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,