries. It was designed like other types of cruisers to operate as a long-range, independent warship, capable of defeating any ship apart from a battleship and fast eno ...

. ''Aki''s turbines were already behind schedule and the suspension allowed the less valuable ship to be completed first, and changes made to its turbines after testing were also incorporated into ''Aki''s turbines. ''Aki'' was finally completed on 11 March 1911 and her first captain was Tatsuo Matsumura. When World War I began in August 1914, ''Aki'' was refitting at Kure Naval Arsenal. She was assigned to the 1st Battleship Squadron upon the completion of her refit and remained with it until she was transferred to the 2nd Battleship Squadron in 1918, seeing no combat during the war. From December 1915 to December 1916, she was commanded by Captain Kiyokazu Abo. The ship was disarmed at Yokosuka in 1922 to comply with the provisions of the

, stricken from the

navy list A Navy Directory, formerly the Navy List or Naval Register is an official list of naval officers, their ranks and seniority, the ships which they command or to which they are appointed, etc., that is published by the government or naval autho ...

during 1923 and converted into a target ship. Her guns were turned over to the

Imperial Japanese Army The was the official ground-based armed force of the Empire of Japan from 1868 to 1945. It was controlled by the Imperial Japanese Army General Staff Office and the Ministry of the Army, both of which were nominally subordinate to the Emperor o ...

for use as

coastal artillery Coastal artillery is the branch of the armed forces concerned with operating anti-ship artillery or fixed gun batteries in coastal fortifications. From the Middle Ages until World War II, coastal artillery and naval artillery in the form of ...

. The rest of her guns were placed in reserve and ultimately scrapped in 1943. Two of her 10-inch gun turrets were installed as

batteries on

Jōgashima is an island in the municipality of Miura, Kanagawa Prefecture, Japan, off the southernmost and western tip of Miura Peninsula, facing Sagami Bay. It is home to the Jōgashima Lighthouse, the fourth oldest western style lighthouse to be built ...

island to protect

Tokyo Bay is a bay located in the southern Kantō region of Japan, and spans the coasts of Tokyo, Kanagawa Prefecture, and Chiba Prefecture. Tokyo Bay is connected to the Pacific Ocean by the Uraga Channel. The Tokyo Bay region is both the most populous ...

. ''Aki'' was sunk by the battlecruiser and the battleship on 2 September 1924 in

.Jentschura, Jung & Mickel, p. 24

Notes

Footnotes

References

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External links

{{DEFAULTSORT:Aki Satsuma-class battleships Ships built by Kure Naval Arsenal 1907 ships World War I battleships of Japan Shipwrecks in the Pacific Ocean Ships sunk as targets Maritime incidents in 1924