Fusō Class Battleship

The Yamashiro, Fusō, and Haruna

Introduction

The Fusō-class battleships were two battleships that served in the Imperial Japanese Navy during World War I. The class displaced 29,330 tons upon completion, making the two ships, Fusō and Yamashiro, the first super-dreadnoughts of the Imperial Japanese Navy. At the time of Fusō’s launching (in 1914), it outclassed any battleship in the Royal Navy or United States Navy in both speed and firepower.

Background

The design of the Fusō class battleship was caused by an international race for superiority of naval forces, and also due to Japanese naval planners who wished to maintain a fleet of first-class vessels that were powerful enough to defeat the United States Navy in a fight in Japanese territorial waters.

Japan’s fleet of battleships had been highly successful in 1905, the last year of the Russo-Japanese War, with final decisive blow which caused the annihilation of the Russian Baltic Fleet in the Battle of Tsushima. Japan immediately looked towards her two remaining rivals for the vast Pacific – the Royal Navy and the United States Navy. Satō Tetsutarō, a Japanese Admiral and military theorist, believed that it was inevitable that a conflict would arise between at least one of the two and Japan. He called for the IJN to maintain a fleet with at least 70% the amount of capital ships as the USN. This, he believed, would enable the IJN to defeat the USN in a decisive battle. To that end, a 1907 Imperial Defense Policy called for the construction of eight modern battleships, 20,000 long tons each, and eight modern cruisers, 18,000 long tons each. This was the beginnings of the Eight-Eight Fleet Program – a development program to produce a cohesive battle line of sixteen first-class vessels.

The launch of the HMS Dreadnought in 1906 by the Royal Navy complicated the Japanese plan. Displacing 17,900 tons and armed with ten 12in guns, the Dreadnought outclassed any other battleship in the world at that time. In 1907, the battlecruiser HMS Invincible was launched, which further complicated the Japanese plans. When Japan launched her two new Satsuma class battleships and two Tsukuba class cruisers, they were already outclassed by the British ships. This caused the Japanese to restart the Eight-Eight Fleet Program.

The first ships built for the restarted program were two battleships of the Kawachi class, ordered in 1907 and laid down in 1908. In 1910 the IJN requested the Diet of Japan (similar to Parliament) to secure funding for the entire Eight-Eight Fleet Program. Due to economic restraints, the Navy Ministry cut the plan down to seven battleships and three cruisers. Then the plan was cut once more by the cabinet, and the Eight-Eight Fleet Program became the Japanese Emergency Expansion bill, which authorized the construction of four cruisers (which became the Kongō class), and one battleship (which became the Fusō).

The Fusō and Yamashiro off of the Japanese coast.

Design

The Fusō class Battleship was based heavily on the design of the Kongo class Cruiser, which was considered a battleship equivalent. After their coordination on the Kongo class, the Japanese had access to the latest British project studies in naval architecture. So as to outdo foreign designs, Japanese planners decided that the new battleship should be armed with twelve 14in guns. Vickers files shows that the Japanese actually had access to British designs for double and triple turrets; however, the Japanese decided to build a ship with six double turrets, as opposed to four triple turrets. The final design, designated A-64 by the IJN, called for a 29,000 long ton displacement and twelve 14in guns in six double turrets – two forward, two aft, and two amidships. The design also called for a top speed of 23 knots. It was superior to any United States counterpart in the elements of armor, armament, and speed. This followed the Japanese doctrine of compensating for quantity with superior quality.

Specifications

Primary Armament

The primary armament of the Fusō class was twelve 14in cannon. Each gun was about 54 feet in length, and weight 85 long tons. The shells used varied during the lifetime of the class. During World War I, Armor-Piercing Type 3 shells were used, each weighing 1,400lbs. In 1925, APC Type 5 shells replaced the Type 3’s, while APC No.6/Type 88 shells replaced these in 1928. During World War II, APC Type 91 shells were used. These weighed 1,485lbs and fired at a muzzle velocity of 2,543 feet per second.

The main guns were mounted in six double turrets, each weighing 615 long tons. Originally the turrets had an elevation capability of -5/+20 degrees. This configuration outclassed all contemporaries of its day, which were armed with either ten 14in or eight 15in guns. However, the location of the third and fourth turrets proved problematic with the design of the class. They were mounted amidships along the centerline, separated by the funnel. This gave them very restricted arcs of fire, and the internal layout of the ships was affected by their location. The shell rooms for each turret had to be separate, which decreased the available space for other machinery, while it also caused trouble with the armor.

The main battery underwent various modifications during the career of the ships. In the first reconstruction, the elevation of the main guns was increased to -5/+43 degrees, giving a maximum range of 20.14 miles. Also the recoil mechanism was changed from a hydraulic to a pneumatic system, which allowed for faster firing.

Secondary Armament

Originally the Fusō class had a secondary armament of sixteen 6in guns, four 3in guns, and six 21in torpedo tubes below the waterline. The 6in guns were mounted in single casemates on the upper deck of the hull, eight guns to a side. They had a horizontal rotation of 130 degrees, and a maximum vertical elevation of +15 degrees. They fired 100lb High Explosive projectiles up to 13.05 miles at about four to six rounds per minute. During the classes reconstruction, the 6in guns maximum elevation was increased to +30 degrees, with the range increasing about 0.56 miles. While the same 6in guns mounted on other Japanese ships were considered to be dual purpose, the restricted elevation on the Fusō class ships made them unsuitable as anti-aircraft weapons.

The 3in guns on the two Fusō class battleships were in single mounts on either side of the forward and aft superstructures, either side of the second funnel, and two other unspecified locations. These guns had a vertical elevation of +75 degrees, and could fire a 13lb projectile vertically at 1500mph, with a maximum ceiling of 24,600ft.

The configuration of the secondary armament changed several times. During the main modernization in the early 1930’s, the two foremost 6in guns were deleted, while all of the 3in guns were replaced with 5in dual-purpose weapons. These weapons could fire High Explosive Anti-Aircraft shells, Shiki Sankaiden (Beehive) incendiary shells, illumination shells, and training shells.

The light anti-aircraft armament of the class changed drastically between 1933 and 1944. During the first reconstruction, the Fusō was fitted with four 13.2mm machine-guns, while the Yamashiro was fitted with eight 25mm twin-mounted automatic cannon. The 13.2mm guns were based on the French Hotchkiss machine-gun, and was a relatively inadequate design. The 25mm AA guns were soon mounted on Fusō in single, double, and triple mounts. They were the standard Japanese light anti-aircraft gun during WWII, but had several problems in the design, making them relatively ineffective. They did not have enough flexibility of movement when in double or triple mounts, were not able to handle fast moving targets, had too much vibration, too small of a magazine, and extreme muzzle blast. The configuration of the 25mm guns notably varied, and by the end of the 1930’s reconstruction, the Fusō class carried eight twin mounts. In 1943, an additional seventeen single and two twin mounts were added for a total of 37 guns. In August of 1944, both ships were given another twenty-three single, six twin, and eight triple mounts to bring the total up to ninety-five anti-aircraft guns.

The Fusō in 1933, running at full speed after her first reconstruction.

Armor

When the Fusō class was completed, its armor was normal for its time. It weighed 8,588 long tons, which was about 29% of its total displacement. The main armor belt was 12in thick, while the underwater belt was between 4in and 6in. The class’s horizontal armor was light for its time, ranging between 1.3in and 2in. The turret’s armor was 12in on the face, 8in on the sides, and 4.5in on the roof. The barbettes on the turrets had 8.1in of armor, and the casemates of the 6in guns were covered in 6in of armor. The conning tower was very strong, utilizing variations of Krupp Cemented Armor up to 13.8in thick in some places.

During the reconstruction of the class, the armor was significantly upgraded. The horizontal armor was increased to a maximum thickness of 3.9in, while another .67in was added aft of the conning tower. Torpedo bulges were added to compensate for the extra weight caused by the extra armor (and also to add underwater protection), resulting in an increase in the beam to 14.5ft. A three inch longitudinal bulkhead was also added to improve underwater protection, along with extra plates covering the original hull. Four inches of plating was added to protect the magazines and machinery. All of this additional armor brought the total armor tonnage to 12,199 long tons, about 31% of the ships total displacement. Despite all of these improvements, the class still could not withstand 14in shells.

Propulsion

When it was constructed, the Fusō’s machinery produced more power than its contemporaries which focused on more armor at the cost of speed. During trials, the ships machinery could produce 40,000 shaft horsepower, which gave the class a maximum speed of 22.5 to 23 knots.

The two Fusō class ships were powered by eight double-ended and sixteen single-ended Miyahara-type boilers, which consumed a mixture of coal and oil, and there were also two sets of Brown-Curtis turbines. The original capacity was 4,000 long tons of coal and 1,000 long tons of oil, which gave the ships an 8,000 nautical mile radius of action.

During the modernization of the ships, the Miyahara boilers were replaced with six Kammpon oil-fired boilers, while the Brown-Curtis turbines were replaced with four Kammpon turbines. This change in machinery allowed for an output of 75,000 to 76,889 shaft horsepower, enabled a maximum speed of 25 knots, and allowed for an 11,800 nautical mile radius of action.

Ships

There were only two Fusō class ships built, both completed from 1912 to 1917. The first, the Fusō, was constructed at the Kure Naval Arsenal, while the second, Yamashiro, was built at the Yokosuka Naval Arsenal. Two advanced versions of the class had been planned, but their final design differed so much from the original class that they were redesignated as the Ise class.

The Fusō is considered the first modern battleship of the Imperial Japanese Navy. When it was completed in 1915, it outclassed all United States Navy counterparts of the New York class in firepower and speed. It was regarded as the best armed battleship in the entire world.

Both ships were extensively modernized during the 1930’s, but were still obsolete at the outbreak of World War II. Due to this fact, both ships were kept near the home waters in the early years of the war, being used as training and transport ships. After Japan lost most of its carrier fleet in 1943, it was proposed to convert both ships into hybrid battleship/carriers. The process was to begin in June 1943, but the plan was cancelled when the two Ise class battleships were converted instead.

The Yamashiro in 1934, after her reconstruction.

Fusō

The Fusō was laid down by the Kure Kaigun Koshō on March 11, 1912, and was launched on March 28, 1914. It was completed on November 18, 1915. One difference between the Fusō and Yamashiro was that the C-turret on Fusō featured an aircraft catapult, while that of the Yamashiro was located on the stern.

The launching of the Fusō.

It saw no major action during WWI, and had its major modifications between the two World Wars. Even though it was extensively modified, it was still too slow and lightly armored to be of any great use, and both ships of the class were kept in the Inland Sea as a reserve force at the time of the Pearl Harbor attack. It did see action before too long.

The Fusō helped in the unsuccessful pursuit of the American task force that launched the Doolittle Raid in April of 1942. It also was a screen for the Aleutian Force during the Battle of Midway in June of that year. It also was able to rescue 353 survivors of the Mutsu when that ship exploded at Hashirajima on June 8, 1943. She also took part in the reinforcement of Truk in August 1943, and the reinforcement of Biak in June 1944. It was planned to convert the Fusō into an aircraft carrier, but this idea went to pieces after the loss of pilots in the Mariana’s.

 In October of 1944, while under the command of Rear Admiral Ban Masami, the Fusō was a part of Admiral Shōji Nishimura’s Southern Force during the Battle of Leyte Gulf. During the Battle of Surigao Strait on October 25, 1944, the Fusō was hit by one or two torpedoes fired by the destroyer USS Melvin, and caught fire, forcing her to leave the action. It has been argued, however, that rather than exploding and breaking in half shortly after this, it merely rolled over and sank with severe loss of life.

It is probable that the Fusō was the largest vessel of any nationality sunk with all hands during World War II. There is evidence that a few survivors were rescued by the destroyer Asagumo, which was sunk as well a short time thereafter. Some of the sailors may have made it ashore, only to be killed by Filipinos. In any event, the Fusō was removed from the Navy List on August 31, 1945.

A line drawing of the Fusō as she appeared in 1944.

Yamashiro

The Yamashiro was laid down in the Yokosuka Naval Arsenal on November 20, 1913, launched November 3, 1915, and commissioned on March 31, 1917. It was the first Japanese vessel to ever be equipped with aircraft catapults. It was named Yamashiro after the Japanese province where Kyoto is located.

After serving most of World War II in territorial waters, it took place in the Battle of Leyte Gulf in October of 1944. During the Battle of Surigao Strait on October 25, she was attacked and sunk by the US Navy, receiving four torpedoes from destroyers and numerous 14” and 16” shells from US Battleships. There were about ten survivors.

A line drawing of the Yamashiro, as she appeared in 1944.

Sources:

Wikipedia

http://en.wikipedia.org/wiki/Fuso_class_battleship

http://en.wikipedia.org/wiki/Japanese_battleship_Fus%C5%8D

http://en.wikipedia.org/wiki/Japanese_battleship_Yamashiro

World Naval Ships

http://www.worldnavalships.com/fuso.htm

World War II Database

     http://ww2db.com/ship_spec.php?ship_id=468