Lwd wrote: The Iowa's and Montanas were developed in parallel. They were both the product of a number of design studies undertaken at the same time, and were expansions upon the South Dakota class. The fast battleship option was selected and the first two Iowa's were authorized in 1938. The next two Iowas and two Montana's were authorized in 1940. The Navy's need for fast battleships was more pressing so the Navy requested that two more Iowas be substituted for the two Montanas and the pennant numbers (BB-65 and 66) were reassigned. CA 45 Wichita was laid down in 1935 and launched 16 November 1937, so she pre-dates the SoDak's and would probably be closer to being a contemporary of the North Carolinas, the first of which was laid down on 27 October 1937. The first of the South Dakotas were laid down in July of 1939 around the time the planning was started on the Baltimores the first of which was authorized in 1940. The first Alaskas were ordered in September 1940. Interest once again was revived in the Montana class and she was again approved for construction in April 1942, to include revisions because of lessons learned in the preceeding classes. This should show that the Baltimores, Alaskas, Iowas and Montanas were all contemporary to one another. If you go with the modified Montana design of 1942, the contemporary cruiser, as I initially said would be the Oregon City class or possibly the Des Moines class, both of which were improved Baltimores. I do not think the chronology supports your pairing of BB and CA types to prove a natural evolution in displacement of CA's as a ratio in relation to BB's.