Their initial design reflected experience gained from peacetime exercises and observation of foreign construction trends during the 1920s. It featured a new dual-purpose main gun battery with fire control on a more seaworthy high-forecastle hull.
There was much experimentation within the nominal 1,500-ton limit as construction progressed (and much more debated but never implemented). A major improvement was the introduction of high-pressure high-temperature steam propulsion machinery.
The tables on this page track major variations among five 1,500-ton classes and the derivative 1,570-ton Sims class funded in fiscal years 1932–37 and designed with this limit in mind—here listed in order of increasing technical sophistication: Farragut, Mahan (including the slightly-modified Dunlap and Fanning, differentiated here as the Dunlap class), Bagley, Gridley, Benham and Sims.
The successor Benson and Gleaves classes, funded beginning in FY 1938 and built on the same hull as the Sims class but with a split powerplant, culminated the sequence of changes begun by the 1,500-tonners, and set the stage for the 2,100-ton Fletcher class—no longer subject to treaty constraints—to follow beginning in FY 1941.
