was an armored cruiser (Sōkō jun'yōkan) built for the Imperial Japanese Navy (IJN) in the late 1890s. As Japan lacked the industrial capacity to build such warships itself, the ship was built in Germany. She participated in most of the naval battles of the Russo-Japanese War of 1904–05, and was lightly damaged during the Battle of the Yellow Sea and the Battle of Tsushima. Yakumo saw no combat during World War I and began the first of many training cruises in 1917, although she was not officially reclassified as a training ship until 1931. Her last training cruise was in 1939, but the ship continued to conduct training in home waters throughout the Pacific War. Yakumo became a repatriation transport after the war and was broken up in 1946–47.
Background and design The 1896 Naval Expansion Plan was made after the First Sino-Japanese War, and included four armored cruisers in addition to four more battleships, all of which had to be ordered from overseas shipyards as Japan lacked the capability to build them itself. Further consideration of the Russian building program caused the IJN to believe that the battleships ordered under the original plan would not be sufficient to counter the Imperial Russian Navy. Budgetary limitations prevented ordering more battleships, and the IJN decided to expand the number of more affordable armored cruisers to be ordered from four to six ships, believing that the recent introduction of tougher Krupp cemented armor would allow them to stand in the line of battle. The revised plan is commonly known as the "Six-Six Fleet". The first four ships were built by Armstrong Whitworth in the United Kingdom, but the last two ships were built in Germany and France. To ensure ammunition compatibility, the IJN required their builders to use the same British guns as the other four ships.Evans & Peattie, pp. 57–62 In general, the IJN provided only a sketch design and specifications that each builder had to comply with; otherwise each builder was free to build the ships as they saw fit. Unlike most of their contemporaries which were designed for commerce raiding or to defend colonies and trade routes, Yakumo and her half-sisters were intended as fleet scouts and to be employed in the battleline.Milanovich, p. 72
Description
The ship was long overall and between perpendiculars. She had a beam of and had an average draft of . Yakumo displaced at normal load and at deep load. The ship had a metacentric height of . She had a double bottom and her hull was subdivided into 247 watertight compartments.Milanovich, pp. 74, 80 Her crew consisted of 670 officers and enlisted men.Jentschura, Jung & Mickel, p. 73
Yakumo had two 4-cylinder triple-expansion steam engines, each driving a single propeller shaft.Milanovich, p. 81 Steam for the engines was provided by 24 Belleville boilers and the engines were rated at a total of . The ship had a designed speed of and reached during her sea trials from . She carried up to of coal and could steam for at a speed of .Jentschura, Jung & Mickel, pp. 73–74
Armament The main armament for all of the "Six-Six Fleet" armored cruisers was four Armstrong Whitworth-built 45-caliber eight-inch guns in twin-gun turrets fore and aft of the superstructure. The electrically operated turrets were capable of 130° rotation left and right, and the guns could be elevated to +30° and depressed to −5°. The turret accommodated 65 shells, but could only be reloaded through doors in the turret floor and the ship's deck that allowed the electric winch in the turret to hoist shells up from the shell room deep in the hull.Milanovich, pp. 76–77 The ship carried a total of 320 eight-inch shells. The guns were manually loaded and had a rate of fire about 1.2 rounds per minute. The 203-millimeter gun fired armor-piercing (AP) projectiles at a muzzle velocity of to a range of .Milanovich, p. 78
The secondary armament consisted of a dozen Elswick Ordnance Company "Pattern Z" quick-firing (QF), 40-caliber, 6-inch guns. Only four of these guns were not mounted in armored casemates on the main and upper decks, and their mounts on the upper deck were protected by gun shields. Their AP shells were fired at a muzzle velocity of .Friedman, p. 276; Milanovich, p. 78 The guns were provided with 150 rounds each. Yakumo was also equipped with a dozen 40-caliber QF 12-pounder 12-cwt guns"Cwt" is the abbreviation for hundredweight, 12 cwt referring to the weight of the gun. and eight QF 2.5-pounder Yamauchi guns as close-range defense against torpedo boats. The former gun fired , projectiles at a muzzle velocity of .Friedman, p. 114
Yakumo was equipped with five torpedo tubes, one above water in the bow and four submerged tubes, two on each broadside. The Type 30 torpedo had a warhead and three range/speed settings: at , at or at .Milanovich, p. 80
Armor All of the "Six-Six Fleet" armored cruisers used the same armor scheme with some minor differences, one of which was that the four later ships all used Krupp cemented armor. The waterline belt ran the full length of the ship and its thickness varied from amidships to at the bow and stern. It had a height of , of which was normally underwater. The upper strake of belt armor was thick and extended from the upper edge of the waterline belt to the main deck. It extended from the forward to the rear barbette. Yakumo had only a single transverse 127 mm armored bulkhead that closed off the forward end of the central armored citadel.Milanovich, pp. 80–81
The barbettes, gun turrets and the front of the casemates were all 152 millimeters thick while the sides and rear of the casemates were protected by of armor. The deck was thick and the armor protecting the conning tower was in thickness.Chesneau & Kolesnik, p. 224
Construction and career
Yakumo, named from a stanza of the waka poem by Susanoo in the Japanese mythology,Masahide, p. 98, also, Yakumo is another name of the .Daiji, p. 219 was ordered on 1 September 1897 and laid down a year later by AG Vulcan Stettin in Stettin, Germany. The ship was launched on 8 July 1899 and completed on 20 June 1900. She departed Stettin two days later and arrived in Yokosuka, Japan, on 30 August.Milanovich, p. 73
Russo-Japanese War At the start of the Russo-Japanese War, Yakumo was assigned to the 2nd Division of the 2nd Fleet.Kowner, p. 465 She participated in the Battle of Port Arthur on 9 February 1904, when Vice Admiral Tōgō Heihachirō led the Combined Fleet in an attack on the Russian ships of the Pacific Squadron anchored just outside Port Arthur. Tōgō had expected the surprise night attack by his destroyers to be much more successful than it was, anticipating that the Russians would be badly disorganized and weakened, but they had recovered from their surprise and were ready for his attack. The Japanese ships were spotted by the protected cruiser , which was patrolling offshore and alerted the Russians. Tōgō chose to attack the Russian coastal defenses with his main armament and engage the ships with his secondary guns. Splitting his fire proved to be a poor decision as the Japanese eight- and six-inch guns inflicted little damage on the Russian ships, which concentrated all their fire on the Japanese ships with some effect.Forczyk, pp. 42–43 Although many ships on both sides were hit, Russian casualties numbered some 150, while the Japanese suffered roughly 90 killed and wounded before Tōgō disengaged.Corbett, I, p. 105 Yakumo was not hit during the engagement, although she did hit the protected cruiser one time with an eight-inch shell.Warner & Warner, p. 200
In early March, Vice Admiral Kamimura Hikonojō was tasked to take the reinforced 2nd Division north and make a diversion off Vladivostok. While scouting for Russian ships in the area, the Japanese cruisers bombarded the harbor and defenses of Vladivostok on 6 March to little effect. Upon their return to Japan a few days later, the 2nd Division was ordered to escort the transports ferrying the Imperial Guards Division to Korea and then to join the ships blockading Port Arthur. Yakumo was then transferred to Rear Admiral Dewa Shigetō's 3rd Division. On 23 June, the ship was Dewa's flagshipCorbett, I, pp. 138–39, 142–45, 160, 177, 208, 294 when the Pacific Squadron sortied in an abortive attempt to reach Vladivostok, but the new squadron commander, Rear Admiral Wilgelm Vitgeft, ordered the squadron to return to Port Arthur when it encountered the Japanese battleline shortly before sunset, as he did not wish to engage his numerically superior opponents in a night battle.Warner & Warner, pp. 305–06
Battle of the Yellow Sea
On the morning of 10 August 1904, Dewa's cruisers were over south of Tōgō's 1st Division when the Russians sortied from Port Arthur in another attempt to reach Vladivostok. In the early stages of the battle, Dewa attempted to engage the Russian cruisers trailing the battleships in accordance with Tōgō's standing orders, but was rebuffed by fire from the battleships. As Dewa closed with the Russians later in the afternoon in another attempt to attack the Russian cruisers, a shell struck Yakumo amidships at 15:40, killing 12 and wounding 11. The range at this time exceeded , beyond the range of any gun in his squadron, so Dewa ordered his ships to disengage. By 17:45, Yakumo had maneuvered to about from the damaged Russian battleship Poltava and opened fire. Yakumo continued to close until the Russian squadron was thrown into confusion by the death of Vitgeft around 18:40.Corbett, I, pp. 383–84, 388, 391, 393
The 3rd Division then followed Tōgō's ships as they circled the Russian ships while they sorted themselves out, now firing at the Russian cruisers with little effect, until Tōgō ordered Dewa to attack the Russian destroyers at about 19:44. Dewa cancelled that last order and turned south around 20:00 in pursuit of several Russian cruisers that were fleeing to the south, in an attempt to intercept them before they reached the isolated flotillas of destroyers and torpedo boats. The Russian ships were engaged by other Japanese cruisers before they could reach the small ships, and Dewa broke off the pursuit around 20:25 as light was fading. He continued south-eastwards overnight and spotted one cruiser and two destroyers, but was unable to catch any of them. On 14 August, Yakumo and the 3rd Division was ordered to Qingdao to confirm that the Germans had indeed interned the battleship and three destroyers that had taken shelter there after the battle. After their return, they were reassigned to the blockade of Port Arthur.Corbett, I, pp. 398, 401–03, 417–19, 456, 458
In mid-September, Yakumo was transferred back to Kamimura's 2nd Division, which was defending the Strait of Tsushima, although she began a refit at the end of the month. The ship returned to Dewa on 15 November and he transferred his flag back to her. On 13 December, the ship attempted to rescue survivors of the after she had struck a mine, but found no one still living. Yakumo was sent to Sasebo Naval Arsenal for another refit five days later. On 1 February 1905, the ship was ordered to join Rear Admiral Shimamura Hayao's 2nd Division blockading Vladivostok, although this only lasted for a few weeks as she was ordered to Kure Naval Arsenal for a final refit in mid-February before the anticipated battle with the Russian ships sent from the Baltic Fleet.Corbett, II, pp. 47, 55–56, 96–97, 113, 128, 159, 162
Battle of Tsushima