HMAS Van Diemen (CV-1914 (1935-mod))


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HMAS Van Diemen (ex Agincourt, ex Sultan Osman I, ex Rio de Janeiro) had probably one of the most chequered careers of any battleship even before she was built. Ordered by Brazil, bought by Turkey and seized by Great Britain on the outbreak of war to stop the ship being completed for Turkey. The only ship with 7 main turrets they were named after the days of the week rather than the usual A, B, Q, X, etc. It was felt that the ship may have problems firing full 14 guns broadsides as it may overstress the hull. The ship confounded the pundits by firing full broadsides at Jutland, even though the flash from the 14 guns looked like another battlecruiser exploding... Surviving the war the ship was placed in reserve and was to be discarded under the terms of the Washington Treaty. She was saved by the Australis Navy wanting a ship of approximately 700 feet for converting to an aircraft carrier.


The ship was transferred to the Australis Navy in 1923 and renamed Van Diemen on arrival in Australis. The ship went to Adelaide where the ship was stripped of its battleship fittings (to be used in other ships rebuilding later). Work proceeded slowly as news reached Australis of the conversions of the ships in Britain, the Furious types, and the newly built  Hermes, while the US Navy was converting the giant Lexington and Saratoga.


Taking the best parts from all of them the rebuild designsers went with the US enclosed bow with the Furious type stern mounting for the flight deck. Only one hangar deck was provided for and aircraft carrying capacity was a maximum of 40, which while only half that of the US and Japanese giants it was enough for the Australis Navies first aircraft carrier trials. Like most early aircraft carriers a lot of 'warship' fitting were kept to the detriment of aircraft carrying capacity.

Below the side view shows the long hull required for mounting 7 turrets also made it a good possibility for conversion to an aircraft carrier.


Displacement 32,500 tons full load
Length 706.5 ft
Breadth 89.5 ft (hull)
Draught 30 ft
Machinery 4 shaft steam turbines 75,000shp
Speed 26 knots
Range 6000 miles at 18 knots
Armour 4.5" side, 3" over machinery & magazines
Armament 12 x 4" (6x2)

16 x 2pd (4x4)

20 x 20mm (4x2 8x1)

Aircraft 40  (in1937 service)

20 Swordfish

8 Skua

12 Hurricane

Torpedoes nil
Complement 1300 (with aircrew)


HMAS Van Diemen at Adelaide dockyards in 1924 undergoing the removal of the weapons and superstructure.


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