Why did the Japanese Navy convert Kaga to an Aircraft Carrier?

Question

The IJN ordered 4 Amagi class battlecruisers (Amagi, Akagi, Atago, and Takao) and 2 Tosa class Battleships (Tosa and Kaga) to form the "Eight-Eight Fleet". All ships started construction between 1920-21, but were terminated by the Washington Naval Treaty. All 6 unfinished warships had to be scrapped.

As the treaty allowed each signatory to use two existing capital ship hulls for aircraft carriers, with a displacement limit of 33,000 tons each. Japan initially chose Amagi and Akagi. However the hull of Amagi was heavily damaged due to Great Kantō earthquake, the hull of Kaga was chosen to be converted as Aircraft Carrier.

Why didn't the Japanese Navy choose the hull of Atago/Takao, and select the slower Kaga to replace Amagi as an aircraft carrier?

Answer 1

The Akagi was a battlecruiser, but when the decision was made for the second carrier, the Japanese wanted a carrier that was even larger than the Akagi, that is, more like a battleship than a cruiser. When the Japanese converted the Akagi, they "supersized" it, making it almost battleship size. The new "Akagi" was much closer in size to the Kaga than to the Takeo, so it would make much more sense to convert the Kaga into the Akagi's sister ship, than the Takeo. Also, the Takeo design was considered "topheavy."

The Japanese soon reconsidered their aircraft carrier designs, and two later ones, the Hiryu and Soryu, were smaller, lighter, faster ships. But by this time, the Takeo and Atago and been "downsized" to heavy cruisers.