Fuso class battleship
Encyclopedia
The Fusō-class battleships (Japanese
Japanese language
is a language spoken by over 130 million people in Japan and in Japanese emigrant communities. It is a member of the Japonic language family, which has a number of proposed relationships with other languages, none of which has gained wide acceptance among historical linguists .Japanese is an...

: 扶桑) were two battleship
Battleship
A battleship is a large armored warship with a main battery consisting of heavy caliber guns. Battleships were larger, better armed and armored than cruisers and destroyers. As the largest armed ships in a fleet, battleships were used to attain command of the sea and represented the apex of a...

s of the Imperial Japanese Navy
Imperial Japanese Navy
The Imperial Japanese Navy was the navy of the Empire of Japan from 1869 until 1947, when it was dissolved following Japan's constitutional renunciation of the use of force as a means of settling international disputes...

 (IJN) constructed during World War I. Displacing 29330 long tons (29,800.7 MT) upon completion, and , the vessels of this class, were the first super-dreadnoughts
Dreadnought
The dreadnought was the predominant type of 20th-century battleship. The first of the kind, the Royal Navy's had such an impact when launched in 1906 that similar battleships built after her were referred to as "dreadnoughts", and earlier battleships became known as pre-dreadnoughts...

 of the IJN. They were completed from 1915 to 1917, both in Japanese shipyards. When launched, they outclassed all battleships of both the Royal Navy
Royal Navy
The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...

 and the United States Navy
United States Navy
The United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. The U.S. Navy is the largest in the world; its battle fleet tonnage is greater than that of the next 13 largest navies combined. The U.S...

 in terms of speed and firepower. Both patrolled briefly off the coast of China in the last year of World War I before being placed in reserve at the war's end. In 1922, Yamashiro became the first battleship in the IJN to successfully launch aircraft.

During the 1930s, both ships underwent a series of modernizations and reconstructions to defer obsolescence. Fusō underwent her modernization in two phases (1930–33, 1937–41), while Yamashiro was reconstructed from 1930 to 1935. The modernization increased their armor, replaced and upgraded their machinery, and rebuilt their superstructure into their distinctive Pagoda mast
Pagoda Mast
The Pagoda mast was a type of superstructure that was common on Japanese capital ships that were reconstructed during the 1930s in a bid to improve their fighting performance...

 style. When they emerged from their reconstruction, they were capable of speeds of 25 kn (30.4 mph; 49 km/h) and displaced 39154 LT (39,782.4 t).

By the eve of World War II, the Fusō class was considered obsolete in comparison to more modern battleships of both the United States and Imperial Japanese Navies. As a result, neither vessel saw significant action in the early years of the war. Fusō served as a troop transport in 1943, while Yamashiro was relegated to training duty in the Inland Sea. Both underwent upgrades to their antiaircraft suite in 1944, before embarking to Singapore in August 1944. Fusō and Yamashiro sailed as part of the Southern Force during the Battle of Leyte Gulf
Battle of Leyte Gulf
The Battle of Leyte Gulf, also called the "Battles for Leyte Gulf", and formerly known as the "Second Battle of the Philippine Sea", is generally considered to be the largest naval battle of World War II and, by some criteria, possibly the largest naval battle in history.It was fought in waters...

. Both battleships were lost in the early hours of 25 October 1944 to American torpedoes and naval gunfire during the Battle of Surigao Strait.

Background

The design of the Fusō-class battleships was shaped both by the international naval arms race and a desire among Japanese naval planners to maintain a fleet of capital ships powerful enough to defeat the United States Navy in a "decisive battle" in Japanese territorial waters.

The Imperial Japanese Navy's fleet of battleships had proven highly successful in 1905—the last year of the Russo-Japanese War
Russo-Japanese War
The Russo-Japanese War was "the first great war of the 20th century." It grew out of rival imperial ambitions of the Russian Empire and Japanese Empire over Manchuria and Korea...

—culminating in the destruction of the Russian Baltic Fleet at the Battle of Tsushima
Battle of Tsushima
The Battle of Tsushima , commonly known as the “Sea of Japan Naval Battle” in Japan and the “Battle of Tsushima Strait”, was the major naval battle fought between Russia and Japan during the Russo-Japanese War...

. In the aftermath, the Japanese Empire immediately turned her focus to the two remaining rivals for imperial dominance in the Pacific Ocean: Britain and the United States. Satō Tetsutarō
Sato Tetsutaro
-Notes:...

, a Japanese Navy admiral and military theorist, speculated that conflict would inevitably arise between Japan and at least one of their two main rivals. To that end, he called for the Japanese Navy to maintain a fleet with at least 70% as many capital ships as the US Navy. This ratio, Satō theorized, would enable the Imperial Japanese Navy to defeat the US Navy in a decisive battle in Japanese waters in any eventual conflict. To that end, the 1907 Imperial Defense Policy called for the construction of a battle fleet of eight modern battleships—20000 long tons (20,321 t) each—and eight modern armored cruisers—18000 long tons (18,288.9 t) each—to match the US Navy. This was the genesis of the Eight-Eight Fleet Program, the development of a cohesive battle line of sixteen capital ships.

The launch of in 1906 by the Royal Navy "revolutionized capital ship design", and complicated Japan's plans. Displacing 17900 LT (18,187.3 t) and armed with ten 12 inches (30.5 cm) guns, Dreadnought rendered all existing battleships obsolete by comparison. The launch of the battlecruiser the following year was a further setback for Japan quest for parity. When Japan's two new Satsuma-class battleships
Satsuma class battleship
-External links:*http://homepage2.nifty.com/nishidah/e/stc0117.htm Materials of the Imperial Japanese Navy]*...

 and two Tsukuba-class armored cruisers
Tsukuba class cruiser
-External links:*...

, launched by 1911, were outclassed by their British counterparts, the Eight-Eight Fleet Program was restarted.

The first battleships built for the Eight-Eight Fleet Program were the two dreadnoughts of the Kawachi class
Kawachi class battleship
-External links:**...

, ordered in 1907 and laid down in 1908. In 1910, the Navy put forward a request to the Diet of Japan (parliament) to secure funding for the entirety of the program at once. Because of economic constraints, the proposal was cut first by the Navy Ministry to seven battleships and three battlecruisers, then by the cabinet to what became the Japanese Naval Emergency Expansion bill, authorizing the construction of four battlecruisers (the Kongō class
Kongo class battlecruiser
The were a class of ships of the Imperial Japanese Navy constructed immediately before World War I. Designed by British naval architect George Thurston, the lead ship of the class was the last Japanese capital ship constructed outside of Japan. Displacing upon completion, the vessels of this...

) and one battleship, later named Fusō.

Design

The Emergency Naval Expansion Bill stipulated the construction of four battlecruisers of the Kongō class and one member of the Fusō class; as a result the latter was designed to work in conjunction with the four battlecruisers. The design drew heavily on George Thurston
George Thurston
Sir George Thurston KBE was a leading British naval architect in the early half of the 20th century.-Life and career:...

's design of the Kongō class and was considered to be the battleship equivalent. After coordination with the British on the Kongō class, Japanese designers had access to the latest British project studies in naval architecture. In an effort to outmatch foreign designs, planners called for a ship armed with twelve 14 inches (35.6 cm) guns. Vickers files show that the Japanese had access to the designs for double and triple turrets, yet opted for six double turrets over four triple turrets. The final design—designated A-64 by the Japanese Navy—called for a displacement of 29000 long tons (29,465.5 t) with twelve 14 inches (35.6 cm) guns in six double turrets (two forward, two aft, two separated amidships). The design also called for a top speed of 23 kn (28 mph; 45.1 km/h). This design was superior to its American counterparts in armament, armor and speed, thus following the Japanese doctrine of compensating for quantitative inferiority with quality.

Ships

The two vessels of the Fusō class were completed from 1912 to 1917. The first, Fusō, was constructed in the shipyard
Shipyard
Shipyards and dockyards are places which repair and build ships. These can be yachts, military vessels, cruise liners or other cargo or passenger ships. Dockyards are sometimes more associated with maintenance and basing activities than shipyards, which are sometimes associated more with initial...

 at Kure Naval Arsenal
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...

, while Yamashiro was built at Yokosuka Naval Arsenal
Yokosuka Naval Arsenal
was one of four principal naval shipyards owned and operated by the Imperial Japanese Navy, and was located at Yokosuka city, Kanagawa prefecture on Tokyo Bay, south of Yokohama...

. Two advanced versions of the class were subsequently planned, but the final design differed so markedly from Fusō that they became the Ise class
Ise class battleship
Originally intended as sister ships of the preceding Fusō class, the of the Imperial Japanese Navy were considered sufficiently different to warrant separate classification....

. When she was completed in 1915, Fusō was considered the first modern battleship of the Japanese Navy. She outclassed her American counterparts of the New York class
New York class battleship
The New York class battleship was the fifth series of two super-dreadnought battleships of the United States Navy which served during World War I and World War II. The class represented the first use of the 14" naval gun by the U.S. Navy...

 in terms of firepower and speed, and was considered the "most powerfully armed battleship in the world". Despite extensive modernization in the 1930s, both battleships were considered obsolete by the commencement of World War II. As a result, both ships spent the early years of the war in the home islands, acting as training ships and transports. Following the loss of much of Japan's aircraft carrier fleet by 1943, a proposal was floated that would have converted both vessels into hybrid battleship-carriers. Work was scheduled to commence in June 1943, but the plan was cancelled and the two Ise-class battleships converted instead.

Fusō

Fusō was laid down
Keel
In boats and ships, keel can refer to either of two parts: a structural element, or a hydrodynamic element. These parts overlap. As the laying down of the keel is the initial step in construction of a ship, in British and American shipbuilding traditions the construction is dated from this event...

 at Kure Naval Arsenal
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...

 11 March 1912, launched
Ship naming and launching
The ceremonies involved in naming and launching naval ships are based in traditions thousands of years old.-Methods of launch:There are three principal methods of conveying a new ship from building site to water, only two of which are called "launching." The oldest, most familiar, and most widely...

 28 March 1914, commissioned
Ship commissioning
Ship commissioning is the act or ceremony of placing a ship in active service, and may be regarded as a particular application of the general concepts and practices of project commissioning. The term is most commonly applied to the placing of a warship in active duty with its country's military...

 8 November 1915 and attached to the 1st Battleship Division of the First Fleet. After conducting patrols off the coast of China in the closing years of World War I, Fusō was placed in reserve in December 1918. Fusō assisted in rescue operations following the Great Kantō Earthquake, before her superstructure was rebuilt in 1924. She underwent two main modernizations throughout her career, the first beginning on 12 April 1930. In the first phase at Yokosuka Naval Yard, torpedo bulges were fitted and her internal machinery upgraded. In the second phase, started at Kure in September 1932, 127 mm (5 in) dual-purpose guns and additional shell-rooms were fitted. This reconstruction resulted in an increased speed and an armor weight nearly 42% that of the entire displacement of the ship. The second major modernization consisted of two phases from 26 February 1937 to 15 September 1941. This reconstruction fitted antiaircraft guns, lengthened her stern, fitted emergency damage-control systems, added rangefinders and reconfigured her secondary armament.

On the eve of World War II, Fusō departed Japan as part of a support task-force for the fleet attacking Pearl Harbor, yet returned to anchorage when no US counterattack materialized. On 29 May 1942, she deployed as part of a distant screening force for the Battle of Midway
Battle of Midway
The Battle of Midway is widely regarded as the most important naval battle of the Pacific Campaign of World War II. Between 4 and 7 June 1942, approximately one month after the Battle of the Coral Sea and six months after Japan's attack on Pearl Harbor, the United States Navy decisively defeated...

. After the disastrous loss of four Japanese fast carriers, Fusō returned to Japan. She would remain in the Japanese home islands for the next fourteen months, undergoing radar and antiaircraft refits in July 1943 before deploying to Truk Lagoon
Truk Lagoon
Truk Lagoon, also known as Chuuk, is a sheltered body of water in the central Pacific. North of New Guinea, it is located mid-ocean at 7 degrees North latitude. The atoll consists of a protective reef, around, enclosing a natural harbour 79 by 50 kilometres , with an area of . It has a land...

 in the Caroline Islands
Caroline Islands
The Caroline Islands are a widely scattered archipelago of tiny islands in the western Pacific Ocean, to the north of New Guinea. Politically they are divided between the Federated States of Micronesia in the eastern part of the group, and Palau at the extreme western end...

 (now Micronesia
Micronesia
Micronesia is a subregion of Oceania, comprising thousands of small islands in the western Pacific Ocean. It is distinct from Melanesia to the south, and Polynesia to the east. The Philippines lie to the west, and Indonesia to the southwest....

) in August. She took part in an unsuccessful attempt to reinforce Biak Island
Battle of Biak
The Battle of Biak was part of the New Guinea campaign of World War II. It was fought between the United States Army and the Japanese Army from May 27 to June 22, 1944. It was the first major tactical use of an ambush by the Japanese during the war....

 in May 1944 before returning to Japan in July. In October 1944, Fusō arrived at Lingga
Lingga Islands
Not to be confused with "Linga", a common Scottish island name, see Linga The Lingga Islands or Lingga Archipelago are a group of islands in Indonesia, located south of Singapore, along both sides of the equator, off the eastern coast of Riau Islands province on Sumatra island...

 in preparation for Operation Sho-go, the Imperial Navy's planned counterattack to the American invasion of the Philippines. Fusō sailed with Yamashiro and the cruiser as part of Admiral Shōji Nishimura's Southern Force. On 24 October, Fusō was attacked by American carrier aircraft in the Sulu Sea, with her aircraft catapult destroyed by a bomb hit to her stern. In the early morning of 25 October, the Southern Force entered Surigao Strait, where Admiral Jesse Oldendorf's Seventh Fleet waited with six battleships, five cruisers and nine destroyers. Hit by two torpedoes, Fusō was exposed to the concentrated shellfire of Oldendorf's battleships. She blew up, capsized and sank at 04:21 on the morning of 25 October, taking her entire crew with her.

Yamashiro

Yamashiro was laid down 20 November 1913, launched 3 November 1915, and commissioned 31 March 1917. She differed from Fusō in that her No. 3 turret's stowed position was the reverse of her sister's. In 1917 she was also fitted with a flying-off platform. She operated briefly off the coast of China in 1918 before being placed in reserve at the war's end. In March 1922, Yamashiro became the first Japanese battleship to launch aircraft, with British Sparrow Hawk and Sopwith Camel
Sopwith Camel
The Sopwith Camel was a British First World War single-seat biplane fighter introduced on the Western Front in 1917. Manufactured by Sopwith Aviation Company, it had a short-coupled fuselage, heavy, powerful rotary engine, and concentrated fire from twin synchronized machine guns. Though difficult...

 fighters taking off from the platform fitted to her No. 2 gun turret. In 1923, Yamashiro joined the other battleships of the Imperial Navy in rescue work after the Kanto Earthquake, and afterward was placed in reserve. Unlike her sister, Yamashiro only underwent one major reconstruction during her life. It was from 18 December 1930 to 30 March 1935, and completely replaced her internal machinery, lengthened the stern, rebuilt her superstructure as a Pagoda mast
Pagoda Mast
The Pagoda mast was a type of superstructure that was common on Japanese capital ships that were reconstructed during the 1930s in a bid to improve their fighting performance...

, added torpedo-bulges and additional horizontal armor (the armored deck), and reconfigured her secondary armament. The result featured a few external differences from her sister's modifications, notably a pagoda-mast that extended further aft and was of a heavier appearance. On the eve of war, Yamashiro was part of the Second Battleship Division, and deployed as part of the support force for the Attack on Pearl Harbor
Attack on Pearl Harbor
The attack on Pearl Harbor was a surprise military strike conducted by the Imperial Japanese Navy against the United States naval base at Pearl Harbor, Hawaii, on the morning of December 7, 1941...

. In April 1942, Yamashiro and the Second Battleship Division deployed to counterattack the American carrier task force that had bombed Tokyo
Doolittle Raid
The Doolittle Raid, on 18 April 1942, was the first air raid by the United States to strike the Japanese Home Islands during World War II. By demonstrating that Japan itself was vulnerable to American air attack, it provided a vital morale boost and opportunity for U.S. retaliation after the...

. She was part of the screening force during the Battle of Midway, and was placed in training reserve with the rest of the Second Division in August. In September 1943, Yamashiro was designated a midshipmen training ship, and served in that capacity until July 1944. In October 1944, Yamashiro sortied with the Southern Force as Admiral Nishimura's flagship during the Battle of Leyte Gulf
Battle of Leyte Gulf
The Battle of Leyte Gulf, also called the "Battles for Leyte Gulf", and formerly known as the "Second Battle of the Philippine Sea", is generally considered to be the largest naval battle of World War II and, by some criteria, possibly the largest naval battle in history.It was fought in waters...

. Yamashiro was sunk by American torpedoes in Surigao Strait sometime between 03:23 and 03:53 on the morning of 25 October 1944. Admiral Nishimura and all but ten of her crew were lost.

Main Battery

The primary armament of the Fusō class was twelve 14-inch/45-caliber
Vickers 14 inch/45 naval gun
The Vickers 14 inch 45 calibre gun was designed and built by Vickers and initially installed on the battlecruiser Kongō which it was building for the Imperial Japanese Navy...

 naval guns. Each gun was 648.4 inches (16.5 m) in length, and weighed 86 metric tons (84.6 LT). The shells fired by the main guns varied throughout the lifespan of the class. During World War I, Armour-Piercing Type 3 shells were used, each of which weighed 1400 pounds (635 kg). In 1925, APC Type 5 shells replaced the previous ammunition, with APC No.6/Type 88 shells replacing these in 1928. During World War II, APC Type 91 shells were used. Each of these shells weighed 1485 pounds (673.6 kg), and was fired at an initial muzzle velocity of 2543 feet per second (2,790.4 km/h).

The main guns of the Fusō class were mounted in six double turrets, each of which weighed 615 long tons (624.9 t). Originally, the turrets had an elevation capability of −5/+20 degrees. This configuration enabled the Fusō battleships to outclass all of her contemporaries, the most powerful of which were armed with ten 14-inch or eight 15-inch guns. However, the location of the third and fourth turrets proved particularly problematic to the design of the class. Mounted amidships along the centreline of the ship (separated by a funnel), they had highly restricted arcs of fire, and their positioning affected the internal layout of the battleships. The shell rooms for each of the mountings had to be positioned separately, which decreased the available space for other machinery and hampered the armor configuration. The resultant ammunition magazines amidships also necessitated a longer hull than Fusō contemporaries.

The main battery of the Fusō class underwent various modernizations throughout the ships' careers. During the first reconstruction of both vessels, the elevation of the main guns was increased to −5/+43 degrees, giving a maximum firing range of 35450 yd (20.1 mi; 32.4 km). The recoil mechanism of the guns was also changed from a hydraulic to pneumatic system, which allowed for a faster firing cycle of the main guns. The purchase of French gun design patents in 1924 also enabled the 14-inch guns of the Fusō class to be heavily modified and upgraded.

Secondary Armament

As built, the Fusō class was fitted with a secondary armament of sixteen 152 millimetres (6 in)/50 caliber guns, four 76 millimetres (3 in)/40 caliber guns, and six submerged 533 millimetres (21 in) torpedo tubes. The 152 mm guns were mounted in single casemates along the upper deck of the hull. Eight guns were mounted per side, and had a horizontal angle of rotation of 130 degrees and a maximum vertical elevation of +15 degrees. Each gun could fire a 45.36 kg (100 lb) high-explosive projectile a maximum distance of 22970 yd (13.1 mi; 21 km) at a rate of between four and six shots per minute. During their reconstruction in the 1930s, the maximum elevation of the guns was increased to +30 degrees, which increased the maximum range by approximately 900 metres. While the same guns mounted on other Japanese warships were considered dual-purpose (antiship and antiaircraft), their restricted firing arcs and training speed in casemates aboard Fusō and Yamashiro made them unsuitable as antiaircraft weapons. The 76 mm high-angle guns were in single mounts on both sides of the forward and aft superstructures, both sides of the second funnel, as well as in two other (unspecified) locations. Each of these guns had a maximum vertical elevation of 75 degrees, and could fire a 6 kg (13.2 lb) projectile at a vertical speed of 680 m/s (1,521.1 mph; 2,448 km/h) with a maximum vertical ceiling of 7500 m (24,606.3 ft).

The configuration of the Fusō class's secondary armament changed significantly over the course of the vessels' lives. During the main modernization of the early 1930s, all eight 76 mm guns were removed and replaced with eight 127 mm (5 in)/40 caliber Dual-Purpose (DP) guns. These guns were fitted on both sides of the forward and aft superstructures, and had the greatest variance in shell type among the guns on Fusō. They could fire high-explosive antiaircraft shells, Shiki Sankaidan ("Beehive") incendiary shells, illumination shells and training shells. During reconstruction, the two foremost 152 mm guns were also removed.

The light antiaircraft armament of the Fusō class changed dramatically during the years 1933–1944. During her first reconstruction, Fusō was fitted with four 13.2 mm (0.519685039370079 in) machine-guns, while Yamashiro was fitted with eight twin mounts of 25 mm (0.984251968503937 in) antiaircraft guns. The 13.2 mm machine-guns were based on the French Hotchkiss Machine Gun, and were considered to be a relatively poor design. The 25 mm was mounted on the Fusō class in single, double and triple mounts. It was the standard Japanese light-antiaircraft gun during World War II, but suffered from severe design shortcomings that rendered it a largely ineffective weapon. The twin and triple mounts "lacked sufficient speed in train or elevation; the gun sights were unable to handle fast targets; the gun exhibited excessive vibration; the magazine was too small, and, finally, the gun produced excessive muzzle blast". The configuration of the antiaircraft guns varied significantly; By the end of their final reconstruction, the Fusō class mounted eight twin mounts. In 1943, seventeen single and two twin-mounts were added for a total of 37. In August 1944, both were fitted with another twenty-three single, six twin and eight triple-mounts, for a total of 95 antiaircraft guns in their final configuration.

Armor

When the Fusō class was completed, the ships' armor was "typical for a pre-Jutland
Battle of Jutland
The Battle of Jutland was a naval battle between the British Royal Navy's Grand Fleet and the Imperial German Navy's High Seas Fleet during the First World War. The battle was fought on 31 May and 1 June 1916 in the North Sea near Jutland, Denmark. It was the largest naval battle and the only...

 battleship". As built, the armor accounted for a displacement of 8588 long tons (8,725.8 t), approximately 29% of the class's total displacement. The main armored belt was 305 millimetres (12 in) thick, while the underwater belt had a varying thickness of 102–152 mm (4–6 in). The horizontal armor was considered light by World War I standards, with a thickness range from 32 to 51 mm (1.3 to 2 in). The turrets were more heavily armored than those of the Kongō class, with a thickness of 305 mm (12 in) on the face, 203 mm (8 in) on the sides, and 115 mm (4.5 in) on the roof. The barbettes of the turrets were protected by 205 millimetres (8.1 in) of armor, while the casemates of the 152 mm guns were covered by 152 mm (6 in) of armor. The conning tower was very heavily armored with variations of Krupp Cemented Armor up to 351 millimetres (13.8 in) thick. Additionally, the vessels contained 737 watertight compartments (574 underneath the armor deck, 163 above) to preserve buoyancy in the event of battle damage.

During their reconstruction in the 1930s, the armor of the Fusō class was substantially upgraded. The horizontal armor was increased to a maximum thickness of 98 mm (3.9 in), while an additional 17 mm (0.669291338582677 in) of armor plating was added aft of the conning tower. Torpedo bulges were also added, both to compensate for the increase in weight and to add underwater protection, increasing the beam of the ship to by 4.43 metres (14.5 ft). A longitudinal bulkhead of 76 mm (3 in) was created to improve the underwater protection, and extra plates were added to cover the original hull. 102 millimetres (4 in) of plating were added to protect the ammunition magazines and machinery. This brought the total armor tonnage up to 12199 long tons (12,394.8 t), approximately 31% of the total displacement of the Fusō class. Even after these improvements, the armor was still incapable of withstanding 14-inch shells.

Propulsion

When the Fusō-class battleships were constructed, their machinery produced more power than other contemporary battleships, whose design focused on armor at the expense of speed. During trials, these power plants could produce 40000 shp, driving the ships through the water at a speed of 22.5 kn (27.4 mph; 44.1 km/h). The power was generated by eight double-ended and sixteen single-ended Miyahara-type boilers, all of which consumed a mixture of coal and oil. The boilers themselves were located in four separate rooms. Both Fusō and Yamashiro were given two sets of Brown-Curtis turbines. Originally, the Fusō-class battleships had a stowage capacity for 4000 LT (4,064.2 t) of coal and 1000 LT (1,016.1 t) of oil, giving the battleships a 8000 nmi (9,206.3 mi; 14,816 km) radius of operation. During their modernization, the machinery of the Fusō class was replaced. The Miyahara boilers were removed and the battleships fitted with six new Kampon oil-fired boilers, while the main engine plant was replaced by four Kampon Turbines with an increased output of 75000 hp. This enabled Fusō and Yamashiro to achieve a top speed of 25 kn (30.4 mph; 49 km/h) with a radius of action of 11800 nmi (13,579.2 mi; 21,853.6 km).

See also

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