Tsukuba-class cruiser

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Japanese cruiser Tsukuba 2.jpg
The Japanese battlecruiser Tsukuba
Class overview
Name: Tsukuba
Builders: Kure Naval Arsenal, Japan
Operators: Naval Ensign of Japan.svg Imperial Japanese Navy
Preceded by: Kasuga class
Succeeded by: Ibuki class
Built: 1905–1908
In service: 1907–1922
Planned: 6
Completed: 2
Cancelled: 4
Lost: 1
Scrapped: 1
General characteristics
Type: Cruiser
Displacement: 13,750 long tons (13,970 t)
Length: 134.11 m (440.0 ft)
Beam: 22.80 m (74.8 ft)
Draft: 7.95 m (26.1 ft)
Propulsion: Two Shaft Reciprocating VTE steam engine; 20 Miyabara boilers, 20,500 shp (15,290 kW)
Speed: 20.5 knots (38 km/h)
Range: 2000 tons coal; 160 tons oil
5,000 nautical miles (9,000 km) at 14 knots (26 km/h)
Complement: 876
  • belt: 100-180 mm
  • barbette & turret: 180 mm
  • conning tower: 200 mm
  • deck: 75 mm

The Tsukuba-class cruisers (筑波型 巡洋戦艦 Tsukuba-gata jun'yōsenkan?) was a class of armored cruiser design and built in Japan immediately after the Russo-Japanese War. Very heavily armed, they were reclassified in 1914 as the first battlecruisers in the Imperial Japanese Navy.[1] Both vessels participated in World War I.


Construction of the Tsukuba-class battlecruisers was ordered under the June 1904 Emergency Fleet Replenishment Budget of the Russo-Japanese War, spurred on by the unexpected loss of the battleships Yashima and Hatsuse to naval mines in the early stages of the war.[2] These were the first major capital ships to be designed and constructed entirely by Japan in a Japanese shipyard.


The Tsukuba-class design had a conventional armored cruiser hull design, powered by two vertical triple-expansion steam engines, with twenty Miyabara boilers, yielding 20,500 shp (15,300 kW) design speed of 20.5 knots (38.0 km/h; 23.6 mph) and a range of 5,000 nautical miles (9,000 km) @ 14 knots (26 km/h; 16 mph). During speed trials in Hiroshima Bay prior to commissioning, Tsukuba attained a top speed of 21.75 knots (40.28 km/h; 25.03 mph).[1] In terms of armament, the Tsukuba-class was one of the most heavily armed cruisers of its time, as Japanese experience in the Russo-Japanese War, particularly at the Battle of the Yellow Sea, when the Imperial Russian cruisers opened fire at 19,000 yards, and in the Battle of Tsushima when Japanese armored cruisers were successfully used in the line of battle against battleships led to the selection of four 12-inch 41st Year Type guns as the main battery.[2] These guns were mounted in twin gun turrets to the fore and aft, along the centerline of the vessel. Secondary armament consisted of twelve 6-inch (152 mm) guns and twelve 4.7-inch 41st Year Type guns, and four QF 3-pounder Hotchkiss guns.[1] Armor protection on the Tsukuba-class consisted of Krupp armor with a thickness of 102 – 178 mm on the belt, 102 mm on the turrets, and 203 mm on the conning tower. The deck had 76 mm of armor.[2]

Both vessels in the Tsukuba-class were completed in a very short time, and as a result suffered from numerous technical and design problems, including strength of their hull, stability and mechanical failures. Although armed similar to a battleship, their armor was relatively weak, and by the time of their completion, they were slower than comparable British or German designs.[2] They were reclassified as battlecruisers in 1912. Ikoma was de-rated back to first class cruiser in 1921.[1]

Ships in class[edit]


Tsukuba was laid down on 14 January 1905, launched on 26 December 1905 and commissioned 14 January 1907.[3] She served patrol duty during World War I primarily in the Pacific Ocean and in Southeast Asia. On 14 January 1917, she exploded while in port at Yokosuka, and sank with a loss of 305 men.


Ikoma was laid down on 15 March 1905, launched on 9 April 1906 and commissioned 24 March 1908.[3] She circumnavigated the southern hemisphere of the globe in 1908. She served patrol duty during World War I primarily in the Pacific Ocean and in Southeast Asia. Ikoma was a scrapped as a result of the Washington Naval Agreement of 1923.


  1. ^ a b c d Jentsura, Hansgeorg (1976). Warships of the Imperial Japanese Navy, 1869-1945. Naval Institute Press. ISBN 0-87021-893-X.  page 77
  2. ^ a b c d Chesneau, Conway's All the World's Fighting Ships, 1905–1921, page 232
  3. ^ a b Nishida, Nishida (2002). stc0114.htm "Tsukuba-class battlecruisers". Imperial Japanese Navy. 


  • Evans, David (1979). Kaigun: Strategy, Tactics, and Technology in the Imperial Japanese Navy, 1887-1941. US Naval Institute Press. ISBN 0-87021-192-7. 
  • Gardiner, Robert; Gray, Randal, eds. (1984). Conway's All the World's Fighting Ships: 1906–1921. Annapolis, Maryland: Naval Institute Press. ISBN 0-85177-245-5. 
  • Jentschura, Hansgeorg; Jung, Dieter; Mickel, Peter (1977). Warships of the Imperial Japanese Navy, 1869–1945. Annapolis, Maryland: United States Naval Institute. ISBN 0-87021-893-X. 

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