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Izumo 1900

Ships

Name	No	Yard No	Builder	Laid down	Launched	Comp	Fate
出雲 [Idzumo]		681	Armstrong, Elswick, UK	5/1898	19.9.1899	25.9.1900	sunk 28.7.1945
磐手 [Iwate]		689	Armstrong, Elswick, UK	11/1898	29.3.1900	18.3.1901	sunk 25.7.1945

Technical data

Displacement normal, t	9750
Displacement full, t	10300
Length, m	121.9 pp 132.3 oa
Breadth, m	20.9
Draught, m	7.37
No of shafts	2
Machinery	2 VTE, 24 Belleville boilers
Power, h. p.	14500
Max speed, kts	20.8
Fuel, t	Idzumo: coal 1402 Iwate: coal 1412
Endurance, nm(kts)	7000(10)
Armour, mm	belt: 178 - 89, bulkheads: 152, upper belt: 127, barbettes: 152 - 102, turrets: 152, casemates: 152, deck: 63 - 51, CT: 356 - 76
Armament	2 x 2 - 203/45 Armstrong U, 14 x 1 - 152/40 Armstrong Z, 12 x 1 - 76/40 Armstrong N, 8 x 1 - 47/30 21/2pdr Hotchkiss Mk I, 4 - 450 TT (beam)
Complement	672

Standard scale images

Graphics

Project history

The design, by Sir Philip Watts, was practically the same as the earlier Asama, but improvements made in machinery design enabled the builders to equip the new class with 24 of the much lighter and more efficient Belleville boilers instead of the 12 single-ended cylindrical boilers of the Asama. Altogether the new machinery led to a saving in weight of some 300t. Armament and protection were also very similar, except that the armour in the new class was of Krupp CS in place of the Harvey NS used in the Asama. The total number of watertight compartments was 166, 30 of which were in the double bottom.

Ship protection

Main 178mm belt had 83.8m length (between barbettes) and 2.1m height, closed by 152mm bulkheads abreast barbettes. Its thickness was 89mm outside barbettes. There was upper 2.1m high 127mm belt (53.3m long on Idzumo and 51.2m on Iwate). 51mm deck was connected with lower edge of main belt by 63mm slopes. It has turtleback form and 63-51mm thickness outside barbettes. CT had 356mm sides and 76mm roof. All 8`` and 6`` guns (but 4 6`` guns with 51mm protection) had 152mm protection.

Modernizations

1924: - 4 x 1 - 76/40, 4 x 1 - 47/30, 2 - 450 TT; + 1 x 1 - 76/40 3-shiki

1931, Iwate: boilers were replaced by 6 Yarrow (oil- and coal-burning), engine power decreased to 7000hp and maximal speed to 16kts; - 6 x 1 - 152/40, 4 x 1 - 76/40, 4 x 1 - 47/30, 2 - 450 TT

1935, Idzumo: boilers were replaced by 6 Kampon (oil- and coal-burning), engine power decreased to 7000hp and maximal speed to 16kts; - 6 x 1 - 152/40, 4 x 1 - 76/40, 4 x 1 - 47/30, 2 - 450 TT

1937 - 1939, Idzumo: - 4 x 1 - 76/40

1937 - 1939, Iwate: - 4 x 1 - 76/40; + 2 x 1 - 76/40 3-shiki

1945, Idzumo: - 2 x 2 - 203/45, 4 x 1 - 152/40; + 2 x 2 - 127/40 89-shiki, 4 x 2 - 25/60 96-shiki, 6 x 1 - 25/60 96-shiki

1945, Iwate: - 2 x 2 - 203/45, 4 x 1 - 152/40; + 2 x 2 - 127/40 89-shiki, 1 x 3 - 25/60 96-shiki, 2 x 2 - 25/60 96-shiki, 2 x 1 - 25/60 96-shiki, 2 x 1 - 13.2/76

Naval service

 Both actively participated in the Russian-Japanese war. In September, 1921 they were reclassified to 1st class coast defence ships. Idzumo in 1932-1942 was a leader of the Japanese so-called Chinese fleet; then for a short while reclassified to 1st class cruiser, and in 1943 to TS. Iwate actually served as TS since 1923 though in 1942 also has been formally enlisted as 1st class cruiser. Both were sunk in July, 1945 at shallow water in Kure by American aircraft, salvaged after war and handed over on demolition in 1947.



Many thanks to Wolfgang Stöhr for additional information on this page.