Design
Originally completed as seaplane tenders the Chitose and Chiyoda were converted into carriers after the Battle of Midway. The original ships were specially designed to facilitate later conversion.
The Chitose and Chiyoda were ordered under the 1931 - 1932 Supplementary Program.
Conversion
To help with stability large bulges were added.
Elevators
There were two elevators that served a single hangar.
Engines
There was a mix of oil and diesel turbines. The diesel allowed for long range, and the oil for speed.
Hangars
There were one / two hangars. The hanger was 300' long.