Amagi-class Battlecruiser
The was a series of four battlecruisers planned for the Imperial Japanese Navy (IJN) as part of the Eight-eight fleet in the early 1920s. The ships were to be named ''Amagi'', , ''Atago'', and ''Takao''. The ''Amagi'' design was essentially a lengthened version of the battleship, but with a thinner armored belt and deck, a more powerful propulsion system, and a modified secondary armament arrangement. They were to have carried the same main battery of ten guns and been capable of a top speed of . Limitations imposed by the 1922 Washington Naval Treaty prevented the class from being completed as designed. However, the treaty had a limited allowance for hulls already under construction to be converted into aircraft carriers. ''Amagi'' and ''Akagi'' were both intended for conversion, but an earthquake damaged the hull of ''Amagi'' so extensively that the ship was scrapped. ''Akagi'' was reconstructed as an aircraft carrier and served with distinction as part of the ''Kido But ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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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 Japanese home islands. Along with the establishment of the navy base, a ship repair facility was also constructed, initially by moving the equipment from the Onohama shipyards near Kobe. Construction was supervised by the French engineer Louis-Émile Bertin. The first warship constructed at Kure, '' Miyako'', was launched in 1897. The "Kure Shipyards" were officially renamed the "Kure Naval Arsenal" in 1903. Kure developed into one of the largest shipbuilding facilities in the Empire of Japan, capable of working with the largest vessels. The Arsenal included a major steel works (built with British assistance), and also facilities for producing naval artillery and projectiles. The battleships ''Yamato'' and '' Nagato'' were designed and con ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Belt Armor
Belt armor is a layer of heavy metal armor plated onto or within the outer hulls of warships, typically on battleships, battlecruisers and cruisers, and aircraft carriers. The belt armor is designed to prevent projectiles from penetrating to the heart of a warship. When struck by an artillery shell or underwater torpedo, the belt armor either absorbs the impact and explosion with its sheer thickness and strength, or else uses sloping to redirect the projectile and its blast downwards. Typically, the main armor belt covers the warship from its main deck down to some distance below the waterline. If, instead of forming the outer hull, the armor belt is built inside the hull, it is installed at a sloped angle for improved protection, as described above. The torpedo bulkhead Frequently, the main belt's armor plates were supplemented with a torpedo bulkhead spaced several meters behind the main belt, designed to maintain the ship's watertight integrity even if the main belt ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Kido Butai
The , also known as the ''Kidō Butai'' ("Mobile Force"), was a name used for a combined carrier battle group comprising most of the aircraft carriers and carrier air groups of the Imperial Japanese Navy (IJN) during the first eight months of the Pacific War. At the time of its best-known operation, the attack on Pearl Harbor, in December 1941, the 1st Air Fleet was the world's largest fleet of aircraft carriers. In its second generation, 1st Air Fleet was a land-based fleet of "kichi kōkūtai" (base air unit(s)). Origins In 1912, the British Royal Navy had established its own flying branch, the Royal Naval Air Service (RNAS). The IJN was modeled on the Royal Navy and the IJN Admiralty sought establishment of their own Naval Air Service. The IJN had also observed technical developments in other countries and saw military potential of the airplane. In 1913, the IJN seaplane carrier ''Wakamiya'' was converted into a seaplane tender and aircraft were purchased. The 1st and 2nd Air ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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1923 Great Kantō Earthquake
The struck the Kantō Plain on the main Japanese island of Honshū at 11:58:44 JST (02:58:44 UTC) on Saturday, September 1, 1923. Varied accounts indicate the duration of the earthquake was between four and ten minutes. Extensive firestorms and even a fire whirl added to the death toll. Civil unrest after the disaster (i.e., the Kantō Massacre) has been documented. The earthquake had a magnitude of 7.9 on the moment magnitude scale (), with its focus deep beneath Izu Ōshima Island in Sagami Bay. The cause was a rupture of part of the convergent boundary where the Philippine Sea Plate is subducting beneath the Okhotsk Plate along the line of the Sagami Trough. Since 1960, September 1 has been designated by the Japanese government as , or a day in remembrance of and to prepare for major natural disasters including tsunami and typhoons. Drills, as well as knowledge promotion events, are centered around that date as well as awards ceremonies for people of merit. Earthquake T ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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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 Naval Conference, held in Washington, D.C., from November 1921 to February 1922, and it was signed by the governments of Great Britain, the United States, France, Italy, and Japan. It limited the construction of battleships, battlecruisers and aircraft carriers by the signatories. The numbers of other categories of warships, including cruisers, destroyers, and submarines, were not limited by the treaty, but those ships were limited to 10,000 tons displacement each. The treaty was concluded on February 6, 1922. Ratifications of that treaty were exchanged in Washington on August 17, 1923, and it was registered in the '' League of Nations Treaty Series'' on April 16, 1924. Later naval arms limitation conferences sought additional limitations o ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Main Battery
A main battery is the primary weapon or group of weapons around which a warship is designed. As such, a main battery was historically a gun or group of guns, as in the broadsides of cannon on a ship of the line. Later, this came to be turreted groups of similar large-caliber naval rifles. With the evolution of technology the term has come to encompass guided missiles as a vessel's principal offensive weapon, deployed both on surface ships and submarines. A main battery features common parts, ammunition, and fire control across the weapons which it comprises. Description In the age of cannon at sea, the main battery was the principal group of weapons around which a ship was designed, usually its heavies. With the coming of naval rifles and subsequent revolving gun turrets, the main battery became the principal group of heaviest guns, regardless of how many turrets they were placed in. As missiles displaced guns both above and below the water their principal group became a ve ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Battleship Secondary Armament
Secondary armament is a term used to refer to smaller, faster-firing weapons that were typically effective at a shorter range than the main (heavy) weapons on military systems, including battleship- and cruiser-type warships, tanks/armored personnel carriers, and rarely other systems. The nature, disposition, size and purpose of Naval secondary weapon systems changed dramatically as the threat changed from torpedo boats, to torpedo-carrying destroyers, to aircraft, to anti-ship missiles. Naval Pre-dreadnought era Pre-dreadnoughts, from the period 1890 to 1905, were typically fitted with 3 or 4 different calibres of weapon. The main guns were usually approximately 12-inch caliber, secondary weapons usually 6-inch but typically in the range 5-inch to 7.5-inch. Guns smaller than 4.7-inch are usually considered "tertiary". (Many pre-dreadnoughts also carried 9.2 to 10-inch "secondary" guns, but they are usually treated instead as a mixed-caliber main armament.) Secondary ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Deck (ship)
A deck is a permanent covering over a compartment or a hull of a ship. On a boat or ship, the primary or upper deck is the horizontal structure that forms the "roof" of the hull, strengthening it and serving as the primary working surface. Vessels often have more than one level both within the hull and in the superstructure above the primary deck, similar to the floors of a multi-storey building, that are also referred to as decks, as are certain compartments and decks built over specific areas of the superstructure. Decks for some purposes have specific names. Structure The main purpose of the upper or primary deck is structural, and only secondarily to provide weather-tightness and support people and equipment. The deck serves as the lid to the complex box girder which can be identified as the hull. It resists tension, compression, and racking forces. The deck's scantling is usually the same as the topsides, or might be heavier if the deck is expected to carry heavier loads ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Belt Armor
Belt armor is a layer of heavy metal armor plated onto or within the outer hulls of warships, typically on battleships, battlecruisers and cruisers, and aircraft carriers. The belt armor is designed to prevent projectiles from penetrating to the heart of a warship. When struck by an artillery shell or underwater torpedo, the belt armor either absorbs the impact and explosion with its sheer thickness and strength, or else uses sloping to redirect the projectile and its blast downwards. Typically, the main armor belt covers the warship from its main deck down to some distance below the waterline. If, instead of forming the outer hull, the armor belt is built inside the hull, it is installed at a sloped angle for improved protection, as described above. The torpedo bulkhead Frequently, the main belt's armor plates were supplemented with a torpedo bulkhead spaced several meters behind the main belt, designed to maintain the ship's watertight integrity even if the main belt ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Eight-eight Fleet
The was a Japanese naval strategy formulated for the development of the Imperial Japanese Navy in the first quarter of the 20th century, which stipulated that the navy should include eight first-class battleships and eight armoured cruisers or battlecruisers. History and development The concept of the "Eight-Eight Fleet" originated in the aftermath of the Russo-Japanese War with the 1907 Imperial Defense Policy between the Japanese government and the competing services of the Army and Navy. The policy called for the construction of a battle fleet of eight modern battleships of 20,000 tons each and eight modern armored cruisers of 18,000 tons each. These were to be complemented by the construction of several lesser warship types, including cruisers and destroyers. The plan was inspired by the Mahanian doctrine of Satō Tetsutarō who advocated that Japanese security could only be guaranteed by a strong navy. Satō argued that to ensure security, Japan should be capable of defea ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Battlecruiser
The battlecruiser (also written as battle cruiser or battle-cruiser) was a type of capital ship of the first half of the 20th century. These were similar in displacement, armament and cost to battleships, but differed in form and balance of attributes. Battlecruisers typically had thinner armour (to a varying degree) and a somewhat lighter main gun battery than contemporary battleships, installed on a longer hull with much higher engine power in order to attain greater speeds. The first battlecruisers were designed in the United Kingdom, as a development of the armoured cruiser, at the same time as the dreadnought succeeded the pre-dreadnought battleship. The goal of the design was to outrun any ship with similar armament, and chase down any ship with lesser armament; they were intended to hunt down slower, older armoured cruisers and destroy them with heavy gunfire while avoiding combat with the more powerful but slower battleships. However, as more and more battlecruisers were ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Ship Class
A ship class is a group of ships of a similar design. This is distinct from a ship type, which might reflect a similarity of tonnage or intended use. For example, is a nuclear aircraft carrier (ship type) of the (ship class). In the course of building a class of ships, design changes might be implemented. In such a case, the ships of different design might not be considered of the same class; each variation would either be its own class, or a subclass of the original class (see for an example). If ships are built of a class whose production had been discontinued, a similar distinction might be made. Ships in a class often have names linked by a common factor: e.g. s' names all begin with T (, , ); and s are named after American battles (, , , ). Ships of the same class may be referred to as sister ships. Naval ship class naming conventions Overview The name of a naval ship class is most commonly the name of the lead ship, the first ship commissioned or built of its design. ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |