Japanese cruiser Tsukuba

Tsukuba in an old postcard
History
Empire of Japan
Name:	Tsukuba
Ordered:	1904 Fiscal Year
Laid down:	14 January 1905
Launched:	26 December 1905
Commissioned:	14 January 1907
Reclassified:	battlecruiser (1912)
Struck:	1 September 1917
Fate:	Explosion, Tokyo Bay 14 January 1917
General characteristics
Class and type:	Tsukuba-class armored cruiser
Displacement:	13,750 long tons (13,970 t) (normal); 15,400 long tons (15,600 t) (max)
Length:	134.11 m (440.0 ft) waterline; 137.11 m (449.8 ft) overall
Beam:	22.80 m (74.8 ft)
Draught:	7.95 m (26.1 ft)
Installed power:	20,500 shp (15,290 kW)
Propulsion:	Two shaft reciprocating VTE steam engine; 20 Miyabara boilers
Speed:	20.5 knots (38 km/h)
Range:	5,000 nautical miles (9,000 km) at 14 knots (26 km/h)
Complement:	879
Armament:	4 × 12-inch (305 mm) guns 12 ×6-inch (152 mm) guns 12 ×120-millimetre (4.724 in) guns 4 ×QF 3-pounder Hotchkiss 3 × 450 mm (18 in) torpedo tubes
Armor:	Belt: 100–180 mm (3.9–7.1 in) Barbette & turret: 180 mm (7.1 in) Conning tower: 200 mm (7.9 in) Deck: 75 mm (3.0 in)

Tsukuba (筑波^?) was the lead ship of the two-ship Tsukuba class of armoured cruisers in the Imperial Japanese Navy. She was named after Mount Tsukuba located in Ibaraki prefecture north of Tokyo. On 28 August 1912, Tsukuba was re-classified as a battlecruiser.

Construction of the Tsukuba-class cruisers 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. These were the first major capital ships to be designed and constructed entirely by Japan in a Japanese shipyard, albeit with imported weaponry and numerous components. However, Tsukuba was designed and completed in a very short time, and suffered from numerous technical and design problems, including strength of its hull, stability and mechanical failures. The ship was reclassified as a battlecruiser in 1912.

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) at 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).