Fusō-class battleship

Fusō running full-power trials on 10 May 1933 after her first reconstruction

The Fusō-class ships had two sets of Brown-Curtis direct-drive steam turbines, each of which drove two propeller shafts. The medium-pressure turbines drove the wing shafts while the high- and low-pressure turbines drove the inner shafts. The turbines were designed to produce a total of 40,000 shaft horsepower (30,000 kW), using steam provided by 24 Miyahara-type water-tube boilers, each of which consumed a mixture of coal and oil. The ships had a stowage capacity of 4,000 long tons (4,100 t) of coal and 1,000 long tons (1,000 t) of fuel oil,[19] giving them a range of 8,000 nautical miles (15,000 km; 9,200 mi) at a speed of 14 knots (26 km/h; 16 mph). Both ships exceeded their designed speed of 22.5 knots (41.7 km/h; 25.9 mph) during their sea trials; Fusō reached 23 knots (43 km/h; 26 mph) from 46,500 shp (34,700 kW) and Yamashiro exceeded that with 23.3 knots (43.2 km/h; 26.8 mph) from 47,730 shp (35,590 kW).[20]

During their 1930s modernization, the Miyahara boilers on each ship were replaced by six new Kanpon oil-fired boilers, fitted into the former aft boiler room, and the forward funnel was removed. The Brown-Curtis turbines were replaced by four geared Kanpon turbines with a designed output of 75,000 shp (56,000 kW).[19] On her trials, Fusō reached a top speed of 24.7 knots (45.7 km/h; 28.4 mph) from 76,889 shp (57,336 kW).[14] The fuel storage of the ships was increased to a total of 5,100 long tons (5,200 t) of fuel oil that gave them a range of 11,800 nautical miles (21,900 km; 13,600 mi) at a speed of 16 knots (30 km/h; 18 mph).[19]

Admiral Sankichi Takahashi commanded Fusō in 1924–1925

The twelve 45-calibre 14-inch guns[13] of the Fusō class were mounted in six twin-gun turrets, numbered from front to rear, each of which weighed 615 long tons (625 t).[21] The turrets had an elevation capability of −5/+20 degrees.[22] They were arranged in an uncommon 2-1-1-2 style with superfiring pairs of turrets fore and aft; the middle turrets were not superfiring, and had a funnel between them.[13] The decision to use six twin turrets rather than four triple turrets greatly affected the entire design of the class because the two extra turrets required a longer ship and increased the amount of armor required to protect the ship. The location of the third and fourth turrets proved particularly problematic to the design of the class because the amidships turrets were not superfiring as in the subsequent Ise-class battleships. This further increased the length of the ships because the barrels of the upper turret did not protrude over the lower turret, requiring more space than a pair of superfiring turrets.[23] Mounted amidships along the centerline of the ship, they had restricted arcs of fire,[13] and their position forced the boiler rooms to be placed in less than ideal locations.[15] Another complication was the need to fit extra insulation and air conditioning in the magazines of the amidships turrets to protect them from the heat generated in the adjacent boiler rooms.[21] Originally both amidship gun turrets faced to the rear, but Fusō's turret No. 3 was moved to face forward during her reconstruction in order to accommodate additional platforms around her funnel.[14]

The main battery of the Fusō class underwent multiple 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 35,450 yards (32,420 m). 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.[22]

By World War II, the guns used Type 91 armor-piercing, capped shells. Each of these shells weighed 673.5 kilograms (1,485 lb) and had a muzzle velocity of 775 meters per second (2,540 ft/s). They had a maximum range of 27,800 meters (30,400 yd) at +30 degrees of elevation and 35,450 meters (38,770 yd) at +43 degrees after modernization.[21] Also available was a 625-kilogram (1,378 lb) high-explosive shell that had a muzzle velocity of 805 meters per second (2,640 ft/s).[24] A special Type 3 Sankaidan incendiary shrapnel shell was developed in the 1930s for anti-aircraft use.[21]

A twin-gun 127 mm mount on board Nagato, the same as used on board the Fusō class

As built, the Fusō class was fitted with a secondary armament of sixteen 50-caliber six-inch guns mounted in single casemates along the sides of the hull at the level of the upper deck. Eight guns were mounted per side, and each had an arc of fire of 130 degrees and a maximum elevation of +15 degrees. Each gun could fire a 45.36-kilogram (100.0 lb) high-explosive projectile a maximum distance of 22,970 yards (21,000 m) 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 their maximum range by approximately 900 metres (980 yd).[25]

The ships also mounted five or six 40-caliber 76 mm anti-aircraft (AA) guns. The 76-millimetre (3 in) high-angle guns were in single mounts on both sides of the forward superstructure, both sides of the second funnel, and each side of the aft superstructure (Fusō lacked the starboard side aft gun). Each of these guns had a maximum elevation of +75 degrees, and could fire a 6 kg (13 lb) projectile with a muzzle velocity of 680 m/s (2,200 ft/s) to a maximum height of 7,500 metres (24,600 ft).[25] Both ships were equipped with six submerged 533-millimetre (21.0 in) torpedo tubes, three on each broadside.[13]

The Fusō class's secondary armament changed significantly over time. During the modernizations of the 1930s, all of the 76 mm guns were replaced with eight 40-caliber 127 mm (5.0 in) dual-purpose guns. These guns were fitted on both sides of the fore and aft superstructures in four twin-gun mounts.[21] When firing at surface targets, the guns had a range of 14,700 metres (16,100 yd); they had a maximum ceiling of 9,440 metres (30,970 ft) at their maximum elevation of +90 degrees. Their maximum rate of fire was 14 rounds a minute, but their sustained rate of fire was around eight rounds per minute.[26] During reconstruction, the two foremost 152 mm guns were also removed.[18]

The light AA armament of the Fusō class changed dramatically from 1933 to 1944. During the first reconstruction, Fusō was fitted with four quadruple 13.2 mm (0.52 in) machine-guns,[27] while Yamashiro was fitted with eight twin 25-millimeter (0.98 in) gun mounts.[28] Both weapons were license-built French Hotchkiss designs.[29] The 25 mm guns were mounted on the Fusō class in single, double and triple mounts. This model was the standard Japanese light anti-aircraft gun during World War II, but it 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".[30] The configuration of the anti-aircraft 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.[31] In August 1944, both were fitted with another twenty-three single, six twin and eight triple-mounts, for a total of 96 anti-aircraft guns in their final configuration.[32]

Yamashiro as she appeared in 1944

When the Fusō class was completed, the ships' armor was "typical for a pre-Jutland battleship".[33] As built, the armor accounted for a displacement of 8,588 long tons (8,726 t), approximately 29% of the class's total displacement.[13] Their waterline armor belt was 305 to 229 millimetres (12 to 9 in) thick; below it was a strake of 102 mm (4 in) armor. The deck armor ranged in thickness from 32 to 51 mm (1.3 to 2.0 in). The turrets were protected with an armor thickness of 279.4 mm (11.0 in) on the face, 228.6 mm (9.0 in) on the sides, and 114.5 mm (4.51 in) on the roof. The barbettes of the turrets were protected by armor 305 mm thick, while the casemates of the 152 mm guns were protected by 152 mm armor plates. The sides of the conning tower were 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.[34]

During their reconstruction, the armor of the battleships was substantially upgraded. Their deck armor was increased to a maximum thickness of 114 mm (4.5 in), and a longitudinal bulkhead of 76 mm (3.0 in) of high-tensile steel was added to improve the underwater protection.[35] This brought the total armor tonnage up to 12,199 long tons (12,395 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.[33]

A Sparrowhawk taking off from Yamashiro

Yamashiro was briefly fitted with an aircraft flying-off platform on Turret No. 2 in 1922. She successfully launched Gloster Sparrowhawk and Sopwith Camel fighters from it, becoming the first Japanese ship to launch aircraft. When she was modernized in the 1930s, a catapult and a collapsible crane were fitted on the stern, and both ships were equipped to operate three floatplanes, although no hangar was provided. The initial Nakajima E4N2 biplanes were replaced by Nakajima E8N2 biplanes in 1938 and then by Mitsubishi F1M biplanes from 1942 on.[36]

When completed in 1915, the ships had two 3.5-meter (11 ft 6 in) and two 1.5-meter (4 ft 11 in) rangefinders in the forward superstructure, a 4.5-meter (14 ft 9 in) rangefinder on the roof of Turret No. 2, and 4.5-meter rangefinders in Turrets 3, 4, and 5. In late 1917 a fire-control director was installed on a platform on the foremast. The 4.5-meter rangefinders were replaced by 8-meter (26 ft 3 in) instruments in 1923. During Fusō's first modernization, four directors for the 12.7 cm AA guns were added, one on each side of the fore and aft superstructures, and an eight-meter rangefinder was installed at the top of the pagoda mast. This was replaced by a 10-meter (32 ft 10 in) rangefinder during 1938. At the same time, the two 3.5-meter rangefinders on the forward superstructure were replaced by directors for the 25 mm AA guns. Additional 25 mm directors were installed on platforms on each side of the funnel.[37][Note 2]

While the ships were in drydock in July 1943, Type 21 air search radar was installed on the roof of the 10-meter rangefinder at the top of the pagoda mast. In August 1944, two Type 22 surface search radar units were installed on the pagoda mast and two Type 13 early warning radar units were fitted. Yamashiro mounted hers on the mainmast, while Fusō was the only Japanese battleship to mount radar on her funnel.[38]

In April and May 1941, Fusō and Yamashiro were attached to the 2nd Division of the 1st Fleet,[47] but the two ships spent most of the war around Japan, mostly at the anchorage at Hashirajima in Hiroshima Bay.[31] When the war started for Japan on 8 December,[Note 4] the division sortied from Hashirajima to the Bonin Islands as distant support for the 1st Air Fleet attacking Pearl Harbor, and returned six days later.[46] On 18 April 1942, they pursued but did not catch the American carrier force that had launched the Doolittle Raid.[46] Commanded by Vice-Admiral Shirō Takasu, the division set sail with the Aleutian Support Group on 28 May, at the same time that most of the Imperial Fleet began an attack on Midway Island (Operation MI).[48][49][50]

Afterwards, Yamashiro returned to home waters, where she stayed until August 1943; the next month, she became a training ship for midshipmen.[31] In July 1943, Yamashiro was at the Yokosuka drydock, then was briefly assigned as a training ship on 15 September before loading troops on 13 October bound for Truk Naval Base, arriving on the 20th. She sailed for Japan on 31 October.[46] On 8 November, the submarine USS Halibut fired torpedoes at Junyo that missed, but hit Yamashiro with a torpedo that failed to detonate.[51] Returning to Japanese waters, Yamashiro resumed her training duties.[46]

During the US invasion of Saipan in June 1944, Japanese troop ships attempting to reinforce the defenses were sunk by submarines. Shigenori Kami, chief of operations of the Navy Staff, volunteered to command Yamashiro to carry troops and equipment to Saipan. If the ship actually reached the island, he intended to deliberately beach the ship before it could be sunk and to use its artillery to defend the island. After Ryūnosuke Kusaka, Chief of Staff of the Combined Fleet, also volunteered to go, Prime Minister Hideki Tōjō approved the plan, known as Operation Y-GO, but the operation was cancelled after the decisive defeat in the Battle of the Philippine Sea on 19 and 20 June.[52]

Fusō was assigned to the Imperial Japanese Naval Academy at Etajima, Hiroshima, for use as a training ship between 15 November 1942 and 15 January 1943. On 8 June, she rescued 353 survivors from Mutsu when that ship exploded at Hashirajima.[53] After carrying supplies to Truk Naval Base in August,[53] Fusō made for Eniwetok two months later to be in a position to intercept an anticipated attack, returning to Truk on October 26.[53] She arrived on 21 February at Lingga Island, and was employed there as a training ship,[54] before refitting at Singapore between 13 and 27 April and returning to Lingga. She was transferred to Tawi-Tawi on 11 May,[53] and provided cover for the abortive attempts to reinforce Biak Island at the end of the month.[31][55] Fusō sailed to Tarakan Island off Borneo to refuel in early July before returning to Japan, escaping an attack by the submarine USS Pomfret. She was refitted in early August at Kure.[53]

Both ships were transferred to Battleship Division 2 of the 2nd Fleet on 10 September. Yamashiro and Fusō alternated in the role of division flagship under Vice Admiral Shōji Nishimura. They departed Kure on 23 September for Lingga Island, carrying the Army's 25th Independent Mixed Regiment, and escaped an attack by the submarine USS Plaice the next day. They arrived on 4 October, then transferred to Brunei to offload their troops and refuel in preparation for Operation Shō-Gō, the attempt to destroy the American fleet conducting the invasion of Leyte.[46]

The Battle of Surigao Strait

Nishimura's "Southern Force" left Brunei at 15:30 on 22 October 1944, heading east into the Sulu Sea and then to the northeast into the Mindanao Sea. Intending to join Vice-Admiral Takeo Kurita's force in Leyte Gulf, they passed west of Mindanao Island into Surigao Strait, where they met a large force of battleships, cruisers and destroyers lying in wait. The Battle of Surigao Strait would become the southernmost action in the Battle of Leyte Gulf.[56]

At 09:08 on 24 October, Yamashiro, Fusō and the heavy cruiser Mogami spotted a group of 27 planes, including Grumman TBF Avenger torpedo bombers and Curtiss SB2C Helldiver dive bombers escorted by Grumman F6F Hellcat fighters, that had been launched from the carrier Enterprise.[57] Around 20 sailors on Yamashiro were killed by strafing and rocket attacks.[58] Fusō's catapult and both floatplanes were destroyed, and another bomb hit the ship near Turret No. 2 and penetrated the decks, killing everyone in No. 1 secondary battery.[59]

Nishimura issued a telegram to Admiral Soemu Toyoda at 20:13: "It is my plan to charge into Leyte Gulf to [reach] a point off Dulag at 04:00 hours on the 25th."[60] At 22:52, his force spotted three or four Motor Torpedo Boats and opened fire, damaging PT-130 and PT-152 and forcing all of them to retreat before they could launch their torpedoes.[61]

One or two torpedoes, possibly fired by the destroyer Melvin, hit Fusō amidships on the starboard side at 03:09 on the 25th; she listed to starboard, slowed down, and fell out of formation.[62] Some Japanese and American eyewitnesses later claimed that Fusō broke in half, and that both halves remained afloat and burning for an hour, but they specifically mentioned only the size of the fire on the water, and not any details of the ship.[63] Historian John Toland agreed in 1970 that Fusō had broken in two,[64] but according to historian Anthony Tully in 2009, "Fuso was torpedoed, and as a result of progressive flooding, upended and capsized within forty minutes."[65] She sank between 03:38 and 03:50; only a few dozen men survived her rapid descent and massive oil fire, and only ten reached shore.[66]

At 03:52, Yamashiro was attacked by a large formation to the north commanded by Rear Admiral Jesse Oldendorf. First came 6- and 8-inch (200 mm) shells from a line of eight cruisers,[67] then 14-inch (360 mm) and 16-inch (410 mm) shells from a line of six battleships.[68] The main bombardment lasted 18 minutes, and Yamashiro was the only target for seven minutes.[69] The first rounds hit the forecastle and pagoda mast, and soon the entire battleship appeared to be ablaze. Yamashiro's two forward turrets targeted her assailants, and the secondary armament targeted the American destroyers plaguing Mogami and the destroyer Asagumo.[70] There was a big explosion at 04:04, possibly from one of the middle turrets. She was hit between 04:03 and 04:09 near the starboard engine room by a torpedo, and Nishimura wired to Kurita: "We proceed till totally annihilated. I have definitely accomplished my mission as pre-arranged. Please rest assured."[71] At the same time, Oldendorf issued a cease-fire order to the entire formation after hearing that the destroyer Albert W. Grant was taking friendly fire, and the Japanese ships also ceased fire.[72]

Yamashiro increased speed,[72] but she had been hit by two to four torpedoes, and after two more torpedo hits near the starboard engine room, she was listing 45 degrees to port. Shinoda gave the command to abandon ship, but neither he nor Nishimura made any attempt to leave the conning tower as the ship capsized within five minutes and quickly sank, stern first, vanishing from radar between 04:19 and 04:21.[73] Only 10 crewmembers of the estimated 1,636 officers and crew on board survived.[74]