There were eight / twelve planned heavy cruisers in the Des Moines class. These were the last of the major heavy cruiser designs of World War II. None were finished in time to serve in World War II.
There were intended to be two catapults for launching the aircraft. Most of the ships didn't have them installed.
Originally the ships were to have the 8" L/55 Mk 16 guns which were automatic rapid firing, but weren't available until late 1945. They were also very heavy and twin turrets were considered.
There was a boiler and a turbine in each of the three forward engine rooms. The fourth room had the turbine and boiler separated.