An item referred to the magazine Marine Rundschau dated June 1938 reporting that the newest Japanese aircraft carriers Hiryu (1) and Soryu (2) of 10.500 tons, armed with 12-12,7cm/5” anti aircraft guns and 24 machineguns, able to carry 40 aircraft needed giro stabilizers to compensate the slim design due to a 10:1 ratio with the dimensions 210 x 20,8 metres. The fact that experiments executed with giro stabilizers on fast Italian passenger ships was according to the Japanese caused by to light stabilizers. Their weight should be 3% of the weight of the ship.
1. Modified enlarged Soruy-design which was originally to be her sister ship and succeeded by the Shokaku-class. Laid down by Yokosuka Naval Arsenal on 8 July 1936, launched on 16 November 1937, commissioned on 5 July 1939, scuttled after the disastrous Battle of the Midway against the US navy on 5 June 1942 and stricken on 25 September 1942. With a displacement of 17.600 (standard)-20.570 (normal) and as dimensions 227,4 (over all) x 22,3 x 7,8 metres or 746’1”x 73’2”x 25’7”.
2. Together with the Hiryu was her building allowed due to the 1931-1932 supplementary naval shipbuilding program. She was laid down at the yard of Kaigun Kosho at Kure, Japan on 20 November 1934, launched on 21 December 1935, commissioned on 29 December 1937 and destroyed by an American air attack during the battle of Midway on 4 June 1942. She was designed as an aircraft carrier in contrary to earlier carriers of the Japanese navy when hulls of battleships of battle cruisers were converted. With a displacement of 15,900 (standard)-19,500 (full load) tons were her dimensions 728’5”x 70’ x 24’5” or 222 x 21 x 7,44 metres. The flight deck had a length of 712” or 217 metres, Her four sets geared steam turbines supplied 152,000 hp while driving four screws allowed a speed of 34,5 knots. Her crew numbered 1,103 men. The armament consisted of 6x2-12,7cm guns, 26x25mm anti aircraft guns and 15-13,2mm anti aircraft guns while she carried with her in 1941 54 planes for which she was fitted out with 3 elevators and 2 fully enclosed hangars.