Izumo-class cruiser

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Izumo-class helicopter destroyer

A postcard of Iwate at speed, circa 1905–1915
Class overview
NameIzumo class
BuildersArmstrong Whitworth, United Kingdom
Operators Imperial Japanese Navy
Preceded byAsama class
Succeeded byYakumo
Built1898–1901
In commission1900–1945
Completed2
Lost2
General characteristics
TypeArmored cruiser
Displacement9,423–9,503 t (9,274–9,353 long tons)
Length132.28 m (434 ft) (o/a)
Beam20.94 m (68 ft 8 in)
Draft7.21–7.26 m (23 ft 8 in – 23 ft 10 in)
Installed power
  • 24
    Belleville boilers
  • 14,500 
    kW
    )
Propulsion2 shafts; 2 triple-expansion steam engines
Speed20.75 knots (38.43 km/h; 23.88 mph)
Range7,000 nmi (13,000 km; 8,100 mi) at 10 knots (19 km/h; 12 mph)
Complement672
Armament
Armor

The Izumo-class cruisers (出雲型装甲巡洋艦, Izumo-gata sōkōjun'yōkan) were a pair of

"Six-Six Fleet" expansion program that began after the defeat of China during the First Sino-Japanese War of 1894–1895. The sister ships participated in three of the four main naval battles of the Russo-Japanese War of 1904–1905—the Battle of Port Arthur, the Battle off Ulsan and the Battle of Tsushima—but played a much more minor role in World War I
.

Iwate was first used as a

series of American air attacks on the naval base at Kure in July 1945. Their wrecks were refloated after the war and scrapped
.

Background and design

Japan initiated the 1896 Naval Expansion Plan after the First Sino-Japanese War of 1894–95. The plan included four armored cruisers and four battleships, all of which had to be ordered from foreign 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. The revised plan is commonly known as the "Six-Six Fleet".[1] These ships were purchased using the £30,000,000 indemnity paid by China after losing the First Sino-Japanese War.[2] Unlike most of their contemporaries, which were designed for commerce raiding or to defend colonies and trade routes, the Izumo class was intended as fleet scouts and to be employed in the battleline.[3]

Construction of the Izumo-class ships was awarded to the

Belleville boilers in lieu of the cylindrical boilers of the earlier ships and used the weight saved to increase the thickness of the protective deck and improve the hull structure. The increased number of boilers required an extra funnel, which became the primary means of distinguishing between the two classes.[5]

Description

Jane's Fighting Ships
, 1904

The Izumo-class ships were 132.28 meters (434 ft 0 in) long

deep load. They had metacentric heights of 0.73 to 0.88 meters (2 ft 5 in to 2 ft 11 in).[6] Their crew consisted of 672 officers and enlisted men.[7]

The ships had two 4-cylinder

sisters had a designed speed of 20.75 knots (38.43 km/h; 23.88 mph) and both exceeded it by at least a 1 knot (1.9 km/h; 1.2 mph) during their sea trials from 15,739 to 16,078 ihp (11,737 to 11,989 kW). They carried up to 1,527 long tons (1,551 t) of coal[9] and could steam for 7,000 nautical miles (13,000 km; 8,100 mi) at a speed of 10 knots (19 km/h; 12 mph).[7]

Armament

Cross-section of the eight-inch gun turret used by all the "Six-Six Fleet" armored cruisers

The

armor-piercing (AP) projectiles at a muzzle velocity of 2,500 feet per second (760 m/s) to a range of 20,000 yards (18,000 m).[11]

Crewmen working the six-inch guns

The

six-inch (152 mm) guns. All but four of these guns were mounted in armored casemates on the main and upper decks, and their mounts on the upper deck were protected by gun shields. Their 100-pound (45.4 kg) AP shells were fired at a muzzle velocity of 2,300 feet per second (700 m/s).[12] The ships were also equipped with a dozen 40-caliber QF 12-pounder (3 in (76 mm)) 12-cwt guns[Note 1] and eight QF 2.5-pounder (1.5 in (38 mm)) Yamauchi guns as close-range defense against torpedo boats.[11] The former gun fired three-inch, 12.5-pound (5.7 kg) projectiles at a muzzle velocity of 2,359 feet per second (719 m/s).[13]

The Izumo-class ships were equipped with four submerged 18-inch (457 mm) torpedo tubes, two on each broadside. The Type 30 torpedo had a 100-kilogram (220 lb) warhead and three range/speed settings: 870 yards (800 m) at 27 knots (50 km/h; 31 mph), 1,100 yards (1,000 m) at 23.6 knots (43.7 km/h; 27.2 mph) or 3,300 yards (3,000 m) at 14.2 knots (26.3 km/h; 16.3 mph).[14]

Protection

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 ships and its thickness varied from 7.0 inches (178 mm) amidships to 3.5 inches (89 mm) at the bow and stern. The thickest part of the belt covered the middle of the ship for a length of 275 feet 2 inches (83.87 m). It had a height of 7 feet 0 inches (2.13 m), of which 4 feet 4 inches to 4 feet 7 inches (1.33 to 1.39 m) was normally underwater. The upper strake of belt armor was 5.0 inches (127 mm) thick and extended from the upper edge of the waterline belt to the main deck. It extended 167 feet 11 inches to 174 feet 11 inches (51.18 to 53.31 m) from the forward to the rear barbette. The Izumo class had oblique 5-inch armored bulkhead that closed off the ends of the central armored citadel.[15]

The barbettes, gun turrets and the front of the casemates were all 6 inches thick while the sides and rear of the casemates were protected by 51 millimeters (2.0 in) of armor. The deck was 63 millimeters (2.5 in) thick and the armor protecting the

double bottom and an additional 136 or 137 between the bottom and the upper deck.[14]

Ships

Construction data
Ship Builder [9]
Laid down[9]
 Launched[9] Completed [17] Fate
Izumo Armstrong Whitworth, Elswick 14 May 1898 19 September 1899 25 September 1900 Sunk, 28 July 1945; broken up, 1947[18]
Iwate 11 November 1898 29 March 1900 18 March 1901 Sunk, 25 July 1945; scrapped, 1946–1947[19]

Service

Russo-Japanese War

The sisters spent most of the Russo-Japanese War as flagships together in the 2nd Division of the

Port Arthur. Tōgō had expected the earlier 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. Iwate was moderately damaged by the Russians, but Izumo only slightly.[21]

A postcard of Iwate at anchor, before 1905

In April 1904, the division was tasked to contain the Russian armored cruisers based at

minefield was laid off Vladivostok, and blockading the Tsugaru Strait until the Russian ships from the Baltic Fleet approached Japan in mid-1905.[23]

Battle of Tsushima

Main article: Battle of Tsushima

The Russian 2nd and 3rd Pacific Squadrons were spotted on the morning on 27 May 1904 and Tōgō ordered his ships to put to sea. Izumo and Iwate had rejoined the 2nd Division in anticipation of this battle and Kamimura's ships confirmed the initial spotting later that morning before joining Tōgō's battleships. Together with most of the Japanese battleships, the division opened fire at 14:10 on the Russian battleship Oslyabya, which was forced to fall out of formation at 14:50 and sank 20 minutes later. After a failed torpedo attack was repulsed by Iwate and several other cruisers around the same time, the Russian battleship Knyaz Suvorov suddenly appeared out of the mist at 15:35 at short range. Kamimura's ships engaged her for five minutes before she disappeared back into the mists. Later in the day, Kamimura led his division in a fruitless pursuit of some of the Russian cruisers around 17:30. He abandoned his chase around 18:03 and encountered the Russian battleline about a half hour later. He stayed at long range and his ships fired when practicable before ceasing fire at 19:30.[24]

A Japanese postcard of Izumo at anchor, 1905

The surviving Russian ships were spotted the next morning and the Japanese ships opened fire and stayed beyond the range at which the Russian ships could effectively reply. Rear Admiral

amphibious landings in northeastern Korea in July and August before the war ended.[27]

Subsequent service

Izumo was ordered to patrol the west coast of

commerce raiders and protect Allied shipping off the western coasts of North and Central America. The ship assisted the armored cruiser Asama in early 1915, when she struck a rock off Baja California.[29] In 1917, Izumo became the flagship of the Japanese squadron deployed in the Mediterranean Sea. After the war, she sailed to Great Britain to take control of some ex-German submarines and then escorted them part of the way back to Japan.[18]

Iwate played a minor role in the war, participating in the

Imperial Japanese Navy Academy in 1916, a task that would last until the end of 1939. Izumo began making training voyages of her own during the 1920s.[32]

Izumo at anchor in Burrard Inlet, Vancouver, Canada, February 1925

In 1924, four of the ships' 12-pounder guns were removed, as were all of their QF 2.5-pounder guns, and a single 40-caliber

anti-aircraft (AA) gun was added.[33] The gun had a maximum elevation of +75 degrees, and could fire a 3-inch, 12.5 lb (5.67 kg) projectile with a muzzle velocity of 2,200 ft/s (680 m/s) to a maximum height of 23,600 feet (7,200 m).[34] Refitted again in 1930–31, their torpedo tubes were removed as were all of her main deck 6-inch guns and their casemates plated over; they now carried only four 12-pounders. At that time, Iwate also had her boilers replaced by six water-tube boilers, but Izumo was not reboilered until 1935.[33] The new boilers produced less steam which limited engine power to 7,000 ihp (5,200 kW) and reduced their top speed to 16 knots (30 km/h; 18 mph).[7]

China service and World War II

Izumo at anchor in the Huangpu River, Shanghai, 1932. The American armored cruiser USS Rochester is anchored to the left.

In 1932, during the

3rd Fleet that garrisoned Japanese-occupied China. Two years later, she was equipped to operate a floatplane at the Sasebo Naval Arsenal.[18] During the Second Sino-Japanese War, the ship participated in the Battle of Shanghai in mid-1937 during which she provided naval gunfire support to Japanese troops ashore.[35]

Still in Shanghai at the beginning of the Pacific War on 8 December 1941, Izumo captured the American river gunboat USS Wake and assisted in sinking the British river gunboat HMS Peterel.[18][36] On 31 December, the cruiser struck a mine in Lingayen Gulf while supporting Japanese forces during the Philippines Campaign. During this period, Iwate was still serving as a training ship in home waters. The sisters were briefly re-classified as 1st-class cruisers on 1 July 1942[18][19] before they became training ships in 1943. Izumo returned to Japan late that year and joined her sister in training naval cadets.[37]

In early 1945, the sisters were rearmed when their 8-inch guns were replaced by four

13.2-millimeter Hotchkiss machine guns in single mounts.[37] The 25 mm (0.98 in) weapon 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. The weapon had a maximum range of 24,600 feet (7,500 m), but effective range was only about 4,900–9,800 feet (1,500–3,000 m).[39]

The sisters were attacked, but not hit, during the American aerial

navy list on 20 November and their wrecks were raised and scrapped in 1946–47.[18][19]

Notes

  1. ^ "Cwt" is the abbreviation for hundredweight, 12 cwt referring to the weight of the gun.

Footnotes

  1. ^ Evans & Peattie, pp. 57–62
  2. ^ Brook 1999, p. 125
  3. ^ Milanovich, p. 72
  4. ^ Brook 1999, pp. 112–13
  5. ^ Milanovich, pp. 74–76
  6. ^ Milanovich, pp. 74, 80
  7. ^ a b c Jentschura, Jung & Mickel, p. 74
  8. ^ Milanovich, p. 81
  9. ^ a b c d Brook 1999, p. 112
  10. ^ Milanovich, pp. 76–77
  11. ^ a b Milanovich, p. 78
  12. ^ Friedman, p. 276; Milanovich, p. 78
  13. ^ Friedman, p. 114
  14. ^ a b Milanovich, p. 80
  15. ^ Milanovich, pp. 80–81
  16. ^ Chesneau & Kolesnik, p. 225
  17. ^ Milanovich, p. 73
  18. ^ a b c d e f Hackett & Kingsepp, Izumo
  19. ^ a b c Hackett & Kingsepp, Iwate
  20. ^ Kowner, pp. 241, 465
  21. ^ Forczyk, pp. 42–43
  22. ^ Brook 2000, pp. 43, 45
  23. ^ Corbett 1994, II, pp. 52, 104, 159–62, 176–77
  24. ^ Campbell 1978, Part 2, pp. 128–32; Part 3, pp. 186–87
  25. ^ a b Corbett 1994, II, pp. 319–20
  26. ^ Brook 1999, p. 113; Campbell 1978, Part 4, p. 263
  27. ^ Corbett, II, pp. 356, 363–65, 377–80
  28. ^ "Japanese Cruiser Sent to Mexico". San Francisco Call. California Digital Newspaper Collection. 12 November 1913. p. 2. Retrieved 24 April 2015.
  29. ^ Estes
  30. ^ Burdick, pp. 228, 241
  31. ^ Corbett 1938, I, pp. 366, 409
  32. ^ Lacroix & Wells, pp. 657–58
  33. ^ a b Chesneau, p. 174
  34. ^ Campbell 1985, pp. 197–98
  35. ^ "Japanese Consulate in Ruins". The Sydney Morning Herald. Trove. 18 August 1937. p. 15. Retrieved 25 April 2015.
  36. ^ Rohwer, p. 123
  37. ^ a b Fukui, p. 4
  38. ^ Campbell 1985, pp. 192–93
  39. ^ Campbell 1985, p. 200

References

External links

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